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Tom Rini83d290c2018-05-06 17:58:06 -04001# SPDX-License-Identifier: GPL-2.0+
wdenkc6097192002-11-03 00:24:07 +00002#
Wolfgang Denkeca3aeb2013-06-21 10:22:36 +02003# (C) Copyright 2000 - 2013
wdenkc6097192002-11-03 00:24:07 +00004# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
wdenkc6097192002-11-03 00:24:07 +00005
6Summary:
7========
8
wdenk24ee89b2002-11-03 17:56:27 +00009This directory contains the source code for U-Boot, a boot loader for
wdenke86e5a02004-10-17 21:12:06 +000010Embedded boards based on PowerPC, ARM, MIPS and several other
11processors, which can be installed in a boot ROM and used to
12initialize and test the hardware or to download and run application
13code.
wdenkc6097192002-11-03 00:24:07 +000014
15The development of U-Boot is closely related to Linux: some parts of
wdenk24ee89b2002-11-03 17:56:27 +000016the source code originate in the Linux source tree, we have some
17header files in common, and special provision has been made to
wdenkc6097192002-11-03 00:24:07 +000018support booting of Linux images.
19
20Some attention has been paid to make this software easily
21configurable and extendable. For instance, all monitor commands are
22implemented with the same call interface, so that it's very easy to
23add new commands. Also, instead of permanently adding rarely used
24code (for instance hardware test utilities) to the monitor, you can
25load and run it dynamically.
26
27
28Status:
29=======
30
31In general, all boards for which a configuration option exists in the
wdenk24ee89b2002-11-03 17:56:27 +000032Makefile have been tested to some extent and can be considered
wdenkc6097192002-11-03 00:24:07 +000033"working". In fact, many of them are used in production systems.
34
Robert P. J. Day7207b362015-12-19 07:16:10 -050035In case of problems see the CHANGELOG file to find out who contributed
36the specific port. In addition, there are various MAINTAINERS files
37scattered throughout the U-Boot source identifying the people or
38companies responsible for various boards and subsystems.
wdenkc6097192002-11-03 00:24:07 +000039
Robert P. J. Day7207b362015-12-19 07:16:10 -050040Note: As of August, 2010, there is no longer a CHANGELOG file in the
41actual U-Boot source tree; however, it can be created dynamically
42from the Git log using:
Robert P. J. Dayadb9d852012-11-14 02:03:20 +000043
44 make CHANGELOG
45
wdenkc6097192002-11-03 00:24:07 +000046
47Where to get help:
48==================
49
wdenk24ee89b2002-11-03 17:56:27 +000050In case you have questions about, problems with or contributions for
Robert P. J. Day7207b362015-12-19 07:16:10 -050051U-Boot, you should send a message to the U-Boot mailing list at
Peter Tyser0c325652008-09-10 09:18:34 -050052<u-boot@lists.denx.de>. There is also an archive of previous traffic
53on the mailing list - please search the archive before asking FAQ's.
54Please see http://lists.denx.de/pipermail/u-boot and
55http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
wdenkc6097192002-11-03 00:24:07 +000056
57
Wolfgang Denk218ca722008-03-26 10:40:12 +010058Where to get source code:
59=========================
60
Robert P. J. Day7207b362015-12-19 07:16:10 -050061The U-Boot source code is maintained in the Git repository at
Wolfgang Denk218ca722008-03-26 10:40:12 +010062git://www.denx.de/git/u-boot.git ; you can browse it online at
63http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
64
65The "snapshot" links on this page allow you to download tarballs of
Marcel Ziswiler11ccc332008-07-09 08:17:15 +020066any version you might be interested in. Official releases are also
Wolfgang Denk218ca722008-03-26 10:40:12 +010067available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
68directory.
69
Anatolij Gustschind4ee7112008-03-26 18:13:33 +010070Pre-built (and tested) images are available from
Wolfgang Denk218ca722008-03-26 10:40:12 +010071ftp://ftp.denx.de/pub/u-boot/images/
72
73
wdenkc6097192002-11-03 00:24:07 +000074Where we come from:
75===================
76
77- start from 8xxrom sources
wdenk24ee89b2002-11-03 17:56:27 +000078- create PPCBoot project (http://sourceforge.net/projects/ppcboot)
wdenkc6097192002-11-03 00:24:07 +000079- clean up code
80- make it easier to add custom boards
81- make it possible to add other [PowerPC] CPUs
82- extend functions, especially:
83 * Provide extended interface to Linux boot loader
84 * S-Record download
85 * network boot
Simon Glass9e5616d2019-08-01 09:47:14 -060086 * ATA disk / SCSI ... boot
wdenk24ee89b2002-11-03 17:56:27 +000087- create ARMBoot project (http://sourceforge.net/projects/armboot)
wdenkc6097192002-11-03 00:24:07 +000088- add other CPU families (starting with ARM)
wdenk24ee89b2002-11-03 17:56:27 +000089- create U-Boot project (http://sourceforge.net/projects/u-boot)
Magnus Lilja0d28f342008-08-06 19:32:33 +020090- current project page: see http://www.denx.de/wiki/U-Boot
wdenk24ee89b2002-11-03 17:56:27 +000091
92
93Names and Spelling:
94===================
95
96The "official" name of this project is "Das U-Boot". The spelling
97"U-Boot" shall be used in all written text (documentation, comments
98in source files etc.). Example:
99
100 This is the README file for the U-Boot project.
101
102File names etc. shall be based on the string "u-boot". Examples:
103
104 include/asm-ppc/u-boot.h
105
106 #include <asm/u-boot.h>
107
108Variable names, preprocessor constants etc. shall be either based on
109the string "u_boot" or on "U_BOOT". Example:
110
111 U_BOOT_VERSION u_boot_logo
112 IH_OS_U_BOOT u_boot_hush_start
wdenkc6097192002-11-03 00:24:07 +0000113
114
wdenk93f19cc2002-12-17 17:55:09 +0000115Versioning:
116===========
117
Thomas Weber360d8832010-09-28 08:06:25 +0200118Starting with the release in October 2008, the names of the releases
119were changed from numerical release numbers without deeper meaning
120into a time stamp based numbering. Regular releases are identified by
121names consisting of the calendar year and month of the release date.
122Additional fields (if present) indicate release candidates or bug fix
123releases in "stable" maintenance trees.
wdenk93f19cc2002-12-17 17:55:09 +0000124
Thomas Weber360d8832010-09-28 08:06:25 +0200125Examples:
Wolfgang Denkc0f40852011-10-26 10:21:21 +0000126 U-Boot v2009.11 - Release November 2009
Thomas Weber360d8832010-09-28 08:06:25 +0200127 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
Jelle van der Waa0de21ec2016-10-30 17:30:30 +0100128 U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
wdenk93f19cc2002-12-17 17:55:09 +0000129
130
wdenkc6097192002-11-03 00:24:07 +0000131Directory Hierarchy:
132====================
133
Peter Tyser8d321b82010-04-12 22:28:21 -0500134/arch Architecture specific files
Masahiro Yamada6eae68e2014-03-07 18:02:02 +0900135 /arc Files generic to ARC architecture
Peter Tyser8d321b82010-04-12 22:28:21 -0500136 /arm Files generic to ARM architecture
Peter Tyser8d321b82010-04-12 22:28:21 -0500137 /m68k Files generic to m68k architecture
Peter Tyser8d321b82010-04-12 22:28:21 -0500138 /microblaze Files generic to microblaze architecture
Peter Tyser8d321b82010-04-12 22:28:21 -0500139 /mips Files generic to MIPS architecture
Macpaul Linafc1ce82011-10-19 20:41:11 +0000140 /nds32 Files generic to NDS32 architecture
Peter Tyser8d321b82010-04-12 22:28:21 -0500141 /nios2 Files generic to Altera NIOS2 architecture
Robert P. J. Day33c77312013-09-15 18:34:15 -0400142 /openrisc Files generic to OpenRISC architecture
Stefan Roesea47a12b2010-04-15 16:07:28 +0200143 /powerpc Files generic to PowerPC architecture
Rick Chen3fafced2017-12-26 13:55:59 +0800144 /riscv Files generic to RISC-V architecture
Robert P. J. Day7207b362015-12-19 07:16:10 -0500145 /sandbox Files generic to HW-independent "sandbox"
Peter Tyser8d321b82010-04-12 22:28:21 -0500146 /sh Files generic to SH architecture
Robert P. J. Day33c77312013-09-15 18:34:15 -0400147 /x86 Files generic to x86 architecture
Peter Tyser8d321b82010-04-12 22:28:21 -0500148/api Machine/arch independent API for external apps
149/board Board dependent files
Xu Ziyuan740f7e52016-08-26 19:54:49 +0800150/cmd U-Boot commands functions
Peter Tyser8d321b82010-04-12 22:28:21 -0500151/common Misc architecture independent functions
Robert P. J. Day7207b362015-12-19 07:16:10 -0500152/configs Board default configuration files
Peter Tyser8d321b82010-04-12 22:28:21 -0500153/disk Code for disk drive partition handling
154/doc Documentation (don't expect too much)
155/drivers Commonly used device drivers
Robert P. J. Day33c77312013-09-15 18:34:15 -0400156/dts Contains Makefile for building internal U-Boot fdt.
Peter Tyser8d321b82010-04-12 22:28:21 -0500157/examples Example code for standalone applications, etc.
158/fs Filesystem code (cramfs, ext2, jffs2, etc.)
159/include Header Files
Robert P. J. Day7207b362015-12-19 07:16:10 -0500160/lib Library routines generic to all architectures
161/Licenses Various license files
Peter Tyser8d321b82010-04-12 22:28:21 -0500162/net Networking code
163/post Power On Self Test
Robert P. J. Day7207b362015-12-19 07:16:10 -0500164/scripts Various build scripts and Makefiles
165/test Various unit test files
Peter Tyser8d321b82010-04-12 22:28:21 -0500166/tools Tools to build S-Record or U-Boot images, etc.
wdenkc6097192002-11-03 00:24:07 +0000167
wdenkc6097192002-11-03 00:24:07 +0000168Software Configuration:
169=======================
170
171Configuration is usually done using C preprocessor defines; the
172rationale behind that is to avoid dead code whenever possible.
173
174There are two classes of configuration variables:
175
176* Configuration _OPTIONS_:
177 These are selectable by the user and have names beginning with
178 "CONFIG_".
179
180* Configuration _SETTINGS_:
181 These depend on the hardware etc. and should not be meddled with if
182 you don't know what you're doing; they have names beginning with
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200183 "CONFIG_SYS_".
wdenkc6097192002-11-03 00:24:07 +0000184
Robert P. J. Day7207b362015-12-19 07:16:10 -0500185Previously, all configuration was done by hand, which involved creating
186symbolic links and editing configuration files manually. More recently,
187U-Boot has added the Kbuild infrastructure used by the Linux kernel,
188allowing you to use the "make menuconfig" command to configure your
189build.
wdenkc6097192002-11-03 00:24:07 +0000190
191
192Selection of Processor Architecture and Board Type:
193---------------------------------------------------
194
195For all supported boards there are ready-to-use default
Holger Freytherab584d62014-08-04 09:26:05 +0200196configurations available; just type "make <board_name>_defconfig".
wdenkc6097192002-11-03 00:24:07 +0000197
198Example: For a TQM823L module type:
199
200 cd u-boot
Holger Freytherab584d62014-08-04 09:26:05 +0200201 make TQM823L_defconfig
wdenkc6097192002-11-03 00:24:07 +0000202
Robert P. J. Day7207b362015-12-19 07:16:10 -0500203Note: If you're looking for the default configuration file for a board
204you're sure used to be there but is now missing, check the file
205doc/README.scrapyard for a list of no longer supported boards.
wdenkc6097192002-11-03 00:24:07 +0000206
Simon Glass75b3c3a2014-03-22 17:12:59 -0600207Sandbox Environment:
208--------------------
209
210U-Boot can be built natively to run on a Linux host using the 'sandbox'
211board. This allows feature development which is not board- or architecture-
212specific to be undertaken on a native platform. The sandbox is also used to
213run some of U-Boot's tests.
214
Keerthy5917d0b2019-07-29 13:52:04 +0530215See doc/arch/index.rst for more details.
Simon Glass75b3c3a2014-03-22 17:12:59 -0600216
217
Simon Glassdb910352015-03-03 08:03:00 -0700218Board Initialisation Flow:
219--------------------------
220
221This is the intended start-up flow for boards. This should apply for both
Robert P. J. Day7207b362015-12-19 07:16:10 -0500222SPL and U-Boot proper (i.e. they both follow the same rules).
Simon Glassdb910352015-03-03 08:03:00 -0700223
Robert P. J. Day7207b362015-12-19 07:16:10 -0500224Note: "SPL" stands for "Secondary Program Loader," which is explained in
225more detail later in this file.
226
227At present, SPL mostly uses a separate code path, but the function names
228and roles of each function are the same. Some boards or architectures
229may not conform to this. At least most ARM boards which use
230CONFIG_SPL_FRAMEWORK conform to this.
231
232Execution typically starts with an architecture-specific (and possibly
233CPU-specific) start.S file, such as:
234
235 - arch/arm/cpu/armv7/start.S
236 - arch/powerpc/cpu/mpc83xx/start.S
237 - arch/mips/cpu/start.S
238
239and so on. From there, three functions are called; the purpose and
240limitations of each of these functions are described below.
Simon Glassdb910352015-03-03 08:03:00 -0700241
242lowlevel_init():
243 - purpose: essential init to permit execution to reach board_init_f()
244 - no global_data or BSS
245 - there is no stack (ARMv7 may have one but it will soon be removed)
246 - must not set up SDRAM or use console
247 - must only do the bare minimum to allow execution to continue to
248 board_init_f()
249 - this is almost never needed
250 - return normally from this function
251
252board_init_f():
253 - purpose: set up the machine ready for running board_init_r():
254 i.e. SDRAM and serial UART
255 - global_data is available
256 - stack is in SRAM
257 - BSS is not available, so you cannot use global/static variables,
258 only stack variables and global_data
259
260 Non-SPL-specific notes:
261 - dram_init() is called to set up DRAM. If already done in SPL this
262 can do nothing
263
264 SPL-specific notes:
265 - you can override the entire board_init_f() function with your own
266 version as needed.
267 - preloader_console_init() can be called here in extremis
268 - should set up SDRAM, and anything needed to make the UART work
269 - these is no need to clear BSS, it will be done by crt0.S
Andreas Dannenberg14254652019-08-08 12:54:49 -0500270 - for specific scenarios on certain architectures an early BSS *can*
271 be made available (via CONFIG_SPL_EARLY_BSS by moving the clearing
272 of BSS prior to entering board_init_f()) but doing so is discouraged.
273 Instead it is strongly recommended to architect any code changes
274 or additions such to not depend on the availability of BSS during
275 board_init_f() as indicated in other sections of this README to
276 maintain compatibility and consistency across the entire code base.
Simon Glassdb910352015-03-03 08:03:00 -0700277 - must return normally from this function (don't call board_init_r()
278 directly)
279
280Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
281this point the stack and global_data are relocated to below
282CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
283memory.
284
285board_init_r():
286 - purpose: main execution, common code
287 - global_data is available
288 - SDRAM is available
289 - BSS is available, all static/global variables can be used
290 - execution eventually continues to main_loop()
291
292 Non-SPL-specific notes:
293 - U-Boot is relocated to the top of memory and is now running from
294 there.
295
296 SPL-specific notes:
297 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
298 CONFIG_SPL_STACK_R_ADDR points into SDRAM
299 - preloader_console_init() can be called here - typically this is
Ley Foon Tan0680f1b2017-05-03 17:13:32 +0800300 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
Simon Glassdb910352015-03-03 08:03:00 -0700301 spl_board_init() function containing this call
302 - loads U-Boot or (in falcon mode) Linux
303
304
305
wdenkc6097192002-11-03 00:24:07 +0000306Configuration Options:
307----------------------
308
309Configuration depends on the combination of board and CPU type; all
310such information is kept in a configuration file
311"include/configs/<board_name>.h".
312
313Example: For a TQM823L module, all configuration settings are in
314"include/configs/TQM823L.h".
315
316
wdenk7f6c2cb2002-11-10 22:06:23 +0000317Many of the options are named exactly as the corresponding Linux
318kernel configuration options. The intention is to make it easier to
319build a config tool - later.
320
Ashish Kumar63b23162017-08-11 11:09:14 +0530321- ARM Platform Bus Type(CCI):
322 CoreLink Cache Coherent Interconnect (CCI) is ARM BUS which
323 provides full cache coherency between two clusters of multi-core
324 CPUs and I/O coherency for devices and I/O masters
325
326 CONFIG_SYS_FSL_HAS_CCI400
327
328 Defined For SoC that has cache coherent interconnect
329 CCN-400
wdenk7f6c2cb2002-11-10 22:06:23 +0000330
Ashish Kumarc055cee2017-08-18 10:54:36 +0530331 CONFIG_SYS_FSL_HAS_CCN504
332
333 Defined for SoC that has cache coherent interconnect CCN-504
334
wdenkc6097192002-11-03 00:24:07 +0000335The following options need to be configured:
336
Kim Phillips26281142007-08-10 13:28:25 -0500337- CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
wdenkc6097192002-11-03 00:24:07 +0000338
Kim Phillips26281142007-08-10 13:28:25 -0500339- Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
Wolfgang Denk6ccec442006-10-24 14:42:37 +0200340
Kumar Gala66412c62011-02-18 05:40:54 -0600341- 85xx CPU Options:
York Sunffd06e02012-10-08 07:44:30 +0000342 CONFIG_SYS_PPC64
343
344 Specifies that the core is a 64-bit PowerPC implementation (implements
345 the "64" category of the Power ISA). This is necessary for ePAPR
346 compliance, among other possible reasons.
347
Kumar Gala66412c62011-02-18 05:40:54 -0600348 CONFIG_SYS_FSL_TBCLK_DIV
349
350 Defines the core time base clock divider ratio compared to the
351 system clock. On most PQ3 devices this is 8, on newer QorIQ
352 devices it can be 16 or 32. The ratio varies from SoC to Soc.
353
Kumar Gala8f290842011-05-20 00:39:21 -0500354 CONFIG_SYS_FSL_PCIE_COMPAT
355
356 Defines the string to utilize when trying to match PCIe device
357 tree nodes for the given platform.
358
Scott Wood33eee332012-08-14 10:14:53 +0000359 CONFIG_SYS_FSL_ERRATUM_A004510
360
361 Enables a workaround for erratum A004510. If set,
362 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
363 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
364
365 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
366 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
367
368 Defines one or two SoC revisions (low 8 bits of SVR)
369 for which the A004510 workaround should be applied.
370
371 The rest of SVR is either not relevant to the decision
372 of whether the erratum is present (e.g. p2040 versus
373 p2041) or is implied by the build target, which controls
374 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
375
376 See Freescale App Note 4493 for more information about
377 this erratum.
378
Prabhakar Kushwaha74fa22e2013-04-16 13:27:44 +0530379 CONFIG_A003399_NOR_WORKAROUND
380 Enables a workaround for IFC erratum A003399. It is only
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -0800381 required during NOR boot.
Prabhakar Kushwaha74fa22e2013-04-16 13:27:44 +0530382
Prabhakar Kushwaha9f074e62014-10-29 22:33:09 +0530383 CONFIG_A008044_WORKAROUND
384 Enables a workaround for T1040/T1042 erratum A008044. It is only
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -0800385 required during NAND boot and valid for Rev 1.0 SoC revision
Prabhakar Kushwaha9f074e62014-10-29 22:33:09 +0530386
Scott Wood33eee332012-08-14 10:14:53 +0000387 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
388
389 This is the value to write into CCSR offset 0x18600
390 according to the A004510 workaround.
391
Priyanka Jain64501c62013-07-02 09:21:04 +0530392 CONFIG_SYS_FSL_DSP_DDR_ADDR
393 This value denotes start offset of DDR memory which is
394 connected exclusively to the DSP cores.
395
Priyanka Jain765b0bd2013-04-04 09:31:54 +0530396 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
397 This value denotes start offset of M2 memory
398 which is directly connected to the DSP core.
399
Priyanka Jain64501c62013-07-02 09:21:04 +0530400 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
401 This value denotes start offset of M3 memory which is directly
402 connected to the DSP core.
403
Priyanka Jain765b0bd2013-04-04 09:31:54 +0530404 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
405 This value denotes start offset of DSP CCSR space.
406
Priyanka Jainb1359912013-12-17 14:25:52 +0530407 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
408 Single Source Clock is clocking mode present in some of FSL SoC's.
409 In this mode, a single differential clock is used to supply
410 clocks to the sysclock, ddrclock and usbclock.
411
Aneesh Bansalfb4a2402014-03-18 23:40:26 +0530412 CONFIG_SYS_CPC_REINIT_F
413 This CONFIG is defined when the CPC is configured as SRAM at the
Bin Menga1875592016-02-05 19:30:11 -0800414 time of U-Boot entry and is required to be re-initialized.
Aneesh Bansalfb4a2402014-03-18 23:40:26 +0530415
Tang Yuantianaade2002014-04-17 15:33:46 +0800416 CONFIG_DEEP_SLEEP
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -0800417 Indicates this SoC supports deep sleep feature. If deep sleep is
Tang Yuantianaade2002014-04-17 15:33:46 +0800418 supported, core will start to execute uboot when wakes up.
419
Daniel Schwierzeck6cb461b2012-04-02 02:57:56 +0000420- Generic CPU options:
421 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
422
423 Defines the endianess of the CPU. Implementation of those
424 values is arch specific.
425
York Sun5614e712013-09-30 09:22:09 -0700426 CONFIG_SYS_FSL_DDR
427 Freescale DDR driver in use. This type of DDR controller is
428 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
429 SoCs.
430
431 CONFIG_SYS_FSL_DDR_ADDR
432 Freescale DDR memory-mapped register base.
433
434 CONFIG_SYS_FSL_DDR_EMU
435 Specify emulator support for DDR. Some DDR features such as
436 deskew training are not available.
437
438 CONFIG_SYS_FSL_DDRC_GEN1
439 Freescale DDR1 controller.
440
441 CONFIG_SYS_FSL_DDRC_GEN2
442 Freescale DDR2 controller.
443
444 CONFIG_SYS_FSL_DDRC_GEN3
445 Freescale DDR3 controller.
446
York Sun34e026f2014-03-27 17:54:47 -0700447 CONFIG_SYS_FSL_DDRC_GEN4
448 Freescale DDR4 controller.
449
York Sun9ac4ffb2013-09-30 14:20:51 -0700450 CONFIG_SYS_FSL_DDRC_ARM_GEN3
451 Freescale DDR3 controller for ARM-based SoCs.
452
York Sun5614e712013-09-30 09:22:09 -0700453 CONFIG_SYS_FSL_DDR1
454 Board config to use DDR1. It can be enabled for SoCs with
455 Freescale DDR1 or DDR2 controllers, depending on the board
456 implemetation.
457
458 CONFIG_SYS_FSL_DDR2
Robert P. J. Day62a3b7d2016-07-15 13:44:45 -0400459 Board config to use DDR2. It can be enabled for SoCs with
York Sun5614e712013-09-30 09:22:09 -0700460 Freescale DDR2 or DDR3 controllers, depending on the board
461 implementation.
462
463 CONFIG_SYS_FSL_DDR3
464 Board config to use DDR3. It can be enabled for SoCs with
York Sun34e026f2014-03-27 17:54:47 -0700465 Freescale DDR3 or DDR3L controllers.
466
467 CONFIG_SYS_FSL_DDR3L
468 Board config to use DDR3L. It can be enabled for SoCs with
469 DDR3L controllers.
470
471 CONFIG_SYS_FSL_DDR4
472 Board config to use DDR4. It can be enabled for SoCs with
473 DDR4 controllers.
York Sun5614e712013-09-30 09:22:09 -0700474
Prabhakar Kushwaha1b4175d2014-01-18 12:28:30 +0530475 CONFIG_SYS_FSL_IFC_BE
476 Defines the IFC controller register space as Big Endian
477
478 CONFIG_SYS_FSL_IFC_LE
479 Defines the IFC controller register space as Little Endian
480
Prabhakar Kushwaha1c407072017-02-02 15:01:26 +0530481 CONFIG_SYS_FSL_IFC_CLK_DIV
482 Defines divider of platform clock(clock input to IFC controller).
483
Prabhakar Kushwahaadd63f92017-02-02 15:02:00 +0530484 CONFIG_SYS_FSL_LBC_CLK_DIV
485 Defines divider of platform clock(clock input to eLBC controller).
486
Prabhakar Kushwaha690e4252014-01-13 11:28:04 +0530487 CONFIG_SYS_FSL_PBL_PBI
488 It enables addition of RCW (Power on reset configuration) in built image.
489 Please refer doc/README.pblimage for more details
490
491 CONFIG_SYS_FSL_PBL_RCW
492 It adds PBI(pre-boot instructions) commands in u-boot build image.
493 PBI commands can be used to configure SoC before it starts the execution.
494 Please refer doc/README.pblimage for more details
495
York Sun4e5b1bd2014-02-10 13:59:42 -0800496 CONFIG_SYS_FSL_DDR_BE
497 Defines the DDR controller register space as Big Endian
498
499 CONFIG_SYS_FSL_DDR_LE
500 Defines the DDR controller register space as Little Endian
501
York Sun6b9e3092014-02-10 13:59:43 -0800502 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
503 Physical address from the view of DDR controllers. It is the
504 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
505 it could be different for ARM SoCs.
506
York Sun6b1e1252014-02-10 13:59:44 -0800507 CONFIG_SYS_FSL_DDR_INTLV_256B
508 DDR controller interleaving on 256-byte. This is a special
509 interleaving mode, handled by Dickens for Freescale layerscape
510 SoCs with ARM core.
511
York Sun1d71efb2014-08-01 15:51:00 -0700512 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
513 Number of controllers used as main memory.
514
515 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
516 Number of controllers used for other than main memory.
517
Prabhakar Kushwaha44937212015-11-09 16:42:07 +0530518 CONFIG_SYS_FSL_HAS_DP_DDR
519 Defines the SoC has DP-DDR used for DPAA.
520
Ruchika Gupta028dbb82014-09-09 11:50:31 +0530521 CONFIG_SYS_FSL_SEC_BE
522 Defines the SEC controller register space as Big Endian
523
524 CONFIG_SYS_FSL_SEC_LE
525 Defines the SEC controller register space as Little Endian
526
Daniel Schwierzeck92bbd642011-07-27 13:22:39 +0200527- MIPS CPU options:
528 CONFIG_SYS_INIT_SP_OFFSET
529
530 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
531 pointer. This is needed for the temporary stack before
532 relocation.
533
Daniel Schwierzeck92bbd642011-07-27 13:22:39 +0200534 CONFIG_XWAY_SWAP_BYTES
535
536 Enable compilation of tools/xway-swap-bytes needed for Lantiq
537 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
538 be swapped if a flash programmer is used.
539
Christian Rieschb67d8812012-02-02 00:44:39 +0000540- ARM options:
541 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
542
543 Select high exception vectors of the ARM core, e.g., do not
544 clear the V bit of the c1 register of CP15.
545
York Sun207774b2015-03-20 19:28:08 -0700546 COUNTER_FREQUENCY
547 Generic timer clock source frequency.
548
549 COUNTER_FREQUENCY_REAL
550 Generic timer clock source frequency if the real clock is
551 different from COUNTER_FREQUENCY, and can only be determined
552 at run time.
553
Stephen Warren73c38932015-01-19 16:25:52 -0700554- Tegra SoC options:
555 CONFIG_TEGRA_SUPPORT_NON_SECURE
556
557 Support executing U-Boot in non-secure (NS) mode. Certain
558 impossible actions will be skipped if the CPU is in NS mode,
559 such as ARM architectural timer initialization.
560
wdenk5da627a2003-10-09 20:09:04 +0000561- Linux Kernel Interface:
wdenkc6097192002-11-03 00:24:07 +0000562 CONFIG_CLOCKS_IN_MHZ
563
564 U-Boot stores all clock information in Hz
565 internally. For binary compatibility with older Linux
566 kernels (which expect the clocks passed in the
567 bd_info data to be in MHz) the environment variable
568 "clocks_in_mhz" can be defined so that U-Boot
569 converts clock data to MHZ before passing it to the
570 Linux kernel.
wdenkc6097192002-11-03 00:24:07 +0000571 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
Wolfgang Denk218ca722008-03-26 10:40:12 +0100572 "clocks_in_mhz=1" is automatically included in the
wdenkc6097192002-11-03 00:24:07 +0000573 default environment.
574
wdenk5da627a2003-10-09 20:09:04 +0000575 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
576
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -0800577 When transferring memsize parameter to Linux, some versions
wdenk5da627a2003-10-09 20:09:04 +0000578 expect it to be in bytes, others in MB.
579 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
580
Gerald Van Barenfec6d9e2008-06-03 20:34:45 -0400581 CONFIG_OF_LIBFDT
Wolfgang Denkf57f70a2005-10-13 01:45:54 +0200582
583 New kernel versions are expecting firmware settings to be
Gerald Van Baren213bf8c2007-03-31 12:23:51 -0400584 passed using flattened device trees (based on open firmware
585 concepts).
586
587 CONFIG_OF_LIBFDT
588 * New libfdt-based support
589 * Adds the "fdt" command
Kim Phillips3bb342f2007-08-10 14:34:14 -0500590 * The bootm command automatically updates the fdt
Gerald Van Baren213bf8c2007-03-31 12:23:51 -0400591
Wolfgang Denkf57f70a2005-10-13 01:45:54 +0200592 OF_TBCLK - The timebase frequency.
Kumar Galac2871f02006-01-11 13:59:02 -0600593 OF_STDOUT_PATH - The path to the console device
Wolfgang Denkf57f70a2005-10-13 01:45:54 +0200594
Marcel Ziswiler11ccc332008-07-09 08:17:15 +0200595 boards with QUICC Engines require OF_QE to set UCC MAC
596 addresses
Kim Phillips3bb342f2007-08-10 14:34:14 -0500597
Kumar Gala4e253132006-01-11 13:54:17 -0600598 CONFIG_OF_BOARD_SETUP
599
600 Board code has addition modification that it wants to make
601 to the flat device tree before handing it off to the kernel
wdenk6705d812004-08-02 23:22:59 +0000602
Simon Glassc654b512014-10-23 18:58:54 -0600603 CONFIG_OF_SYSTEM_SETUP
604
605 Other code has addition modification that it wants to make
606 to the flat device tree before handing it off to the kernel.
607 This causes ft_system_setup() to be called before booting
608 the kernel.
609
Heiko Schocher3887c3f2009-09-23 07:56:08 +0200610 CONFIG_OF_IDE_FIXUP
611
612 U-Boot can detect if an IDE device is present or not.
613 If not, and this new config option is activated, U-Boot
614 removes the ATA node from the DTS before booting Linux,
615 so the Linux IDE driver does not probe the device and
616 crash. This is needed for buggy hardware (uc101) where
617 no pull down resistor is connected to the signal IDE5V_DD7.
618
Igor Grinberg7eb29392011-07-14 05:45:07 +0000619 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
620
621 This setting is mandatory for all boards that have only one
622 machine type and must be used to specify the machine type
623 number as it appears in the ARM machine registry
624 (see http://www.arm.linux.org.uk/developer/machines/).
625 Only boards that have multiple machine types supported
626 in a single configuration file and the machine type is
627 runtime discoverable, do not have to use this setting.
628
Niklaus Giger0b2f4ec2008-11-03 22:13:47 +0100629- vxWorks boot parameters:
630
631 bootvx constructs a valid bootline using the following
Bin Meng9e98b7e2015-10-07 20:19:17 -0700632 environments variables: bootdev, bootfile, ipaddr, netmask,
633 serverip, gatewayip, hostname, othbootargs.
Niklaus Giger0b2f4ec2008-11-03 22:13:47 +0100634 It loads the vxWorks image pointed bootfile.
635
Niklaus Giger0b2f4ec2008-11-03 22:13:47 +0100636 Note: If a "bootargs" environment is defined, it will overwride
637 the defaults discussed just above.
