blob: d3fea5d56fc4d588bb719e0a45305d28ae9aa639 [file] [log] [blame]
Bin Meng5dad97e2014-12-17 15:50:48 +08001#
2# Copyright (C) 2014, Simon Glass <sjg@chromium.org>
3# Copyright (C) 2014, Bin Meng <bmeng.cn@gmail.com>
4#
5# SPDX-License-Identifier: GPL-2.0+
6#
7
8U-Boot on x86
9=============
10
11This document describes the information about U-Boot running on x86 targets,
12including supported boards, build instructions, todo list, etc.
13
14Status
15------
16U-Boot supports running as a coreboot [1] payload on x86. So far only Link
Bin Meng1ae5b782015-05-07 21:34:12 +080017(Chromebook Pixel) and QEMU [2] x86 targets have been tested, but it should
18work with minimal adjustments on other x86 boards since coreboot deals with
19most of the low-level details.
Bin Meng5dad97e2014-12-17 15:50:48 +080020
Stoppa, Igor28a85362015-08-13 16:43:35 +030021U-Boot also supports booting directly from x86 reset vector, without coreboot.
22In this case, known as bare mode, from the fact that it runs on the
23'bare metal', U-Boot acts like a BIOS replacement. Currently Link, QEMU x86
24targets and all Intel boards support running U-Boot 'bare metal'.
Bin Meng5dad97e2014-12-17 15:50:48 +080025
Simon Glass3a1a18f2015-01-27 22:13:47 -070026As for loading an OS, U-Boot supports directly booting a 32-bit or 64-bit
27Linux kernel as part of a FIT image. It also supports a compressed zImage.
Bin Meng3619e942015-10-07 20:19:20 -070028U-Boot supports loading an x86 VxWorks kernel. Please check README.vxworks
29for more details.
Bin Meng5dad97e2014-12-17 15:50:48 +080030
Stoppa, Igor28a85362015-08-13 16:43:35 +030031Build Instructions for U-Boot as coreboot payload
32-------------------------------------------------
Bin Meng5dad97e2014-12-17 15:50:48 +080033Building U-Boot as a coreboot payload is just like building U-Boot for targets
34on other architectures, like below:
35
36$ make coreboot-x86_defconfig
37$ make all
38
Bin Meng1ae5b782015-05-07 21:34:12 +080039Note this default configuration will build a U-Boot payload for the QEMU board.
Bin Meng617b8672015-01-06 22:14:24 +080040To build a coreboot payload against another board, you can change the build
41configuration during the 'make menuconfig' process.
42
43x86 architecture --->
44 ...
Bin Meng1ae5b782015-05-07 21:34:12 +080045 (qemu-x86) Board configuration file
Bin Meng683b09d2015-06-03 09:20:04 +080046 (qemu-x86_i440fx) Board Device Tree Source (dts) file
Bin Meng1ae5b782015-05-07 21:34:12 +080047 (0x01920000) Board specific Cache-As-RAM (CAR) address
Bin Meng617b8672015-01-06 22:14:24 +080048 (0x4000) Board specific Cache-As-RAM (CAR) size
49
50Change the 'Board configuration file' and 'Board Device Tree Source (dts) file'
51to point to a new board. You can also change the Cache-As-RAM (CAR) related
52settings here if the default values do not fit your new board.
53
Stoppa, Igor28a85362015-08-13 16:43:35 +030054Build Instructions for U-Boot as BIOS replacement (bare mode)
55-------------------------------------------------------------
Simon Glass3a1a18f2015-01-27 22:13:47 -070056Building a ROM version of U-Boot (hereafter referred to as u-boot.rom) is a
Bin Meng5dad97e2014-12-17 15:50:48 +080057little bit tricky, as generally it requires several binary blobs which are not
58shipped in the U-Boot source tree. Due to this reason, the u-boot.rom build is
59not turned on by default in the U-Boot source tree. Firstly, you need turn it
Simon Glasseea0f112015-01-27 22:13:32 -070060on by enabling the ROM build:
Bin Meng5dad97e2014-12-17 15:50:48 +080061
Simon Glasseea0f112015-01-27 22:13:32 -070062$ export BUILD_ROM=y
63
64This tells the Makefile to build u-boot.rom as a target.
Bin Meng5dad97e2014-12-17 15:50:48 +080065
Stoppa, Igor28a85362015-08-13 16:43:35 +030066---
67
68Chromebook Link specific instructions for bare mode:
Bin Meng5dad97e2014-12-17 15:50:48 +080069
70First, you need the following binary blobs:
71
72* descriptor.bin - Intel flash descriptor
73* me.bin - Intel Management Engine
74* mrc.bin - Memory Reference Code, which sets up SDRAM
75* video ROM - sets up the display
76
77You can get these binary blobs by:
78
79$ git clone http://review.coreboot.org/p/blobs.git
80$ cd blobs
81
82Find the following files:
83
84* ./mainboard/google/link/descriptor.bin
85* ./mainboard/google/link/me.bin
Simon Glass8712af92015-04-19 22:05:37 -060086* ./northbridge/intel/sandybridge/systemagent-r6.bin
Bin Meng5dad97e2014-12-17 15:50:48 +080087
88The 3rd one should be renamed to mrc.bin.
Bin Meng786a08e2015-07-06 16:31:33 +080089As for the video ROM, you can get it here [3] and rename it to vga.bin.
Bin Meng5dad97e2014-12-17 15:50:48 +080090Make sure all these binary blobs are put in the board directory.
91
92Now you can build U-Boot and obtain u-boot.rom:
93
94$ make chromebook_link_defconfig
95$ make all
96
Stoppa, Igor28a85362015-08-13 16:43:35 +030097---
98
99Intel Crown Bay specific instructions for bare mode:
Bin Meng5dad97e2014-12-17 15:50:48 +0800100
Bin Meng1ae5b782015-05-07 21:34:12 +0800101U-Boot support of Intel Crown Bay board [4] relies on a binary blob called
102Firmware Support Package [5] to perform all the necessary initialization steps
Bin Meng5dad97e2014-12-17 15:50:48 +0800103as documented in the BIOS Writer Guide, including initialization of the CPU,
104memory controller, chipset and certain bus interfaces.
105
106Download the Intel FSP for Atom E6xx series and Platform Controller Hub EG20T,
107install it on your host and locate the FSP binary blob. Note this platform
108also requires a Chipset Micro Code (CMC) state machine binary to be present in
109the SPI flash where u-boot.rom resides, and this CMC binary blob can be found
110in this FSP package too.
111
112* ./FSP/QUEENSBAY_FSP_GOLD_001_20-DECEMBER-2013.fd
113* ./Microcode/C0_22211.BIN
114
115Rename the first one to fsp.bin and second one to cmc.bin and put them in the
116board directory.
117
Bin Meng83d97122015-03-05 11:21:03 +0800118Note the FSP release version 001 has a bug which could cause random endless
119loop during the FspInit call. This bug was published by Intel although Intel
120did not describe any details. We need manually apply the patch to the FSP
121binary using any hex editor (eg: bvi). Go to the offset 0x1fcd8 of the FSP
122binary, change the following five bytes values from orginally E8 42 FF FF FF
123to B8 00 80 0B 00.
124
Bin Meng7aaff9b2015-07-06 16:31:35 +0800125As for the video ROM, you need manually extract it from the Intel provided
126BIOS for Crown Bay here [6], using the AMI MMTool [7]. Check PCI option ROM
127ID 8086:4108, extract and save it as vga.bin in the board directory.
128
Bin Meng617b8672015-01-06 22:14:24 +0800129Now you can build U-Boot and obtain u-boot.rom
Bin Meng5dad97e2014-12-17 15:50:48 +0800130
131$ make crownbay_defconfig
132$ make all
133
Stoppa, Igor28a85362015-08-13 16:43:35 +0300134---
135
Bin Menga2e3b052016-02-17 00:16:25 -0800136Intel Cougar Canyon 2 specific instructions for bare mode:
137
138This uses Intel FSP for 3rd generation Intel Core and Intel Celeron processors
139with mobile Intel HM76 and QM77 chipsets platform. Download it from Intel FSP
140website and put the .fd file (CHIEFRIVER_FSP_GOLD_001_09-OCTOBER-2013.fd at the
141time of writing) in the board directory and rename it to fsp.bin.
142
143Now build U-Boot and obtain u-boot.rom
144
145$ make cougarcanyon2_defconfig
146$ make all
147
148The board has two 8MB SPI flashes mounted, which are called SPI-0 and SPI-1 in
149the board manual. The SPI-0 flash should have flash descriptor plus ME firmware
150and SPI-1 flash is used to store U-Boot. For convenience, the complete 8MB SPI-0
151flash image is included in the FSP package (named Rom00_8M_MB_PPT.bin). Program
152this image to the SPI-0 flash according to the board manual just once and we are
153all set. For programming U-Boot we just need to program SPI-1 flash.
154
155---
156
Bin Meng03bfc782016-02-17 00:47:04 -0800157Intel Bay Trail based board instructions for bare mode:
Simon Glass3a1a18f2015-01-27 22:13:47 -0700158
159This uses as FSP as with Crown Bay, except it is for the Atom E3800 series.
Bin Meng03bfc782016-02-17 00:47:04 -0800160Two boards that use this configuration are Bayley Bay and Minnowboard MAX.
Simon Glass3a1a18f2015-01-27 22:13:47 -0700161Download this and get the .fd file (BAYTRAIL_FSP_GOLD_003_16-SEP-2014.fd at
Bin Meng03bfc782016-02-17 00:47:04 -0800162the time of writing). Put it in the corresponding board directory and rename
163it to fsp.bin.
Simon Glass3a1a18f2015-01-27 22:13:47 -0700164
165Obtain the VGA RAM (Vga.dat at the time of writing) and put it into the same
Bin Meng03bfc782016-02-17 00:47:04 -0800166board directory as vga.bin.
Simon Glass3a1a18f2015-01-27 22:13:47 -0700167
Bin Meng03bfc782016-02-17 00:47:04 -0800168You still need two more binary blobs. For Bayley Bay, they can be extracted
169from the sample SPI image provided in the FSP (SPI.bin at the time of writing).
170
171 $ ./tools/ifdtool -x BayleyBay/SPI.bin
172 $ cp flashregion_0_flashdescriptor.bin board/intel/bayleybay/descriptor.bin
173 $ cp flashregion_2_intel_me.bin board/intel/bayleybay/me.bin
174
175For Minnowboard MAX, we can reuse the same ME firmware above, but for flash
176descriptor, we need get that somewhere else, as the one above does not seem to
177work, probably because it is not designed for the Minnowboard MAX. Now download
178the original firmware image for this board from:
Simon Glass68522482015-04-25 11:46:43 -0600179
180http://firmware.intel.com/sites/default/files/2014-WW42.4-MinnowBoardMax.73-64-bit.bin_Release.zip
181
182Unzip it:
183
184 $ unzip 2014-WW42.4-MinnowBoardMax.73-64-bit.bin_Release.zip
Simon Glass3a1a18f2015-01-27 22:13:47 -0700185
186Use ifdtool in the U-Boot tools directory to extract the images from that
187file, for example:
188
Simon Glass68522482015-04-25 11:46:43 -0600189 $ ./tools/ifdtool -x MNW2MAX1.X64.0073.R02.1409160934.bin
190
191This will provide the descriptor file - copy this into the correct place:
192
193 $ cp flashregion_0_flashdescriptor.bin board/intel/minnowmax/descriptor.bin
194
Simon Glass3a1a18f2015-01-27 22:13:47 -0700195Now you can build U-Boot and obtain u-boot.rom
Bin Meng03bfc782016-02-17 00:47:04 -0800196Note: below are examples/information for Minnowboard MAX.