638
Aneesh V2c451f72011-06-16 23:30:47 +0000639- Cache Configuration:
Aneesh V2c451f72011-06-16 23:30:47 +0000640 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
641
Aneesh V93bc2192011-06-16 23:30:51 +0000642- Cache Configuration for ARM:
643 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
644 controller
645 CONFIG_SYS_PL310_BASE - Physical base address of PL310
646 controller register space
647
wdenk6705d812004-08-02 23:22:59 +0000648- Serial Ports:
Andreas Engel48d01922008-09-08 14:30:53 +0200649 CONFIG_PL010_SERIAL
wdenk6705d812004-08-02 23:22:59 +0000650
651 Define this if you want support for Amba PrimeCell PL010 UARTs.
652
Andreas Engel48d01922008-09-08 14:30:53 +0200653 CONFIG_PL011_SERIAL
wdenk6705d812004-08-02 23:22:59 +0000654
655 Define this if you want support for Amba PrimeCell PL011 UARTs.
656
657 CONFIG_PL011_CLOCK
658
659 If you have Amba PrimeCell PL011 UARTs, set this variable to
660 the clock speed of the UARTs.
661
662 CONFIG_PL01x_PORTS
663
664 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
665 define this to a list of base addresses for each (supported)
666 port. See e.g. include/configs/versatile.h
667
Karicheri, Muralidharand57dee52014-04-09 15:38:46 -0400668 CONFIG_SERIAL_HW_FLOW_CONTROL
669
670 Define this variable to enable hw flow control in serial driver.
671 Current user of this option is drivers/serial/nsl16550.c driver
wdenk6705d812004-08-02 23:22:59 +0000672
wdenkc6097192002-11-03 00:24:07 +0000673- Console Baudrate:
674 CONFIG_BAUDRATE - in bps
675 Select one of the baudrates listed in
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200676 CONFIG_SYS_BAUDRATE_TABLE, see below.
wdenkc6097192002-11-03 00:24:07 +0000677
wdenkc6097192002-11-03 00:24:07 +0000678- Autoboot Command:
679 CONFIG_BOOTCOMMAND
680 Only needed when CONFIG_BOOTDELAY is enabled;
681 define a command string that is automatically executed
682 when no character is read on the console interface
683 within "Boot Delay" after reset.
684
wdenkc6097192002-11-03 00:24:07 +0000685 CONFIG_RAMBOOT and CONFIG_NFSBOOT
wdenk43d96162003-03-06 00:02:04 +0000686 The value of these goes into the environment as
687 "ramboot" and "nfsboot" respectively, and can be used
688 as a convenience, when switching between booting from
Marcel Ziswiler11ccc332008-07-09 08:17:15 +0200689 RAM and NFS.
wdenkc6097192002-11-03 00:24:07 +0000690
wdenkc6097192002-11-03 00:24:07 +0000691- Serial Download Echo Mode:
692 CONFIG_LOADS_ECHO
693 If defined to 1, all characters received during a
694 serial download (using the "loads" command) are
695 echoed back. This might be needed by some terminal
696 emulations (like "cu"), but may as well just take
697 time on others. This setting #define's the initial
698 value of the "loads_echo" environment variable.
699
Jon Loeliger602ad3b2007-06-11 19:03:39 -0500700- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
wdenkc6097192002-11-03 00:24:07 +0000701 CONFIG_KGDB_BAUDRATE
702 Select one of the baudrates listed in
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200703 CONFIG_SYS_BAUDRATE_TABLE, see below.
wdenkc6097192002-11-03 00:24:07 +0000704
Simon Glass302a6482016-03-13 19:07:28 -0600705- Removal of commands
706 If no commands are needed to boot, you can disable
707 CONFIG_CMDLINE to remove them. In this case, the command line
708 will not be available, and when U-Boot wants to execute the
709 boot command (on start-up) it will call board_run_command()
710 instead. This can reduce image size significantly for very
711 simple boot procedures.
712
Wolfgang Denka5ecbe62013-03-23 23:50:31 +0000713- Regular expression support:
714 CONFIG_REGEX
Wolfgang Denk93e14592013-10-04 17:43:24 +0200715 If this variable is defined, U-Boot is linked against
716 the SLRE (Super Light Regular Expression) library,
717 which adds regex support to some commands, as for
718 example "env grep" and "setexpr".
Wolfgang Denka5ecbe62013-03-23 23:50:31 +0000719
Simon Glass45ba8072011-10-15 05:48:20 +0000720- Device tree:
721 CONFIG_OF_CONTROL
722 If this variable is defined, U-Boot will use a device tree
723 to configure its devices, instead of relying on statically
724 compiled #defines in the board file. This option is
725 experimental and only available on a few boards. The device
726 tree is available in the global data as gd->fdt_blob.
727
Simon Glass2c0f79e2011-10-24 19:15:31 +0000728 U-Boot needs to get its device tree from somewhere. This can
Alex Deymo82f766d2017-04-02 01:25:20 -0700729 be done using one of the three options below:
Simon Glassbbb0b122011-10-15 05:48:21 +0000730
731 CONFIG_OF_EMBED
732 If this variable is defined, U-Boot will embed a device tree
733 binary in its image. This device tree file should be in the
734 board directory and called <soc>-<board>.dts. The binary file
735 is then picked up in board_init_f() and made available through
Nobuhiro Iwamatsueb3eb602017-08-26 07:34:14 +0900736 the global data structure as gd->fdt_blob.
Simon Glass45ba8072011-10-15 05:48:20 +0000737
Simon Glass2c0f79e2011-10-24 19:15:31 +0000738 CONFIG_OF_SEPARATE
739 If this variable is defined, U-Boot will build a device tree
740 binary. It will be called u-boot.dtb. Architecture-specific
741 code will locate it at run-time. Generally this works by:
742
743 cat u-boot.bin u-boot.dtb >image.bin
744
745 and in fact, U-Boot does this for you, creating a file called
746 u-boot-dtb.bin which is useful in the common case. You can
747 still use the individual files if you need something more
748 exotic.
749
Alex Deymo82f766d2017-04-02 01:25:20 -0700750 CONFIG_OF_BOARD
751 If this variable is defined, U-Boot will use the device tree
752 provided by the board at runtime instead of embedding one with
753 the image. Only boards defining board_fdt_blob_setup() support
754 this option (see include/fdtdec.h file).
755
wdenkc6097192002-11-03 00:24:07 +0000756- Watchdog:
757 CONFIG_WATCHDOG
758 If this variable is defined, it enables watchdog
Detlev Zundel6abe6fb2011-04-27 05:25:59 +0000759 support for the SoC. There must be support in the SoC
Christophe Leroy907208c2017-07-06 10:23:22 +0200760 specific code for a watchdog. For the 8xx
761 CPUs, the SIU Watchdog feature is enabled in the SYPCR
762 register. When supported for a specific SoC is
763 available, then no further board specific code should
764 be needed to use it.
Detlev Zundel6abe6fb2011-04-27 05:25:59 +0000765
766 CONFIG_HW_WATCHDOG
767 When using a watchdog circuitry external to the used
768 SoC, then define this variable and provide board
769 specific code for the "hw_watchdog_reset" function.
wdenkc6097192002-11-03 00:24:07 +0000770
771- Real-Time Clock:
772
Jon Loeliger602ad3b2007-06-11 19:03:39 -0500773 When CONFIG_CMD_DATE is selected, the type of the RTC
wdenkc6097192002-11-03 00:24:07 +0000774 has to be selected, too. Define exactly one of the
775 following options:
776
wdenkc6097192002-11-03 00:24:07 +0000777 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
Fabio Estevam4e8b7542011-10-24 06:44:15 +0000778 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
wdenkc6097192002-11-03 00:24:07 +0000779 CONFIG_RTC_MC146818 - use MC146818 RTC
wdenk1cb8e982003-03-06 21:55:29 +0000780 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
wdenkc6097192002-11-03 00:24:07 +0000781 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
wdenk7f70e852003-05-20 14:25:27 +0000782 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
Markus Niebel412921d2014-07-21 11:06:16 +0200783 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
wdenk3bac3512003-03-12 10:41:04 +0000784 CONFIG_RTC_DS164x - use Dallas DS164x RTC
Tor Krill9536dfc2008-03-15 15:40:26 +0100785 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
wdenk4c0d4c32004-06-09 17:34:58 +0000786 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
Chris Packham2bd3cab2017-05-30 12:03:33 +1200787 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
Heiko Schocher71d19f32011-03-28 09:24:22 +0200788 CONFIG_SYS_RV3029_TCR - enable trickle charger on
789 RV3029 RTC.
wdenkc6097192002-11-03 00:24:07 +0000790
wdenkb37c7e52003-06-30 16:24:52 +0000791 Note that if the RTC uses I2C, then the I2C interface
792 must also be configured. See I2C Support, below.
793
Peter Tysere92739d2008-12-17 16:36:21 -0600794- GPIO Support:
795 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
Peter Tysere92739d2008-12-17 16:36:21 -0600796
Chris Packham5dec49c2010-12-19 10:12:13 +0000797 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
798 chip-ngpio pairs that tell the PCA953X driver the number of
799 pins supported by a particular chip.
800
Peter Tysere92739d2008-12-17 16:36:21 -0600801 Note that if the GPIO device uses I2C, then the I2C interface
802 must also be configured. See I2C Support, below.
803
Simon Glassaa532332014-06-11 23:29:41 -0600804- I/O tracing:
805 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
806 accesses and can checksum them or write a list of them out
807 to memory. See the 'iotrace' command for details. This is
808 useful for testing device drivers since it can confirm that
809 the driver behaves the same way before and after a code
810 change. Currently this is supported on sandbox and arm. To
811 add support for your architecture, add '#include <iotrace.h>'
812 to the bottom of arch/<arch>/include/asm/io.h and test.
813
814 Example output from the 'iotrace stats' command is below.
815 Note that if the trace buffer is exhausted, the checksum will
816 still continue to operate.
817
818 iotrace is enabled
819 Start: 10000000 (buffer start address)
820 Size: 00010000 (buffer size)
821 Offset: 00000120 (current buffer offset)
822 Output: 10000120 (start + offset)
823 Count: 00000018 (number of trace records)
824 CRC32: 9526fb66 (CRC32 of all trace records)
825
wdenkc6097192002-11-03 00:24:07 +0000826- Timestamp Support:
827
wdenk43d96162003-03-06 00:02:04 +0000828 When CONFIG_TIMESTAMP is selected, the timestamp
829 (date and time) of an image is printed by image
830 commands like bootm or iminfo. This option is
Jon Loeliger602ad3b2007-06-11 19:03:39 -0500831 automatically enabled when you select CONFIG_CMD_DATE .
wdenkc6097192002-11-03 00:24:07 +0000832
Karl O. Pinc923c46f2012-08-16 06:20:15 +0000833- Partition Labels (disklabels) Supported:
834 Zero or more of the following:
835 CONFIG_MAC_PARTITION Apple's MacOS partition table.
Karl O. Pinc923c46f2012-08-16 06:20:15 +0000836 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
837 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
838 bootloader. Note 2TB partition limit; see
839 disk/part_efi.c
Simon Glassc649e3c2016-05-01 11:36:02 -0600840 CONFIG_SCSI) you must configure support for at
Karl O. Pinc923c46f2012-08-16 06:20:15 +0000841 least one non-MTD partition type as well.
wdenkc6097192002-11-03 00:24:07 +0000842
843- IDE Reset method:
wdenk4d13cba2004-03-14 14:09:05 +0000844 CONFIG_IDE_RESET_ROUTINE - this is defined in several
845 board configurations files but used nowhere!
wdenkc6097192002-11-03 00:24:07 +0000846
wdenk4d13cba2004-03-14 14:09:05 +0000847 CONFIG_IDE_RESET - is this is defined, IDE Reset will
848 be performed by calling the function
849 ide_set_reset(int reset)
850 which has to be defined in a board specific file
wdenkc6097192002-11-03 00:24:07 +0000851
852- ATAPI Support:
853 CONFIG_ATAPI
854
855 Set this to enable ATAPI support.
856
wdenkc40b2952004-03-13 23:29:43 +0000857- LBA48 Support
858 CONFIG_LBA48
859
860 Set this to enable support for disks larger than 137GB
Heiko Schocher4b142fe2009-12-03 11:21:21 +0100861 Also look at CONFIG_SYS_64BIT_LBA.
wdenkc40b2952004-03-13 23:29:43 +0000862 Whithout these , LBA48 support uses 32bit variables and will 'only'
863 support disks up to 2.1TB.
864
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200865 CONFIG_SYS_64BIT_LBA:
wdenkc40b2952004-03-13 23:29:43 +0000866 When enabled, makes the IDE subsystem use 64bit sector addresses.
867 Default is 32bit.
868
wdenkc6097192002-11-03 00:24:07 +0000869- SCSI Support:
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200870 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
871 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
872 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
wdenkc6097192002-11-03 00:24:07 +0000873 maximum numbers of LUNs, SCSI ID's and target
874 devices.
wdenkc6097192002-11-03 00:24:07 +0000875
Wolfgang Denk93e14592013-10-04 17:43:24 +0200876 The environment variable 'scsidevs' is set to the number of
877 SCSI devices found during the last scan.
Stefan Reinauer447c0312012-10-29 05:23:48 +0000878
wdenkc6097192002-11-03 00:24:07 +0000879- NETWORK Support (PCI):
wdenk682011f2003-06-03 23:54:09 +0000880 CONFIG_E1000
Kyle Moffettce5207e2011-10-18 11:05:29 +0000881 Support for Intel 8254x/8257x gigabit chips.
882
883 CONFIG_E1000_SPI
884 Utility code for direct access to the SPI bus on Intel 8257x.
885 This does not do anything useful unless you set at least one
886 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
887
888 CONFIG_E1000_SPI_GENERIC
889 Allow generic access to the SPI bus on the Intel 8257x, for
890 example with the "sspi" command.
891
wdenkc6097192002-11-03 00:24:07 +0000892 CONFIG_EEPRO100
893 Support for Intel 82557/82559/82559ER chips.
Marcel Ziswiler11ccc332008-07-09 08:17:15 +0200894 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
wdenkc6097192002-11-03 00:24:07 +0000895 write routine for first time initialisation.
896
897 CONFIG_TULIP
898 Support for Digital 2114x chips.
wdenkc6097192002-11-03 00:24:07 +0000899
900 CONFIG_NATSEMI
901 Support for National dp83815 chips.
902
903 CONFIG_NS8382X
904 Support for National dp8382[01] gigabit chips.
905
wdenk45219c42003-05-12 21:50:16 +0000906- NETWORK Support (other):
907
Jens Scharsigc041e9d2010-01-23 12:03:45 +0100908 CONFIG_DRIVER_AT91EMAC
909 Support for AT91RM9200 EMAC.
910
911 CONFIG_RMII
912 Define this to use reduced MII inteface
913
914 CONFIG_DRIVER_AT91EMAC_QUIET
915 If this defined, the driver is quiet.
916 The driver doen't show link status messages.
917
Rob Herringefdd7312011-12-15 11:15:49 +0000918 CONFIG_CALXEDA_XGMAC
919 Support for the Calxeda XGMAC device
920
Ashok3bb46d22012-10-15 06:20:47 +0000921 CONFIG_LAN91C96
wdenk45219c42003-05-12 21:50:16 +0000922 Support for SMSC's LAN91C96 chips.
923
wdenk45219c42003-05-12 21:50:16 +0000924 CONFIG_LAN91C96_USE_32_BIT
925 Define this to enable 32 bit addressing
926
Ashok3bb46d22012-10-15 06:20:47 +0000927 CONFIG_SMC91111
wdenkf39748a2004-06-09 13:37:52 +0000928 Support for SMSC's LAN91C111 chip
929
930 CONFIG_SMC91111_BASE
931 Define this to hold the physical address
932 of the device (I/O space)
933
934 CONFIG_SMC_USE_32_BIT
935 Define this if data bus is 32 bits
936
937 CONFIG_SMC_USE_IOFUNCS
938 Define this to use i/o functions instead of macros
939 (some hardware wont work with macros)
940
Heiko Schocherdc02bad2011-11-15 10:00:04 -0500941 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
942 Define this if you have more then 3 PHYs.
943
Macpaul Linb3dbf4a52010-12-21 16:59:46 +0800944 CONFIG_FTGMAC100
945 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
946
947 CONFIG_FTGMAC100_EGIGA
948 Define this to use GE link update with gigabit PHY.
949 Define this if FTGMAC100 is connected to gigabit PHY.
950 If your system has 10/100 PHY only, it might not occur
951 wrong behavior. Because PHY usually return timeout or
952 useless data when polling gigabit status and gigabit
953 control registers. This behavior won't affect the
954 correctnessof 10/100 link speed update.
955
Yoshihiro Shimoda3d0075f2011-01-27 10:06:03 +0900956 CONFIG_SH_ETHER
957 Support for Renesas on-chip Ethernet controller
958
959 CONFIG_SH_ETHER_USE_PORT
960 Define the number of ports to be used
961
962 CONFIG_SH_ETHER_PHY_ADDR
963 Define the ETH PHY's address
964
Yoshihiro Shimoda68260aa2011-01-27 10:06:08 +0900965 CONFIG_SH_ETHER_CACHE_WRITEBACK
966 If this option is set, the driver enables cache flush.
967
Vadim Bendebury5e124722011-10-17 08:36:14 +0000968- TPM Support:
Che-liang Chiou90899cc2013-04-12 11:04:34 +0000969 CONFIG_TPM
970 Support TPM devices.
971
Christophe Ricard0766ad22015-10-06 22:54:41 +0200972 CONFIG_TPM_TIS_INFINEON
973 Support for Infineon i2c bus TPM devices. Only one device
Tom Wai-Hong Tam1b393db2013-04-12 11:04:37 +0000974 per system is supported at this time.
975
Tom Wai-Hong Tam1b393db2013-04-12 11:04:37 +0000976 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
977 Define the burst count bytes upper limit
978
Christophe Ricard3aa74082016-01-21 23:27:13 +0100979 CONFIG_TPM_ST33ZP24
980 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
981
982 CONFIG_TPM_ST33ZP24_I2C
983 Support for STMicroelectronics ST33ZP24 I2C devices.
984 Requires TPM_ST33ZP24 and I2C.
985
Christophe Ricardb75fdc12016-01-21 23:27:14 +0100986 CONFIG_TPM_ST33ZP24_SPI
987 Support for STMicroelectronics ST33ZP24 SPI devices.
988 Requires TPM_ST33ZP24 and SPI.
989
Dirk Eibachc01939c2013-06-26 15:55:15 +0200990 CONFIG_TPM_ATMEL_TWI
991 Support for Atmel TWI TPM device. Requires I2C support.
992
Che-liang Chiou90899cc2013-04-12 11:04:34 +0000993 CONFIG_TPM_TIS_LPC
Vadim Bendebury5e124722011-10-17 08:36:14 +0000994 Support for generic parallel port TPM devices. Only one device
995 per system is supported at this time.
996
997 CONFIG_TPM_TIS_BASE_ADDRESS
998 Base address where the generic TPM device is mapped
999 to. Contemporary x86 systems usually map it at
1000 0xfed40000.
1001
Reinhard Pfaube6c1522013-06-26 15:55:13 +02001002 CONFIG_TPM
1003 Define this to enable the TPM support library which provides
1004 functional interfaces to some TPM commands.
1005 Requires support for a TPM device.
1006
1007 CONFIG_TPM_AUTH_SESSIONS
1008 Define this to enable authorized functions in the TPM library.
1009 Requires CONFIG_TPM and CONFIG_SHA1.
1010
wdenkc6097192002-11-03 00:24:07 +00001011- USB Support:
1012 At the moment only the UHCI host controller is
Heiko Schocher064b55c2017-06-14 05:49:40 +02001013 supported (PIP405, MIP405); define
wdenkc6097192002-11-03 00:24:07 +00001014 CONFIG_USB_UHCI to enable it.
1015 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
wdenk30d56fa2004-10-09 22:44:59 +00001016 and define CONFIG_USB_STORAGE to enable the USB
wdenkc6097192002-11-03 00:24:07 +00001017 storage devices.
1018 Note:
1019 Supported are USB Keyboards and USB Floppy drives
1020 (TEAC FD-05PUB).
wdenk4d13cba2004-03-14 14:09:05 +00001021
Simon Glass9ab4ce22012-02-27 10:52:47 +00001022 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1023 txfilltuning field in the EHCI controller on reset.
1024
Oleksandr Tymoshenko6e9e0622014-02-01 21:51:25 -07001025 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1026 HW module registers.
1027
Wolfgang Denk16c8d5e2006-06-14 17:45:53 +02001028- USB Device:
1029 Define the below if you wish to use the USB console.
1030 Once firmware is rebuilt from a serial console issue the
1031 command "setenv stdin usbtty; setenv stdout usbtty" and
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02001032 attach your USB cable. The Unix command "dmesg" should print
Wolfgang Denk16c8d5e2006-06-14 17:45:53 +02001033 it has found a new device. The environment variable usbtty
1034 can be set to gserial or cdc_acm to enable your device to
Wolfgang Denk386eda02006-06-14 18:14:56 +02001035 appear to a USB host as a Linux gserial device or a
Wolfgang Denk16c8d5e2006-06-14 17:45:53 +02001036 Common Device Class Abstract Control Model serial device.
1037 If you select usbtty = gserial you should be able to enumerate
1038 a Linux host by
1039 # modprobe usbserial vendor=0xVendorID product=0xProductID
1040 else if using cdc_acm, simply setting the environment
1041 variable usbtty to be cdc_acm should suffice. The following
1042 might be defined in YourBoardName.h
Wolfgang Denk386eda02006-06-14 18:14:56 +02001043
Wolfgang Denk16c8d5e2006-06-14 17:45:53 +02001044 CONFIG_USB_DEVICE
1045 Define this to build a UDC device
wdenkc6097192002-11-03 00:24:07 +00001046
Wolfgang Denk16c8d5e2006-06-14 17:45:53 +02001047 CONFIG_USB_TTY
1048 Define this to have a tty type of device available to
1049 talk to the UDC device
Wolfgang Denk386eda02006-06-14 18:14:56 +02001050
Vipin KUMARf9da0f82012-03-26 15:38:06 +05301051 CONFIG_USBD_HS
1052 Define this to enable the high speed support for usb
1053 device and usbtty. If this feature is enabled, a routine
1054 int is_usbd_high_speed(void)
1055 also needs to be defined by the driver to dynamically poll
1056 whether the enumeration has succeded at high speed or full
1057 speed.
1058
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001059 CONFIG_SYS_CONSOLE_IS_IN_ENV
Wolfgang Denk16c8d5e2006-06-14 17:45:53 +02001060 Define this if you want stdin, stdout &/or stderr to
1061 be set to usbtty.
1062
Wolfgang Denk386eda02006-06-14 18:14:56 +02001063 If you have a USB-IF assigned VendorID then you may wish to
Wolfgang Denk16c8d5e2006-06-14 17:45:53 +02001064 define your own vendor specific values either in BoardName.h
Wolfgang Denk386eda02006-06-14 18:14:56 +02001065 or directly in usbd_vendor_info.h. If you don't define
Wolfgang Denk16c8d5e2006-06-14 17:45:53 +02001066 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1067 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1068 should pretend to be a Linux device to it's target host.
1069
1070 CONFIG_USBD_MANUFACTURER
1071 Define this string as the name of your company for
1072 - CONFIG_USBD_MANUFACTURER "my company"
Wolfgang Denk386eda02006-06-14 18:14:56 +02001073
Wolfgang Denk16c8d5e2006-06-14 17:45:53 +02001074 CONFIG_USBD_PRODUCT_NAME
1075 Define this string as the name of your product
1076 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1077
1078 CONFIG_USBD_VENDORID
1079 Define this as your assigned Vendor ID from the USB
1080 Implementors Forum. This *must* be a genuine Vendor ID
1081 to avoid polluting the USB namespace.
1082 - CONFIG_USBD_VENDORID 0xFFFF
Wolfgang Denk386eda02006-06-14 18:14:56 +02001083
Wolfgang Denk16c8d5e2006-06-14 17:45:53 +02001084 CONFIG_USBD_PRODUCTID
1085 Define this as the unique Product ID
1086 for your device
1087 - CONFIG_USBD_PRODUCTID 0xFFFF
wdenkc6097192002-11-03 00:24:07 +00001088
Igor Grinbergd70a5602011-12-12 12:08:35 +02001089- ULPI Layer Support:
1090 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1091 the generic ULPI layer. The generic layer accesses the ULPI PHY
1092 via the platform viewport, so you need both the genric layer and
1093 the viewport enabled. Currently only Chipidea/ARC based
1094 viewport is supported.
1095 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1096 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
Lucas Stach6d365ea2012-10-01 00:44:35 +02001097 If your ULPI phy needs a different reference clock than the
1098 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1099 the appropriate value in Hz.
wdenkc6097192002-11-03 00:24:07 +00001100
1101- MMC Support:
1102 The MMC controller on the Intel PXA is supported. To
1103 enable this define CONFIG_MMC. The MMC can be
1104 accessed from the boot prompt by mapping the device
1105 to physical memory similar to flash. Command line is
Jon Loeliger602ad3b2007-06-11 19:03:39 -05001106 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1107 the FAT fs. This is enabled with CONFIG_CMD_FAT.
wdenkc6097192002-11-03 00:24:07 +00001108
Yoshihiro Shimodaafb35662011-07-04 22:21:22 +00001109 CONFIG_SH_MMCIF
1110 Support for Renesas on-chip MMCIF controller
1111
1112 CONFIG_SH_MMCIF_ADDR
1113 Define the base address of MMCIF registers
1114
1115 CONFIG_SH_MMCIF_CLK
1116 Define the clock frequency for MMCIF
1117
Tom Rinib3ba6e92013-03-14 05:32:47 +00001118- USB Device Firmware Update (DFU) class support:
Marek Vasutbb4059a2018-02-16 16:41:18 +01001119 CONFIG_DFU_OVER_USB
Tom Rinib3ba6e92013-03-14 05:32:47 +00001120 This enables the USB portion of the DFU USB class
1121
Pantelis Antoniouc6631762013-03-14 05:32:52 +00001122 CONFIG_DFU_NAND
1123 This enables support for exposing NAND devices via DFU.
1124
Afzal Mohammeda9479f02013-09-18 01:15:24 +05301125 CONFIG_DFU_RAM
1126 This enables support for exposing RAM via DFU.
1127 Note: DFU spec refer to non-volatile memory usage, but
1128 allow usages beyond the scope of spec - here RAM usage,
1129 one that would help mostly the developer.
1130
Heiko Schochere7e75c72013-06-12 06:05:51 +02001131 CONFIG_SYS_DFU_DATA_BUF_SIZE
1132 Dfu transfer uses a buffer before writing data to the
1133 raw storage device. Make the size (in bytes) of this buffer
1134 configurable. The size of this buffer is also configurable
1135 through the "dfu_bufsiz" environment variable.
1136
Pantelis Antoniouea2453d2013-03-14 05:32:48 +00001137 CONFIG_SYS_DFU_MAX_FILE_SIZE
1138 When updating files rather than the raw storage device,
1139 we use a static buffer to copy the file into and then write
1140 the buffer once we've been given the whole file. Define
1141 this to the maximum filesize (in bytes) for the buffer.
1142 Default is 4 MiB if undefined.
1143
Heiko Schocher001a8312014-03-18 08:09:56 +01001144 DFU_DEFAULT_POLL_TIMEOUT
1145 Poll timeout [ms], is the timeout a device can send to the
1146 host. The host must wait for this timeout before sending
1147 a subsequent DFU_GET_STATUS request to the device.
1148
1149 DFU_MANIFEST_POLL_TIMEOUT
1150 Poll timeout [ms], which the device sends to the host when
1151 entering dfuMANIFEST state. Host waits this timeout, before
1152 sending again an USB request to the device.
1153
wdenk6705d812004-08-02 23:22:59 +00001154- Journaling Flash filesystem support:
Simon Glassb2482df2016-10-02 18:00:59 -06001155 CONFIG_JFFS2_NAND
wdenk6705d812004-08-02 23:22:59 +00001156 Define these for a default partition on a NAND device
1157
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001158 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1159 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
wdenk6705d812004-08-02 23:22:59 +00001160 Define these for a default partition on a NOR device
1161
wdenkc6097192002-11-03 00:24:07 +00001162- Keyboard Support:
Simon Glass39f615e2015-11-11 10:05:47 -07001163 See Kconfig help for available keyboard drivers.
1164
1165 CONFIG_KEYBOARD
1166
1167 Define this to enable a custom keyboard support.
1168 This simply calls drv_keyboard_init() which must be
1169 defined in your board-specific files. This option is deprecated
1170 and is only used by novena. For new boards, use driver model
1171 instead.
wdenkc6097192002-11-03 00:24:07 +00001172
1173- Video support:
Timur Tabi7d3053f2011-02-15 17:09:19 -06001174 CONFIG_FSL_DIU_FB
Wolfgang Denk04e5ae72011-09-11 21:24:09 +02001175 Enable the Freescale DIU video driver. Reference boards for
Timur Tabi7d3053f2011-02-15 17:09:19 -06001176 SOCs that have a DIU should define this macro to enable DIU
1177 support, and should also define these other macros:
1178
1179 CONFIG_SYS_DIU_ADDR
1180 CONFIG_VIDEO
Timur Tabi7d3053f2011-02-15 17:09:19 -06001181 CONFIG_CFB_CONSOLE
1182 CONFIG_VIDEO_SW_CURSOR
1183 CONFIG_VGA_AS_SINGLE_DEVICE
1184 CONFIG_VIDEO_LOGO
1185 CONFIG_VIDEO_BMP_LOGO
1186
Timur Tabiba8e76b2011-04-11 14:18:22 -05001187 The DIU driver will look for the 'video-mode' environment
1188 variable, and if defined, enable the DIU as a console during
Fabio Estevam8eca9432016-04-02 11:53:18 -03001189 boot. See the documentation file doc/README.video for a
Timur Tabiba8e76b2011-04-11 14:18:22 -05001190 description of this variable.
Timur Tabi7d3053f2011-02-15 17:09:19 -06001191
wdenkc6097192002-11-03 00:24:07 +00001192- LCD Support: CONFIG_LCD
1193
1194 Define this to enable LCD support (for output to LCD
1195 display); also select one of the supported displays
1196 by defining one of these:
1197
Stelian Pop39cf4802008-05-09 21:57:18 +02001198 CONFIG_ATMEL_LCD:
1199
1200 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1201
wdenkfd3103b2003-11-25 16:55:19 +00001202 CONFIG_NEC_NL6448AC33:
wdenkc6097192002-11-03 00:24:07 +00001203
wdenkfd3103b2003-11-25 16:55:19 +00001204 NEC NL6448AC33-18. Active, color, single scan.
wdenkc6097192002-11-03 00:24:07 +00001205
wdenkfd3103b2003-11-25 16:55:19 +00001206 CONFIG_NEC_NL6448BC20
wdenkc6097192002-11-03 00:24:07 +00001207
wdenkfd3103b2003-11-25 16:55:19 +00001208 NEC NL6448BC20-08. 6.5", 640x480.
1209 Active, color, single scan.
1210
1211 CONFIG_NEC_NL6448BC33_54
1212
1213 NEC NL6448BC33-54. 10.4", 640x480.
wdenkc6097192002-11-03 00:24:07 +00001214 Active, color, single scan.
1215
1216 CONFIG_SHARP_16x9
1217
1218 Sharp 320x240. Active, color, single scan.
1219 It isn't 16x9, and I am not sure what it is.
1220
1221 CONFIG_SHARP_LQ64D341
1222
1223 Sharp LQ64D341 display, 640x480.
1224 Active, color, single scan.
1225
1226 CONFIG_HLD1045
1227
1228 HLD1045 display, 640x480.
1229 Active, color, single scan.
1230
1231 CONFIG_OPTREX_BW
1232
1233 Optrex CBL50840-2 NF-FW 99 22 M5
1234 or
1235 Hitachi LMG6912RPFC-00T
1236 or
1237 Hitachi SP14Q002
1238
1239 320x240. Black & white.
1240
Simon Glass676d3192012-10-17 13:24:54 +00001241 CONFIG_LCD_ALIGNMENT
1242
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08001243 Normally the LCD is page-aligned (typically 4KB). If this is
Simon Glass676d3192012-10-17 13:24:54 +00001244 defined then the LCD will be aligned to this value instead.