Simon Glass3a1a18f2015-01-27 22:13:47 -0700197
198$ make minnowmax_defconfig
199$ make all
200
Simon Glassdf898672015-07-03 18:28:28 -0600201Checksums are as follows (but note that newer versions will invalidate this):
202
203$ md5sum -b board/intel/minnowmax/*.bin
204ffda9a3b94df5b74323afb328d51e6b4 board/intel/minnowmax/descriptor.bin
20569f65b9a580246291d20d08cbef9d7c5 board/intel/minnowmax/fsp.bin
206894a97d371544ec21de9c3e8e1716c4b board/intel/minnowmax/me.bin
207a2588537da387da592a27219d56e9962 board/intel/minnowmax/vga.bin
208
Simon Glass537ccba2015-07-03 18:28:24 -0600209The ROM image is broken up into these parts:
210
211Offset Description Controlling config
212------------------------------------------------------------
213000000 descriptor.bin Hard-coded to 0 in ifdtool
214001000 me.bin Set by the descriptor
215500000 <spare>
Bin Meng638a0582015-10-11 21:37:44 -07002166f0000 MRC cache CONFIG_ENABLE_MRC_CACHE
Simon Glass537ccba2015-07-03 18:28:24 -0600217700000 u-boot-dtb.bin CONFIG_SYS_TEXT_BASE
Bin Meng7f72cdf2015-08-27 08:38:16 -0700218790000 vga.bin CONFIG_VGA_BIOS_ADDR
Simon Glass537ccba2015-07-03 18:28:24 -06002197c0000 fsp.bin CONFIG_FSP_ADDR
2207f8000 <spare> (depends on size of fsp.bin)
2217fe000 Environment CONFIG_ENV_OFFSET
2227ff800 U-Boot 16-bit boot CONFIG_SYS_X86_START16
223
224Overall ROM image size is controlled by CONFIG_ROM_SIZE.
225
Stoppa, Igor28a85362015-08-13 16:43:35 +0300226---
Simon Glass537ccba2015-07-03 18:28:24 -0600227
Stoppa, Igor28a85362015-08-13 16:43:35 +0300228Intel Galileo instructions for bare mode:
Bin Meng67582c02015-02-04 16:26:14 +0800229
230Only one binary blob is needed for Remote Management Unit (RMU) within Intel
231Quark SoC. Not like FSP, U-Boot does not call into the binary. The binary is
232needed by the Quark SoC itself.
233
234You can get the binary blob from Quark Board Support Package from Intel website:
235
236* ./QuarkSocPkg/QuarkNorthCluster/Binary/QuarkMicrocode/RMU.bin
237
238Rename the file and put it to the board directory by:
239
240 $ cp RMU.bin board/intel/galileo/rmu.bin
241
242Now you can build U-Boot and obtain u-boot.rom
243
244$ make galileo_defconfig
245$ make all
Simon Glass3a1a18f2015-01-27 22:13:47 -0700246
Bin Meng03bfc782016-02-17 00:47:04 -0800247---
248
249QEMU x86 target instructions for bare mode:
Bin Meng1ae5b782015-05-07 21:34:12 +0800250
251To build u-boot.rom for QEMU x86 targets, just simply run
252
253$ make qemu-x86_defconfig
254$ make all
255
Bin Meng683b09d2015-06-03 09:20:04 +0800256Note this default configuration will build a U-Boot for the QEMU x86 i440FX
257board. To build a U-Boot against QEMU x86 Q35 board, you can change the build
258configuration during the 'make menuconfig' process like below:
259
260Device Tree Control --->
261 ...
262 (qemu-x86_q35) Default Device Tree for DT control
263
Bin Meng617b8672015-01-06 22:14:24 +0800264Test with coreboot
265------------------
266For testing U-Boot as the coreboot payload, there are things that need be paid
267attention to. coreboot supports loading an ELF executable and a 32-bit plain
268binary, as well as other supported payloads. With the default configuration,
269U-Boot is set up to use a separate Device Tree Blob (dtb). As of today, the
270generated u-boot-dtb.bin needs to be packaged by the cbfstool utility (a tool
271provided by coreboot) manually as coreboot's 'make menuconfig' does not provide
272this capability yet. The command is as follows:
273
274# in the coreboot root directory
275$ ./build/util/cbfstool/cbfstool build/coreboot.rom add-flat-binary \
Bin Meng330728d2015-08-13 00:29:07 -0700276 -f u-boot-dtb.bin -n fallback/payload -c lzma -l 0x1110000 -e 0x1110000
Bin Meng617b8672015-01-06 22:14:24 +0800277
Bin Meng330728d2015-08-13 00:29:07 -0700278Make sure 0x1110000 matches CONFIG_SYS_TEXT_BASE, which is the symbol address
279of _x86boot_start (in arch/x86/cpu/start.S).
Bin Meng617b8672015-01-06 22:14:24 +0800280
281If you want to use ELF as the coreboot payload, change U-Boot configuration to
Simon Glasseea0f112015-01-27 22:13:32 -0700282use CONFIG_OF_EMBED instead of CONFIG_OF_SEPARATE.