1245 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1246 here, since it is cheaper to change data cache settings on
1247 a per-section basis.
1248
1249
Hannes Petermaier604c7d42015-03-27 08:01:38 +01001250 CONFIG_LCD_ROTATION
1251
1252 Sometimes, for example if the display is mounted in portrait
1253 mode or even if it's mounted landscape but rotated by 180degree,
1254 we need to rotate our content of the display relative to the
1255 framebuffer, so that user can read the messages which are
1256 printed out.
1257 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1258 initialized with a given rotation from "vl_rot" out of
1259 "vidinfo_t" which is provided by the board specific code.
1260 The value for vl_rot is coded as following (matching to
1261 fbcon=rotate:<n> linux-kernel commandline):
1262 0 = no rotation respectively 0 degree
1263 1 = 90 degree rotation
1264 2 = 180 degree rotation
1265 3 = 270 degree rotation
1266
1267 If CONFIG_LCD_ROTATION is not defined, the console will be
1268 initialized with 0degree rotation.
1269
Tom Wai-Hong Tam45d7f522012-09-28 15:11:16 +00001270 CONFIG_LCD_BMP_RLE8
1271
1272 Support drawing of RLE8-compressed bitmaps on the LCD.
1273
Tom Wai-Hong Tam735987c2012-12-05 14:46:40 +00001274 CONFIG_I2C_EDID
1275
1276 Enables an 'i2c edid' command which can read EDID
1277 information over I2C from an attached LCD display.
1278
wdenk7152b1d2003-09-05 23:19:14 +00001279- Splash Screen Support: CONFIG_SPLASH_SCREEN
wdenkd791b1d2003-04-20 14:04:18 +00001280
wdenk8bde7f72003-06-27 21:31:46 +00001281 If this option is set, the environment is checked for
1282 a variable "splashimage". If found, the usual display
1283 of logo, copyright and system information on the LCD
wdenke94d2cd2004-06-30 22:59:18 +00001284 is suppressed and the BMP image at the address
wdenk8bde7f72003-06-27 21:31:46 +00001285 specified in "splashimage" is loaded instead. The
1286 console is redirected to the "nulldev", too. This
1287 allows for a "silent" boot where a splash screen is
1288 loaded very quickly after power-on.
wdenkd791b1d2003-04-20 14:04:18 +00001289
Nikita Kiryanovc0880482013-02-24 21:28:43 +00001290 CONFIG_SPLASHIMAGE_GUARD
1291
1292 If this option is set, then U-Boot will prevent the environment
1293 variable "splashimage" from being set to a problematic address
Fabio Estevamab5645f2016-03-23 12:46:12 -03001294 (see doc/README.displaying-bmps).
Nikita Kiryanovc0880482013-02-24 21:28:43 +00001295 This option is useful for targets where, due to alignment
1296 restrictions, an improperly aligned BMP image will cause a data
1297 abort. If you think you will not have problems with unaligned
1298 accesses (for example because your toolchain prevents them)
1299 there is no need to set this option.
1300
Matthias Weisser1ca298c2009-07-09 16:07:30 +02001301 CONFIG_SPLASH_SCREEN_ALIGN
1302
1303 If this option is set the splash image can be freely positioned
1304 on the screen. Environment variable "splashpos" specifies the
1305 position as "x,y". If a positive number is given it is used as
1306 number of pixel from left/top. If a negative number is given it
1307 is used as number of pixel from right/bottom. You can also
1308 specify 'm' for centering the image.
1309
1310 Example:
1311 setenv splashpos m,m
1312 => image at center of screen
1313
1314 setenv splashpos 30,20
1315 => image at x = 30 and y = 20
1316
1317 setenv splashpos -10,m
1318 => vertically centered image
1319 at x = dspWidth - bmpWidth - 9
1320
Stefan Roese98f4a3d2005-09-22 09:04:17 +02001321- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1322
1323 If this option is set, additionally to standard BMP
1324 images, gzipped BMP images can be displayed via the
1325 splashscreen support or the bmp command.
1326
Anatolij Gustschind5011762010-03-15 14:50:25 +01001327- Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1328
1329 If this option is set, 8-bit RLE compressed BMP images
1330 can be displayed via the splashscreen support or the
1331 bmp command.
1332
wdenkc29fdfc2003-08-29 20:57:53 +00001333- Compression support:
Kees Cook8ef70472013-08-16 07:59:12 -07001334 CONFIG_GZIP
1335
1336 Enabled by default to support gzip compressed images.
1337
wdenkc29fdfc2003-08-29 20:57:53 +00001338 CONFIG_BZIP2
1339
1340 If this option is set, support for bzip2 compressed
1341 images is included. If not, only uncompressed and gzip
1342 compressed images are supported.
1343
wdenk42d1f032003-10-15 23:53:47 +00001344 NOTE: the bzip2 algorithm requires a lot of RAM, so
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001345 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
wdenk42d1f032003-10-15 23:53:47 +00001346 be at least 4MB.
wdenkd791b1d2003-04-20 14:04:18 +00001347
wdenk17ea1172004-06-06 21:51:03 +00001348- MII/PHY support:
wdenk17ea1172004-06-06 21:51:03 +00001349 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1350
1351 The clock frequency of the MII bus
1352
wdenk17ea1172004-06-06 21:51:03 +00001353 CONFIG_PHY_RESET_DELAY
1354
1355 Some PHY like Intel LXT971A need extra delay after
1356 reset before any MII register access is possible.
1357 For such PHY, set this option to the usec delay
1358 required. (minimum 300usec for LXT971A)
1359
1360 CONFIG_PHY_CMD_DELAY (ppc4xx)
1361
1362 Some PHY like Intel LXT971A need extra delay after
1363 command issued before MII status register can be read
1364
wdenkc6097192002-11-03 00:24:07 +00001365- IP address:
1366 CONFIG_IPADDR
1367
1368 Define a default value for the IP address to use for
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02001369 the default Ethernet interface, in case this is not
wdenkc6097192002-11-03 00:24:07 +00001370 determined through e.g. bootp.
Wolfgang Denk1ebcd652011-10-26 10:21:22 +00001371 (Environment variable "ipaddr")
wdenkc6097192002-11-03 00:24:07 +00001372
1373- Server IP address:
1374 CONFIG_SERVERIP
1375
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02001376 Defines a default value for the IP address of a TFTP
wdenkc6097192002-11-03 00:24:07 +00001377 server to contact when using the "tftboot" command.
Wolfgang Denk1ebcd652011-10-26 10:21:22 +00001378 (Environment variable "serverip")
wdenkc6097192002-11-03 00:24:07 +00001379
Robin Getz97cfe862009-07-21 12:15:28 -04001380 CONFIG_KEEP_SERVERADDR
1381
1382 Keeps the server's MAC address, in the env 'serveraddr'
1383 for passing to bootargs (like Linux's netconsole option)
1384
Wolfgang Denk1ebcd652011-10-26 10:21:22 +00001385- Gateway IP address:
1386 CONFIG_GATEWAYIP
1387
1388 Defines a default value for the IP address of the
1389 default router where packets to other networks are
1390 sent to.
1391 (Environment variable "gatewayip")
1392
1393- Subnet mask:
1394 CONFIG_NETMASK
1395
1396 Defines a default value for the subnet mask (or
1397 routing prefix) which is used to determine if an IP
1398 address belongs to the local subnet or needs to be
1399 forwarded through a router.
1400 (Environment variable "netmask")
1401
wdenkc6097192002-11-03 00:24:07 +00001402- BOOTP Recovery Mode:
1403 CONFIG_BOOTP_RANDOM_DELAY
1404
1405 If you have many targets in a network that try to
1406 boot using BOOTP, you may want to avoid that all
1407 systems send out BOOTP requests at precisely the same
1408 moment (which would happen for instance at recovery
1409 from a power failure, when all systems will try to
1410 boot, thus flooding the BOOTP server. Defining
1411 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1412 inserted before sending out BOOTP requests. The
Wolfgang Denk6c33c782007-08-06 23:21:05 +02001413 following delays are inserted then:
wdenkc6097192002-11-03 00:24:07 +00001414
1415 1st BOOTP request: delay 0 ... 1 sec
1416 2nd BOOTP request: delay 0 ... 2 sec
1417 3rd BOOTP request: delay 0 ... 4 sec
1418 4th and following
1419 BOOTP requests: delay 0 ... 8 sec
1420
Thierry Reding92ac8ac2014-08-19 10:21:24 +02001421 CONFIG_BOOTP_ID_CACHE_SIZE
1422
1423 BOOTP packets are uniquely identified using a 32-bit ID. The
1424 server will copy the ID from client requests to responses and
1425 U-Boot will use this to determine if it is the destination of
1426 an incoming response. Some servers will check that addresses
1427 aren't in use before handing them out (usually using an ARP
1428 ping) and therefore take up to a few hundred milliseconds to
1429 respond. Network congestion may also influence the time it
1430 takes for a response to make it back to the client. If that
1431 time is too long, U-Boot will retransmit requests. In order
1432 to allow earlier responses to still be accepted after these
1433 retransmissions, U-Boot's BOOTP client keeps a small cache of
1434 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1435 cache. The default is to keep IDs for up to four outstanding
1436 requests. Increasing this will allow U-Boot to accept offers
1437 from a BOOTP client in networks with unusually high latency.
1438
stroesefe389a82003-08-28 14:17:32 +00001439- DHCP Advanced Options:
Jon Loeliger1fe80d72007-07-09 22:08:34 -05001440 You can fine tune the DHCP functionality by defining
1441 CONFIG_BOOTP_* symbols:
stroesefe389a82003-08-28 14:17:32 +00001442
Jon Loeliger1fe80d72007-07-09 22:08:34 -05001443 CONFIG_BOOTP_NISDOMAIN
Jon Loeliger1fe80d72007-07-09 22:08:34 -05001444 CONFIG_BOOTP_BOOTFILESIZE
Jon Loeliger1fe80d72007-07-09 22:08:34 -05001445 CONFIG_BOOTP_SEND_HOSTNAME
1446 CONFIG_BOOTP_NTPSERVER
1447 CONFIG_BOOTP_TIMEOFFSET
1448 CONFIG_BOOTP_VENDOREX
Joe Hershberger2c00e092012-05-23 07:59:19 +00001449 CONFIG_BOOTP_MAY_FAIL
stroesefe389a82003-08-28 14:17:32 +00001450
Wilson Callan5d110f02007-07-28 10:56:13 -04001451 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1452 environment variable, not the BOOTP server.
stroesefe389a82003-08-28 14:17:32 +00001453
Joe Hershberger2c00e092012-05-23 07:59:19 +00001454 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1455 after the configured retry count, the call will fail
1456 instead of starting over. This can be used to fail over
1457 to Link-local IP address configuration if the DHCP server
1458 is not available.
1459
stroesefe389a82003-08-28 14:17:32 +00001460 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1461 to do a dynamic update of a DNS server. To do this, they
1462 need the hostname of the DHCP requester.
Wilson Callan5d110f02007-07-28 10:56:13 -04001463 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
Jon Loeliger1fe80d72007-07-09 22:08:34 -05001464 of the "hostname" environment variable is passed as
1465 option 12 to the DHCP server.
stroesefe389a82003-08-28 14:17:32 +00001466
Aras Vaichasd9a2f412008-03-26 09:43:57 +11001467 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1468
1469 A 32bit value in microseconds for a delay between
1470 receiving a "DHCP Offer" and sending the "DHCP Request".
1471 This fixes a problem with certain DHCP servers that don't
1472 respond 100% of the time to a "DHCP request". E.g. On an
1473 AT91RM9200 processor running at 180MHz, this delay needed
1474 to be *at least* 15,000 usec before a Windows Server 2003
1475 DHCP server would reply 100% of the time. I recommend at
1476 least 50,000 usec to be safe. The alternative is to hope
1477 that one of the retries will be successful but note that
1478 the DHCP timeout and retry process takes a longer than
1479 this delay.
1480
Joe Hershbergerd22c3382012-05-23 08:00:12 +00001481 - Link-local IP address negotiation:
1482 Negotiate with other link-local clients on the local network
1483 for an address that doesn't require explicit configuration.
1484 This is especially useful if a DHCP server cannot be guaranteed
1485 to exist in all environments that the device must operate.
1486
1487 See doc/README.link-local for more information.
1488
Prabhakar Kushwaha24acb832017-11-23 16:51:32 +05301489 - MAC address from environment variables
1490
1491 FDT_SEQ_MACADDR_FROM_ENV
1492
1493 Fix-up device tree with MAC addresses fetched sequentially from
1494 environment variables. This config work on assumption that
1495 non-usable ethernet node of device-tree are either not present
1496 or their status has been marked as "disabled".
1497
wdenka3d991b2004-04-15 21:48:45 +00001498 - CDP Options:
wdenk6e592382004-04-18 17:39:38 +00001499 CONFIG_CDP_DEVICE_ID
wdenka3d991b2004-04-15 21:48:45 +00001500
1501 The device id used in CDP trigger frames.
1502
1503 CONFIG_CDP_DEVICE_ID_PREFIX
1504
1505 A two character string which is prefixed to the MAC address
1506 of the device.
1507
1508 CONFIG_CDP_PORT_ID
1509
1510 A printf format string which contains the ascii name of
1511 the port. Normally is set to "eth%d" which sets
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02001512 eth0 for the first Ethernet, eth1 for the second etc.
wdenka3d991b2004-04-15 21:48:45 +00001513
1514 CONFIG_CDP_CAPABILITIES
1515
1516 A 32bit integer which indicates the device capabilities;
1517 0x00000010 for a normal host which does not forwards.
1518
1519 CONFIG_CDP_VERSION
1520
1521 An ascii string containing the version of the software.
1522
1523 CONFIG_CDP_PLATFORM
1524
1525 An ascii string containing the name of the platform.
1526
1527 CONFIG_CDP_TRIGGER
1528
1529 A 32bit integer sent on the trigger.
1530
1531 CONFIG_CDP_POWER_CONSUMPTION
1532
1533 A 16bit integer containing the power consumption of the
1534 device in .1 of milliwatts.
1535
1536 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1537
1538 A byte containing the id of the VLAN.
1539
Uri Mashiach79267ed2017-01-19 10:51:05 +02001540- Status LED: CONFIG_LED_STATUS
wdenkc6097192002-11-03 00:24:07 +00001541
1542 Several configurations allow to display the current
1543 status using a LED. For instance, the LED will blink
1544 fast while running U-Boot code, stop blinking as
1545 soon as a reply to a BOOTP request was received, and
1546 start blinking slow once the Linux kernel is running
1547 (supported by a status LED driver in the Linux
Uri Mashiach79267ed2017-01-19 10:51:05 +02001548 kernel). Defining CONFIG_LED_STATUS enables this
wdenkc6097192002-11-03 00:24:07 +00001549 feature in U-Boot.
1550
Igor Grinberg1df7bbb2013-11-08 01:03:50 +02001551 Additional options:
1552
Uri Mashiach79267ed2017-01-19 10:51:05 +02001553 CONFIG_LED_STATUS_GPIO
Igor Grinberg1df7bbb2013-11-08 01:03:50 +02001554 The status LED can be connected to a GPIO pin.
1555 In such cases, the gpio_led driver can be used as a
Uri Mashiach79267ed2017-01-19 10:51:05 +02001556 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
Igor Grinberg1df7bbb2013-11-08 01:03:50 +02001557 to include the gpio_led driver in the U-Boot binary.
1558
Igor Grinberg9dfdcdf2013-11-08 01:03:52 +02001559 CONFIG_GPIO_LED_INVERTED_TABLE
1560 Some GPIO connected LEDs may have inverted polarity in which
1561 case the GPIO high value corresponds to LED off state and
1562 GPIO low value corresponds to LED on state.
1563 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1564 with a list of GPIO LEDs that have inverted polarity.
1565
Heiko Schocher3f4978c2012-01-16 21:12:24 +00001566- I2C Support: CONFIG_SYS_I2C
wdenkc6097192002-11-03 00:24:07 +00001567
Heiko Schocher3f4978c2012-01-16 21:12:24 +00001568 This enable the NEW i2c subsystem, and will allow you to use
1569 i2c commands at the u-boot command line (as long as you set
1570 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
1571 based realtime clock chips or other i2c devices. See
1572 common/cmd_i2c.c for a description of the command line
1573 interface.
1574
1575 ported i2c driver to the new framework:
Heiko Schocherea818db2013-01-29 08:53:15 +01001576 - drivers/i2c/soft_i2c.c:
1577 - activate first bus with CONFIG_SYS_I2C_SOFT define
1578 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
1579 for defining speed and slave address
1580 - activate second bus with I2C_SOFT_DECLARATIONS2 define
1581 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
1582 for defining speed and slave address
1583 - activate third bus with I2C_SOFT_DECLARATIONS3 define
1584 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
1585 for defining speed and slave address
1586 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
1587 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
1588 for defining speed and slave address
Heiko Schocher3f4978c2012-01-16 21:12:24 +00001589
Heiko Schocher00f792e2012-10-24 13:48:22 +02001590 - drivers/i2c/fsl_i2c.c:
1591 - activate i2c driver with CONFIG_SYS_I2C_FSL
1592 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
1593 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
1594 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
1595 bus.
Wolfgang Denk93e14592013-10-04 17:43:24 +02001596 - If your board supports a second fsl i2c bus, define
Heiko Schocher00f792e2012-10-24 13:48:22 +02001597 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
1598 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
1599 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
1600 second bus.
1601
Simon Glass1f2ba722012-10-30 07:28:53 +00001602 - drivers/i2c/tegra_i2c.c:
Nobuhiro Iwamatsu10cee512013-10-11 16:23:53 +09001603 - activate this driver with CONFIG_SYS_I2C_TEGRA
1604 - This driver adds 4 i2c buses with a fix speed from
1605 100000 and the slave addr 0!
Simon Glass1f2ba722012-10-30 07:28:53 +00001606
Dirk Eibach880540d2013-04-25 02:40:01 +00001607 - drivers/i2c/ppc4xx_i2c.c
1608 - activate this driver with CONFIG_SYS_I2C_PPC4XX
1609 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
1610 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
1611
tremfac96402013-09-21 18:13:35 +02001612 - drivers/i2c/i2c_mxc.c
1613 - activate this driver with CONFIG_SYS_I2C_MXC
Albert ARIBAUD \\(3ADEV\\)03544c62015-09-21 22:43:38 +02001614 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
1615 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
1616 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
1617 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
tremfac96402013-09-21 18:13:35 +02001618 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
1619 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
1620 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
1621 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
1622 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
1623 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
Albert ARIBAUD \\(3ADEV\\)03544c62015-09-21 22:43:38 +02001624 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
1625 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08001626 If those defines are not set, default value is 100000
tremfac96402013-09-21 18:13:35 +02001627 for speed, and 0 for slave.
1628
Nobuhiro Iwamatsu1086bfa2013-09-27 16:58:30 +09001629 - drivers/i2c/rcar_i2c.c:
1630 - activate this driver with CONFIG_SYS_I2C_RCAR
1631 - This driver adds 4 i2c buses
1632
Nobuhiro Iwamatsu2035d772013-10-29 13:33:51 +09001633 - drivers/i2c/sh_i2c.c:
1634 - activate this driver with CONFIG_SYS_I2C_SH
1635 - This driver adds from 2 to 5 i2c buses
1636
1637 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
1638 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
1639 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
1640 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
1641 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
1642 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
1643 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
1644 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
1645 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
1646 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08001647 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
Nobuhiro Iwamatsu2035d772013-10-29 13:33:51 +09001648
Heiko Schocher6789e842013-10-22 11:03:18 +02001649 - drivers/i2c/omap24xx_i2c.c
1650 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
1651 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
1652 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
1653 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
1654 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
1655 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
1656 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
1657 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
1658 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
1659 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
1660 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
1661
Naveen Krishna Che717fc62013-12-06 12:12:38 +05301662 - drivers/i2c/s3c24x0_i2c.c:
1663 - activate this driver with CONFIG_SYS_I2C_S3C24X0
1664 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
1665 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
1666 with a fix speed from 100000 and the slave addr 0!
1667
Dirk Eibachb46226b2014-07-03 09:28:18 +02001668 - drivers/i2c/ihs_i2c.c
1669 - activate this driver with CONFIG_SYS_I2C_IHS
1670 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
1671 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
1672 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
1673 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
1674 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
1675 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
1676 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
1677 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
1678 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
1679 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
1680 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
1681 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
Dirk Eibach071be892015-10-28 11:46:22 +01001682 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
1683 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
1684 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
1685 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
1686 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
1687 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
1688 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
1689 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
1690 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
Dirk Eibachb46226b2014-07-03 09:28:18 +02001691
Heiko Schocher3f4978c2012-01-16 21:12:24 +00001692 additional defines:
1693
1694 CONFIG_SYS_NUM_I2C_BUSES
Simon Glass945a18e2016-10-02 18:01:05 -06001695 Hold the number of i2c buses you want to use.
Heiko Schocher3f4978c2012-01-16 21:12:24 +00001696
1697 CONFIG_SYS_I2C_DIRECT_BUS
1698 define this, if you don't use i2c muxes on your hardware.
1699 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
1700 omit this define.
1701
1702 CONFIG_SYS_I2C_MAX_HOPS
1703 define how many muxes are maximal consecutively connected
1704 on one i2c bus. If you not use i2c muxes, omit this
1705 define.
1706
1707 CONFIG_SYS_I2C_BUSES
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08001708 hold a list of buses you want to use, only used if
Heiko Schocher3f4978c2012-01-16 21:12:24 +00001709 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
1710 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
1711 CONFIG_SYS_NUM_I2C_BUSES = 9:
1712
1713 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
1714 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
1715 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
1716 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
1717 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
1718 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
1719 {1, {I2C_NULL_HOP}}, \
1720 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
1721 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
1722 }
1723
1724 which defines
1725 bus 0 on adapter 0 without a mux
Heiko Schocherea818db2013-01-29 08:53:15 +01001726 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
1727 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
1728 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
1729 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
1730 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
Heiko Schocher3f4978c2012-01-16 21:12:24 +00001731 bus 6 on adapter 1 without a mux
Heiko Schocherea818db2013-01-29 08:53:15 +01001732 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
1733 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
Heiko Schocher3f4978c2012-01-16 21:12:24 +00001734
1735 If you do not have i2c muxes on your board, omit this define.
1736
Simon Glassce3b5d62017-05-12 21:10:00 -06001737- Legacy I2C Support:
Heiko Schocherea818db2013-01-29 08:53:15 +01001738 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
wdenkb37c7e52003-06-30 16:24:52 +00001739 then the following macros need to be defined (examples are
1740 from include/configs/lwmon.h):
wdenkc6097192002-11-03 00:24:07 +00001741
1742 I2C_INIT
1743
wdenkb37c7e52003-06-30 16:24:52 +00001744 (Optional). Any commands necessary to enable the I2C
wdenk43d96162003-03-06 00:02:04 +00001745 controller or configure ports.
wdenkc6097192002-11-03 00:24:07 +00001746
wdenkba56f622004-02-06 23:19:44 +00001747 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
wdenkb37c7e52003-06-30 16:24:52 +00001748
wdenkc6097192002-11-03 00:24:07 +00001749 I2C_ACTIVE
1750
1751 The code necessary to make the I2C data line active
1752 (driven). If the data line is open collector, this
1753 define can be null.
1754
wdenkb37c7e52003-06-30 16:24:52 +00001755 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1756
wdenkc6097192002-11-03 00:24:07 +00001757 I2C_TRISTATE
1758
1759 The code necessary to make the I2C data line tri-stated
1760 (inactive). If the data line is open collector, this
1761 define can be null.
1762
wdenkb37c7e52003-06-30 16:24:52 +00001763 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1764
wdenkc6097192002-11-03 00:24:07 +00001765 I2C_READ
1766
York Sun472d5462013-04-01 11:29:11 -07001767 Code that returns true if the I2C data line is high,
1768 false if it is low.
wdenkc6097192002-11-03 00:24:07 +00001769
wdenkb37c7e52003-06-30 16:24:52 +00001770 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1771
wdenkc6097192002-11-03 00:24:07 +00001772 I2C_SDA(bit)
1773
York Sun472d5462013-04-01 11:29:11 -07001774 If <bit> is true, sets the I2C data line high. If it
1775 is false, it clears it (low).
wdenkc6097192002-11-03 00:24:07 +00001776
wdenkb37c7e52003-06-30 16:24:52 +00001777 eg: #define I2C_SDA(bit) \
wdenk2535d602003-07-17 23:16:40 +00001778 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
wdenkba56f622004-02-06 23:19:44 +00001779 else immr->im_cpm.cp_pbdat &= ~PB_SDA
wdenkb37c7e52003-06-30 16:24:52 +00001780
wdenkc6097192002-11-03 00:24:07 +00001781 I2C_SCL(bit)
1782
York Sun472d5462013-04-01 11:29:11 -07001783 If <bit> is true, sets the I2C clock line high. If it
1784 is false, it clears it (low).
wdenkc6097192002-11-03 00:24:07 +00001785
wdenkb37c7e52003-06-30 16:24:52 +00001786 eg: #define I2C_SCL(bit) \
wdenk2535d602003-07-17 23:16:40 +00001787 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
wdenkba56f622004-02-06 23:19:44 +00001788 else immr->im_cpm.cp_pbdat &= ~PB_SCL
wdenkb37c7e52003-06-30 16:24:52 +00001789
wdenkc6097192002-11-03 00:24:07 +00001790 I2C_DELAY
1791
1792 This delay is invoked four times per clock cycle so this
1793 controls the rate of data transfer. The data rate thus
wdenkb37c7e52003-06-30 16:24:52 +00001794 is 1 / (I2C_DELAY * 4). Often defined to be something
wdenk945af8d2003-07-16 21:53:01 +00001795 like:
1796
wdenkb37c7e52003-06-30 16:24:52 +00001797 #define I2C_DELAY udelay(2)
wdenkc6097192002-11-03 00:24:07 +00001798
Mike Frysinger793b5722010-07-21 13:38:02 -04001799 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1800
1801 If your arch supports the generic GPIO framework (asm/gpio.h),
1802 then you may alternatively define the two GPIOs that are to be
1803 used as SCL / SDA. Any of the previous I2C_xxx macros will
1804 have GPIO-based defaults assigned to them as appropriate.
1805
1806 You should define these to the GPIO value as given directly to
1807 the generic GPIO functions.
1808
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001809 CONFIG_SYS_I2C_INIT_BOARD
wdenk47cd00f2003-03-06 13:39:27 +00001810
wdenk8bde7f72003-06-27 21:31:46 +00001811 When a board is reset during an i2c bus transfer
1812 chips might think that the current transfer is still
1813 in progress. On some boards it is possible to access
1814 the i2c SCLK line directly, either by using the
1815 processor pin as a GPIO or by having a second pin
1816 connected to the bus. If this option is defined a
1817 custom i2c_init_board() routine in boards/xxx/board.c
1818 is run early in the boot sequence.
wdenk47cd00f2003-03-06 13:39:27 +00001819
Ben Warrenbb99ad62006-09-07 16:50:54 -04001820 CONFIG_I2C_MULTI_BUS
1821
1822 This option allows the use of multiple I2C buses, each of which
Wolfgang Denkc0f40852011-10-26 10:21:21 +00001823 must have a controller. At any point in time, only one bus is
1824 active. To switch to a different bus, use the 'i2c dev' command.
Ben Warrenbb99ad62006-09-07 16:50:54 -04001825 Note that bus numbering is zero-based.
1826
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001827 CONFIG_SYS_I2C_NOPROBES
Ben Warrenbb99ad62006-09-07 16:50:54 -04001828
1829 This option specifies a list of I2C devices that will be skipped
Wolfgang Denkc0f40852011-10-26 10:21:21 +00001830 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
Peter Tyser0f89c542009-04-18 22:34:03 -05001831 is set, specify a list of bus-device pairs. Otherwise, specify
1832 a 1D array of device addresses
Ben Warrenbb99ad62006-09-07 16:50:54 -04001833
1834 e.g.
1835 #undef CONFIG_I2C_MULTI_BUS
Wolfgang Denkc0f40852011-10-26 10:21:21 +00001836 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
Ben Warrenbb99ad62006-09-07 16:50:54 -04001837
1838 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1839
Wolfgang Denkc0f40852011-10-26 10:21:21 +00001840 #define CONFIG_I2C_MULTI_BUS
Simon Glass945a18e2016-10-02 18:01:05 -06001841 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
Ben Warrenbb99ad62006-09-07 16:50:54 -04001842
1843 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1844
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001845 CONFIG_SYS_SPD_BUS_NUM
Timur Tabibe5e6182006-11-03 19:15:00 -06001846
1847 If defined, then this indicates the I2C bus number for DDR SPD.
1848 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1849
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001850 CONFIG_SYS_RTC_BUS_NUM
Stefan Roese0dc018e2007-02-20 10:51:26 +01001851
1852 If defined, then this indicates the I2C bus number for the RTC.
1853 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1854
Andrew Dyer2ac69852008-12-29 17:36:01 -06001855 CONFIG_SOFT_I2C_READ_REPEATED_START
1856
1857 defining this will force the i2c_read() function in
1858 the soft_i2c driver to perform an I2C repeated start
1859 between writing the address pointer and reading the
1860 data. If this define is omitted the default behaviour
1861 of doing a stop-start sequence will be used. Most I2C
1862 devices can use either method, but some require one or
1863 the other.
Timur Tabibe5e6182006-11-03 19:15:00 -06001864
wdenkc6097192002-11-03 00:24:07 +00001865- SPI Support: CONFIG_SPI
1866
1867 Enables SPI driver (so far only tested with
1868 SPI EEPROM, also an instance works with Crystal A/D and
1869 D/As on the SACSng board)
1870
wdenkc6097192002-11-03 00:24:07 +00001871 CONFIG_SOFT_SPI
1872
wdenk43d96162003-03-06 00:02:04 +00001873 Enables a software (bit-bang) SPI driver rather than
1874 using hardware support. This is a general purpose
1875 driver that only requires three general I/O port pins
1876 (two outputs, one input) to function. If this is
1877 defined, the board configuration must define several
1878 SPI configuration items (port pins to use, etc). For
1879 an example, see include/configs/sacsng.h.
wdenkc6097192002-11-03 00:24:07 +00001880
Heiko Schocherf659b572014-07-14 10:22:11 +02001881 CONFIG_SYS_SPI_MXC_WAIT
1882 Timeout for waiting until spi transfer completed.
1883 default: (CONFIG_SYS_HZ/100) /* 10 ms */
1884
Matthias Fuchs01335022007-12-27 17:12:34 +01001885- FPGA Support: CONFIG_FPGA
1886
1887 Enables FPGA subsystem.
1888
1889 CONFIG_FPGA_<vendor>
1890
1891 Enables support for specific chip vendors.
1892 (ALTERA, XILINX)
1893
1894 CONFIG_FPGA_<family>
1895
1896 Enables support for FPGA family.
1897 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1898
1899 CONFIG_FPGA_COUNT
wdenkc6097192002-11-03 00:24:07 +00001900
wdenk43d96162003-03-06 00:02:04 +00001901 Specify the number of FPGA devices to support.
wdenkc6097192002-11-03 00:24:07 +00001902
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001903 CONFIG_SYS_FPGA_PROG_FEEDBACK
wdenkc6097192002-11-03 00:24:07 +00001904
wdenk8bde7f72003-06-27 21:31:46 +00001905 Enable printing of hash marks during FPGA configuration.
wdenkc6097192002-11-03 00:24:07 +00001906
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001907 CONFIG_SYS_FPGA_CHECK_BUSY
wdenkc6097192002-11-03 00:24:07 +00001908
wdenk43d96162003-03-06 00:02:04 +00001909 Enable checks on FPGA configuration interface busy
1910 status by the configuration function. This option
1911 will require a board or device specific function to
1912 be written.
wdenkc6097192002-11-03 00:24:07 +00001913
1914 CONFIG_FPGA_DELAY
1915
1916 If defined, a function that provides delays in the FPGA
1917 configuration driver.