Bin Meng617b8672015-01-06 22:14:24 +0800283
Simon Glass3a1a18f2015-01-27 22:13:47 -0700284To enable video you must enable these options in coreboot:
285
286 - Set framebuffer graphics resolution (1280x1024 32k-color (1:5:5))
287 - Keep VESA framebuffer
288
289At present it seems that for Minnowboard Max, coreboot does not pass through
290the video information correctly (it always says the resolution is 0x0). This
291works correctly for link though.
292
Stoppa, Igor28a85362015-08-13 16:43:35 +0300293Test with QEMU for bare mode
294----------------------------
Bin Meng1ae5b782015-05-07 21:34:12 +0800295QEMU is a fancy emulator that can enable us to test U-Boot without access to
Bin Meng9c4f5412015-05-11 07:36:30 +0800296a real x86 board. Please make sure your QEMU version is 2.3.0 or above test
297U-Boot. To launch QEMU with u-boot.rom, call QEMU as follows:
Bin Meng1ae5b782015-05-07 21:34:12 +0800298
299$ qemu-system-i386 -nographic -bios path/to/u-boot.rom
300
301This will instantiate an emulated x86 board with i440FX and PIIX chipset. QEMU
302also supports emulating an x86 board with Q35 and ICH9 based chipset, which is
303also supported by U-Boot. To instantiate such a machine, call QEMU with:
304
305$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -M q35
306
307Note by default QEMU instantiated boards only have 128 MiB system memory. But
308it is enough to have U-Boot boot and function correctly. You can increase the
309system memory by pass '-m' parameter to QEMU if you want more memory:
310
311$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -m 1024
312
313This creates a board with 1 GiB system memory. Currently U-Boot for QEMU only
314supports 3 GiB maximum system memory and reserves the last 1 GiB address space
315for PCI device memory-mapped I/O and other stuff, so the maximum value of '-m'
316would be 3072.
Simon Glass3a1a18f2015-01-27 22:13:47 -0700317
Bin Meng9c4f5412015-05-11 07:36:30 +0800318QEMU emulates a graphic card which U-Boot supports. Removing '-nographic' will
319show QEMU's VGA console window. Note this will disable QEMU's serial output.
320If you want to check both consoles, use '-serial stdio'.
321
Bin Menga2eb65f2015-07-27 19:16:08 +0800322Multicore is also supported by QEMU via '-smp n' where n is the number of cores
Miao Yan5c2ed612016-01-07 01:32:06 -0800323to instantiate. Note, the maximum supported CPU number in QEMU is 255.
324
325The fw_cfg interface in QEMU also provides information about kernel data, initrd,
326command-line arguments and more. U-Boot supports directly accessing these informtion
327from fw_cfg interface, this saves the time of loading them from hard disk or
328network again, through emulated devices. To use it , simply providing them in
329QEMU command line:
330
331$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -m 1024 -kernel /path/to/bzImage
332 -append 'root=/dev/ram console=ttyS0' -initrd /path/to/initrd -smp 8
333
334Note: -initrd and -smp are both optional
335
336Then start QEMU, in U-Boot command line use the following U-Boot command to setup kernel:
337
338 => qfw
339qfw - QEMU firmware interface
340
341Usage:
342qfw <command>
343 - list : print firmware(s) currently loaded
344 - cpus : print online cpu number
345 - load <kernel addr> <initrd addr> : load kernel and initrd (if any) and setup for zboot
346
347=> qfw load
348loading kernel to address 01000000 size 5d9d30 initrd 04000000 size 1b1ab50
349
350Here the kernel (bzImage) is loaded to 01000000 and initrd is to 04000000. Then, 'zboot'
351can be used to boot the kernel:
352
353=> zboot 02000000 - 04000000 1b1ab50
Bin Menga2eb65f2015-07-27 19:16:08 +0800354
Bin Meng5dad97e2014-12-17 15:50:48 +0800355CPU Microcode
356-------------
Bin Meng7aaff9b2015-07-06 16:31:35 +0800357Modern CPUs usually require a special bit stream called microcode [8] to be
Bin Meng5dad97e2014-12-17 15:50:48 +0800358loaded on the processor after power up in order to function properly. U-Boot
359has already integrated these as hex dumps in the source tree.
360
Bin Meng1281a1f2015-06-23 12:18:53 +0800361SMP Support
362-----------
363On a multicore system, U-Boot is executed on the bootstrap processor (BSP).
364Additional application processors (AP) can be brought up by U-Boot. In order to
365have an SMP kernel to discover all of the available processors, U-Boot needs to
366prepare configuration tables which contain the multi-CPUs information before
367loading the OS kernel. Currently U-Boot supports generating two types of tables
Bin Meng7aaff9b2015-07-06 16:31:35 +0800368for SMP, called Simple Firmware Interface (SFI) [9] and Multi-Processor (MP)
369[10] tables. The writing of these two tables are controlled by two Kconfig
370options GENERATE_SFI_TABLE and GENERATE_MP_TABLE.
Bin Meng1281a1f2015-06-23 12:18:53 +0800371
Bin Meng5dad97e2014-12-17 15:50:48 +0800372Driver Model
373------------
374x86 has been converted to use driver model for serial and GPIO.
375
376Device Tree
377-----------
378x86 uses device tree to configure the board thus requires CONFIG_OF_CONTROL to
Bin Meng617b8672015-01-06 22:14:24 +0800379be turned on. Not every device on the board is configured via device tree, but
Bin Meng5dad97e2014-12-17 15:50:48 +0800380more and more devices will be added as time goes by. Check out the directory
381arch/x86/dts/ for these device tree source files.
382
Simon Glasscb3b2e62015-01-01 16:18:15 -0700383Useful Commands
384---------------
Simon Glasscb3b2e62015-01-01 16:18:15 -0700385In keeping with the U-Boot philosophy of providing functions to check and
386adjust internal settings, there are several x86-specific commands that may be
387useful:
388
Bin Meng62716eb2015-10-10 01:47:58 -0700389fsp - Display information about Intel Firmware Support Package (FSP).
390 This is only available on platforms which use FSP, mostly Atom.
Simon Glasscb3b2e62015-01-01 16:18:15 -0700391iod - Display I/O memory
392iow - Write I/O memory
393mtrr - List and set the Memory Type Range Registers (MTRR). These are used to
394 tell the CPU whether memory is cacheable and if so the cache write
395 mode to use. U-Boot sets up some reasonable values but you can
396 adjust then with this command.
397
Simon Glass7bea5272015-07-27 15:47:31 -0600398Booting Ubuntu
399--------------
400As an example of how to set up your boot flow with U-Boot, here are
401instructions for starting Ubuntu from U-Boot. These instructions have been
402tested on Minnowboard MAX with a SATA driver but are equally applicable on
403other platforms and other media. There are really only four steps and its a
404very simple script, but a more detailed explanation is provided here for
405completeness.
406
407Note: It is possible to set up U-Boot to boot automatically using syslinux.
408It could also use the grub.cfg file (/efi/ubuntu/grub.cfg) to obtain the
409GUID. If you figure these out, please post patches to this README.
410
411Firstly, you will need Ubunutu installed on an available disk. It should be
412possible to make U-Boot start a USB start-up disk but for now let's assume
413that you used another boot loader to install Ubuntu.
414
415Use the U-Boot command line to find the UUID of the partition you want to
416boot. For example our disk is SCSI device 0:
417
418=> part list scsi 0
419
420Partition Map for SCSI device 0 -- Partition Type: EFI
421
422 Part Start LBA End LBA Name
423 Attributes
424 Type GUID
425 Partition GUID
426 1 0x00000800 0x001007ff ""
427 attrs: 0x0000000000000000
428 type: c12a7328-f81f-11d2-ba4b-00a0c93ec93b
429 guid: 9d02e8e4-4d59-408f-a9b0-fd497bc9291c
430 2 0x00100800 0x037d8fff ""
431 attrs: 0x0000000000000000
432 type: 0fc63daf-8483-4772-8e79-3d69d8477de4
433 guid: 965c59ee-1822-4326-90d2-b02446050059
434 3 0x037d9000 0x03ba27ff ""
435 attrs: 0x0000000000000000
436 type: 0657fd6d-a4ab-43c4-84e5-0933c84b4f4f
437 guid: 2c4282bd-1e82-4bcf-a5ff-51dedbf39f17
438 =>
439
440This shows that your SCSI disk has three partitions. The really long hex
441strings are called Globally Unique Identifiers (GUIDs). You can look up the
442'type' ones here [11]. On this disk the first partition is for EFI and is in
443VFAT format (DOS/Windows):
444
445 => fatls scsi 0:1
446 efi/
447
448 0 file(s), 1 dir(s)
449
450
451Partition 2 is 'Linux filesystem data' so that will be our root disk. It is
452in ext2 format:
453
454 => ext2ls scsi 0:2
455 <DIR> 4096 .
456 <DIR> 4096 ..
457 <DIR> 16384 lost+found
458 <DIR> 4096 boot
459 <DIR> 12288 etc
460 <DIR> 4096 media
461 <DIR> 4096 bin
462 <DIR> 4096 dev
463 <DIR> 4096 home
464 <DIR> 4096 lib
465 <DIR> 4096 lib64
466 <DIR> 4096 mnt
467 <DIR> 4096 opt
468 <DIR> 4096 proc
469 <DIR> 4096 root
470 <DIR> 4096 run
471 <DIR> 12288 sbin
472 <DIR> 4096 srv
473 <DIR> 4096 sys
474 <DIR> 4096 tmp
475 <DIR> 4096 usr
476 <DIR> 4096 var
477 <SYM> 33 initrd.img
478 <SYM> 30 vmlinuz
479 <DIR> 4096 cdrom
480 <SYM> 33 initrd.img.old
481 =>
482
483and if you look in the /boot directory you will see the kernel:
484
485 => ext2ls scsi 0:2 /boot
486 <DIR> 4096 .
487 <DIR> 4096 ..
488 <DIR> 4096 efi
489 <DIR> 4096 grub
490 3381262 System.map-3.13.0-32-generic
491 1162712 abi-3.13.0-32-generic
492 165611 config-3.13.0-32-generic
493 176500 memtest86+.bin
494 178176 memtest86+.elf
495 178680 memtest86+_multiboot.bin
496 5798112 vmlinuz-3.13.0-32-generic
497 165762 config-3.13.0-58-generic
498 1165129 abi-3.13.0-58-generic
499 5823136 vmlinuz-3.13.0-58-generic
500 19215259 initrd.img-3.13.0-58-generic
501 3391763 System.map-3.13.0-58-generic
502 5825048 vmlinuz-3.13.0-58-generic.efi.signed
503 28304443 initrd.img-3.13.0-32-generic
504 =>
505
506The 'vmlinuz' files contain a packaged Linux kernel. The format is a kind of
507self-extracting compressed file mixed with some 'setup' configuration data.
508Despite its size (uncompressed it is >10MB) this only includes a basic set of
509device drivers, enough to boot on most hardware types.