1918
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001919 CONFIG_SYS_FPGA_CHECK_CTRLC
wdenkc6097192002-11-03 00:24:07 +00001920 Allow Control-C to interrupt FPGA configuration
1921
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001922 CONFIG_SYS_FPGA_CHECK_ERROR
wdenkc6097192002-11-03 00:24:07 +00001923
wdenk43d96162003-03-06 00:02:04 +00001924 Check for configuration errors during FPGA bitfile
1925 loading. For example, abort during Virtex II
1926 configuration if the INIT_B line goes low (which
1927 indicated a CRC error).
wdenkc6097192002-11-03 00:24:07 +00001928
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001929 CONFIG_SYS_FPGA_WAIT_INIT
wdenkc6097192002-11-03 00:24:07 +00001930
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08001931 Maximum time to wait for the INIT_B line to de-assert
1932 after PROB_B has been de-asserted during a Virtex II
wdenk43d96162003-03-06 00:02:04 +00001933 FPGA configuration sequence. The default time is 500
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02001934 ms.
wdenkc6097192002-11-03 00:24:07 +00001935
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001936 CONFIG_SYS_FPGA_WAIT_BUSY
wdenkc6097192002-11-03 00:24:07 +00001937
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08001938 Maximum time to wait for BUSY to de-assert during
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02001939 Virtex II FPGA configuration. The default is 5 ms.
wdenkc6097192002-11-03 00:24:07 +00001940
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02001941 CONFIG_SYS_FPGA_WAIT_CONFIG
wdenkc6097192002-11-03 00:24:07 +00001942
wdenk43d96162003-03-06 00:02:04 +00001943 Time to wait after FPGA configuration. The default is
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02001944 200 ms.
wdenkc6097192002-11-03 00:24:07 +00001945
1946- Configuration Management:
Stefan Roeseb2b8a692014-10-22 12:13:24 +02001947
wdenkc6097192002-11-03 00:24:07 +00001948 CONFIG_IDENT_STRING
1949
wdenk43d96162003-03-06 00:02:04 +00001950 If defined, this string will be added to the U-Boot
1951 version information (U_BOOT_VERSION)
wdenkc6097192002-11-03 00:24:07 +00001952
1953- Vendor Parameter Protection:
1954
wdenk43d96162003-03-06 00:02:04 +00001955 U-Boot considers the values of the environment
1956 variables "serial#" (Board Serial Number) and
wdenk7152b1d2003-09-05 23:19:14 +00001957 "ethaddr" (Ethernet Address) to be parameters that
wdenk43d96162003-03-06 00:02:04 +00001958 are set once by the board vendor / manufacturer, and
1959 protects these variables from casual modification by
1960 the user. Once set, these variables are read-only,
1961 and write or delete attempts are rejected. You can
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02001962 change this behaviour:
wdenkc6097192002-11-03 00:24:07 +00001963
1964 If CONFIG_ENV_OVERWRITE is #defined in your config
1965 file, the write protection for vendor parameters is
wdenk47cd00f2003-03-06 13:39:27 +00001966 completely disabled. Anybody can change or delete
wdenkc6097192002-11-03 00:24:07 +00001967 these parameters.
1968
Joe Hershberger92ac5202015-05-04 14:55:14 -05001969 Alternatively, if you define _both_ an ethaddr in the
1970 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02001971 Ethernet address is installed in the environment,
wdenkc6097192002-11-03 00:24:07 +00001972 which can be changed exactly ONCE by the user. [The
1973 serial# is unaffected by this, i. e. it remains
1974 read-only.]
1975
Joe Hershberger25980902012-12-11 22:16:31 -06001976 The same can be accomplished in a more flexible way
1977 for any variable by configuring the type of access
1978 to allow for those variables in the ".flags" variable
1979 or define CONFIG_ENV_FLAGS_LIST_STATIC.
1980
wdenkc6097192002-11-03 00:24:07 +00001981- Protected RAM:
1982 CONFIG_PRAM
1983
1984 Define this variable to enable the reservation of
1985 "protected RAM", i. e. RAM which is not overwritten
1986 by U-Boot. Define CONFIG_PRAM to hold the number of
1987 kB you want to reserve for pRAM. You can overwrite
1988 this default value by defining an environment
1989 variable "pram" to the number of kB you want to
1990 reserve. Note that the board info structure will
1991 still show the full amount of RAM. If pRAM is
1992 reserved, a new environment variable "mem" will
1993 automatically be defined to hold the amount of
1994 remaining RAM in a form that can be passed as boot
1995 argument to Linux, for instance like that:
1996
Wolfgang Denkfe126d82005-11-20 21:40:11 +01001997 setenv bootargs ... mem=\${mem}
wdenkc6097192002-11-03 00:24:07 +00001998 saveenv
1999
2000 This way you can tell Linux not to use this memory,
2001 either, which results in a memory region that will
2002 not be affected by reboots.
2003
2004 *WARNING* If your board configuration uses automatic
2005 detection of the RAM size, you must make sure that
2006 this memory test is non-destructive. So far, the
2007 following board configurations are known to be
2008 "pRAM-clean":
2009
Heiko Schocher5b8e76c2017-06-07 17:33:09 +02002010 IVMS8, IVML24, SPD8xx,
Wolfgang Denk1b0757e2012-10-24 02:36:15 +00002011 HERMES, IP860, RPXlite, LWMON,
Heiko Schocher2eb48ff2017-06-07 17:33:10 +02002012 FLAGADM
wdenkc6097192002-11-03 00:24:07 +00002013
Gabe Black40fef042012-12-02 04:55:18 +00002014- Access to physical memory region (> 4GB)
2015 Some basic support is provided for operations on memory not
2016 normally accessible to U-Boot - e.g. some architectures
2017 support access to more than 4GB of memory on 32-bit
2018 machines using physical address extension or similar.
2019 Define CONFIG_PHYSMEM to access this basic support, which
2020 currently only supports clearing the memory.
2021
wdenkc6097192002-11-03 00:24:07 +00002022- Error Recovery:
wdenkc6097192002-11-03 00:24:07 +00002023 CONFIG_NET_RETRY_COUNT
2024
wdenk43d96162003-03-06 00:02:04 +00002025 This variable defines the number of retries for
2026 network operations like ARP, RARP, TFTP, or BOOTP
2027 before giving up the operation. If not defined, a
2028 default value of 5 is used.
wdenkc6097192002-11-03 00:24:07 +00002029
Guennadi Liakhovetski40cb90e2008-04-03 17:04:19 +02002030 CONFIG_ARP_TIMEOUT
2031
2032 Timeout waiting for an ARP reply in milliseconds.
2033
Tetsuyuki Kobayashi48a3e992012-07-03 22:25:21 +00002034 CONFIG_NFS_TIMEOUT
2035
2036 Timeout in milliseconds used in NFS protocol.
2037 If you encounter "ERROR: Cannot umount" in nfs command,
2038 try longer timeout such as
2039 #define CONFIG_NFS_TIMEOUT 10000UL
2040
wdenkc6097192002-11-03 00:24:07 +00002041- Command Interpreter:
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002042 CONFIG_SYS_PROMPT_HUSH_PS2
wdenkc6097192002-11-03 00:24:07 +00002043
2044 This defines the secondary prompt string, which is
2045 printed when the command interpreter needs more input
2046 to complete a command. Usually "> ".
2047
2048 Note:
2049
wdenk8bde7f72003-06-27 21:31:46 +00002050 In the current implementation, the local variables
2051 space and global environment variables space are
2052 separated. Local variables are those you define by
2053 simply typing `name=value'. To access a local
2054 variable later on, you have write `$name' or
2055 `${name}'; to execute the contents of a variable
2056 directly type `$name' at the command prompt.
wdenkc6097192002-11-03 00:24:07 +00002057
wdenk43d96162003-03-06 00:02:04 +00002058 Global environment variables are those you use
2059 setenv/printenv to work with. To run a command stored
2060 in such a variable, you need to use the run command,
2061 and you must not use the '$' sign to access them.
wdenkc6097192002-11-03 00:24:07 +00002062
2063 To store commands and special characters in a
2064 variable, please use double quotation marks
2065 surrounding the whole text of the variable, instead
2066 of the backslashes before semicolons and special
2067 symbols.
2068
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08002069- Command Line Editing and History:
Marek Vasutf3b267b2016-01-27 04:47:55 +01002070 CONFIG_CMDLINE_PS_SUPPORT
2071
2072 Enable support for changing the command prompt string
2073 at run-time. Only static string is supported so far.
2074 The string is obtained from environment variables PS1
2075 and PS2.
2076
wdenka8c7c702003-12-06 19:49:23 +00002077- Default Environment:
wdenkc6097192002-11-03 00:24:07 +00002078 CONFIG_EXTRA_ENV_SETTINGS
2079
wdenk43d96162003-03-06 00:02:04 +00002080 Define this to contain any number of null terminated
2081 strings (variable = value pairs) that will be part of
wdenk7152b1d2003-09-05 23:19:14 +00002082 the default environment compiled into the boot image.
wdenk2262cfe2002-11-18 00:14:45 +00002083
wdenk43d96162003-03-06 00:02:04 +00002084 For example, place something like this in your
2085 board's config file:
wdenkc6097192002-11-03 00:24:07 +00002086
2087 #define CONFIG_EXTRA_ENV_SETTINGS \
2088 "myvar1=value1\0" \
2089 "myvar2=value2\0"
2090
wdenk43d96162003-03-06 00:02:04 +00002091 Warning: This method is based on knowledge about the
2092 internal format how the environment is stored by the
2093 U-Boot code. This is NOT an official, exported
2094 interface! Although it is unlikely that this format
wdenk7152b1d2003-09-05 23:19:14 +00002095 will change soon, there is no guarantee either.
wdenkc6097192002-11-03 00:24:07 +00002096 You better know what you are doing here.
2097
wdenk43d96162003-03-06 00:02:04 +00002098 Note: overly (ab)use of the default environment is
2099 discouraged. Make sure to check other ways to preset
Wolfgang Denk74de7ae2009-04-01 23:34:12 +02002100 the environment like the "source" command or the
wdenk43d96162003-03-06 00:02:04 +00002101 boot command first.
wdenkc6097192002-11-03 00:24:07 +00002102
Simon Glass06fd8532012-11-30 13:01:17 +00002103 CONFIG_DELAY_ENVIRONMENT
2104
2105 Normally the environment is loaded when the board is
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08002106 initialised so that it is available to U-Boot. This inhibits
Simon Glass06fd8532012-11-30 13:01:17 +00002107 that so that the environment is not available until
2108 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2109 this is instead controlled by the value of
2110 /config/load-environment.
2111
Wolfgang Denkecb0ccd2005-09-24 22:37:32 +02002112- TFTP Fixed UDP Port:
2113 CONFIG_TFTP_PORT
2114
Wolfgang Denk28cb9372005-09-24 23:25:46 +02002115 If this is defined, the environment variable tftpsrcp
Wolfgang Denkecb0ccd2005-09-24 22:37:32 +02002116 is used to supply the TFTP UDP source port value.
Wolfgang Denk28cb9372005-09-24 23:25:46 +02002117 If tftpsrcp isn't defined, the normal pseudo-random port
Wolfgang Denkecb0ccd2005-09-24 22:37:32 +02002118 number generator is used.
2119
Wolfgang Denk28cb9372005-09-24 23:25:46 +02002120 Also, the environment variable tftpdstp is used to supply
2121 the TFTP UDP destination port value. If tftpdstp isn't
2122 defined, the normal port 69 is used.
2123
2124 The purpose for tftpsrcp is to allow a TFTP server to
Wolfgang Denkecb0ccd2005-09-24 22:37:32 +02002125 blindly start the TFTP transfer using the pre-configured
2126 target IP address and UDP port. This has the effect of
2127 "punching through" the (Windows XP) firewall, allowing
2128 the remainder of the TFTP transfer to proceed normally.
2129 A better solution is to properly configure the firewall,
2130 but sometimes that is not allowed.
2131
Wolfgang Denk4cf26092011-10-07 09:58:21 +02002132 CONFIG_STANDALONE_LOAD_ADDR
2133
Wolfgang Denk6feff892011-10-09 21:06:34 +02002134 This option defines a board specific value for the
2135 address where standalone program gets loaded, thus
2136 overwriting the architecture dependent default
Wolfgang Denk4cf26092011-10-07 09:58:21 +02002137 settings.
2138
2139- Frame Buffer Address:
2140 CONFIG_FB_ADDR
2141
2142 Define CONFIG_FB_ADDR if you want to use specific
Wolfgang Denk44a53b52013-01-03 00:43:59 +00002143 address for frame buffer. This is typically the case
2144 when using a graphics controller has separate video
2145 memory. U-Boot will then place the frame buffer at
2146 the given address instead of dynamically reserving it
2147 in system RAM by calling lcd_setmem(), which grabs
2148 the memory for the frame buffer depending on the
2149 configured panel size.
Wolfgang Denk4cf26092011-10-07 09:58:21 +02002150
2151 Please see board_init_f function.
2152
Detlev Zundelcccfc2a2009-12-01 17:16:19 +01002153- Automatic software updates via TFTP server
2154 CONFIG_UPDATE_TFTP
2155 CONFIG_UPDATE_TFTP_CNT_MAX
2156 CONFIG_UPDATE_TFTP_MSEC_MAX
2157
2158 These options enable and control the auto-update feature;
2159 for a more detailed description refer to doc/README.update.
2160
2161- MTD Support (mtdparts command, UBI support)
Heiko Schocherff94bc42014-06-24 10:10:04 +02002162 CONFIG_MTD_UBI_WL_THRESHOLD
2163 This parameter defines the maximum difference between the highest
2164 erase counter value and the lowest erase counter value of eraseblocks
2165 of UBI devices. When this threshold is exceeded, UBI starts performing
2166 wear leveling by means of moving data from eraseblock with low erase
2167 counter to eraseblocks with high erase counter.
2168
2169 The default value should be OK for SLC NAND flashes, NOR flashes and
2170 other flashes which have eraseblock life-cycle 100000 or more.
2171 However, in case of MLC NAND flashes which typically have eraseblock
2172 life-cycle less than 10000, the threshold should be lessened (e.g.,
2173 to 128 or 256, although it does not have to be power of 2).
2174
2175 default: 4096
Simon Glassc654b512014-10-23 18:58:54 -06002176
Heiko Schocherff94bc42014-06-24 10:10:04 +02002177 CONFIG_MTD_UBI_BEB_LIMIT
2178 This option specifies the maximum bad physical eraseblocks UBI
2179 expects on the MTD device (per 1024 eraseblocks). If the
2180 underlying flash does not admit of bad eraseblocks (e.g. NOR
2181 flash), this value is ignored.
2182
2183 NAND datasheets often specify the minimum and maximum NVM
2184 (Number of Valid Blocks) for the flashes' endurance lifetime.
2185 The maximum expected bad eraseblocks per 1024 eraseblocks
2186 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2187 which gives 20 for most NANDs (MaxNVB is basically the total
2188 count of eraseblocks on the chip).
2189
2190 To put it differently, if this value is 20, UBI will try to
2191 reserve about 1.9% of physical eraseblocks for bad blocks
2192 handling. And that will be 1.9% of eraseblocks on the entire
2193 NAND chip, not just the MTD partition UBI attaches. This means
2194 that if you have, say, a NAND flash chip admits maximum 40 bad
2195 eraseblocks, and it is split on two MTD partitions of the same
2196 size, UBI will reserve 40 eraseblocks when attaching a
2197 partition.
2198
2199 default: 20
2200
2201 CONFIG_MTD_UBI_FASTMAP
2202 Fastmap is a mechanism which allows attaching an UBI device
2203 in nearly constant time. Instead of scanning the whole MTD device it
2204 only has to locate a checkpoint (called fastmap) on the device.
2205 The on-flash fastmap contains all information needed to attach
2206 the device. Using fastmap makes only sense on large devices where
2207 attaching by scanning takes long. UBI will not automatically install
2208 a fastmap on old images, but you can set the UBI parameter
2209 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
2210 that fastmap-enabled images are still usable with UBI implementations
2211 without fastmap support. On typical flash devices the whole fastmap
2212 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
2213
2214 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
2215 Set this parameter to enable fastmap automatically on images
2216 without a fastmap.
2217 default: 0
2218
Heiko Schocher0195a7b2015-10-22 06:19:21 +02002219 CONFIG_MTD_UBI_FM_DEBUG
2220 Enable UBI fastmap debug
2221 default: 0
2222
Daniel Schwierzeck6a11cf42011-07-18 07:48:07 +00002223- SPL framework
Wolfgang Denk04e5ae72011-09-11 21:24:09 +02002224 CONFIG_SPL
2225 Enable building of SPL globally.
Daniel Schwierzeck6a11cf42011-07-18 07:48:07 +00002226
Tom Rini95579792012-02-14 07:29:40 +00002227 CONFIG_SPL_LDSCRIPT
2228 LDSCRIPT for linking the SPL binary.
2229
Albert ARIBAUD6ebc3462013-04-12 05:14:30 +00002230 CONFIG_SPL_MAX_FOOTPRINT
2231 Maximum size in memory allocated to the SPL, BSS included.
2232 When defined, the linker checks that the actual memory
2233 used by SPL from _start to __bss_end does not exceed it.
Albert ARIBAUD8960af82013-04-14 04:48:38 +00002234 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
Albert ARIBAUD6ebc3462013-04-12 05:14:30 +00002235 must not be both defined at the same time.
2236
Tom Rini95579792012-02-14 07:29:40 +00002237 CONFIG_SPL_MAX_SIZE
Albert ARIBAUD6ebc3462013-04-12 05:14:30 +00002238 Maximum size of the SPL image (text, data, rodata, and
2239 linker lists sections), BSS excluded.
2240 When defined, the linker checks that the actual size does
2241 not exceed it.
Tom Rini95579792012-02-14 07:29:40 +00002242
Scott Wood94a45bb2012-09-20 19:05:12 -05002243 CONFIG_SPL_RELOC_TEXT_BASE
2244 Address to relocate to. If unspecified, this is equal to
2245 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2246
Tom Rini95579792012-02-14 07:29:40 +00002247 CONFIG_SPL_BSS_START_ADDR
2248 Link address for the BSS within the SPL binary.
2249
2250 CONFIG_SPL_BSS_MAX_SIZE
Albert ARIBAUD6ebc3462013-04-12 05:14:30 +00002251 Maximum size in memory allocated to the SPL BSS.
2252 When defined, the linker checks that the actual memory used
2253 by SPL from __bss_start to __bss_end does not exceed it.
Albert ARIBAUD8960af82013-04-14 04:48:38 +00002254 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
Albert ARIBAUD6ebc3462013-04-12 05:14:30 +00002255 must not be both defined at the same time.
Tom Rini95579792012-02-14 07:29:40 +00002256
2257 CONFIG_SPL_STACK
2258 Adress of the start of the stack SPL will use
2259
Albert ARIBAUD \(3ADEV\)8c80eb32015-03-31 11:40:50 +02002260 CONFIG_SPL_PANIC_ON_RAW_IMAGE
2261 When defined, SPL will panic() if the image it has
2262 loaded does not have a signature.
2263 Defining this is useful when code which loads images
2264 in SPL cannot guarantee that absolutely all read errors
2265 will be caught.
2266 An example is the LPC32XX MLC NAND driver, which will
2267 consider that a completely unreadable NAND block is bad,
2268 and thus should be skipped silently.
2269
Scott Wood94a45bb2012-09-20 19:05:12 -05002270 CONFIG_SPL_RELOC_STACK
2271 Adress of the start of the stack SPL will use after
2272 relocation. If unspecified, this is equal to
2273 CONFIG_SPL_STACK.
2274
Tom Rini95579792012-02-14 07:29:40 +00002275 CONFIG_SYS_SPL_MALLOC_START
2276 Starting address of the malloc pool used in SPL.
Fabio Estevam9ac4fc82015-11-12 12:30:19 -02002277 When this option is set the full malloc is used in SPL and
2278 it is set up by spl_init() and before that, the simple malloc()
2279 can be used if CONFIG_SYS_MALLOC_F is defined.
Tom Rini95579792012-02-14 07:29:40 +00002280
2281 CONFIG_SYS_SPL_MALLOC_SIZE
2282 The size of the malloc pool used in SPL.
Daniel Schwierzeck6a11cf42011-07-18 07:48:07 +00002283
Tom Rini9607faf2014-03-28 12:03:39 -04002284 CONFIG_SPL_OS_BOOT
2285 Enable booting directly to an OS from SPL.
2286 See also: doc/README.falcon
2287
Tom Rini861a86f2012-08-13 11:37:56 -07002288 CONFIG_SPL_DISPLAY_PRINT
2289 For ARM, enable an optional function to print more information
2290 about the running system.
2291
Scott Wood4b919722012-09-20 16:35:21 -05002292 CONFIG_SPL_INIT_MINIMAL
2293 Arch init code should be built for a very small image
2294
Paul Kocialkowskib97300b2014-11-08 23:14:56 +01002295 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
2296 Partition on the MMC to load U-Boot from when the MMC is being
2297 used in raw mode
2298
Peter Korsgaard2b75b0a2013-05-13 08:36:29 +00002299 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
2300 Sector to load kernel uImage from when MMC is being
2301 used in raw mode (for Falcon mode)
2302
2303 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
2304 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
2305 Sector and number of sectors to load kernel argument
2306 parameters from when MMC is being used in raw mode
2307 (for falcon mode)
2308
Paul Kocialkowskie2ccdf82014-11-08 23:14:55 +01002309 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
2310 Partition on the MMC to load U-Boot from when the MMC is being
2311 used in fs mode
2312
Guillaume GARDETfae81c72014-10-15 17:53:13 +02002313 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
2314 Filename to read to load U-Boot when reading from filesystem
2315
2316 CONFIG_SPL_FS_LOAD_KERNEL_NAME
Peter Korsgaard7ad2cc72013-05-13 08:36:27 +00002317 Filename to read to load kernel uImage when reading
Guillaume GARDETfae81c72014-10-15 17:53:13 +02002318 from filesystem (for Falcon mode)
Peter Korsgaard7ad2cc72013-05-13 08:36:27 +00002319
Guillaume GARDETfae81c72014-10-15 17:53:13 +02002320 CONFIG_SPL_FS_LOAD_ARGS_NAME
Peter Korsgaard7ad2cc72013-05-13 08:36:27 +00002321 Filename to read to load kernel argument parameters
Guillaume GARDETfae81c72014-10-15 17:53:13 +02002322 when reading from filesystem (for Falcon mode)
Peter Korsgaard7ad2cc72013-05-13 08:36:27 +00002323
Scott Wood06f60ae2012-12-06 13:33:17 +00002324 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2325 Set this for NAND SPL on PPC mpc83xx targets, so that
2326 start.S waits for the rest of the SPL to load before
2327 continuing (the hardware starts execution after just
2328 loading the first page rather than the full 4K).
2329
Prabhakar Kushwaha651fcf62014-04-08 19:12:31 +05302330 CONFIG_SPL_SKIP_RELOCATE
2331 Avoid SPL relocation
2332
Scott Wood6f2f01b2012-09-20 19:09:07 -05002333 CONFIG_SPL_NAND_BASE
2334 Include nand_base.c in the SPL. Requires
2335 CONFIG_SPL_NAND_DRIVERS.
2336
2337 CONFIG_SPL_NAND_DRIVERS
2338 SPL uses normal NAND drivers, not minimal drivers.
2339
Jörg Krause15e207f2018-01-14 19:26:38 +01002340 CONFIG_SPL_NAND_IDENT
2341 SPL uses the chip ID list to identify the NAND flash.
2342 Requires CONFIG_SPL_NAND_BASE.
2343
Scott Wood6f2f01b2012-09-20 19:09:07 -05002344 CONFIG_SPL_NAND_ECC
2345 Include standard software ECC in the SPL
2346
Tom Rini95579792012-02-14 07:29:40 +00002347 CONFIG_SPL_NAND_SIMPLE
Scott Wood7d4b7952012-09-21 18:35:27 -05002348 Support for NAND boot using simple NAND drivers that
2349 expose the cmd_ctrl() interface.
Tom Rini95579792012-02-14 07:29:40 +00002350
Thomas Gleixner6f4e7d32016-07-12 20:28:12 +02002351 CONFIG_SPL_UBI
2352 Support for a lightweight UBI (fastmap) scanner and
2353 loader
2354
Heiko Schocher0c3117b2014-10-31 08:31:00 +01002355 CONFIG_SPL_NAND_RAW_ONLY
2356 Support to boot only raw u-boot.bin images. Use this only
2357 if you need to save space.
2358
Ying Zhang7c8eea52013-08-16 15:16:12 +08002359 CONFIG_SPL_COMMON_INIT_DDR
2360 Set for common ddr init with serial presence detect in
2361 SPL binary.
2362
Tom Rini95579792012-02-14 07:29:40 +00002363 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2364 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2365 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2366 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2367 CONFIG_SYS_NAND_ECCBYTES
2368 Defines the size and behavior of the NAND that SPL uses
Scott Wood7d4b7952012-09-21 18:35:27 -05002369 to read U-Boot
Tom Rini95579792012-02-14 07:29:40 +00002370
2371 CONFIG_SYS_NAND_U_BOOT_OFFS
Scott Wood7d4b7952012-09-21 18:35:27 -05002372 Location in NAND to read U-Boot from
2373
2374 CONFIG_SYS_NAND_U_BOOT_DST
2375 Location in memory to load U-Boot to
2376
2377 CONFIG_SYS_NAND_U_BOOT_SIZE
2378 Size of image to load
Tom Rini95579792012-02-14 07:29:40 +00002379
2380 CONFIG_SYS_NAND_U_BOOT_START
Scott Wood7d4b7952012-09-21 18:35:27 -05002381 Entry point in loaded image to jump to
Tom Rini95579792012-02-14 07:29:40 +00002382
2383 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2384 Define this if you need to first read the OOB and then the
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08002385 data. This is used, for example, on davinci platforms.
Tom Rini95579792012-02-14 07:29:40 +00002386
Pavel Machekc57b9532012-08-30 22:42:11 +02002387 CONFIG_SPL_RAM_DEVICE
2388 Support for running image already present in ram, in SPL binary
2389
Scott Wood74752ba2012-12-06 13:33:16 +00002390 CONFIG_SPL_PAD_TO
Benoît Thébaudeau6113d3f2013-04-11 09:35:49 +00002391 Image offset to which the SPL should be padded before appending
2392 the SPL payload. By default, this is defined as
2393 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2394 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2395 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
Scott Wood74752ba2012-12-06 13:33:16 +00002396
Scott Woodca2fca22012-09-21 16:27:32 -05002397 CONFIG_SPL_TARGET
2398 Final target image containing SPL and payload. Some SPLs
2399 use an arch-specific makefile fragment instead, for
2400 example if more than one image needs to be produced.
2401
Marek Vasutb527b9c2018-05-13 00:22:52 +02002402 CONFIG_SPL_FIT_PRINT
Simon Glass87ebee32013-05-08 08:05:59 +00002403 Printing information about a FIT image adds quite a bit of
2404 code to SPL. So this is normally disabled in SPL. Use this
2405 option to re-enable it. This will affect the output of the
2406 bootm command when booting a FIT image.
2407
Ying Zhang3aa29de2013-08-16 15:16:15 +08002408- TPL framework
2409 CONFIG_TPL
2410 Enable building of TPL globally.
2411
2412 CONFIG_TPL_PAD_TO
2413 Image offset to which the TPL should be padded before appending
2414 the TPL payload. By default, this is defined as
Wolfgang Denk93e14592013-10-04 17:43:24 +02002415 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2416 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2417 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
Ying Zhang3aa29de2013-08-16 15:16:15 +08002418
wdenka8c7c702003-12-06 19:49:23 +00002419- Interrupt support (PPC):
2420
wdenkd4ca31c2004-01-02 14:00:00 +00002421 There are common interrupt_init() and timer_interrupt()
2422 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02002423 for CPU specific initialization. interrupt_init_cpu()
wdenkd4ca31c2004-01-02 14:00:00 +00002424 should set decrementer_count to appropriate value. If
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02002425 CPU resets decrementer automatically after interrupt
wdenkd4ca31c2004-01-02 14:00:00 +00002426 (ppc4xx) it should set decrementer_count to zero.
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02002427 timer_interrupt() calls timer_interrupt_cpu() for CPU
wdenkd4ca31c2004-01-02 14:00:00 +00002428 specific handling. If board has watchdog / status_led
2429 / other_activity_monitor it works automatically from
2430 general timer_interrupt().
wdenka8c7c702003-12-06 19:49:23 +00002431
wdenkc6097192002-11-03 00:24:07 +00002432
Helmut Raiger9660e442011-10-20 04:19:47 +00002433Board initialization settings:
2434------------------------------
2435
2436During Initialization u-boot calls a number of board specific functions
2437to allow the preparation of board specific prerequisites, e.g. pin setup
2438before drivers are initialized. To enable these callbacks the
2439following configuration macros have to be defined. Currently this is
2440architecture specific, so please check arch/your_architecture/lib/board.c
2441typically in board_init_f() and board_init_r().
2442
2443- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2444- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2445- CONFIG_BOARD_LATE_INIT: Call board_late_init()
2446- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
wdenkc6097192002-11-03 00:24:07 +00002447
wdenkc6097192002-11-03 00:24:07 +00002448Configuration Settings:
2449-----------------------
2450
Simon Glass4d979bf2019-12-28 10:45:10 -07002451- MEM_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
York Sun4d1fd7f2014-02-26 17:03:19 -08002452 Optionally it can be defined to support 64-bit memory commands.
2453
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002454- CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
wdenkc6097192002-11-03 00:24:07 +00002455 undefine this when you're short of memory.
2456
Peter Tyser2fb26042009-01-27 18:03:12 -06002457- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2458 width of the commands listed in the 'help' command output.
2459
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002460- CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
wdenkc6097192002-11-03 00:24:07 +00002461 prompt for user input.
2462
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002463- CONFIG_SYS_CBSIZE: Buffer size for input from the Console
wdenkc6097192002-11-03 00:24:07 +00002464
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002465- CONFIG_SYS_PBSIZE: Buffer size for Console output
wdenkc6097192002-11-03 00:24:07 +00002466
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002467- CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
wdenkc6097192002-11-03 00:24:07 +00002468
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002469- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
wdenkc6097192002-11-03 00:24:07 +00002470 the application (usually a Linux kernel) when it is
2471 booted
2472
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002473- CONFIG_SYS_BAUDRATE_TABLE:
wdenkc6097192002-11-03 00:24:07 +00002474 List of legal baudrate settings for this board.
2475
York Sune8149522015-12-04 11:57:07 -08002476- CONFIG_SYS_MEM_RESERVE_SECURE
York Sune61a7532016-06-24 16:46:18 -07002477 Only implemented for ARMv8 for now.
York Sune8149522015-12-04 11:57:07 -08002478 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
2479 is substracted from total RAM and won't be reported to OS.
2480 This memory can be used as secure memory. A variable
York Sune61a7532016-06-24 16:46:18 -07002481 gd->arch.secure_ram is used to track the location. In systems
York Sune8149522015-12-04 11:57:07 -08002482 the RAM base is not zero, or RAM is divided into banks,
2483 this variable needs to be recalcuated to get the address.
2484
York Sunaabd7dd2015-12-07 11:05:29 -08002485- CONFIG_SYS_MEM_TOP_HIDE:
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002486 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
Stefan Roese14f73ca2008-03-26 10:14:11 +01002487 this specified memory area will get subtracted from the top
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02002488 (end) of RAM and won't get "touched" at all by U-Boot. By
Stefan Roese14f73ca2008-03-26 10:14:11 +01002489 fixing up gd->ram_size the Linux kernel should gets passed
2490 the now "corrected" memory size and won't touch it either.
2491 This should work for arch/ppc and arch/powerpc. Only Linux
Stefan Roese5e12e752008-03-28 11:02:53 +01002492 board ports in arch/powerpc with bootwrapper support that
Stefan Roese14f73ca2008-03-26 10:14:11 +01002493 recalculate the memory size from the SDRAM controller setup
Stefan Roese5e12e752008-03-28 11:02:53 +01002494 will have to get fixed in Linux additionally.
Stefan Roese14f73ca2008-03-26 10:14:11 +01002495
2496 This option can be used as a workaround for the 440EPx/GRx
2497 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2498 be touched.
2499
2500 WARNING: Please make sure that this value is a multiple of
2501 the Linux page size (normally 4k). If this is not the case,
2502 then the end address of the Linux memory will be located at a
2503 non page size aligned address and this could cause major
2504 problems.
2505
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002506- CONFIG_SYS_LOADS_BAUD_CHANGE:
wdenkc6097192002-11-03 00:24:07 +00002507 Enable temporary baudrate change while serial download
2508
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002509- CONFIG_SYS_SDRAM_BASE:
wdenkc6097192002-11-03 00:24:07 +00002510 Physical start address of SDRAM. _Must_ be 0 here.
2511
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002512- CONFIG_SYS_FLASH_BASE:
wdenkc6097192002-11-03 00:24:07 +00002513 Physical start address of Flash memory.
2514
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002515- CONFIG_SYS_MONITOR_BASE:
wdenkc6097192002-11-03 00:24:07 +00002516 Physical start address of boot monitor code (set by
2517 make config files to be same as the text base address
Wolfgang Denk14d0a022010-10-07 21:51:12 +02002518 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002519 CONFIG_SYS_FLASH_BASE when booting from flash.
wdenkc6097192002-11-03 00:24:07 +00002520
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002521- CONFIG_SYS_MONITOR_LEN:
wdenk8bde7f72003-06-27 21:31:46 +00002522 Size of memory reserved for monitor code, used to
2523 determine _at_compile_time_ (!) if the environment is
2524 embedded within the U-Boot image, or in a separate
2525 flash sector.
wdenkc6097192002-11-03 00:24:07 +00002526
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002527- CONFIG_SYS_MALLOC_LEN:
wdenkc6097192002-11-03 00:24:07 +00002528 Size of DRAM reserved for malloc() use.
2529
Simon Glassd59476b2014-07-10 22:23:28 -06002530- CONFIG_SYS_MALLOC_F_LEN
2531 Size of the malloc() pool for use before relocation. If
2532 this is defined, then a very simple malloc() implementation
2533 will become available before relocation. The address is just
2534 below the global data, and the stack is moved down to make
2535 space.
2536
2537 This feature allocates regions with increasing addresses
2538 within the region. calloc() is supported, but realloc()
2539 is not available. free() is supported but does nothing.
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08002540 The memory will be freed (or in fact just forgotten) when
Simon Glassd59476b2014-07-10 22:23:28 -06002541 U-Boot relocates itself.
2542
Simon Glass38687ae2014-11-10 17:16:54 -07002543- CONFIG_SYS_MALLOC_SIMPLE
2544 Provides a simple and small malloc() and calloc() for those
2545 boards which do not use the full malloc in SPL (which is
2546 enabled with CONFIG_SYS_SPL_MALLOC_START).
2547
Thierry Reding1dfdd9b2014-12-09 22:25:22 -07002548- CONFIG_SYS_NONCACHED_MEMORY:
2549 Size of non-cached memory area. This area of memory will be
2550 typically located right below the malloc() area and mapped
2551 uncached in the MMU. This is useful for drivers that would
2552 otherwise require a lot of explicit cache maintenance. For
2553 some drivers it's also impossible to properly maintain the
2554 cache. For example if the regions that need to be flushed
2555 are not a multiple of the cache-line size, *and* padding
2556 cannot be allocated between the regions to align them (i.e.
2557 if the HW requires a contiguous array of regions, and the
2558 size of each region is not cache-aligned), then a flush of
2559 one region may result in overwriting data that hardware has
2560 written to another region in the same cache-line. This can
2561 happen for example in network drivers where descriptors for
2562 buffers are typically smaller than the CPU cache-line (e.g.
2563 16 bytes vs. 32 or 64 bytes).
2564
2565 Non-cached memory is only supported on 32-bit ARM at present.
2566
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002567- CONFIG_SYS_BOOTM_LEN:
Stefan Roese15940c92006-03-13 11:16:36 +01002568 Normally compressed uImages are limited to an
2569 uncompressed size of 8 MBytes. If this is not enough,
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002570 you can define CONFIG_SYS_BOOTM_LEN in your board config file
Stefan Roese15940c92006-03-13 11:16:36 +01002571 to adjust this setting to your needs.
2572
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002573- CONFIG_SYS_BOOTMAPSZ:
wdenkc6097192002-11-03 00:24:07 +00002574 Maximum size of memory mapped by the startup code of
2575 the Linux kernel; all data that must be processed by
Bartlomiej Sieka7d721e32008-04-14 15:44:16 +02002576 the Linux kernel (bd_info, boot arguments, FDT blob if
2577 used) must be put below this limit, unless "bootm_low"
Robert P. J. Day1bce2ae2013-09-16 07:15:45 -04002578 environment variable is defined and non-zero. In such case
Bartlomiej Sieka7d721e32008-04-14 15:44:16 +02002579 all data for the Linux kernel must be between "bootm_low"
Wolfgang Denkc0f40852011-10-26 10:21:21 +00002580 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
Grant Likelyc3624e62011-03-28 09:58:43 +00002581 variable "bootm_mapsize" will override the value of
2582 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2583 then the value in "bootm_size" will be used instead.
wdenkc6097192002-11-03 00:24:07 +00002584
John Rigbyfca43cc2010-10-13 13:57:35 -06002585- CONFIG_SYS_BOOT_RAMDISK_HIGH:
2586 Enable initrd_high functionality. If defined then the
2587 initrd_high feature is enabled and the bootm ramdisk subcommand
2588 is enabled.
2589
2590- CONFIG_SYS_BOOT_GET_CMDLINE:
2591 Enables allocating and saving kernel cmdline in space between
2592 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2593
2594- CONFIG_SYS_BOOT_GET_KBD:
2595 Enables allocating and saving a kernel copy of the bd_info in
2596 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2597
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002598- CONFIG_SYS_MAX_FLASH_BANKS:
wdenkc6097192002-11-03 00:24:07 +00002599 Max number of Flash memory banks
2600
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002601- CONFIG_SYS_MAX_FLASH_SECT:
wdenkc6097192002-11-03 00:24:07 +00002602 Max number of sectors on a Flash chip
2603
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002604- CONFIG_SYS_FLASH_ERASE_TOUT:
wdenkc6097192002-11-03 00:24:07 +00002605 Timeout for Flash erase operations (in ms)
2606
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002607- CONFIG_SYS_FLASH_WRITE_TOUT:
wdenkc6097192002-11-03 00:24:07 +00002608 Timeout for Flash write operations (in ms)
2609
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002610- CONFIG_SYS_FLASH_LOCK_TOUT
wdenk8564acf2003-07-14 22:13:32 +00002611 Timeout for Flash set sector lock bit operation (in ms)
2612
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002613- CONFIG_SYS_FLASH_UNLOCK_TOUT
wdenk8564acf2003-07-14 22:13:32 +00002614 Timeout for Flash clear lock bits operation (in ms)
2615
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002616- CONFIG_SYS_FLASH_PROTECTION
wdenk8564acf2003-07-14 22:13:32 +00002617 If defined, hardware flash sectors protection is used
2618 instead of U-Boot software protection.
2619
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002620- CONFIG_SYS_DIRECT_FLASH_TFTP:
wdenkc6097192002-11-03 00:24:07 +00002621
2622 Enable TFTP transfers directly to flash memory;
2623 without this option such a download has to be
2624 performed in two steps: (1) download to RAM, and (2)
2625 copy from RAM to flash.
2626
2627 The two-step approach is usually more reliable, since
2628 you can check if the download worked before you erase
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02002629 the flash, but in some situations (when system RAM is
2630 too limited to allow for a temporary copy of the
wdenkc6097192002-11-03 00:24:07 +00002631 downloaded image) this option may be very useful.
2632
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002633- CONFIG_SYS_FLASH_CFI:
wdenk43d96162003-03-06 00:02:04 +00002634 Define if the flash driver uses extra elements in the
wdenk5653fc32004-02-08 22:55:38 +00002635 common flash structure for storing flash geometry.
2636
Jean-Christophe PLAGNIOL-VILLARD00b18832008-08-13 01:40:42 +02002637- CONFIG_FLASH_CFI_DRIVER
wdenk5653fc32004-02-08 22:55:38 +00002638 This option also enables the building of the cfi_flash driver
2639 in the drivers directory
wdenkc6097192002-11-03 00:24:07 +00002640
Piotr Ziecik91809ed2008-11-17 15:57:58 +01002641- CONFIG_FLASH_CFI_MTD
2642 This option enables the building of the cfi_mtd driver
2643 in the drivers directory. The driver exports CFI flash
2644 to the MTD layer.
2645
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002646- CONFIG_SYS_FLASH_USE_BUFFER_WRITE
Guennadi Liakhovetski96ef8312008-04-03 13:36:02 +02002647 Use buffered writes to flash.
2648
2649- CONFIG_FLASH_SPANSION_S29WS_N
2650 s29ws-n MirrorBit flash has non-standard addresses for buffered
2651 write commands.
2652
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002653- CONFIG_SYS_FLASH_QUIET_TEST
Stefan Roese5568e612005-11-22 13:20:42 +01002654 If this option is defined, the common CFI flash doesn't
2655 print it's warning upon not recognized FLASH banks. This
2656 is useful, if some of the configured banks are only
2657 optionally available.
2658
Jerry Van Baren9a042e92008-03-08 13:48:01 -05002659- CONFIG_FLASH_SHOW_PROGRESS
2660 If defined (must be an integer), print out countdown
2661 digits and dots. Recommended value: 45 (9..1) for 80
2662 column displays, 15 (3..1) for 40 column displays.
2663
Stefan Roese352ef3f2013-04-04 15:53:14 +02002664- CONFIG_FLASH_VERIFY
2665 If defined, the content of the flash (destination) is compared
2666 against the source after the write operation. An error message
2667 will be printed when the contents are not identical.
2668 Please note that this option is useless in nearly all cases,
2669 since such flash programming errors usually are detected earlier
2670 while unprotecting/erasing/programming. Please only enable
2671 this option if you really know what you are doing.
2672
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002673- CONFIG_SYS_RX_ETH_BUFFER:
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02002674 Defines the number of Ethernet receive buffers. On some
2675 Ethernet controllers it is recommended to set this value
stroese53cf9432003-06-05 15:39:44 +00002676 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2677 buffers can be full shortly after enabling the interface
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02002678 on high Ethernet traffic.
stroese53cf9432003-06-05 15:39:44 +00002679 Defaults to 4 if not defined.
2680
Wolfgang Denkea882ba2010-06-20 23:33:59 +02002681- CONFIG_ENV_MAX_ENTRIES
2682
Wolfgang Denk071bc922010-10-27 22:48:30 +02002683 Maximum number of entries in the hash table that is used
2684 internally to store the environment settings. The default
2685 setting is supposed to be generous and should work in most
2686 cases. This setting can be used to tune behaviour; see
2687 lib/hashtable.c for details.
Wolfgang Denkea882ba2010-06-20 23:33:59 +02002688
Joe Hershberger25980902012-12-11 22:16:31 -06002689- CONFIG_ENV_FLAGS_LIST_DEFAULT
2690- CONFIG_ENV_FLAGS_LIST_STATIC
Robert P. J. Day1bce2ae2013-09-16 07:15:45 -04002691 Enable validation of the values given to environment variables when
Joe Hershberger25980902012-12-11 22:16:31 -06002692 calling env set. Variables can be restricted to only decimal,
2693 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
2694 the variables can also be restricted to IP address or MAC address.
2695
2696 The format of the list is:
2697 type_attribute = [s|d|x|b|i|m]
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08002698 access_attribute = [a|r|o|c]
2699 attributes = type_attribute[access_attribute]
Joe Hershberger25980902012-12-11 22:16:31 -06002700 entry = variable_name[:attributes]
2701 list = entry[,list]
2702
2703 The type attributes are:
2704 s - String (default)
2705 d - Decimal
2706 x - Hexadecimal
2707 b - Boolean ([1yYtT|0nNfF])
2708 i - IP address
2709 m - MAC address
2710
Joe Hershberger267541f2012-12-11 22:16:34 -06002711 The access attributes are:
2712 a - Any (default)
2713 r - Read-only
2714 o - Write-once
2715 c - Change-default
2716
Joe Hershberger25980902012-12-11 22:16:31 -06002717 - CONFIG_ENV_FLAGS_LIST_DEFAULT
2718 Define this to a list (string) to define the ".flags"
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08002719 environment variable in the default or embedded environment.
Joe Hershberger25980902012-12-11 22:16:31 -06002720
2721 - CONFIG_ENV_FLAGS_LIST_STATIC
2722 Define this to a list (string) to define validation that
2723 should be done if an entry is not found in the ".flags"
2724 environment variable. To override a setting in the static
2725 list, simply add an entry for the same variable name to the
2726 ".flags" variable.
2727
Joe Hershbergerbdf1fe42015-05-20 14:27:20 -05002728 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
2729 regular expression. This allows multiple variables to define the same
2730 flags without explicitly listing them for each variable.
2731
wdenkc6097192002-11-03 00:24:07 +00002732The following definitions that deal with the placement and management
2733of environment data (variable area); in general, we support the
2734following configurations:
2735
Mike Frysingerc3eb3fe2011-07-08 10:44:25 +00002736- CONFIG_BUILD_ENVCRC:
2737
2738 Builds up envcrc with the target environment so that external utils
2739 may easily extract it and embed it in final U-Boot images.
2740
wdenkc6097192002-11-03 00:24:07 +00002741BE CAREFUL! The first access to the environment happens quite early
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08002742in U-Boot initialization (when we try to get the setting of for the
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02002743console baudrate). You *MUST* have mapped your NVRAM area then, or
wdenkc6097192002-11-03 00:24:07 +00002744U-Boot will hang.
2745
2746Please note that even with NVRAM we still use a copy of the
2747environment in RAM: we could work on NVRAM directly, but we want to
2748keep settings there always unmodified except somebody uses "saveenv"
2749to save the current settings.
2750
Liu Gang0a85a9e2012-03-08 00:33:20 +00002751BE CAREFUL! For some special cases, the local device can not use
2752"saveenv" command. For example, the local device will get the
Liu Gangfc54c7f2012-08-09 05:10:01 +00002753environment stored in a remote NOR flash by SRIO or PCIE link,
2754but it can not erase, write this NOR flash by SRIO or PCIE interface.
Liu Gang0a85a9e2012-03-08 00:33:20 +00002755
Guennadi Liakhovetskib74ab732009-05-18 16:07:22 +02002756- CONFIG_NAND_ENV_DST
2757
2758 Defines address in RAM to which the nand_spl code should copy the
2759 environment. If redundant environment is used, it will be copied to
2760 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2761
Bruce Adlere881cb52007-11-02 13:15:42 -07002762Please note that the environment is read-only until the monitor
wdenkc6097192002-11-03 00:24:07 +00002763has been relocated to RAM and a RAM copy of the environment has been
Simon Glass00caae62017-08-03 12:22:12 -06002764created; also, when using EEPROM you will have to use env_get_f()
wdenkc6097192002-11-03 00:24:07 +00002765until then to read environment variables.
2766
wdenk85ec0bc2003-03-31 16:34:49 +00002767The environment is protected by a CRC32 checksum. Before the monitor
2768is relocated into RAM, as a result of a bad CRC you will be working
2769with the compiled-in default environment - *silently*!!! [This is
2770necessary, because the first environment variable we need is the
2771"baudrate" setting for the console - if we have a bad CRC, we don't
2772have any device yet where we could complain.]
wdenkc6097192002-11-03 00:24:07 +00002773
2774Note: once the monitor has been relocated, then it will complain if
2775the default environment is used; a new CRC is computed as soon as you
wdenk85ec0bc2003-03-31 16:34:49 +00002776use the "saveenv" command to store a valid environment.
wdenkc6097192002-11-03 00:24:07 +00002777
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002778- CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
wdenk42d1f032003-10-15 23:53:47 +00002779 Echo the inverted Ethernet link state to the fault LED.
wdenkfc3e2162003-10-08 22:33:00 +00002780
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002781 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
wdenkfc3e2162003-10-08 22:33:00 +00002782 also needs to be defined.
2783
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002784- CONFIG_SYS_FAULT_MII_ADDR:
wdenk42d1f032003-10-15 23:53:47 +00002785 MII address of the PHY to check for the Ethernet link state.
wdenkc6097192002-11-03 00:24:07 +00002786
Ron Madridf5675aa2009-02-18 14:30:44 -08002787- CONFIG_NS16550_MIN_FUNCTIONS:
2788 Define this if you desire to only have use of the NS16550_init
2789 and NS16550_putc functions for the serial driver located at
2790 drivers/serial/ns16550.c. This option is useful for saving
2791 space for already greatly restricted images, including but not
2792 limited to NAND_SPL configurations.
2793
Simon Glassb2b92f52012-11-30 13:01:18 +00002794- CONFIG_DISPLAY_BOARDINFO
2795 Display information about the board that U-Boot is running on
2796 when U-Boot starts up. The board function checkboard() is called
2797 to do this.
2798
Simon Glasse2e3e2b2012-11-30 13:01:19 +00002799- CONFIG_DISPLAY_BOARDINFO_LATE
2800 Similar to the previous option, but display this information
2801 later, once stdio is running and output goes to the LCD, if
2802 present.
2803
Sascha Silbefeb85802013-08-11 16:40:43 +02002804- CONFIG_BOARD_SIZE_LIMIT:
2805 Maximum size of the U-Boot image. When defined, the
2806 build system checks that the actual size does not
2807 exceed it.
2808
wdenkc6097192002-11-03 00:24:07 +00002809Low Level (hardware related) configuration options:
wdenkdc7c9a12003-03-26 06:55:25 +00002810---------------------------------------------------
wdenkc6097192002-11-03 00:24:07 +00002811
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002812- CONFIG_SYS_CACHELINE_SIZE:
wdenkc6097192002-11-03 00:24:07 +00002813 Cache Line Size of the CPU.
2814
Timur Tabie46fedf2011-08-04 18:03:41 -05002815- CONFIG_SYS_CCSRBAR_DEFAULT:
2816 Default (power-on reset) physical address of CCSR on Freescale
2817 PowerPC SOCs.
2818
2819- CONFIG_SYS_CCSRBAR:
2820 Virtual address of CCSR. On a 32-bit build, this is typically
2821 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
2822
Timur Tabie46fedf2011-08-04 18:03:41 -05002823- CONFIG_SYS_CCSRBAR_PHYS:
2824 Physical address of CCSR. CCSR can be relocated to a new
2825 physical address, if desired. In this case, this macro should
Wolfgang Denkc0f40852011-10-26 10:21:21 +00002826 be set to that address. Otherwise, it should be set to the
Timur Tabie46fedf2011-08-04 18:03:41 -05002827 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
2828 is typically relocated on 36-bit builds. It is recommended
2829 that this macro be defined via the _HIGH and _LOW macros:
2830
2831 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
2832 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
2833
2834- CONFIG_SYS_CCSRBAR_PHYS_HIGH:
Wolfgang Denk4cf26092011-10-07 09:58:21 +02002835 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
2836 either 0 (32-bit build) or 0xF (36-bit build). This macro is
Timur Tabie46fedf2011-08-04 18:03:41 -05002837 used in assembly code, so it must not contain typecasts or
2838 integer size suffixes (e.g. "ULL").
2839
2840- CONFIG_SYS_CCSRBAR_PHYS_LOW:
2841 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
2842 used in assembly code, so it must not contain typecasts or
2843 integer size suffixes (e.g. "ULL").
2844
2845- CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
2846 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
2847 forced to a value that ensures that CCSR is not relocated.
2848
Macpaul Lin0abddf82011-04-11 20:45:32 +00002849- CONFIG_IDE_AHB:
2850 Most IDE controllers were designed to be connected with PCI
2851 interface. Only few of them were designed for AHB interface.
2852 When software is doing ATA command and data transfer to
2853 IDE devices through IDE-AHB controller, some additional
2854 registers accessing to these kind of IDE-AHB controller
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08002855 is required.
Macpaul Lin0abddf82011-04-11 20:45:32 +00002856
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002857- CONFIG_SYS_IMMR: Physical address of the Internal Memory.
wdenkefe2a4d2004-12-16 21:44:03 +00002858 DO NOT CHANGE unless you know exactly what you're
Christophe Leroy907208c2017-07-06 10:23:22 +02002859 doing! (11-4) [MPC8xx systems only]
wdenkc6097192002-11-03 00:24:07 +00002860
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002861- CONFIG_SYS_INIT_RAM_ADDR:
wdenkc6097192002-11-03 00:24:07 +00002862
wdenk7152b1d2003-09-05 23:19:14 +00002863 Start address of memory area that can be used for
wdenkc6097192002-11-03 00:24:07 +00002864 initial data and stack; please note that this must be
2865 writable memory that is working WITHOUT special
2866 initialization, i. e. you CANNOT use normal RAM which
2867 will become available only after programming the
2868 memory controller and running certain initialization
2869 sequences.
2870
2871 U-Boot uses the following memory types:
Christophe Leroy907208c2017-07-06 10:23:22 +02002872 - MPC8xx: IMMR (internal memory of the CPU)
wdenkc6097192002-11-03 00:24:07 +00002873
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002874- CONFIG_SYS_GBL_DATA_OFFSET:
wdenkc6097192002-11-03 00:24:07 +00002875
2876 Offset of the initial data structure in the memory
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002877 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2878 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
wdenkc6097192002-11-03 00:24:07 +00002879 data is located at the end of the available space
Wolfgang Denk553f0982010-10-26 13:32:32 +02002880 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
Simon Glassacd51f92016-10-02 18:01:06 -06002881 GENERATED_GBL_DATA_SIZE), and the initial stack is just
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002882 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2883 CONFIG_SYS_GBL_DATA_OFFSET) downward.
wdenkc6097192002-11-03 00:24:07 +00002884
2885 Note:
2886 On the MPC824X (or other systems that use the data
2887 cache for initial memory) the address chosen for
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002888 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
wdenkc6097192002-11-03 00:24:07 +00002889 point to an otherwise UNUSED address space between
2890 the top of RAM and the start of the PCI space.
2891
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002892- CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
wdenkc6097192002-11-03 00:24:07 +00002893
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002894- CONFIG_SYS_OR_TIMING_SDRAM:
wdenkc6097192002-11-03 00:24:07 +00002895 SDRAM timing
2896
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002897- CONFIG_SYS_MAMR_PTA:
wdenkc6097192002-11-03 00:24:07 +00002898 periodic timer for refresh
2899
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002900- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
2901 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
2902 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
2903 CONFIG_SYS_BR1_PRELIM:
wdenkc6097192002-11-03 00:24:07 +00002904 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2905
2906- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002907 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
2908 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
wdenkc6097192002-11-03 00:24:07 +00002909 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2910
Andrew Sharp69fd2d32012-08-29 14:16:32 +00002911- CONFIG_PCI_ENUM_ONLY
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08002912 Only scan through and get the devices on the buses.
Andrew Sharp69fd2d32012-08-29 14:16:32 +00002913 Don't do any setup work, presumably because someone or
2914 something has already done it, and we don't need to do it
2915 a second time. Useful for platforms that are pre-booted
2916 by coreboot or similar.
2917
Gabor Juhos842033e2013-05-30 07:06:12 +00002918- CONFIG_PCI_INDIRECT_BRIDGE:
2919 Enable support for indirect PCI bridges.
2920
Kumar Galaa09b9b62010-12-30 12:09:53 -06002921- CONFIG_SYS_SRIO:
2922 Chip has SRIO or not
2923
2924- CONFIG_SRIO1:
2925 Board has SRIO 1 port available
2926
2927- CONFIG_SRIO2:
2928 Board has SRIO 2 port available
2929
Liu Gangc8b28152013-05-07 16:30:46 +08002930- CONFIG_SRIO_PCIE_BOOT_MASTER
2931 Board can support master function for Boot from SRIO and PCIE
2932
Kumar Galaa09b9b62010-12-30 12:09:53 -06002933- CONFIG_SYS_SRIOn_MEM_VIRT:
2934 Virtual Address of SRIO port 'n' memory region
2935
Simon Glass62f9b652019-11-14 12:57:09 -07002936- CONFIG_SYS_SRIOn_MEM_PHYxS:
Kumar Galaa09b9b62010-12-30 12:09:53 -06002937 Physical Address of SRIO port 'n' memory region
2938
2939- CONFIG_SYS_SRIOn_MEM_SIZE:
2940 Size of SRIO port 'n' memory region
2941
Fabio Estevam66bd1842013-04-11 09:35:34 +00002942- CONFIG_SYS_NAND_BUSWIDTH_16BIT
2943 Defined to tell the NAND controller that the NAND chip is using
2944 a 16 bit bus.
2945 Not all NAND drivers use this symbol.
Fabio Estevama430e912013-04-11 09:35:35 +00002946 Example of drivers that use it:
Miquel Raynala430fa02018-08-16 17:30:07 +02002947 - drivers/mtd/nand/raw/ndfc.c
2948 - drivers/mtd/nand/raw/mxc_nand.c
Alex Watermaneced4622011-05-19 15:08:36 -04002949
2950- CONFIG_SYS_NDFC_EBC0_CFG
2951 Sets the EBC0_CFG register for the NDFC. If not defined
2952 a default value will be used.
2953
Ben Warrenbb99ad62006-09-07 16:50:54 -04002954- CONFIG_SPD_EEPROM
Wolfgang Denk218ca722008-03-26 10:40:12 +01002955 Get DDR timing information from an I2C EEPROM. Common
2956 with pluggable memory modules such as SODIMMs
2957
Ben Warrenbb99ad62006-09-07 16:50:54 -04002958 SPD_EEPROM_ADDRESS
2959 I2C address of the SPD EEPROM
2960
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002961- CONFIG_SYS_SPD_BUS_NUM
Wolfgang Denk218ca722008-03-26 10:40:12 +01002962 If SPD EEPROM is on an I2C bus other than the first
2963 one, specify here. Note that the value must resolve
2964 to something your driver can deal with.
Ben Warrenbb99ad62006-09-07 16:50:54 -04002965
York Sun1b3e3c42011-06-07 09:42:16 +08002966- CONFIG_SYS_DDR_RAW_TIMING
2967 Get DDR timing information from other than SPD. Common with
2968 soldered DDR chips onboard without SPD. DDR raw timing
2969 parameters are extracted from datasheet and hard-coded into
2970 header files or board specific files.
2971
York Sun6f5e1dc2011-09-16 13:21:35 -07002972- CONFIG_FSL_DDR_INTERACTIVE
2973 Enable interactive DDR debugging. See doc/README.fsl-ddr.
2974
York Sune32d59a2015-01-06 13:18:55 -08002975- CONFIG_FSL_DDR_SYNC_REFRESH
2976 Enable sync of refresh for multiple controllers.
2977
York Sun4516ff82015-03-19 09:30:28 -07002978- CONFIG_FSL_DDR_BIST
2979 Enable built-in memory test for Freescale DDR controllers.
2980
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02002981- CONFIG_SYS_83XX_DDR_USES_CS0
Wolfgang Denk218ca722008-03-26 10:40:12 +01002982 Only for 83xx systems. If specified, then DDR should
2983 be configured using CS0 and CS1 instead of CS2 and CS3.
Timur Tabi2ad6b512006-10-31 18:44:42 -06002984
wdenkc26e4542004-04-18 10:13:26 +00002985- CONFIG_RMII
2986 Enable RMII mode for all FECs.
2987 Note that this is a global option, we can't
2988 have one FEC in standard MII mode and another in RMII mode.
2989
wdenk5cf91d62004-04-23 20:32:05 +00002990- CONFIG_CRC32_VERIFY
2991 Add a verify option to the crc32 command.
2992 The syntax is:
2993
2994 => crc32 -v <address> <count> <crc32>
2995
2996 Where address/count indicate a memory area
2997 and crc32 is the correct crc32 which the
2998 area should have.
2999
wdenk56523f12004-07-11 17:40:54 +00003000- CONFIG_LOOPW
3001 Add the "loopw" memory command. This only takes effect if
Simon Glass493f4202017-08-04 16:34:27 -06003002 the memory commands are activated globally (CONFIG_CMD_MEMORY).
wdenk56523f12004-07-11 17:40:54 +00003003
Joel Johnson72732312020-01-29 09:17:18 -07003004- CONFIG_CMD_MX_CYCLIC
stroese7b466642004-12-16 18:46:55 +00003005 Add the "mdc" and "mwc" memory commands. These are cyclic
3006 "md/mw" commands.
3007 Examples:
3008
wdenkefe2a4d2004-12-16 21:44:03 +00003009 => mdc.b 10 4 500
stroese7b466642004-12-16 18:46:55 +00003010 This command will print 4 bytes (10,11,12,13) each 500 ms.
3011
wdenkefe2a4d2004-12-16 21:44:03 +00003012 => mwc.l 100 12345678 10
stroese7b466642004-12-16 18:46:55 +00003013 This command will write 12345678 to address 100 all 10 ms.
3014
wdenkefe2a4d2004-12-16 21:44:03 +00003015 This only takes effect if the memory commands are activated
Simon Glass493f4202017-08-04 16:34:27 -06003016 globally (CONFIG_CMD_MEMORY).
stroese7b466642004-12-16 18:46:55 +00003017
wdenk8aa1a2d2005-04-04 12:44:11 +00003018- CONFIG_SKIP_LOWLEVEL_INIT
Rick Chen3fafced2017-12-26 13:55:59 +08003019 [ARM, NDS32, MIPS, RISC-V only] If this variable is defined, then certain
Wolfgang Denk844f07d2010-11-27 23:30:56 +01003020 low level initializations (like setting up the memory
3021 controller) are omitted and/or U-Boot does not
3022 relocate itself into RAM.
wdenk8aa1a2d2005-04-04 12:44:11 +00003023
Wolfgang Denk844f07d2010-11-27 23:30:56 +01003024 Normally this variable MUST NOT be defined. The only
3025 exception is when U-Boot is loaded (to RAM) by some
3026 other boot loader or by a debugger which performs
3027 these initializations itself.
wdenk8aa1a2d2005-04-04 12:44:11 +00003028
Simon Glassb5bd0982016-05-05 07:28:06 -06003029- CONFIG_SKIP_LOWLEVEL_INIT_ONLY
3030 [ARM926EJ-S only] This allows just the call to lowlevel_init()
yeongjun Kim90211f72016-07-20 22:56:12 +09003031 to be skipped. The normal CP15 init (such as enabling the
Simon Glassb5bd0982016-05-05 07:28:06 -06003032 instruction cache) is still performed.
3033
Aneesh V401bb302011-07-13 05:11:07 +00003034- CONFIG_SPL_BUILD
Thomas Hebb32f2ca22019-11-13 18:18:03 -08003035 Set when the currently-running compilation is for an artifact
3036 that will end up in the SPL (as opposed to the TPL or U-Boot
3037 proper). Code that needs stage-specific behavior should check
3038 this.
wdenk400558b2005-04-02 23:52:25 +00003039
Ying Zhang3aa29de2013-08-16 15:16:15 +08003040- CONFIG_TPL_BUILD
Thomas Hebb32f2ca22019-11-13 18:18:03 -08003041 Set when the currently-running compilation is for an artifact
3042 that will end up in the TPL (as opposed to the SPL or U-Boot
3043 proper). Code that needs stage-specific behavior should check
3044 this.
Ying Zhang3aa29de2013-08-16 15:16:15 +08003045
Ying Zhang5df572f2013-05-20 14:07:23 +08003046- CONFIG_SYS_MPC85XX_NO_RESETVEC
3047 Only for 85xx systems. If this variable is specified, the section
3048 .resetvec is not kept and the section .bootpg is placed in the
3049 previous 4k of the .text section.
3050
Simon Glass4213fc22013-02-24 17:33:14 +00003051- CONFIG_ARCH_MAP_SYSMEM
3052 Generally U-Boot (and in particular the md command) uses
3053 effective address. It is therefore not necessary to regard
3054 U-Boot address as virtual addresses that need to be translated
3055 to physical addresses. However, sandbox requires this, since
3056 it maintains its own little RAM buffer which contains all
3057 addressable memory. This option causes some memory accesses
3058 to be mapped through map_sysmem() / unmap_sysmem().