510
511The 'initrd' files contain a RAM disk. This is something that can be loaded
512into RAM and will appear to Linux like a disk. Ubuntu uses this to hold lots
513of drivers for whatever hardware you might have. It is loaded before the
514real root disk is accessed.
515
516The numbers after the end of each file are the version. Here it is Linux
517version 3.13. You can find the source code for this in the Linux tree with
518the tag v3.13. The '.0' allows for additional Linux releases to fix problems,
519but normally this is not needed. The '-58' is used by Ubuntu. Each time they
520release a new kernel they increment this number. New Ubuntu versions might
521include kernel patches to fix reported bugs. Stable kernels can exist for
522some years so this number can get quite high.
523
524The '.efi.signed' kernel is signed for EFI's secure boot. U-Boot has its own
525secure boot mechanism - see [12] [13] and cannot read .efi files at present.
526
527To boot Ubuntu from U-Boot the steps are as follows:
528
5291. Set up the boot arguments. Use the GUID for the partition you want to
530boot:
531
532 => setenv bootargs root=/dev/disk/by-partuuid/965c59ee-1822-4326-90d2-b02446050059 ro
533
534Here root= tells Linux the location of its root disk. The disk is specified
535by its GUID, using '/dev/disk/by-partuuid/', a Linux path to a 'directory'
536containing all the GUIDs Linux has found. When it starts up, there will be a
537file in that directory with this name in it. It is also possible to use a
538device name here, see later.
539
5402. Load the kernel. Since it is an ext2/4 filesystem we can do:
541
542 => ext2load scsi 0:2 03000000 /boot/vmlinuz-3.13.0-58-generic
543
544The address 30000000 is arbitrary, but there seem to be problems with using
545small addresses (sometimes Linux cannot find the ramdisk). This is 48MB into
546the start of RAM (which is at 0 on x86).
547
5483. Load the ramdisk (to 64MB):
549
550 => ext2load scsi 0:2 04000000 /boot/initrd.img-3.13.0-58-generic
551
5524. Start up the kernel. We need to know the size of the ramdisk, but can use
553a variable for that. U-Boot sets 'filesize' to the size of the last file it
554loaded.
555
556 => zboot 03000000 0 04000000 ${filesize}
557
558Type 'help zboot' if you want to see what the arguments are. U-Boot on x86 is
559quite verbose when it boots a kernel. You should see these messages from
560U-Boot:
561
562 Valid Boot Flag
563 Setup Size = 0x00004400
564 Magic signature found
565 Using boot protocol version 2.0c
566 Linux kernel version 3.13.0-58-generic (buildd@allspice) #97-Ubuntu SMP Wed Jul 8 02:56:15 UTC 2015
567 Building boot_params at 0x00090000
568 Loading bzImage at address 100000 (5805728 bytes)
569 Magic signature found
570 Initial RAM disk at linear address 0x04000000, size 19215259 bytes
571 Kernel command line: "console=ttyS0,115200 root=/dev/disk/by-partuuid/965c59ee-1822-4326-90d2-b02446050059 ro"
572
573 Starting kernel ...
574
575U-Boot prints out some bootstage timing. This is more useful if you put the
576above commands into a script since then it will be faster.
577
578 Timer summary in microseconds:
579 Mark Elapsed Stage
580 0 0 reset
581 241,535 241,535 board_init_r
582 2,421,611 2,180,076 id=64
583 2,421,790 179 id=65
584 2,428,215 6,425 main_loop
585 48,860,584 46,432,369 start_kernel
586
587 Accumulated time:
588 240,329 ahci
589 1,422,704 vesa display
590
591Now the kernel actually starts:
592
593 [ 0.000000] Initializing cgroup subsys cpuset
594 [ 0.000000] Initializing cgroup subsys cpu
595 [ 0.000000] Initializing cgroup subsys cpuacct
596 [ 0.000000] Linux version 3.13.0-58-generic (buildd@allspice) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #97-Ubuntu SMP Wed Jul 8 02:56:15 UTC 2015 (Ubuntu 3.13.0-58.97-generic 3.13.11-ckt22)
597 [ 0.000000] Command line: console=ttyS0,115200 root=/dev/disk/by-partuuid/965c59ee-1822-4326-90d2-b02446050059 ro
598
599It continues for a long time. Along the way you will see it pick up your
600ramdisk:
601
602 [ 0.000000] RAMDISK: [mem 0x04000000-0x05253fff]
603...
604 [ 0.788540] Trying to unpack rootfs image as initramfs...
605 [ 1.540111] Freeing initrd memory: 18768K (ffff880004000000 - ffff880005254000)
606...
607
608Later it actually starts using it:
609
610 Begin: Running /scripts/local-premount ... done.
611
612You should also see your boot disk turn up:
613
614 [ 4.357243] scsi 1:0:0:0: Direct-Access ATA ADATA SP310 5.2 PQ: 0 ANSI: 5
615 [ 4.366860] sd 1:0:0:0: [sda] 62533296 512-byte logical blocks: (32.0 GB/29.8 GiB)
616 [ 4.375677] sd 1:0:0:0: Attached scsi generic sg0 type 0
617 [ 4.381859] sd 1:0:0:0: [sda] Write Protect is off
618 [ 4.387452] sd 1:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
619 [ 4.399535] sda: sda1 sda2 sda3
620
621Linux has found the three partitions (sda1-3). Mercifully it doesn't print out
622the GUIDs. In step 1 above we could have used:
623
624 setenv bootargs root=/dev/sda2 ro
625
626instead of the GUID. However if you add another drive to your board the
627numbering may change whereas the GUIDs will not. So if your boot partition
628becomes sdb2, it will still boot. For embedded systems where you just want to
629boot the first disk, you have that option.