3059
Simon Glass588a13f2013-02-14 04:18:54 +00003060- CONFIG_X86_RESET_VECTOR
3061 If defined, the x86 reset vector code is included. This is not
3062 needed when U-Boot is running from Coreboot.
Gabe Blackb16f5212012-11-27 21:08:06 +00003063
Karicheri, Muralidharan999d7d32014-04-04 13:16:50 -04003064- CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
3065 Option to disable subpage write in NAND driver
3066 driver that uses this:
Miquel Raynala430fa02018-08-16 17:30:07 +02003067 drivers/mtd/nand/raw/davinci_nand.c
Karicheri, Muralidharan999d7d32014-04-04 13:16:50 -04003068
Timur Tabif2717b42011-11-22 09:21:25 -06003069Freescale QE/FMAN Firmware Support:
3070-----------------------------------
3071
3072The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3073loading of "firmware", which is encoded in the QE firmware binary format.
3074This firmware often needs to be loaded during U-Boot booting, so macros
3075are used to identify the storage device (NOR flash, SPI, etc) and the address
3076within that device.
3077
Zhao Qiangdcf1d772014-03-21 16:21:44 +08003078- CONFIG_SYS_FMAN_FW_ADDR
3079 The address in the storage device where the FMAN microcode is located. The
Tom Rinicc1e98b2019-05-12 07:59:12 -04003080 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
Zhao Qiangdcf1d772014-03-21 16:21:44 +08003081 is also specified.
3082
3083- CONFIG_SYS_QE_FW_ADDR
3084 The address in the storage device where the QE microcode is located. The
Tom Rinicc1e98b2019-05-12 07:59:12 -04003085 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
Timur Tabif2717b42011-11-22 09:21:25 -06003086 is also specified.
3087
3088- CONFIG_SYS_QE_FMAN_FW_LENGTH
3089 The maximum possible size of the firmware. The firmware binary format
3090 has a field that specifies the actual size of the firmware, but it
3091 might not be possible to read any part of the firmware unless some
3092 local storage is allocated to hold the entire firmware first.
3093
3094- CONFIG_SYS_QE_FMAN_FW_IN_NOR
3095 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3096 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3097 virtual address in NOR flash.
3098
3099- CONFIG_SYS_QE_FMAN_FW_IN_NAND
3100 Specifies that QE/FMAN firmware is located in NAND flash.
3101 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3102
3103- CONFIG_SYS_QE_FMAN_FW_IN_MMC
3104 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3105 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3106
Liu Gang292dc6c2012-03-08 00:33:18 +00003107- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3108 Specifies that QE/FMAN firmware is located in the remote (master)
3109 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
Liu Gangfc54c7f2012-08-09 05:10:01 +00003110 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3111 window->master inbound window->master LAW->the ucode address in
3112 master's memory space.
Timur Tabif2717b42011-11-22 09:21:25 -06003113
J. German Riverab940ca62014-06-23 15:15:55 -07003114Freescale Layerscape Management Complex Firmware Support:
3115---------------------------------------------------------
3116The Freescale Layerscape Management Complex (MC) supports the loading of
3117"firmware".
3118This firmware often needs to be loaded during U-Boot booting, so macros
3119are used to identify the storage device (NOR flash, SPI, etc) and the address
3120within that device.
3121
3122- CONFIG_FSL_MC_ENET
3123 Enable the MC driver for Layerscape SoCs.
3124
Prabhakar Kushwaha5c055082015-06-02 10:55:52 +05303125Freescale Layerscape Debug Server Support:
3126-------------------------------------------
3127The Freescale Layerscape Debug Server Support supports the loading of
3128"Debug Server firmware" and triggering SP boot-rom.
3129This firmware often needs to be loaded during U-Boot booting.
3130
York Sunc0492142015-12-07 11:08:58 -08003131- CONFIG_SYS_MC_RSV_MEM_ALIGN
3132 Define alignment of reserved memory MC requires
Prabhakar Kushwaha5c055082015-06-02 10:55:52 +05303133
Paul Kocialkowskif3f431a2015-07-26 18:48:15 +02003134Reproducible builds
3135-------------------
3136
3137In order to achieve reproducible builds, timestamps used in the U-Boot build
3138process have to be set to a fixed value.
3139
3140This is done using the SOURCE_DATE_EPOCH environment variable.
3141SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
3142option for U-Boot or an environment variable in U-Boot.
3143
3144SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
3145
wdenkc6097192002-11-03 00:24:07 +00003146Building the Software:
3147======================
3148
Wolfgang Denk218ca722008-03-26 10:40:12 +01003149Building U-Boot has been tested in several native build environments
3150and in many different cross environments. Of course we cannot support
3151all possibly existing versions of cross development tools in all
3152(potentially obsolete) versions. In case of tool chain problems we
3153recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3154which is extensively used to build and test U-Boot.
wdenkc6097192002-11-03 00:24:07 +00003155
Wolfgang Denk218ca722008-03-26 10:40:12 +01003156If you are not using a native environment, it is assumed that you
3157have GNU cross compiling tools available in your path. In this case,
3158you must set the environment variable CROSS_COMPILE in your shell.
3159Note that no changes to the Makefile or any other source files are
3160necessary. For example using the ELDK on a 4xx CPU, please enter:
wdenkc6097192002-11-03 00:24:07 +00003161
Wolfgang Denk218ca722008-03-26 10:40:12 +01003162 $ CROSS_COMPILE=ppc_4xx-
3163 $ export CROSS_COMPILE
wdenkc6097192002-11-03 00:24:07 +00003164
Wolfgang Denk218ca722008-03-26 10:40:12 +01003165U-Boot is intended to be simple to build. After installing the
3166sources you must configure U-Boot for one specific board type. This
wdenkc6097192002-11-03 00:24:07 +00003167is done by typing:
3168
Holger Freytherab584d62014-08-04 09:26:05 +02003169 make NAME_defconfig
wdenkc6097192002-11-03 00:24:07 +00003170
Holger Freytherab584d62014-08-04 09:26:05 +02003171where "NAME_defconfig" is the name of one of the existing configu-
Heinrich Schuchardtecb3a0a2020-02-24 18:36:30 +01003172rations; see configs/*_defconfig for supported names.
wdenk54387ac2003-10-08 22:45:44 +00003173
Heinrich Schuchardtecb3a0a2020-02-24 18:36:30 +01003174Note: for some boards special configuration names may exist; check if
wdenk2729af92004-05-03 20:45:30 +00003175 additional information is available from the board vendor; for
3176 instance, the TQM823L systems are available without (standard)
3177 or with LCD support. You can select such additional "features"
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02003178 when choosing the configuration, i. e.
wdenkc6097192002-11-03 00:24:07 +00003179
Holger Freytherab584d62014-08-04 09:26:05 +02003180 make TQM823L_defconfig
wdenk2729af92004-05-03 20:45:30 +00003181 - will configure for a plain TQM823L, i. e. no LCD support
wdenkc6097192002-11-03 00:24:07 +00003182
Holger Freytherab584d62014-08-04 09:26:05 +02003183 make TQM823L_LCD_defconfig
wdenk2729af92004-05-03 20:45:30 +00003184 - will configure for a TQM823L with U-Boot console on LCD
wdenkc6097192002-11-03 00:24:07 +00003185
wdenk2729af92004-05-03 20:45:30 +00003186 etc.
wdenkc6097192002-11-03 00:24:07 +00003187
wdenkc6097192002-11-03 00:24:07 +00003188
wdenk2729af92004-05-03 20:45:30 +00003189Finally, type "make all", and you should get some working U-Boot
3190images ready for download to / installation on your system:
wdenkc6097192002-11-03 00:24:07 +00003191
wdenk2729af92004-05-03 20:45:30 +00003192- "u-boot.bin" is a raw binary image
3193- "u-boot" is an image in ELF binary format
3194- "u-boot.srec" is in Motorola S-Record format
wdenkc6097192002-11-03 00:24:07 +00003195
Marian Balakowiczbaf31242006-09-07 17:25:40 +02003196By default the build is performed locally and the objects are saved
3197in the source directory. One of the two methods can be used to change
3198this behavior and build U-Boot to some external directory:
3199
32001. Add O= to the make command line invocations:
3201
3202 make O=/tmp/build distclean
Holger Freytherab584d62014-08-04 09:26:05 +02003203 make O=/tmp/build NAME_defconfig
Marian Balakowiczbaf31242006-09-07 17:25:40 +02003204 make O=/tmp/build all
3205
Timo Ketolaadbba992014-11-06 14:39:05 +020032062. Set environment variable KBUILD_OUTPUT to point to the desired location:
Marian Balakowiczbaf31242006-09-07 17:25:40 +02003207
Timo Ketolaadbba992014-11-06 14:39:05 +02003208 export KBUILD_OUTPUT=/tmp/build
Marian Balakowiczbaf31242006-09-07 17:25:40 +02003209 make distclean
Holger Freytherab584d62014-08-04 09:26:05 +02003210 make NAME_defconfig
Marian Balakowiczbaf31242006-09-07 17:25:40 +02003211 make all
3212
Timo Ketolaadbba992014-11-06 14:39:05 +02003213Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
Marian Balakowiczbaf31242006-09-07 17:25:40 +02003214variable.
3215
Daniel Schwierzeck215bb1c2018-01-26 16:31:04 +01003216User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by
3217setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS.
3218For example to treat all compiler warnings as errors:
3219
3220 make KCFLAGS=-Werror
wdenkc6097192002-11-03 00:24:07 +00003221
wdenk2729af92004-05-03 20:45:30 +00003222Please be aware that the Makefiles assume you are using GNU make, so
3223for instance on NetBSD you might need to use "gmake" instead of
3224native "make".
wdenkc6097192002-11-03 00:24:07 +00003225
wdenkc6097192002-11-03 00:24:07 +00003226
wdenk2729af92004-05-03 20:45:30 +00003227If the system board that you have is not listed, then you will need
3228to port U-Boot to your hardware platform. To do this, follow these
3229steps:
wdenkc6097192002-11-03 00:24:07 +00003230
Phil Sutter3c1496c2015-12-25 14:41:18 +010032311. Create a new directory to hold your board specific code. Add any
wdenk2729af92004-05-03 20:45:30 +00003232 files you need. In your board directory, you will need at least
Phil Sutter3c1496c2015-12-25 14:41:18 +01003233 the "Makefile" and a "<board>.c".
32342. Create a new configuration file "include/configs/<board>.h" for
3235 your board.
wdenk2729af92004-05-03 20:45:30 +000032363. If you're porting U-Boot to a new CPU, then also create a new
3237 directory to hold your CPU specific code. Add any files you need.
Holger Freytherab584d62014-08-04 09:26:05 +020032384. Run "make <board>_defconfig" with your new name.
wdenk2729af92004-05-03 20:45:30 +000032395. Type "make", and you should get a working "u-boot.srec" file
3240 to be installed on your target system.
32416. Debug and solve any problems that might arise.
3242 [Of course, this last step is much harder than it sounds.]
wdenkc6097192002-11-03 00:24:07 +00003243
wdenkc6097192002-11-03 00:24:07 +00003244
wdenk2729af92004-05-03 20:45:30 +00003245Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3246==============================================================
wdenkc6097192002-11-03 00:24:07 +00003247
Wolfgang Denk218ca722008-03-26 10:40:12 +01003248If you have modified U-Boot sources (for instance added a new board
3249or support for new devices, a new CPU, etc.) you are expected to
wdenk2729af92004-05-03 20:45:30 +00003250provide feedback to the other developers. The feedback normally takes
Thomas Hebb32f2ca22019-11-13 18:18:03 -08003251the form of a "patch", i.e. a context diff against a certain (latest
Wolfgang Denk218ca722008-03-26 10:40:12 +01003252official or latest in the git repository) version of U-Boot sources.
wdenkc6097192002-11-03 00:24:07 +00003253
Wolfgang Denk218ca722008-03-26 10:40:12 +01003254But before you submit such a patch, please verify that your modifi-
3255cation did not break existing code. At least make sure that *ALL* of
wdenk2729af92004-05-03 20:45:30 +00003256the supported boards compile WITHOUT ANY compiler warnings. To do so,
Simon Glass6de80f22016-07-27 20:33:08 -06003257just run the buildman script (tools/buildman/buildman), which will
3258configure and build U-Boot for ALL supported system. Be warned, this
3259will take a while. Please see the buildman README, or run 'buildman -H'
3260for documentation.
Marian Balakowiczbaf31242006-09-07 17:25:40 +02003261
3262
wdenk2729af92004-05-03 20:45:30 +00003263See also "U-Boot Porting Guide" below.
wdenkc6097192002-11-03 00:24:07 +00003264
wdenkc6097192002-11-03 00:24:07 +00003265
wdenk2729af92004-05-03 20:45:30 +00003266Monitor Commands - Overview:
3267============================
wdenkc6097192002-11-03 00:24:07 +00003268
wdenk2729af92004-05-03 20:45:30 +00003269go - start application at address 'addr'
3270run - run commands in an environment variable
3271bootm - boot application image from memory
3272bootp - boot image via network using BootP/TFTP protocol
Marek Vasut44f074c2012-03-14 21:52:45 +00003273bootz - boot zImage from memory
wdenk2729af92004-05-03 20:45:30 +00003274tftpboot- boot image via network using TFTP protocol
3275 and env variables "ipaddr" and "serverip"
3276 (and eventually "gatewayip")
Simon Glass1fb7cd42011-10-24 18:00:07 +00003277tftpput - upload a file via network using TFTP protocol
wdenk2729af92004-05-03 20:45:30 +00003278rarpboot- boot image via network using RARP/TFTP protocol
3279diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3280loads - load S-Record file over serial line
3281loadb - load binary file over serial line (kermit mode)
3282md - memory display
3283mm - memory modify (auto-incrementing)
3284nm - memory modify (constant address)
3285mw - memory write (fill)
3286cp - memory copy
3287cmp - memory compare
3288crc32 - checksum calculation
Peter Tyser0f89c542009-04-18 22:34:03 -05003289i2c - I2C sub-system
wdenk2729af92004-05-03 20:45:30 +00003290sspi - SPI utility commands
3291base - print or set address offset
3292printenv- print environment variables
3293setenv - set environment variables
3294saveenv - save environment variables to persistent storage
3295protect - enable or disable FLASH write protection
3296erase - erase FLASH memory
3297flinfo - print FLASH memory information
Karl O. Pinc10635af2012-08-03 05:57:21 +00003298nand - NAND memory operations (see doc/README.nand)
wdenk2729af92004-05-03 20:45:30 +00003299bdinfo - print Board Info structure
3300iminfo - print header information for application image
3301coninfo - print console devices and informations
3302ide - IDE sub-system
3303loop - infinite loop on address range
wdenk56523f12004-07-11 17:40:54 +00003304loopw - infinite write loop on address range
wdenk2729af92004-05-03 20:45:30 +00003305mtest - simple RAM test
3306icache - enable or disable instruction cache
3307dcache - enable or disable data cache
3308reset - Perform RESET of the CPU
3309echo - echo args to console
3310version - print monitor version
3311help - print online help
3312? - alias for 'help'
wdenkc6097192002-11-03 00:24:07 +00003313
wdenkc6097192002-11-03 00:24:07 +00003314
wdenk2729af92004-05-03 20:45:30 +00003315Monitor Commands - Detailed Description:
3316========================================
wdenkc6097192002-11-03 00:24:07 +00003317
wdenk2729af92004-05-03 20:45:30 +00003318TODO.
wdenkc6097192002-11-03 00:24:07 +00003319
wdenk2729af92004-05-03 20:45:30 +00003320For now: just type "help <command>".
wdenkc6097192002-11-03 00:24:07 +00003321
3322
wdenk2729af92004-05-03 20:45:30 +00003323Environment Variables:
3324======================
wdenkc6097192002-11-03 00:24:07 +00003325
wdenk2729af92004-05-03 20:45:30 +00003326U-Boot supports user configuration using Environment Variables which
3327can be made persistent by saving to Flash memory.
wdenkc6097192002-11-03 00:24:07 +00003328
wdenk2729af92004-05-03 20:45:30 +00003329Environment Variables are set using "setenv", printed using
3330"printenv", and saved to Flash using "saveenv". Using "setenv"
3331without a value can be used to delete a variable from the
3332environment. As long as you don't save the environment you are
3333working with an in-memory copy. In case the Flash area containing the
3334environment is erased by accident, a default environment is provided.
wdenkc6097192002-11-03 00:24:07 +00003335
Wolfgang Denkc96f86e2010-01-17 23:55:53 +01003336Some configuration options can be set using Environment Variables.
3337
3338List of environment variables (most likely not complete):
wdenkc6097192002-11-03 00:24:07 +00003339
wdenk2729af92004-05-03 20:45:30 +00003340 baudrate - see CONFIG_BAUDRATE
wdenkc6097192002-11-03 00:24:07 +00003341
wdenk2729af92004-05-03 20:45:30 +00003342 bootdelay - see CONFIG_BOOTDELAY
wdenkc6097192002-11-03 00:24:07 +00003343
wdenk2729af92004-05-03 20:45:30 +00003344 bootcmd - see CONFIG_BOOTCOMMAND
wdenkc6097192002-11-03 00:24:07 +00003345
wdenk2729af92004-05-03 20:45:30 +00003346 bootargs - Boot arguments when booting an RTOS image
wdenkc6097192002-11-03 00:24:07 +00003347
wdenk2729af92004-05-03 20:45:30 +00003348 bootfile - Name of the image to load with TFTP
wdenkc6097192002-11-03 00:24:07 +00003349
Bartlomiej Sieka7d721e32008-04-14 15:44:16 +02003350 bootm_low - Memory range available for image processing in the bootm
3351 command can be restricted. This variable is given as
3352 a hexadecimal number and defines lowest address allowed
3353 for use by the bootm command. See also "bootm_size"
3354 environment variable. Address defined by "bootm_low" is
3355 also the base of the initial memory mapping for the Linux
Grant Likelyc3624e62011-03-28 09:58:43 +00003356 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3357 bootm_mapsize.
3358
Wolfgang Denkc0f40852011-10-26 10:21:21 +00003359 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
Grant Likelyc3624e62011-03-28 09:58:43 +00003360 This variable is given as a hexadecimal number and it
3361 defines the size of the memory region starting at base
3362 address bootm_low that is accessible by the Linux kernel
3363 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3364 as the default value if it is defined, and bootm_size is
3365 used otherwise.
Bartlomiej Sieka7d721e32008-04-14 15:44:16 +02003366
3367 bootm_size - Memory range available for image processing in the bootm
3368 command can be restricted. This variable is given as
3369 a hexadecimal number and defines the size of the region
3370 allowed for use by the bootm command. See also "bootm_low"
3371 environment variable.
3372
Simon Glass88fa4be2019-07-20 20:51:17 -06003373 bootstopkeysha256, bootdelaykey, bootstopkey - See README.autoboot
3374
Bartlomiej Sieka4bae9092008-10-01 15:26:31 +02003375 updatefile - Location of the software update file on a TFTP server, used
3376 by the automatic software update feature. Please refer to
3377 documentation in doc/README.update for more details.
3378
wdenk2729af92004-05-03 20:45:30 +00003379 autoload - if set to "no" (any string beginning with 'n'),
3380 "bootp" will just load perform a lookup of the
3381 configuration from the BOOTP server, but not try to
3382 load any image using TFTP
wdenkc6097192002-11-03 00:24:07 +00003383
wdenk2729af92004-05-03 20:45:30 +00003384 autostart - if set to "yes", an image loaded using the "bootp",
3385 "rarpboot", "tftpboot" or "diskboot" commands will
3386 be automatically started (by internally calling
3387 "bootm")
wdenkc6097192002-11-03 00:24:07 +00003388
wdenk2729af92004-05-03 20:45:30 +00003389 If set to "no", a standalone image passed to the
3390 "bootm" command will be copied to the load address
3391 (and eventually uncompressed), but NOT be started.
3392 This can be used to load and uncompress arbitrary
3393 data.
wdenkc6097192002-11-03 00:24:07 +00003394
David A. Longa28afca2011-07-09 16:40:19 -04003395 fdt_high - if set this restricts the maximum address that the
3396 flattened device tree will be copied into upon boot.
Shawn Guofa34f6b2012-01-09 21:54:08 +00003397 For example, if you have a system with 1 GB memory
3398 at physical address 0x10000000, while Linux kernel
3399 only recognizes the first 704 MB as low memory, you
3400 may need to set fdt_high as 0x3C000000 to have the
3401 device tree blob be copied to the maximum address
3402 of the 704 MB low memory, so that Linux kernel can
3403 access it during the boot procedure.
3404
David A. Longa28afca2011-07-09 16:40:19 -04003405 If this is set to the special value 0xFFFFFFFF then
3406 the fdt will not be copied at all on boot. For this
3407 to work it must reside in writable memory, have
3408 sufficient padding on the end of it for u-boot to
3409 add the information it needs into it, and the memory
3410 must be accessible by the kernel.
3411
Simon Glasseea63e02011-10-24 19:15:34 +00003412 fdtcontroladdr- if set this is the address of the control flattened
3413 device tree used by U-Boot when CONFIG_OF_CONTROL is
3414 defined.
3415
wdenk17ea1172004-06-06 21:51:03 +00003416 i2cfast - (PPC405GP|PPC405EP only)
3417 if set to 'y' configures Linux I2C driver for fast
3418 mode (400kHZ). This environment variable is used in
3419 initialization code. So, for changes to be effective
3420 it must be saved and board must be reset.
3421
wdenk2729af92004-05-03 20:45:30 +00003422 initrd_high - restrict positioning of initrd images:
3423 If this variable is not set, initrd images will be
3424 copied to the highest possible address in RAM; this
3425 is usually what you want since it allows for
3426 maximum initrd size. If for some reason you want to
3427 make sure that the initrd image is loaded below the
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02003428 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
wdenk2729af92004-05-03 20:45:30 +00003429 variable to a value of "no" or "off" or "0".
3430 Alternatively, you can set it to a maximum upper
3431 address to use (U-Boot will still check that it
3432 does not overwrite the U-Boot stack and data).
wdenkc6097192002-11-03 00:24:07 +00003433
wdenk2729af92004-05-03 20:45:30 +00003434 For instance, when you have a system with 16 MB
3435 RAM, and want to reserve 4 MB from use by Linux,
3436 you can do this by adding "mem=12M" to the value of
3437 the "bootargs" variable. However, now you must make
3438 sure that the initrd image is placed in the first
3439 12 MB as well - this can be done with
wdenkc6097192002-11-03 00:24:07 +00003440
wdenk2729af92004-05-03 20:45:30 +00003441 setenv initrd_high 00c00000
wdenkc6097192002-11-03 00:24:07 +00003442
wdenk2729af92004-05-03 20:45:30 +00003443 If you set initrd_high to 0xFFFFFFFF, this is an
3444 indication to U-Boot that all addresses are legal
3445 for the Linux kernel, including addresses in flash
3446 memory. In this case U-Boot will NOT COPY the
3447 ramdisk at all. This may be useful to reduce the
3448 boot time on your system, but requires that this
3449 feature is supported by your Linux kernel.
wdenk4a6fd342003-04-12 23:38:12 +00003450
wdenk2729af92004-05-03 20:45:30 +00003451 ipaddr - IP address; needed for tftpboot command
wdenkc6097192002-11-03 00:24:07 +00003452
wdenk2729af92004-05-03 20:45:30 +00003453 loadaddr - Default load address for commands like "bootp",
3454 "rarpboot", "tftpboot", "loadb" or "diskboot"
wdenkc6097192002-11-03 00:24:07 +00003455
wdenk2729af92004-05-03 20:45:30 +00003456 loads_echo - see CONFIG_LOADS_ECHO
wdenkc6097192002-11-03 00:24:07 +00003457
wdenk2729af92004-05-03 20:45:30 +00003458 serverip - TFTP server IP address; needed for tftpboot command
wdenk38b99262003-05-23 23:18:21 +00003459
wdenk2729af92004-05-03 20:45:30 +00003460 bootretry - see CONFIG_BOOT_RETRY_TIME
wdenkc6097192002-11-03 00:24:07 +00003461
wdenk2729af92004-05-03 20:45:30 +00003462 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
wdenkc6097192002-11-03 00:24:07 +00003463
wdenk2729af92004-05-03 20:45:30 +00003464 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
wdenkc6097192002-11-03 00:24:07 +00003465
Mike Frysingere2a53452011-10-02 10:01:27 +00003466 ethprime - controls which interface is used first.
wdenkc6097192002-11-03 00:24:07 +00003467
Mike Frysingere2a53452011-10-02 10:01:27 +00003468 ethact - controls which interface is currently active.
3469 For example you can do the following
wdenkc6097192002-11-03 00:24:07 +00003470
Heiko Schocher48690d82010-07-20 17:45:02 +02003471 => setenv ethact FEC
3472 => ping 192.168.0.1 # traffic sent on FEC
3473 => setenv ethact SCC
3474 => ping 10.0.0.1 # traffic sent on SCC
wdenkc6097192002-11-03 00:24:07 +00003475
Matthias Fuchse1692572008-01-17 07:45:05 +01003476 ethrotate - When set to "no" U-Boot does not go through all
3477 available network interfaces.
3478 It just stays at the currently selected interface.
3479
Wolfgang Denkc96f86e2010-01-17 23:55:53 +01003480 netretry - When set to "no" each network operation will
wdenk2729af92004-05-03 20:45:30 +00003481 either succeed or fail without retrying.
3482 When set to "once" the network operation will
3483 fail when all the available network interfaces
3484 are tried once without success.
3485 Useful on scripts which control the retry operation
3486 themselves.
wdenkc6097192002-11-03 00:24:07 +00003487
Jean-Christophe PLAGNIOL-VILLARDb4e2f892009-01-31 09:53:39 +01003488 npe_ucode - set load address for the NPE microcode
Jean-Christophe PLAGNIOL-VILLARDa1cf0272008-01-07 08:41:34 +01003489
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08003490 silent_linux - If set then Linux will be told to boot silently, by
Simon Glass8d51aac2013-07-16 20:10:00 -07003491 changing the console to be empty. If "yes" it will be
3492 made silent. If "no" it will not be made silent. If
3493 unset, then it will be made silent if the U-Boot console
3494 is silent.
3495
Albert ARIBAUD \(3ADEV\)f5fb7342015-10-12 00:02:57 +02003496 tftpsrcp - If this is set, the value is used for TFTP's
Wolfgang Denkecb0ccd2005-09-24 22:37:32 +02003497 UDP source port.
3498
Albert ARIBAUD \(3ADEV\)f5fb7342015-10-12 00:02:57 +02003499 tftpdstp - If this is set, the value is used for TFTP's UDP
Wolfgang Denk28cb9372005-09-24 23:25:46 +02003500 destination port instead of the Well Know Port 69.
3501
Wolfgang Denkc96f86e2010-01-17 23:55:53 +01003502 tftpblocksize - Block size to use for TFTP transfers; if not set,
3503 we use the TFTP server's default block size
3504
3505 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3506 seconds, minimum value is 1000 = 1 second). Defines
3507 when a packet is considered to be lost so it has to
3508 be retransmitted. The default is 5000 = 5 seconds.
3509 Lowering this value may make downloads succeed
3510 faster in networks with high packet loss rates or
3511 with unreliable TFTP servers.
3512
Albert ARIBAUD \(3ADEV\)f5fb7342015-10-12 00:02:57 +02003513 tftptimeoutcountmax - maximum count of TFTP timeouts (no
3514 unit, minimum value = 0). Defines how many timeouts
3515 can happen during a single file transfer before that
3516 transfer is aborted. The default is 10, and 0 means
3517 'no timeouts allowed'. Increasing this value may help
3518 downloads succeed with high packet loss rates, or with
3519 unreliable TFTP servers or client hardware.
3520
Wolfgang Denkc96f86e2010-01-17 23:55:53 +01003521 vlan - When set to a value < 4095 the traffic over
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02003522 Ethernet is encapsulated/received over 802.1q
wdenk2729af92004-05-03 20:45:30 +00003523 VLAN tagged frames.
wdenka3d991b2004-04-15 21:48:45 +00003524
Alexandre Messier50768f52016-02-01 17:08:57 -05003525 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
3526 Unsigned value, in milliseconds. If not set, the period will
3527 be either the default (28000), or a value based on
3528 CONFIG_NET_RETRY_COUNT, if defined. This value has
3529 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
3530
Jason Hobbsdc0b7b02011-08-31 05:37:28 +00003531The following image location variables contain the location of images
3532used in booting. The "Image" column gives the role of the image and is
3533not an environment variable name. The other columns are environment
3534variable names. "File Name" gives the name of the file on a TFTP
3535server, "RAM Address" gives the location in RAM the image will be
3536loaded to, and "Flash Location" gives the image's address in NOR
3537flash or offset in NAND flash.
3538
3539*Note* - these variables don't have to be defined for all boards, some
Fabio Estevamaed9fed2015-04-25 18:53:10 -03003540boards currently use other variables for these purposes, and some
Jason Hobbsdc0b7b02011-08-31 05:37:28 +00003541boards use these variables for other purposes.
3542
Wolfgang Denkc0f40852011-10-26 10:21:21 +00003543Image File Name RAM Address Flash Location
3544----- --------- ----------- --------------
3545u-boot u-boot u-boot_addr_r u-boot_addr
3546Linux kernel bootfile kernel_addr_r kernel_addr
3547device tree blob fdtfile fdt_addr_r fdt_addr
3548ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
Jason Hobbsdc0b7b02011-08-31 05:37:28 +00003549
wdenk2729af92004-05-03 20:45:30 +00003550The following environment variables may be used and automatically
3551updated by the network boot commands ("bootp" and "rarpboot"),
3552depending the information provided by your boot server:
wdenka3d991b2004-04-15 21:48:45 +00003553
wdenk2729af92004-05-03 20:45:30 +00003554 bootfile - see above
3555 dnsip - IP address of your Domain Name Server
3556 dnsip2 - IP address of your secondary Domain Name Server
3557 gatewayip - IP address of the Gateway (Router) to use
3558 hostname - Target hostname
3559 ipaddr - see above
3560 netmask - Subnet Mask
3561 rootpath - Pathname of the root filesystem on the NFS server
3562 serverip - see above
wdenka3d991b2004-04-15 21:48:45 +00003563
wdenka3d991b2004-04-15 21:48:45 +00003564
wdenk2729af92004-05-03 20:45:30 +00003565There are two special Environment Variables:
wdenkc6097192002-11-03 00:24:07 +00003566
wdenk2729af92004-05-03 20:45:30 +00003567 serial# - contains hardware identification information such
3568 as type string and/or serial number
3569 ethaddr - Ethernet address
wdenkc6097192002-11-03 00:24:07 +00003570
wdenk2729af92004-05-03 20:45:30 +00003571These variables can be set only once (usually during manufacturing of
3572the board). U-Boot refuses to delete or overwrite these variables
3573once they have been set once.
wdenkc6097192002-11-03 00:24:07 +00003574
3575
wdenk2729af92004-05-03 20:45:30 +00003576Further special Environment Variables:
wdenkc6097192002-11-03 00:24:07 +00003577
wdenk2729af92004-05-03 20:45:30 +00003578 ver - Contains the U-Boot version string as printed
3579 with the "version" command. This variable is
3580 readonly (see CONFIG_VERSION_VARIABLE).
wdenkc6097192002-11-03 00:24:07 +00003581
wdenkc6097192002-11-03 00:24:07 +00003582
wdenk2729af92004-05-03 20:45:30 +00003583Please note that changes to some configuration parameters may take
3584only effect after the next boot (yes, that's just like Windoze :-).
wdenkc6097192002-11-03 00:24:07 +00003585
stroesec1551ea2003-04-04 15:53:41 +00003586
Joe Hershberger170ab112012-12-11 22:16:24 -06003587Callback functions for environment variables:
3588---------------------------------------------
3589
3590For some environment variables, the behavior of u-boot needs to change
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08003591when their values are changed. This functionality allows functions to
Joe Hershberger170ab112012-12-11 22:16:24 -06003592be associated with arbitrary variables. On creation, overwrite, or
3593deletion, the callback will provide the opportunity for some side
3594effect to happen or for the change to be rejected.
3595
3596The callbacks are named and associated with a function using the
3597U_BOOT_ENV_CALLBACK macro in your board or driver code.
3598
3599These callbacks are associated with variables in one of two ways. The
3600static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
3601in the board configuration to a string that defines a list of
3602associations. The list must be in the following format:
3603
3604 entry = variable_name[:callback_name]
3605 list = entry[,list]
3606
3607If the callback name is not specified, then the callback is deleted.
3608Spaces are also allowed anywhere in the list.
3609
3610Callbacks can also be associated by defining the ".callbacks" variable
3611with the same list format above. Any association in ".callbacks" will
3612override any association in the static list. You can define
3613CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08003614".callbacks" environment variable in the default or embedded environment.
Joe Hershberger170ab112012-12-11 22:16:24 -06003615
Joe Hershbergerbdf1fe42015-05-20 14:27:20 -05003616If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3617regular expression. This allows multiple variables to be connected to
3618the same callback without explicitly listing them all out.
3619
Heinrich Schuchardt1b040472018-07-29 11:08:14 +02003620The signature of the callback functions is:
3621
3622 int callback(const char *name, const char *value, enum env_op op, int flags)
3623
3624* name - changed environment variable
3625* value - new value of the environment variable
3626* op - operation (create, overwrite, or delete)
3627* flags - attributes of the environment variable change, see flags H_* in
3628 include/search.h
3629
3630The return value is 0 if the variable change is accepted and 1 otherwise.
Joe Hershberger170ab112012-12-11 22:16:24 -06003631
wdenk2729af92004-05-03 20:45:30 +00003632Command Line Parsing:
3633=====================
stroesec1551ea2003-04-04 15:53:41 +00003634
wdenk2729af92004-05-03 20:45:30 +00003635There are two different command line parsers available with U-Boot:
3636the old "simple" one, and the much more powerful "hush" shell:
stroesec1551ea2003-04-04 15:53:41 +00003637
wdenk2729af92004-05-03 20:45:30 +00003638Old, simple command line parser:
3639--------------------------------
wdenkc6097192002-11-03 00:24:07 +00003640
wdenk2729af92004-05-03 20:45:30 +00003641- supports environment variables (through setenv / saveenv commands)
3642- several commands on one line, separated by ';'
Wolfgang Denkfe126d82005-11-20 21:40:11 +01003643- variable substitution using "... ${name} ..." syntax
wdenk2729af92004-05-03 20:45:30 +00003644- special characters ('$', ';') can be escaped by prefixing with '\',
3645 for example:
Wolfgang Denkfe126d82005-11-20 21:40:11 +01003646 setenv bootcmd bootm \${address}
wdenk2729af92004-05-03 20:45:30 +00003647- You can also escape text by enclosing in single apostrophes, for example:
3648 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
wdenkc6097192002-11-03 00:24:07 +00003649
wdenk2729af92004-05-03 20:45:30 +00003650Hush shell:
3651-----------
wdenkf07771c2003-05-28 08:06:31 +00003652
wdenk2729af92004-05-03 20:45:30 +00003653- similar to Bourne shell, with control structures like
3654 if...then...else...fi, for...do...done; while...do...done,
3655 until...do...done, ...
3656- supports environment ("global") variables (through setenv / saveenv
3657 commands) and local shell variables (through standard shell syntax
3658 "name=value"); only environment variables can be used with "run"
3659 command
wdenkf07771c2003-05-28 08:06:31 +00003660
wdenk2729af92004-05-03 20:45:30 +00003661General rules:
3662--------------
wdenkf07771c2003-05-28 08:06:31 +00003663
wdenk2729af92004-05-03 20:45:30 +00003664(1) If a command line (or an environment variable executed by a "run"
3665 command) contains several commands separated by semicolon, and
3666 one of these commands fails, then the remaining commands will be
3667 executed anyway.
wdenkf07771c2003-05-28 08:06:31 +00003668
wdenk2729af92004-05-03 20:45:30 +00003669(2) If you execute several variables with one call to run (i. e.
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02003670 calling run with a list of variables as arguments), any failing
wdenk2729af92004-05-03 20:45:30 +00003671 command will cause "run" to terminate, i. e. the remaining
3672 variables are not executed.
wdenkf07771c2003-05-28 08:06:31 +00003673
wdenk2729af92004-05-03 20:45:30 +00003674Note for Redundant Ethernet Interfaces:
3675=======================================
wdenkf07771c2003-05-28 08:06:31 +00003676
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02003677Some boards come with redundant Ethernet interfaces; U-Boot supports
wdenk2729af92004-05-03 20:45:30 +00003678such configurations and is capable of automatic selection of a
3679"working" interface when needed. MAC assignment works as follows:
wdenkf07771c2003-05-28 08:06:31 +00003680
wdenk2729af92004-05-03 20:45:30 +00003681Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3682MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3683"eth1addr" (=>eth1), "eth2addr", ...
wdenkf07771c2003-05-28 08:06:31 +00003684
wdenk2729af92004-05-03 20:45:30 +00003685If the network interface stores some valid MAC address (for instance
3686in SROM), this is used as default address if there is NO correspon-
3687ding setting in the environment; if the corresponding environment
3688variable is set, this overrides the settings in the card; that means:
wdenkf07771c2003-05-28 08:06:31 +00003689
wdenk2729af92004-05-03 20:45:30 +00003690o If the SROM has a valid MAC address, and there is no address in the
3691 environment, the SROM's address is used.
wdenkc6097192002-11-03 00:24:07 +00003692
wdenk2729af92004-05-03 20:45:30 +00003693o If there is no valid address in the SROM, and a definition in the
3694 environment exists, then the value from the environment variable is
3695 used.
wdenkc6097192002-11-03 00:24:07 +00003696
wdenk2729af92004-05-03 20:45:30 +00003697o If both the SROM and the environment contain a MAC address, and
3698 both addresses are the same, this MAC address is used.
wdenkc6097192002-11-03 00:24:07 +00003699
wdenk2729af92004-05-03 20:45:30 +00003700o If both the SROM and the environment contain a MAC address, and the
3701 addresses differ, the value from the environment is used and a
3702 warning is printed.
wdenkc6097192002-11-03 00:24:07 +00003703
wdenk2729af92004-05-03 20:45:30 +00003704o If neither SROM nor the environment contain a MAC address, an error
Joe Hershbergerbef10142015-05-04 14:55:13 -05003705 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
3706 a random, locally-assigned MAC is used.
wdenkc6097192002-11-03 00:24:07 +00003707
Ben Warrenecee9322010-04-26 11:11:46 -07003708If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
Wolfgang Denkc0f40852011-10-26 10:21:21 +00003709will be programmed into hardware as part of the initialization process. This
Ben Warrenecee9322010-04-26 11:11:46 -07003710may be skipped by setting the appropriate 'ethmacskip' environment variable.
3711The naming convention is as follows:
3712"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
wdenkc6097192002-11-03 00:24:07 +00003713
wdenk2729af92004-05-03 20:45:30 +00003714Image Formats:
3715==============
wdenkc6097192002-11-03 00:24:07 +00003716
Marian Balakowicz3310c542008-03-12 12:13:13 +01003717U-Boot is capable of booting (and performing other auxiliary operations on)
3718images in two formats:
3719
3720New uImage format (FIT)
3721-----------------------
3722
3723Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3724to Flattened Device Tree). It allows the use of images with multiple
3725components (several kernels, ramdisks, etc.), with contents protected by
3726SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3727
3728
3729Old uImage format
3730-----------------
3731
3732Old image format is based on binary files which can be basically anything,
3733preceded by a special header; see the definitions in include/image.h for
3734details; basically, the header defines the following image properties:
wdenkc6097192002-11-03 00:24:07 +00003735
wdenk2729af92004-05-03 20:45:30 +00003736* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3737 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
Peter Tyserf5ed9e32008-09-08 14:56:49 -05003738 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3739 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3740 INTEGRITY).
Andy Shevchenkodaab59a2017-07-05 16:25:22 +03003741* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
Macpaul Linafc1ce82011-10-19 20:41:11 +00003742 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
Andy Shevchenkodaab59a2017-07-05 16:25:22 +03003743 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
wdenk2729af92004-05-03 20:45:30 +00003744* Compression Type (uncompressed, gzip, bzip2)
3745* Load Address
3746* Entry Point
3747* Image Name
3748* Image Timestamp
wdenkc6097192002-11-03 00:24:07 +00003749
wdenk2729af92004-05-03 20:45:30 +00003750The header is marked by a special Magic Number, and both the header
3751and the data portions of the image are secured against corruption by
3752CRC32 checksums.
wdenkc6097192002-11-03 00:24:07 +00003753
wdenkc6097192002-11-03 00:24:07 +00003754
wdenk2729af92004-05-03 20:45:30 +00003755Linux Support:
3756==============
wdenkc6097192002-11-03 00:24:07 +00003757
wdenk2729af92004-05-03 20:45:30 +00003758Although U-Boot should support any OS or standalone application
3759easily, the main focus has always been on Linux during the design of
3760U-Boot.
wdenkc6097192002-11-03 00:24:07 +00003761
wdenk2729af92004-05-03 20:45:30 +00003762U-Boot includes many features that so far have been part of some
3763special "boot loader" code within the Linux kernel. Also, any
3764"initrd" images to be used are no longer part of one big Linux image;
3765instead, kernel and "initrd" are separate images. This implementation
3766serves several purposes:
wdenkc6097192002-11-03 00:24:07 +00003767
wdenk2729af92004-05-03 20:45:30 +00003768- the same features can be used for other OS or standalone
3769 applications (for instance: using compressed images to reduce the
3770 Flash memory footprint)
wdenkc6097192002-11-03 00:24:07 +00003771
wdenk2729af92004-05-03 20:45:30 +00003772- it becomes much easier to port new Linux kernel versions because
3773 lots of low-level, hardware dependent stuff are done by U-Boot
wdenkc6097192002-11-03 00:24:07 +00003774
wdenk2729af92004-05-03 20:45:30 +00003775- the same Linux kernel image can now be used with different "initrd"
3776 images; of course this also means that different kernel images can
3777 be run with the same "initrd". This makes testing easier (you don't
3778 have to build a new "zImage.initrd" Linux image when you just
3779 change a file in your "initrd"). Also, a field-upgrade of the
3780 software is easier now.
wdenkc6097192002-11-03 00:24:07 +00003781
wdenkc6097192002-11-03 00:24:07 +00003782
wdenk2729af92004-05-03 20:45:30 +00003783Linux HOWTO:
3784============
wdenkc6097192002-11-03 00:24:07 +00003785
wdenk2729af92004-05-03 20:45:30 +00003786Porting Linux to U-Boot based systems:
3787---------------------------------------
wdenkc6097192002-11-03 00:24:07 +00003788
wdenk2729af92004-05-03 20:45:30 +00003789U-Boot cannot save you from doing all the necessary modifications to
3790configure the Linux device drivers for use with your target hardware
3791(no, we don't intend to provide a full virtual machine interface to
3792Linux :-).
wdenkc6097192002-11-03 00:24:07 +00003793
Stefan Roesea47a12b2010-04-15 16:07:28 +02003794But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
wdenkc6097192002-11-03 00:24:07 +00003795
wdenk2729af92004-05-03 20:45:30 +00003796Just make sure your machine specific header file (for instance
3797include/asm-ppc/tqm8xx.h) includes the same definition of the Board
Markus Heidelberg1dc30692008-09-07 20:18:27 +02003798Information structure as we define in include/asm-<arch>/u-boot.h,
3799and make sure that your definition of IMAP_ADDR uses the same value
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02003800as your U-Boot configuration in CONFIG_SYS_IMMR.
wdenkc6097192002-11-03 00:24:07 +00003801
Simon Glass2eb31b12014-06-11 23:29:46 -06003802Note that U-Boot now has a driver model, a unified model for drivers.
3803If you are adding a new driver, plumb it into driver model. If there
3804is no uclass available, you are encouraged to create one. See
3805doc/driver-model.
3806
wdenkc6097192002-11-03 00:24:07 +00003807
wdenk2729af92004-05-03 20:45:30 +00003808Configuring the Linux kernel:
3809-----------------------------
wdenkc6097192002-11-03 00:24:07 +00003810
wdenk2729af92004-05-03 20:45:30 +00003811No specific requirements for U-Boot. Make sure you have some root
3812device (initial ramdisk, NFS) for your target system.
wdenkc6097192002-11-03 00:24:07 +00003813
wdenkc6097192002-11-03 00:24:07 +00003814
wdenk2729af92004-05-03 20:45:30 +00003815Building a Linux Image:
3816-----------------------
wdenkc6097192002-11-03 00:24:07 +00003817
wdenk2729af92004-05-03 20:45:30 +00003818With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3819not used. If you use recent kernel source, a new build target
3820"uImage" will exist which automatically builds an image usable by
3821U-Boot. Most older kernels also have support for a "pImage" target,
3822which was introduced for our predecessor project PPCBoot and uses a
3823100% compatible format.
wdenkc6097192002-11-03 00:24:07 +00003824
wdenk2729af92004-05-03 20:45:30 +00003825Example:
wdenkc6097192002-11-03 00:24:07 +00003826
Holger Freytherab584d62014-08-04 09:26:05 +02003827 make TQM850L_defconfig
wdenk2729af92004-05-03 20:45:30 +00003828 make oldconfig
3829 make dep
3830 make uImage
wdenkc6097192002-11-03 00:24:07 +00003831
wdenk2729af92004-05-03 20:45:30 +00003832The "uImage" build target uses a special tool (in 'tools/mkimage') to
3833encapsulate a compressed Linux kernel image with header information,
3834CRC32 checksum etc. for use with U-Boot. This is what we are doing:
wdenkc6097192002-11-03 00:24:07 +00003835
wdenk2729af92004-05-03 20:45:30 +00003836* build a standard "vmlinux" kernel image (in ELF binary format):
wdenkc6097192002-11-03 00:24:07 +00003837
wdenk2729af92004-05-03 20:45:30 +00003838* convert the kernel into a raw binary image:
wdenkc6097192002-11-03 00:24:07 +00003839
wdenk2729af92004-05-03 20:45:30 +00003840 ${CROSS_COMPILE}-objcopy -O binary \
3841 -R .note -R .comment \
3842 -S vmlinux linux.bin
wdenkc6097192002-11-03 00:24:07 +00003843
wdenk2729af92004-05-03 20:45:30 +00003844* compress the binary image:
wdenkc6097192002-11-03 00:24:07 +00003845
wdenk2729af92004-05-03 20:45:30 +00003846 gzip -9 linux.bin
wdenkc6097192002-11-03 00:24:07 +00003847
wdenk2729af92004-05-03 20:45:30 +00003848* package compressed binary image for U-Boot:
wdenk24ee89b2002-11-03 17:56:27 +00003849
wdenk2729af92004-05-03 20:45:30 +00003850 mkimage -A ppc -O linux -T kernel -C gzip \
3851 -a 0 -e 0 -n "Linux Kernel Image" \
3852 -d linux.bin.gz uImage
wdenk24ee89b2002-11-03 17:56:27 +00003853
wdenk24ee89b2002-11-03 17:56:27 +00003854
wdenk2729af92004-05-03 20:45:30 +00003855The "mkimage" tool can also be used to create ramdisk images for use
3856with U-Boot, either separated from the Linux kernel image, or
3857combined into one file. "mkimage" encapsulates the images with a 64
3858byte header containing information about target architecture,
3859operating system, image type, compression method, entry points, time
3860stamp, CRC32 checksums, etc.
wdenk24ee89b2002-11-03 17:56:27 +00003861
wdenk2729af92004-05-03 20:45:30 +00003862"mkimage" can be called in two ways: to verify existing images and
3863print the header information, or to build new images.
wdenk24ee89b2002-11-03 17:56:27 +00003864
wdenk2729af92004-05-03 20:45:30 +00003865In the first form (with "-l" option) mkimage lists the information
3866contained in the header of an existing U-Boot image; this includes
3867checksum verification:
wdenk24ee89b2002-11-03 17:56:27 +00003868
wdenk2729af92004-05-03 20:45:30 +00003869 tools/mkimage -l image
3870 -l ==> list image header information
wdenk24ee89b2002-11-03 17:56:27 +00003871
wdenk2729af92004-05-03 20:45:30 +00003872The second form (with "-d" option) is used to build a U-Boot image
3873from a "data file" which is used as image payload:
wdenk24ee89b2002-11-03 17:56:27 +00003874
wdenk2729af92004-05-03 20:45:30 +00003875 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3876 -n name -d data_file image
3877 -A ==> set architecture to 'arch'
3878 -O ==> set operating system to 'os'
3879 -T ==> set image type to 'type'
3880 -C ==> set compression type 'comp'
3881 -a ==> set load address to 'addr' (hex)
3882 -e ==> set entry point to 'ep' (hex)
3883 -n ==> set image name to 'name'
3884 -d ==> use image data from 'datafile'
wdenk24ee89b2002-11-03 17:56:27 +00003885
wdenk69459792004-05-29 16:53:29 +00003886Right now, all Linux kernels for PowerPC systems use the same load
3887address (0x00000000), but the entry point address depends on the
3888kernel version:
wdenkc6097192002-11-03 00:24:07 +00003889
wdenk2729af92004-05-03 20:45:30 +00003890- 2.2.x kernels have the entry point at 0x0000000C,
3891- 2.3.x and later kernels have the entry point at 0x00000000.
wdenkc6097192002-11-03 00:24:07 +00003892
wdenk2729af92004-05-03 20:45:30 +00003893So a typical call to build a U-Boot image would read:
wdenkc6097192002-11-03 00:24:07 +00003894
wdenk2729af92004-05-03 20:45:30 +00003895 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3896 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
Stefan Roesea47a12b2010-04-15 16:07:28 +02003897 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
wdenk2729af92004-05-03 20:45:30 +00003898 > examples/uImage.TQM850L
3899 Image Name: 2.4.4 kernel for TQM850L
3900 Created: Wed Jul 19 02:34:59 2000
3901 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3902 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3903 Load Address: 0x00000000
3904 Entry Point: 0x00000000
wdenkc6097192002-11-03 00:24:07 +00003905
wdenk2729af92004-05-03 20:45:30 +00003906To verify the contents of the image (or check for corruption):
wdenkc6097192002-11-03 00:24:07 +00003907
wdenk2729af92004-05-03 20:45:30 +00003908 -> tools/mkimage -l examples/uImage.TQM850L
3909 Image Name: 2.4.4 kernel for TQM850L
3910 Created: Wed Jul 19 02:34:59 2000
3911 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3912 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3913 Load Address: 0x00000000
3914 Entry Point: 0x00000000
wdenkc6097192002-11-03 00:24:07 +00003915
wdenk2729af92004-05-03 20:45:30 +00003916NOTE: for embedded systems where boot time is critical you can trade
3917speed for memory and install an UNCOMPRESSED image instead: this
3918needs more space in Flash, but boots much faster since it does not
3919need to be uncompressed:
wdenkc6097192002-11-03 00:24:07 +00003920
Stefan Roesea47a12b2010-04-15 16:07:28 +02003921 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
wdenk2729af92004-05-03 20:45:30 +00003922 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3923 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
Stefan Roesea47a12b2010-04-15 16:07:28 +02003924 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
wdenk2729af92004-05-03 20:45:30 +00003925 > examples/uImage.TQM850L-uncompressed
3926 Image Name: 2.4.4 kernel for TQM850L
3927 Created: Wed Jul 19 02:34:59 2000
3928 Image Type: PowerPC Linux Kernel Image (uncompressed)
3929 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3930 Load Address: 0x00000000
3931 Entry Point: 0x00000000
wdenkc6097192002-11-03 00:24:07 +00003932
wdenkc6097192002-11-03 00:24:07 +00003933
wdenk2729af92004-05-03 20:45:30 +00003934Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3935when your kernel is intended to use an initial ramdisk:
wdenkdb01a2e2004-04-15 23:14:49 +00003936
wdenk2729af92004-05-03 20:45:30 +00003937 -> tools/mkimage -n 'Simple Ramdisk Image' \
3938 > -A ppc -O linux -T ramdisk -C gzip \
3939 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3940 Image Name: Simple Ramdisk Image
3941 Created: Wed Jan 12 14:01:50 2000
3942 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3943 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3944 Load Address: 0x00000000
3945 Entry Point: 0x00000000
wdenkdb01a2e2004-04-15 23:14:49 +00003946
Guilherme Maciel Ferreiraa804b5c2013-12-01 12:43:11 -07003947The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
3948option performs the converse operation of the mkimage's second form (the "-d"
3949option). Given an image built by mkimage, the dumpimage extracts a "data file"
3950from the image:
3951
Guilherme Maciel Ferreiraf41f5b72015-01-15 02:54:40 -02003952 tools/dumpimage -i image -T type -p position data_file
3953 -i ==> extract from the 'image' a specific 'data_file'
3954 -T ==> set image type to 'type'
3955 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
Guilherme Maciel Ferreiraa804b5c2013-12-01 12:43:11 -07003956
wdenkdb01a2e2004-04-15 23:14:49 +00003957
wdenk2729af92004-05-03 20:45:30 +00003958Installing a Linux Image:
3959-------------------------
wdenkdb01a2e2004-04-15 23:14:49 +00003960
wdenk2729af92004-05-03 20:45:30 +00003961To downloading a U-Boot image over the serial (console) interface,
3962you must convert the image to S-Record format:
wdenkdb01a2e2004-04-15 23:14:49 +00003963
wdenk2729af92004-05-03 20:45:30 +00003964 objcopy -I binary -O srec examples/image examples/image.srec
wdenkdb01a2e2004-04-15 23:14:49 +00003965
wdenk2729af92004-05-03 20:45:30 +00003966The 'objcopy' does not understand the information in the U-Boot
3967image header, so the resulting S-Record file will be relative to
3968address 0x00000000. To load it to a given address, you need to
3969specify the target address as 'offset' parameter with the 'loads'
3970command.
wdenkc6097192002-11-03 00:24:07 +00003971
wdenk2729af92004-05-03 20:45:30 +00003972Example: install the image to address 0x40100000 (which on the
3973TQM8xxL is in the first Flash bank):
wdenkc6097192002-11-03 00:24:07 +00003974
wdenk2729af92004-05-03 20:45:30 +00003975 => erase 40100000 401FFFFF
wdenkc6097192002-11-03 00:24:07 +00003976
wdenk2729af92004-05-03 20:45:30 +00003977 .......... done
3978 Erased 8 sectors
wdenkc6097192002-11-03 00:24:07 +00003979
wdenk2729af92004-05-03 20:45:30 +00003980 => loads 40100000
3981 ## Ready for S-Record download ...
3982 ~>examples/image.srec
3983 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3984 ...
3985 15989 15990 15991 15992
3986 [file transfer complete]
3987 [connected]
3988 ## Start Addr = 0x00000000
wdenkc6097192002-11-03 00:24:07 +00003989
3990
wdenk2729af92004-05-03 20:45:30 +00003991You can check the success of the download using the 'iminfo' command;
Wolfgang Denk218ca722008-03-26 10:40:12 +01003992this includes a checksum verification so you can be sure no data
wdenk2729af92004-05-03 20:45:30 +00003993corruption happened:
wdenkc6097192002-11-03 00:24:07 +00003994
wdenk2729af92004-05-03 20:45:30 +00003995 => imi 40100000
wdenkc6097192002-11-03 00:24:07 +00003996
wdenk2729af92004-05-03 20:45:30 +00003997 ## Checking Image at 40100000 ...
3998 Image Name: 2.2.13 for initrd on TQM850L
3999 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4000 Data Size: 335725 Bytes = 327 kB = 0 MB
4001 Load Address: 00000000
4002 Entry Point: 0000000c
4003 Verifying Checksum ... OK
wdenkc6097192002-11-03 00:24:07 +00004004
4005
wdenk2729af92004-05-03 20:45:30 +00004006Boot Linux:
4007-----------
wdenkc6097192002-11-03 00:24:07 +00004008
wdenk2729af92004-05-03 20:45:30 +00004009The "bootm" command is used to boot an application that is stored in
4010memory (RAM or Flash). In case of a Linux kernel image, the contents
4011of the "bootargs" environment variable is passed to the kernel as
4012parameters. You can check and modify this variable using the
4013"printenv" and "setenv" commands:
wdenkc6097192002-11-03 00:24:07 +00004014
4015
wdenk2729af92004-05-03 20:45:30 +00004016 => printenv bootargs
4017 bootargs=root=/dev/ram
wdenkc6097192002-11-03 00:24:07 +00004018
wdenk2729af92004-05-03 20:45:30 +00004019 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
wdenkc6097192002-11-03 00:24:07 +00004020
wdenk2729af92004-05-03 20:45:30 +00004021 => printenv bootargs
4022 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
wdenkc6097192002-11-03 00:24:07 +00004023
wdenk2729af92004-05-03 20:45:30 +00004024 => bootm 40020000
4025 ## Booting Linux kernel at 40020000 ...
4026 Image Name: 2.2.13 for NFS on TQM850L
4027 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4028 Data Size: 381681 Bytes = 372 kB = 0 MB
4029 Load Address: 00000000
4030 Entry Point: 0000000c
4031 Verifying Checksum ... OK
4032 Uncompressing Kernel Image ... OK
4033 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
4034 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4035 time_init: decrementer frequency = 187500000/60
4036 Calibrating delay loop... 49.77 BogoMIPS
4037 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4038 ...
wdenkc6097192002-11-03 00:24:07 +00004039
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02004040If you want to boot a Linux kernel with initial RAM disk, you pass
wdenk2729af92004-05-03 20:45:30 +00004041the memory addresses of both the kernel and the initrd image (PPBCOOT
4042format!) to the "bootm" command:
wdenkc6097192002-11-03 00:24:07 +00004043
wdenk2729af92004-05-03 20:45:30 +00004044 => imi 40100000 40200000
wdenkc6097192002-11-03 00:24:07 +00004045
wdenk2729af92004-05-03 20:45:30 +00004046 ## Checking Image at 40100000 ...
4047 Image Name: 2.2.13 for initrd on TQM850L
4048 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4049 Data Size: 335725 Bytes = 327 kB = 0 MB
4050 Load Address: 00000000
4051 Entry Point: 0000000c
4052 Verifying Checksum ... OK
wdenkc6097192002-11-03 00:24:07 +00004053
wdenk2729af92004-05-03 20:45:30 +00004054 ## Checking Image at 40200000 ...
4055 Image Name: Simple Ramdisk Image
4056 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4057 Data Size: 566530 Bytes = 553 kB = 0 MB
4058 Load Address: 00000000
4059 Entry Point: 00000000
4060 Verifying Checksum ... OK
wdenkc6097192002-11-03 00:24:07 +00004061
wdenk2729af92004-05-03 20:45:30 +00004062 => bootm 40100000 40200000
4063 ## Booting Linux kernel at 40100000 ...
4064 Image Name: 2.2.13 for initrd on TQM850L
4065 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4066 Data Size: 335725 Bytes = 327 kB = 0 MB
4067 Load Address: 00000000
4068 Entry Point: 0000000c
4069 Verifying Checksum ... OK
4070 Uncompressing Kernel Image ... OK
4071 ## Loading RAMDisk Image at 40200000 ...
4072 Image Name: Simple Ramdisk Image
4073 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4074 Data Size: 566530 Bytes = 553 kB = 0 MB
4075 Load Address: 00000000
4076 Entry Point: 00000000
4077 Verifying Checksum ... OK
4078 Loading Ramdisk ... OK
4079 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
4080 Boot arguments: root=/dev/ram
4081 time_init: decrementer frequency = 187500000/60
4082 Calibrating delay loop... 49.77 BogoMIPS
4083 ...
4084 RAMDISK: Compressed image found at block 0
4085 VFS: Mounted root (ext2 filesystem).
wdenkc6097192002-11-03 00:24:07 +00004086
wdenk2729af92004-05-03 20:45:30 +00004087 bash#
wdenkc6097192002-11-03 00:24:07 +00004088
Matthew McClintock02677682006-06-28 10:41:37 -05004089Boot Linux and pass a flat device tree:
4090-----------
4091
4092First, U-Boot must be compiled with the appropriate defines. See the section
4093titled "Linux Kernel Interface" above for a more in depth explanation. The
4094following is an example of how to start a kernel and pass an updated
4095flat device tree:
4096
4097=> print oftaddr
4098oftaddr=0x300000
4099=> print oft
4100oft=oftrees/mpc8540ads.dtb
4101=> tftp $oftaddr $oft
4102Speed: 1000, full duplex
4103Using TSEC0 device
4104TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4105Filename 'oftrees/mpc8540ads.dtb'.
4106Load address: 0x300000
4107Loading: #
4108done
4109Bytes transferred = 4106 (100a hex)
4110=> tftp $loadaddr $bootfile
4111Speed: 1000, full duplex
4112Using TSEC0 device
4113TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4114Filename 'uImage'.
4115Load address: 0x200000
4116Loading:############
4117done
4118Bytes transferred = 1029407 (fb51f hex)
4119=> print loadaddr
4120loadaddr=200000
4121=> print oftaddr
4122oftaddr=0x300000
4123=> bootm $loadaddr - $oftaddr
4124## Booting image at 00200000 ...
Wolfgang Denka9398e02006-11-27 15:32:42 +01004125 Image Name: Linux-2.6.17-dirty
4126 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4127 Data Size: 1029343 Bytes = 1005.2 kB
Matthew McClintock02677682006-06-28 10:41:37 -05004128 Load Address: 00000000
Wolfgang Denka9398e02006-11-27 15:32:42 +01004129 Entry Point: 00000000
Matthew McClintock02677682006-06-28 10:41:37 -05004130 Verifying Checksum ... OK
4131 Uncompressing Kernel Image ... OK
4132Booting using flat device tree at 0x300000
4133Using MPC85xx ADS machine description
4134Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4135[snip]
4136
4137
wdenk2729af92004-05-03 20:45:30 +00004138More About U-Boot Image Types:
4139------------------------------
wdenk6069ff22003-02-28 00:49:47 +00004140
wdenk2729af92004-05-03 20:45:30 +00004141U-Boot supports the following image types:
wdenk6069ff22003-02-28 00:49:47 +00004142
wdenk2729af92004-05-03 20:45:30 +00004143 "Standalone Programs" are directly runnable in the environment
4144 provided by U-Boot; it is expected that (if they behave
4145 well) you can continue to work in U-Boot after return from
4146 the Standalone Program.
4147 "OS Kernel Images" are usually images of some Embedded OS which
4148 will take over control completely. Usually these programs
4149 will install their own set of exception handlers, device
4150 drivers, set up the MMU, etc. - this means, that you cannot
4151 expect to re-enter U-Boot except by resetting the CPU.
4152 "RAMDisk Images" are more or less just data blocks, and their
4153 parameters (address, size) are passed to an OS kernel that is
4154 being started.
4155 "Multi-File Images" contain several images, typically an OS
4156 (Linux) kernel image and one or more data images like
4157 RAMDisks. This construct is useful for instance when you want
4158 to boot over the network using BOOTP etc., where the boot
4159 server provides just a single image file, but you want to get
4160 for instance an OS kernel and a RAMDisk image.
stroesec1551ea2003-04-04 15:53:41 +00004161
wdenk2729af92004-05-03 20:45:30 +00004162 "Multi-File Images" start with a list of image sizes, each
4163 image size (in bytes) specified by an "uint32_t" in network
4164 byte order. This list is terminated by an "(uint32_t)0".
4165 Immediately after the terminating 0 follow the images, one by
4166 one, all aligned on "uint32_t" boundaries (size rounded up to
4167 a multiple of 4 bytes).
stroesec1551ea2003-04-04 15:53:41 +00004168
wdenk2729af92004-05-03 20:45:30 +00004169 "Firmware Images" are binary images containing firmware (like
4170 U-Boot or FPGA images) which usually will be programmed to
4171 flash memory.
stroesec1551ea2003-04-04 15:53:41 +00004172
wdenk2729af92004-05-03 20:45:30 +00004173 "Script files" are command sequences that will be executed by
4174 U-Boot's command interpreter; this feature is especially
4175 useful when you configure U-Boot to use a real shell (hush)
4176 as command interpreter.
wdenk6069ff22003-02-28 00:49:47 +00004177
Marek Vasut44f074c2012-03-14 21:52:45 +00004178Booting the Linux zImage:
4179-------------------------
4180
4181On some platforms, it's possible to boot Linux zImage. This is done
4182using the "bootz" command. The syntax of "bootz" command is the same
4183as the syntax of "bootm" command.