630
631The last thing you will see on the console is mention of plymouth (which
632displays the Ubuntu start-up screen) and a lot of 'Starting' messages:
633
634 * Starting Mount filesystems on boot [ OK ]
635
636After a pause you should see a login screen on your display and you are done.
637
638If you want to put this in a script you can use something like this:
639
640 setenv bootargs root=UUID=b2aaf743-0418-4d90-94cc-3e6108d7d968 ro
641 setenv boot zboot 03000000 0 04000000 \${filesize}
642 setenv bootcmd "ext2load scsi 0:2 03000000 /boot/vmlinuz-3.13.0-58-generic; ext2load scsi 0:2 04000000 /boot/initrd.img-3.13.0-58-generic; run boot"
643 saveenv
644
645The \ is to tell the shell not to evaluate ${filesize} as part of the setenv
646command.
647
648You will also need to add this to your board configuration file, e.g.
649include/configs/minnowmax.h:
650
651 #define CONFIG_BOOTDELAY 2
652
653Now when you reset your board it wait a few seconds (in case you want to
654interrupt) and then should boot straight into Ubuntu.
655
656You can also bake this behaviour into your build by hard-coding the
657environment variables if you add this to minnowmax.h:
658
659#undef CONFIG_BOOTARGS
660#undef CONFIG_BOOTCOMMAND
661
662#define CONFIG_BOOTARGS \
663 "root=/dev/sda2 ro"
664#define CONFIG_BOOTCOMMAND \
665 "ext2load scsi 0:2 03000000 /boot/vmlinuz-3.13.0-58-generic; " \
666 "ext2load scsi 0:2 04000000 /boot/initrd.img-3.13.0-58-generic; " \
667 "run boot"
668
669#undef CONFIG_EXTRA_ENV_SETTINGS
670#define CONFIG_EXTRA_ENV_SETTINGS "boot=zboot 03000000 0 04000000 ${filesize}"
671
672
Simon Glass00bdd952015-01-27 22:13:46 -0700673Development Flow
674----------------
Simon Glass00bdd952015-01-27 22:13:46 -0700675These notes are for those who want to port U-Boot to a new x86 platform.
676
677Since x86 CPUs boot from SPI flash, a SPI flash emulator is a good investment.
678The Dediprog em100 can be used on Linux. The em100 tool is available here:
679
680 http://review.coreboot.org/p/em100.git
681
682On Minnowboard Max the following command line can be used:
683
684 sudo em100 -s -p LOW -d u-boot.rom -c W25Q64DW -r
685
686A suitable clip for connecting over the SPI flash chip is here:
687
688 http://www.dediprog.com/pd/programmer-accessories/EM-TC-8
689
690This allows you to override the SPI flash contents for development purposes.
691Typically you can write to the em100 in around 1200ms, considerably faster
692than programming the real flash device each time. The only important
693limitation of the em100 is that it only supports SPI bus speeds up to 20MHz.
694This means that images must be set to boot with that speed. This is an
695Intel-specific feature - e.g. tools/ifttool has an option to set the SPI
696speed in the SPI descriptor region.
697
698If your chip/board uses an Intel Firmware Support Package (FSP) it is fairly
699easy to fit it in. You can follow the Minnowboard Max implementation, for
700example. Hopefully you will just need to create new files similar to those
701in arch/x86/cpu/baytrail which provide Bay Trail support.
702
703If you are not using an FSP you have more freedom and more responsibility.
704The ivybridge support works this way, although it still uses a ROM for
705graphics and still has binary blobs containing Intel code. You should aim to
706support all important peripherals on your platform including video and storage.
707Use the device tree for configuration where possible.
708
709For the microcode you can create a suitable device tree file using the
710microcode tool:
711
Simon Glass03e3c312015-08-15 14:37:48 -0600712 ./tools/microcode-tool -d microcode.dat -m <model> create
Simon Glass00bdd952015-01-27 22:13:46 -0700713
714or if you only have header files and not the full Intel microcode.dat database:
715
716 ./tools/microcode-tool -H BAY_TRAIL_FSP_KIT/Microcode/M0130673322.h \
717 -H BAY_TRAIL_FSP_KIT/Microcode/M0130679901.h \
Simon Glass03e3c312015-08-15 14:37:48 -0600718 -m all create
Simon Glass00bdd952015-01-27 22:13:46 -0700719
720These are written to arch/x86/dts/microcode/ by default.
721
722Note that it is possible to just add the micrcode for your CPU if you know its
723model. U-Boot prints this information when it starts
724
725 CPU: x86_64, vendor Intel, device 30673h
726
727so here we can use the M0130673322 file.
728
729If you platform can display POST codes on two little 7-segment displays on
730the board, then you can use post_code() calls from C or assembler to monitor
731boot progress. This can be good for debugging.
732
733If not, you can try to get serial working as early as possible. The early
Stefan Roesed5211972016-01-19 14:24:12 +0100734debug serial port may be useful here. See setup_internal_uart() for an example.
Simon Glass00bdd952015-01-27 22:13:46 -0700735
Bin Meng12c75102015-08-02 20:33:35 -0700736During the U-Boot porting, one of the important steps is to write correct PIRQ
737routing information in the board device tree. Without it, device drivers in the
738Linux kernel won't function correctly due to interrupt is not working. Please
739refer to U-Boot doc [14] for the device tree bindings of Intel interrupt router.
740Here we have more details on the intel,pirq-routing property below.
741
742 intel,pirq-routing = <
743 PCI_BDF(0, 2, 0) INTA PIRQA
744 ...
745 >;
746
747As you see each entry has 3 cells. For the first one, we need describe all pci
748devices mounted on the board. For SoC devices, normally there is a chapter on
749the chipset datasheet which lists all the available PCI devices. For example on
750Bay Trail, this is chapter 4.3 (PCI configuration space). For the second one, we
751can get the interrupt pin either from datasheet or hardware via U-Boot shell.
752The reliable source is the hardware as sometimes chipset datasheet is not 100%
753up-to-date. Type 'pci header' plus the device's pci bus/device/function number
754from U-Boot shell below.
755
756 => pci header 0.1e.1
757 vendor ID = 0x8086
758 device ID = 0x0f08
759 ...
760 interrupt line = 0x09
761 interrupt pin = 0x04
762 ...
763
764It shows this PCI device is using INTD pin as it reports 4 in the interrupt pin
765register. Repeat this until you get interrupt pins for all the devices. The last
766cell is the PIRQ line which a particular interrupt pin is mapped to. On Intel
767chipset, the power-up default mapping is INTA/B/C/D maps to PIRQA/B/C/D. This
768can be changed by registers in LPC bridge. So far Intel FSP does not touch those
769registers so we can write down the PIRQ according to the default mapping rule.
770
771Once we get the PIRQ routing information in the device tree, the interrupt
772allocation and assignment will be done by U-Boot automatically. Now you can
773enable CONFIG_GENERATE_PIRQ_TABLE for testing Linux kernel using i8259 PIC and
774CONFIG_GENERATE_MP_TABLE for testing Linux kernel using local APIC and I/O APIC.
775
Simon Glass590870e2015-08-13 10:36:17 -0600776This script might be useful. If you feed it the output of 'pci long' from
777U-Boot then it will generate a device tree fragment with the interrupt
778configuration for each device (note it needs gawk 4.0.0):
779
780 $ cat console_output |awk '/PCI/ {device=$4} /interrupt line/ {line=$4} \
781 /interrupt pin/ {pin = $4; if (pin != "0x00" && pin != "0xff") \
782 {patsplit(device, bdf, "[0-9a-f]+"); \
783 printf "PCI_BDF(%d, %d, %d) INT%c PIRQ%c\n", strtonum("0x" bdf[1]), \
784 strtonum("0x" bdf[2]), bdf[3], strtonum(pin) + 64, 64 + strtonum(pin)}}'
785
786Example output:
787 PCI_BDF(0, 2, 0) INTA PIRQA
788 PCI_BDF(0, 3, 0) INTA PIRQA
789...
790
Bin Meng448719c2015-09-09 23:20:29 -0700791Porting Hints
792-------------
793
794Quark-specific considerations:
795
796To port U-Boot to other boards based on the Intel Quark SoC, a few things need
797to be taken care of. The first important part is the Memory Reference Code (MRC)
798parameters. Quark MRC supports memory-down configuration only. All these MRC
799parameters are supplied via the board device tree. To get started, first copy
800the MRC section of arch/x86/dts/galileo.dts to your board's device tree, then
801change these values by consulting board manuals or your hardware vendor.
802Available MRC parameter values are listed in include/dt-bindings/mrc/quark.h.
803The other tricky part is with PCIe. Quark SoC integrates two PCIe root ports,
804but by default they are held in reset after power on. In U-Boot, PCIe
805initialization is properly handled as per Quark's firmware writer guide.
806In your board support codes, you need provide two routines to aid PCIe
807initialization, which are board_assert_perst() and board_deassert_perst().
808The two routines need implement a board-specific mechanism to assert/deassert
809PCIe PERST# pin. Care must be taken that in those routines that any APIs that
810may trigger PCI enumeration process are strictly forbidden, as any access to
811PCIe root port's configuration registers will cause system hang while it is
812held in reset. For more details, check how they are implemented by the Intel
813Galileo board support codes in board/intel/galileo/galileo.c.
814
Bin Meng5dad97e2014-12-17 15:50:48 +0800815TODO List
816---------
Bin Meng5dad97e2014-12-17 15:50:48 +0800817- Audio
818- Chrome OS verified boot
819- SMI and ACPI support, to provide platform info and facilities to Linux
820
821References
822----------
823[1] http://www.coreboot.org
Bin Meng1ae5b782015-05-07 21:34:12 +0800824[2] http://www.qemu.org
825[3] http://www.coreboot.org/~stepan/pci8086,0166.rom
826[4] http://www.intel.com/content/www/us/en/embedded/design-tools/evaluation-platforms/atom-e660-eg20t-development-kit.html
827[5] http://www.intel.com/fsp
Bin Meng7aaff9b2015-07-06 16:31:35 +0800828[6] http://www.intel.com/content/www/us/en/secure/intelligent-systems/privileged/e6xx-35-b1-cmc22211.html
829[7] http://www.ami.com/products/bios-uefi-tools-and-utilities/bios-uefi-utilities/
830[8] http://en.wikipedia.org/wiki/Microcode
831[9] http://simplefirmware.org
832[10] http://www.intel.com/design/archives/processors/pro/docs/242016.htm
Simon Glass7bea5272015-07-27 15:47:31 -0600833[11] https://en.wikipedia.org/wiki/GUID_Partition_Table
834[12] http://events.linuxfoundation.org/sites/events/files/slides/chromeos_and_diy_vboot_0.pdf
835[13] http://events.linuxfoundation.org/sites/events/files/slides/elce-2014.pdf
Bin Meng12c75102015-08-02 20:33:35 -0700836[14] doc/device-tree-bindings/misc/intel,irq-router.txt