4184
Tom Rini8ac28562013-05-16 11:40:11 -04004185Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
Marek Vasut017e1f32012-03-18 11:47:58 +00004186kernel with raw initrd images. The syntax is slightly different, the
4187address of the initrd must be augmented by it's size, in the following
4188format: "<initrd addres>:<initrd size>".
4189
wdenkc6097192002-11-03 00:24:07 +00004190
wdenk2729af92004-05-03 20:45:30 +00004191Standalone HOWTO:
4192=================
wdenkc6097192002-11-03 00:24:07 +00004193
wdenk2729af92004-05-03 20:45:30 +00004194One of the features of U-Boot is that you can dynamically load and
4195run "standalone" applications, which can use some resources of
4196U-Boot like console I/O functions or interrupt services.
wdenkc6097192002-11-03 00:24:07 +00004197
wdenk2729af92004-05-03 20:45:30 +00004198Two simple examples are included with the sources:
wdenkc6097192002-11-03 00:24:07 +00004199
wdenk2729af92004-05-03 20:45:30 +00004200"Hello World" Demo:
4201-------------------
wdenkc6097192002-11-03 00:24:07 +00004202
wdenk2729af92004-05-03 20:45:30 +00004203'examples/hello_world.c' contains a small "Hello World" Demo
4204application; it is automatically compiled when you build U-Boot.
4205It's configured to run at address 0x00040004, so you can play with it
4206like that:
wdenkc6097192002-11-03 00:24:07 +00004207
wdenk2729af92004-05-03 20:45:30 +00004208 => loads
4209 ## Ready for S-Record download ...
4210 ~>examples/hello_world.srec
4211 1 2 3 4 5 6 7 8 9 10 11 ...
4212 [file transfer complete]
4213 [connected]
4214 ## Start Addr = 0x00040004
wdenkc6097192002-11-03 00:24:07 +00004215
wdenk2729af92004-05-03 20:45:30 +00004216 => go 40004 Hello World! This is a test.
4217 ## Starting application at 0x00040004 ...
4218 Hello World
4219 argc = 7
4220 argv[0] = "40004"
4221 argv[1] = "Hello"
4222 argv[2] = "World!"
4223 argv[3] = "This"
4224 argv[4] = "is"
4225 argv[5] = "a"
4226 argv[6] = "test."
4227 argv[7] = "<NULL>"
4228 Hit any key to exit ...
wdenkc6097192002-11-03 00:24:07 +00004229
wdenk2729af92004-05-03 20:45:30 +00004230 ## Application terminated, rc = 0x0
wdenkc6097192002-11-03 00:24:07 +00004231
wdenk2729af92004-05-03 20:45:30 +00004232Another example, which demonstrates how to register a CPM interrupt
4233handler with the U-Boot code, can be found in 'examples/timer.c'.
4234Here, a CPM timer is set up to generate an interrupt every second.
4235The interrupt service routine is trivial, just printing a '.'
4236character, but this is just a demo program. The application can be
4237controlled by the following keys:
wdenkc6097192002-11-03 00:24:07 +00004238
wdenk2729af92004-05-03 20:45:30 +00004239 ? - print current values og the CPM Timer registers
4240 b - enable interrupts and start timer
4241 e - stop timer and disable interrupts
4242 q - quit application
wdenkc6097192002-11-03 00:24:07 +00004243
wdenk2729af92004-05-03 20:45:30 +00004244 => loads
4245 ## Ready for S-Record download ...
4246 ~>examples/timer.srec
4247 1 2 3 4 5 6 7 8 9 10 11 ...
4248 [file transfer complete]
4249 [connected]
4250 ## Start Addr = 0x00040004
wdenkc6097192002-11-03 00:24:07 +00004251
wdenk2729af92004-05-03 20:45:30 +00004252 => go 40004
4253 ## Starting application at 0x00040004 ...
4254 TIMERS=0xfff00980
4255 Using timer 1
4256 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
wdenkc6097192002-11-03 00:24:07 +00004257
wdenk2729af92004-05-03 20:45:30 +00004258Hit 'b':
4259 [q, b, e, ?] Set interval 1000000 us
4260 Enabling timer
4261Hit '?':
4262 [q, b, e, ?] ........
4263 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4264Hit '?':
4265 [q, b, e, ?] .
4266 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4267Hit '?':
4268 [q, b, e, ?] .
4269 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4270Hit '?':
4271 [q, b, e, ?] .
4272 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4273Hit 'e':
4274 [q, b, e, ?] ...Stopping timer
4275Hit 'q':
4276 [q, b, e, ?] ## Application terminated, rc = 0x0
wdenkc6097192002-11-03 00:24:07 +00004277
4278
wdenk2729af92004-05-03 20:45:30 +00004279Minicom warning:
4280================
wdenk85ec0bc2003-03-31 16:34:49 +00004281
wdenk2729af92004-05-03 20:45:30 +00004282Over time, many people have reported problems when trying to use the
4283"minicom" terminal emulation program for serial download. I (wd)
4284consider minicom to be broken, and recommend not to use it. Under
4285Unix, I recommend to use C-Kermit for general purpose use (and
4286especially for kermit binary protocol download ("loadb" command), and
Karl O. Pince53515a2012-10-01 05:11:56 +00004287use "cu" for S-Record download ("loads" command). See
4288http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4289for help with kermit.
4290
wdenk85ec0bc2003-03-31 16:34:49 +00004291
wdenk2729af92004-05-03 20:45:30 +00004292Nevertheless, if you absolutely want to use it try adding this
4293configuration to your "File transfer protocols" section:
wdenk52f52c12003-06-19 23:04:19 +00004294
wdenk2729af92004-05-03 20:45:30 +00004295 Name Program Name U/D FullScr IO-Red. Multi
4296 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4297 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
wdenk52f52c12003-06-19 23:04:19 +00004298
4299
wdenk2729af92004-05-03 20:45:30 +00004300NetBSD Notes:
4301=============
wdenkc6097192002-11-03 00:24:07 +00004302
wdenk2729af92004-05-03 20:45:30 +00004303Starting at version 0.9.2, U-Boot supports NetBSD both as host
4304(build U-Boot) and target system (boots NetBSD/mpc8xx).
wdenkc6097192002-11-03 00:24:07 +00004305
wdenk2729af92004-05-03 20:45:30 +00004306Building requires a cross environment; it is known to work on
4307NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4308need gmake since the Makefiles are not compatible with BSD make).
4309Note that the cross-powerpc package does not install include files;
4310attempting to build U-Boot will fail because <machine/ansi.h> is
4311missing. This file has to be installed and patched manually:
wdenkc6097192002-11-03 00:24:07 +00004312
wdenk2729af92004-05-03 20:45:30 +00004313 # cd /usr/pkg/cross/powerpc-netbsd/include
4314 # mkdir powerpc
4315 # ln -s powerpc machine
4316 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4317 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
wdenkc6097192002-11-03 00:24:07 +00004318
wdenk2729af92004-05-03 20:45:30 +00004319Native builds *don't* work due to incompatibilities between native
4320and U-Boot include files.
wdenkc6097192002-11-03 00:24:07 +00004321
wdenk2729af92004-05-03 20:45:30 +00004322Booting assumes that (the first part of) the image booted is a
4323stage-2 loader which in turn loads and then invokes the kernel
4324proper. Loader sources will eventually appear in the NetBSD source
4325tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
wdenk2a8af182005-04-13 10:02:42 +00004326meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
wdenkc6097192002-11-03 00:24:07 +00004327
4328
wdenk2729af92004-05-03 20:45:30 +00004329Implementation Internals:
4330=========================
wdenkc6097192002-11-03 00:24:07 +00004331
wdenk2729af92004-05-03 20:45:30 +00004332The following is not intended to be a complete description of every
4333implementation detail. However, it should help to understand the
4334inner workings of U-Boot and make it easier to port it to custom
4335hardware.
wdenkc6097192002-11-03 00:24:07 +00004336
4337
wdenk2729af92004-05-03 20:45:30 +00004338Initial Stack, Global Data:
4339---------------------------
wdenkc6097192002-11-03 00:24:07 +00004340
wdenk2729af92004-05-03 20:45:30 +00004341The implementation of U-Boot is complicated by the fact that U-Boot
4342starts running out of ROM (flash memory), usually without access to
4343system RAM (because the memory controller is not initialized yet).
4344This means that we don't have writable Data or BSS segments, and BSS
4345is not initialized as zero. To be able to get a C environment working
4346at all, we have to allocate at least a minimal stack. Implementation
4347options for this are defined and restricted by the CPU used: Some CPU
4348models provide on-chip memory (like the IMMR area on MPC8xx and
4349MPC826x processors), on others (parts of) the data cache can be
4350locked as (mis-) used as memory, etc.
wdenkc6097192002-11-03 00:24:07 +00004351
Wolfgang Denk218ca722008-03-26 10:40:12 +01004352 Chris Hallinan posted a good summary of these issues to the
Wolfgang Denk06682362008-12-30 22:56:11 +01004353 U-Boot mailing list:
wdenk43d96162003-03-06 00:02:04 +00004354
wdenk2729af92004-05-03 20:45:30 +00004355 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4356 From: "Chris Hallinan" <clh@net1plus.com>
4357 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4358 ...
wdenk43d96162003-03-06 00:02:04 +00004359
wdenk2729af92004-05-03 20:45:30 +00004360 Correct me if I'm wrong, folks, but the way I understand it
4361 is this: Using DCACHE as initial RAM for Stack, etc, does not
4362 require any physical RAM backing up the cache. The cleverness
4363 is that the cache is being used as a temporary supply of
4364 necessary storage before the SDRAM controller is setup. It's
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02004365 beyond the scope of this list to explain the details, but you
wdenk2729af92004-05-03 20:45:30 +00004366 can see how this works by studying the cache architecture and
4367 operation in the architecture and processor-specific manuals.
wdenk43d96162003-03-06 00:02:04 +00004368
wdenk2729af92004-05-03 20:45:30 +00004369 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4370 is another option for the system designer to use as an
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02004371 initial stack/RAM area prior to SDRAM being available. Either
wdenk2729af92004-05-03 20:45:30 +00004372 option should work for you. Using CS 4 should be fine if your
4373 board designers haven't used it for something that would
4374 cause you grief during the initial boot! It is frequently not
4375 used.
wdenk43d96162003-03-06 00:02:04 +00004376
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02004377 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
wdenk2729af92004-05-03 20:45:30 +00004378 with your processor/board/system design. The default value
4379 you will find in any recent u-boot distribution in
Stefan Roese8a316c92005-08-01 16:49:12 +02004380 walnut.h should work for you. I'd set it to a value larger
wdenk2729af92004-05-03 20:45:30 +00004381 than your SDRAM module. If you have a 64MB SDRAM module, set
4382 it above 400_0000. Just make sure your board has no resources
4383 that are supposed to respond to that address! That code in
4384 start.S has been around a while and should work as is when
4385 you get the config right.
wdenk43d96162003-03-06 00:02:04 +00004386
wdenk2729af92004-05-03 20:45:30 +00004387 -Chris Hallinan
4388 DS4.COM, Inc.
wdenk43d96162003-03-06 00:02:04 +00004389
wdenk2729af92004-05-03 20:45:30 +00004390It is essential to remember this, since it has some impact on the C
4391code for the initialization procedures:
wdenkc6097192002-11-03 00:24:07 +00004392
wdenk2729af92004-05-03 20:45:30 +00004393* Initialized global data (data segment) is read-only. Do not attempt
4394 to write it.
wdenkc6097192002-11-03 00:24:07 +00004395
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08004396* Do not use any uninitialized global data (or implicitly initialized
wdenk2729af92004-05-03 20:45:30 +00004397 as zero data - BSS segment) at all - this is undefined, initiali-
4398 zation is performed later (when relocating to RAM).
wdenkc6097192002-11-03 00:24:07 +00004399
wdenk2729af92004-05-03 20:45:30 +00004400* Stack space is very limited. Avoid big data buffers or things like
4401 that.
wdenkc6097192002-11-03 00:24:07 +00004402
wdenk2729af92004-05-03 20:45:30 +00004403Having only the stack as writable memory limits means we cannot use
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08004404normal global data to share information between the code. But it
wdenk2729af92004-05-03 20:45:30 +00004405turned out that the implementation of U-Boot can be greatly
4406simplified by making a global data structure (gd_t) available to all
4407functions. We could pass a pointer to this data as argument to _all_
4408functions, but this would bloat the code. Instead we use a feature of
4409the GCC compiler (Global Register Variables) to share the data: we
4410place a pointer (gd) to the global data into a register which we
4411reserve for this purpose.
wdenkc6097192002-11-03 00:24:07 +00004412
wdenk2729af92004-05-03 20:45:30 +00004413When choosing a register for such a purpose we are restricted by the
4414relevant (E)ABI specifications for the current architecture, and by
4415GCC's implementation.
wdenkc6097192002-11-03 00:24:07 +00004416
wdenk2729af92004-05-03 20:45:30 +00004417For PowerPC, the following registers have specific use:
4418 R1: stack pointer
Wolfgang Denke7670f62008-02-14 22:43:22 +01004419 R2: reserved for system use
wdenk2729af92004-05-03 20:45:30 +00004420 R3-R4: parameter passing and return values
4421 R5-R10: parameter passing
4422 R13: small data area pointer
4423 R30: GOT pointer
4424 R31: frame pointer
wdenkc6097192002-11-03 00:24:07 +00004425
Joakim Tjernlunde6bee802010-01-19 14:41:58 +01004426 (U-Boot also uses R12 as internal GOT pointer. r12
4427 is a volatile register so r12 needs to be reset when
4428 going back and forth between asm and C)
wdenkc6097192002-11-03 00:24:07 +00004429
Wolfgang Denke7670f62008-02-14 22:43:22 +01004430 ==> U-Boot will use R2 to hold a pointer to the global data
wdenkc6097192002-11-03 00:24:07 +00004431
wdenk2729af92004-05-03 20:45:30 +00004432 Note: on PPC, we could use a static initializer (since the
4433 address of the global data structure is known at compile time),
4434 but it turned out that reserving a register results in somewhat
4435 smaller code - although the code savings are not that big (on
4436 average for all boards 752 bytes for the whole U-Boot image,
4437 624 text + 127 data).
wdenkc6097192002-11-03 00:24:07 +00004438
wdenk2729af92004-05-03 20:45:30 +00004439On ARM, the following registers are used:
wdenkc6097192002-11-03 00:24:07 +00004440
wdenk2729af92004-05-03 20:45:30 +00004441 R0: function argument word/integer result
4442 R1-R3: function argument word
Jeroen Hofstee12eba1b2013-09-21 14:04:42 +02004443 R9: platform specific
4444 R10: stack limit (used only if stack checking is enabled)
wdenk2729af92004-05-03 20:45:30 +00004445 R11: argument (frame) pointer
4446 R12: temporary workspace
4447 R13: stack pointer
4448 R14: link register
4449 R15: program counter
wdenkc6097192002-11-03 00:24:07 +00004450
Jeroen Hofstee12eba1b2013-09-21 14:04:42 +02004451 ==> U-Boot will use R9 to hold a pointer to the global data
4452
4453 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
wdenkc6097192002-11-03 00:24:07 +00004454
Thomas Chou0df01fd2010-05-21 11:08:03 +08004455On Nios II, the ABI is documented here:
4456 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4457
4458 ==> U-Boot will use gp to hold a pointer to the global data
4459
4460 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4461 to access small data sections, so gp is free.
4462
Macpaul Linafc1ce82011-10-19 20:41:11 +00004463On NDS32, the following registers are used:
4464
4465 R0-R1: argument/return
4466 R2-R5: argument
4467 R15: temporary register for assembler
4468 R16: trampoline register
4469 R28: frame pointer (FP)
4470 R29: global pointer (GP)
4471 R30: link register (LP)
4472 R31: stack pointer (SP)
4473 PC: program counter (PC)
4474
4475 ==> U-Boot will use R10 to hold a pointer to the global data
4476
Wolfgang Denkd87080b2006-03-31 18:32:53 +02004477NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4478or current versions of GCC may "optimize" the code too much.
wdenkc6097192002-11-03 00:24:07 +00004479
Rick Chen3fafced2017-12-26 13:55:59 +08004480On RISC-V, the following registers are used:
4481
4482 x0: hard-wired zero (zero)
4483 x1: return address (ra)
4484 x2: stack pointer (sp)
4485 x3: global pointer (gp)
4486 x4: thread pointer (tp)
4487 x5: link register (t0)
4488 x8: frame pointer (fp)
4489 x10-x11: arguments/return values (a0-1)
4490 x12-x17: arguments (a2-7)
4491 x28-31: temporaries (t3-6)
4492 pc: program counter (pc)
4493
4494 ==> U-Boot will use gp to hold a pointer to the global data
4495
wdenk2729af92004-05-03 20:45:30 +00004496Memory Management:
4497------------------
wdenkc6097192002-11-03 00:24:07 +00004498
wdenk2729af92004-05-03 20:45:30 +00004499U-Boot runs in system state and uses physical addresses, i.e. the
4500MMU is not used either for address mapping nor for memory protection.
wdenkc6097192002-11-03 00:24:07 +00004501
wdenk2729af92004-05-03 20:45:30 +00004502The available memory is mapped to fixed addresses using the memory
4503controller. In this process, a contiguous block is formed for each
4504memory type (Flash, SDRAM, SRAM), even when it consists of several
4505physical memory banks.
wdenkc6097192002-11-03 00:24:07 +00004506
wdenk2729af92004-05-03 20:45:30 +00004507U-Boot is installed in the first 128 kB of the first Flash bank (on
4508TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4509booting and sizing and initializing DRAM, the code relocates itself
4510to the upper end of DRAM. Immediately below the U-Boot code some
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +02004511memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
wdenk2729af92004-05-03 20:45:30 +00004512configuration setting]. Below that, a structure with global Board
4513Info data is placed, followed by the stack (growing downward).
wdenkc6097192002-11-03 00:24:07 +00004514
wdenk2729af92004-05-03 20:45:30 +00004515Additionally, some exception handler code is copied to the low 8 kB
4516of DRAM (0x00000000 ... 0x00001FFF).
wdenkc6097192002-11-03 00:24:07 +00004517
wdenk2729af92004-05-03 20:45:30 +00004518So a typical memory configuration with 16 MB of DRAM could look like
4519this:
wdenkc6097192002-11-03 00:24:07 +00004520
wdenk2729af92004-05-03 20:45:30 +00004521 0x0000 0000 Exception Vector code
4522 :
4523 0x0000 1FFF
4524 0x0000 2000 Free for Application Use
4525 :
4526 :
wdenkc6097192002-11-03 00:24:07 +00004527
wdenk2729af92004-05-03 20:45:30 +00004528 :
4529 :
4530 0x00FB FF20 Monitor Stack (Growing downward)
4531 0x00FB FFAC Board Info Data and permanent copy of global data
4532 0x00FC 0000 Malloc Arena
4533 :
4534 0x00FD FFFF
4535 0x00FE 0000 RAM Copy of Monitor Code
4536 ... eventually: LCD or video framebuffer
4537 ... eventually: pRAM (Protected RAM - unchanged by reset)
4538 0x00FF FFFF [End of RAM]
wdenkc6097192002-11-03 00:24:07 +00004539
4540
wdenk2729af92004-05-03 20:45:30 +00004541System Initialization:
4542----------------------
wdenkc6097192002-11-03 00:24:07 +00004543
wdenk2729af92004-05-03 20:45:30 +00004544In the reset configuration, U-Boot starts at the reset entry point
Marcel Ziswiler11ccc332008-07-09 08:17:15 +02004545(on most PowerPC systems at address 0x00000100). Because of the reset
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08004546configuration for CS0# this is a mirror of the on board Flash memory.
wdenk2729af92004-05-03 20:45:30 +00004547To be able to re-map memory U-Boot then jumps to its link address.
4548To be able to implement the initialization code in C, a (small!)
4549initial stack is set up in the internal Dual Ported RAM (in case CPUs
Heiko Schocher2eb48ff2017-06-07 17:33:10 +02004550which provide such a feature like), or in a locked part of the data
4551cache. After that, U-Boot initializes the CPU core, the caches and
4552the SIU.
wdenkc6097192002-11-03 00:24:07 +00004553
wdenk2729af92004-05-03 20:45:30 +00004554Next, all (potentially) available memory banks are mapped using a
4555preliminary mapping. For example, we put them on 512 MB boundaries
4556(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4557on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4558programmed for SDRAM access. Using the temporary configuration, a
4559simple memory test is run that determines the size of the SDRAM
4560banks.
wdenkc6097192002-11-03 00:24:07 +00004561
wdenk2729af92004-05-03 20:45:30 +00004562When there is more than one SDRAM bank, and the banks are of
4563different size, the largest is mapped first. For equal size, the first
4564bank (CS2#) is mapped first. The first mapping is always for address
45650x00000000, with any additional banks following immediately to create
4566contiguous memory starting from 0.
wdenkc6097192002-11-03 00:24:07 +00004567
wdenk2729af92004-05-03 20:45:30 +00004568Then, the monitor installs itself at the upper end of the SDRAM area
4569and allocates memory for use by malloc() and for the global Board
4570Info data; also, the exception vector code is copied to the low RAM
4571pages, and the final stack is set up.
wdenkc6097192002-11-03 00:24:07 +00004572
wdenk2729af92004-05-03 20:45:30 +00004573Only after this relocation will you have a "normal" C environment;
4574until that you are restricted in several ways, mostly because you are
4575running from ROM, and because the code will have to be relocated to a
4576new address in RAM.
wdenkc6097192002-11-03 00:24:07 +00004577
4578
wdenk2729af92004-05-03 20:45:30 +00004579U-Boot Porting Guide:
4580----------------------
wdenkc6097192002-11-03 00:24:07 +00004581
wdenk2729af92004-05-03 20:45:30 +00004582[Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4583list, October 2002]
wdenkc6097192002-11-03 00:24:07 +00004584
4585
Jerry Van Baren6c3fef22009-07-15 20:42:59 -04004586int main(int argc, char *argv[])
wdenk2729af92004-05-03 20:45:30 +00004587{
4588 sighandler_t no_more_time;
wdenkc6097192002-11-03 00:24:07 +00004589
Jerry Van Baren6c3fef22009-07-15 20:42:59 -04004590 signal(SIGALRM, no_more_time);
4591 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
wdenkc6097192002-11-03 00:24:07 +00004592
wdenk2729af92004-05-03 20:45:30 +00004593 if (available_money > available_manpower) {
Jerry Van Baren6c3fef22009-07-15 20:42:59 -04004594 Pay consultant to port U-Boot;
wdenkc6097192002-11-03 00:24:07 +00004595 return 0;
4596 }
4597
wdenk2729af92004-05-03 20:45:30 +00004598 Download latest U-Boot source;
4599
Wolfgang Denk06682362008-12-30 22:56:11 +01004600 Subscribe to u-boot mailing list;
wdenk2729af92004-05-03 20:45:30 +00004601
Jerry Van Baren6c3fef22009-07-15 20:42:59 -04004602 if (clueless)
4603 email("Hi, I am new to U-Boot, how do I get started?");
wdenkc6097192002-11-03 00:24:07 +00004604
wdenk2729af92004-05-03 20:45:30 +00004605 while (learning) {
4606 Read the README file in the top level directory;
Jerry Van Baren6c3fef22009-07-15 20:42:59 -04004607 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
Patrick Delaunay24bcaec2020-02-28 15:18:10 +01004608 Read applicable doc/README.*;
wdenk2729af92004-05-03 20:45:30 +00004609 Read the source, Luke;
Jerry Van Baren6c3fef22009-07-15 20:42:59 -04004610 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
wdenk2729af92004-05-03 20:45:30 +00004611 }
wdenkc6097192002-11-03 00:24:07 +00004612
Jerry Van Baren6c3fef22009-07-15 20:42:59 -04004613 if (available_money > toLocalCurrency ($2500))
4614 Buy a BDI3000;
4615 else
wdenk2729af92004-05-03 20:45:30 +00004616 Add a lot of aggravation and time;
Jerry Van Baren6c3fef22009-07-15 20:42:59 -04004617
4618 if (a similar board exists) { /* hopefully... */
4619 cp -a board/<similar> board/<myboard>
4620 cp include/configs/<similar>.h include/configs/<myboard>.h
4621 } else {
4622 Create your own board support subdirectory;
4623 Create your own board include/configs/<myboard>.h file;
wdenk2729af92004-05-03 20:45:30 +00004624 }
Jerry Van Baren6c3fef22009-07-15 20:42:59 -04004625 Edit new board/<myboard> files
4626 Edit new include/configs/<myboard>.h
wdenkc6097192002-11-03 00:24:07 +00004627
Jerry Van Baren6c3fef22009-07-15 20:42:59 -04004628 while (!accepted) {
4629 while (!running) {
4630 do {
4631 Add / modify source code;
4632 } until (compiles);
4633 Debug;
4634 if (clueless)
4635 email("Hi, I am having problems...");
4636 }
4637 Send patch file to the U-Boot email list;
4638 if (reasonable critiques)
4639 Incorporate improvements from email list code review;
4640 else
4641 Defend code as written;
wdenk2729af92004-05-03 20:45:30 +00004642 }
wdenkc6097192002-11-03 00:24:07 +00004643
wdenk2729af92004-05-03 20:45:30 +00004644 return 0;
4645}
4646
4647void no_more_time (int sig)
4648{
4649 hire_a_guru();
4650}
wdenkc6097192002-11-03 00:24:07 +00004651
4652
wdenk2729af92004-05-03 20:45:30 +00004653Coding Standards:
4654-----------------
wdenkc6097192002-11-03 00:24:07 +00004655
wdenk2729af92004-05-03 20:45:30 +00004656All contributions to U-Boot should conform to the Linux kernel
Baruch Siach659208d2017-12-10 17:34:35 +02004657coding style; see the kernel coding style guide at
4658https://www.kernel.org/doc/html/latest/process/coding-style.html, and the
4659script "scripts/Lindent" in your Linux kernel source directory.
wdenk2729af92004-05-03 20:45:30 +00004660
Detlev Zundel2c051652006-09-01 15:39:02 +02004661Source files originating from a different project (for example the
4662MTD subsystem) are generally exempt from these guidelines and are not
Jeremiah Mahlerb445bbb2015-01-04 18:56:50 -08004663reformatted to ease subsequent migration to newer versions of those
Detlev Zundel2c051652006-09-01 15:39:02 +02004664sources.
4665
4666Please note that U-Boot is implemented in C (and to some small parts in
4667Assembler); no C++ is used, so please do not use C++ style comments (//)
4668in your code.
wdenk2729af92004-05-03 20:45:30 +00004669
4670Please also stick to the following formatting rules:
4671- remove any trailing white space
Wolfgang Denk7ca92962011-07-27 10:59:55 +00004672- use TAB characters for indentation and vertical alignment, not spaces
wdenk2729af92004-05-03 20:45:30 +00004673- make sure NOT to use DOS '\r\n' line feeds
Wolfgang Denk7ca92962011-07-27 10:59:55 +00004674- do not add more than 2 consecutive empty lines to source files
wdenk2729af92004-05-03 20:45:30 +00004675- do not add trailing empty lines to source files
4676
4677Submissions which do not conform to the standards may be returned
4678with a request to reformat the changes.
wdenkc6097192002-11-03 00:24:07 +00004679
4680
wdenk2729af92004-05-03 20:45:30 +00004681Submitting Patches:
4682-------------------
wdenkc6097192002-11-03 00:24:07 +00004683
wdenk2729af92004-05-03 20:45:30 +00004684Since the number of patches for U-Boot is growing, we need to
4685establish some rules. Submissions which do not conform to these rules
4686may be rejected, even when they contain important and valuable stuff.
wdenkc6097192002-11-03 00:24:07 +00004687
Magnus Lilja0d28f342008-08-06 19:32:33 +02004688Please see http://www.denx.de/wiki/U-Boot/Patches for details.
Wolfgang Denk218ca722008-03-26 10:40:12 +01004689
Wolfgang Denk06682362008-12-30 22:56:11 +01004690Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
S. Lockwood-Childs1dade182017-11-14 22:56:42 -08004691see https://lists.denx.de/listinfo/u-boot
Wolfgang Denk06682362008-12-30 22:56:11 +01004692
wdenk2729af92004-05-03 20:45:30 +00004693When you send a patch, please include the following information with
4694it:
wdenkc6097192002-11-03 00:24:07 +00004695
wdenk2729af92004-05-03 20:45:30 +00004696* For bug fixes: a description of the bug and how your patch fixes
4697 this bug. Please try to include a way of demonstrating that the
4698 patch actually fixes something.
wdenkc6097192002-11-03 00:24:07 +00004699
wdenk2729af92004-05-03 20:45:30 +00004700* For new features: a description of the feature and your
4701 implementation.
wdenkc6097192002-11-03 00:24:07 +00004702
Robert P. J. Day7207b362015-12-19 07:16:10 -05004703* For major contributions, add a MAINTAINERS file with your
4704 information and associated file and directory references.
wdenk2729af92004-05-03 20:45:30 +00004705
Albert ARIBAUD27af9302013-09-11 15:52:51 +02004706* When you add support for a new board, don't forget to add a
4707 maintainer e-mail address to the boards.cfg file, too.
wdenk2729af92004-05-03 20:45:30 +00004708
4709* If your patch adds new configuration options, don't forget to
4710 document these in the README file.
4711
Wolfgang Denk218ca722008-03-26 10:40:12 +01004712* The patch itself. If you are using git (which is *strongly*
4713 recommended) you can easily generate the patch using the
Wolfgang Denk7ca92962011-07-27 10:59:55 +00004714 "git format-patch". If you then use "git send-email" to send it to
Wolfgang Denk218ca722008-03-26 10:40:12 +01004715 the U-Boot mailing list, you will avoid most of the common problems
4716 with some other mail clients.
wdenk2729af92004-05-03 20:45:30 +00004717
Wolfgang Denk218ca722008-03-26 10:40:12 +01004718 If you cannot use git, use "diff -purN OLD NEW". If your version of
4719 diff does not support these options, then get the latest version of
4720 GNU diff.
wdenk2729af92004-05-03 20:45:30 +00004721
Wolfgang Denk218ca722008-03-26 10:40:12 +01004722 The current directory when running this command shall be the parent
4723 directory of the U-Boot source tree (i. e. please make sure that
4724 your patch includes sufficient directory information for the
4725 affected files).
4726
4727 We prefer patches as plain text. MIME attachments are discouraged,
4728 and compressed attachments must not be used.
wdenk2729af92004-05-03 20:45:30 +00004729
4730* If one logical set of modifications affects or creates several
4731 files, all these changes shall be submitted in a SINGLE patch file.
4732
4733* Changesets that contain different, unrelated modifications shall be
4734 submitted as SEPARATE patches, one patch per changeset.
4735
4736
4737Notes:
4738
Simon Glass6de80f22016-07-27 20:33:08 -06004739* Before sending the patch, run the buildman script on your patched
wdenk2729af92004-05-03 20:45:30 +00004740 source tree and make sure that no errors or warnings are reported
4741 for any of the boards.
4742
4743* Keep your modifications to the necessary minimum: A patch
4744 containing several unrelated changes or arbitrary reformats will be
4745 returned with a request to re-formatting / split it.
4746
4747* If you modify existing code, make sure that your new code does not
4748 add to the memory footprint of the code ;-) Small is beautiful!
4749 When adding new features, these should compile conditionally only
4750 (using #ifdef), and the resulting code with the new feature
4751 disabled must not need more memory than the old code without your
4752 modification.
wdenk90dc6702005-05-03 14:12:25 +00004753
Wolfgang Denk06682362008-12-30 22:56:11 +01004754* Remember that there is a size limit of 100 kB per message on the
4755 u-boot mailing list. Bigger patches will be moderated. If they are
4756 reasonable and not too big, they will be acknowledged. But patches
4757 bigger than the size limit should be avoided.