blob: cc307aa8d5eb99692beeed97da5133718bec105d [file] [log] [blame]
Bin Menga70e2ac2019-07-18 00:34:26 -07001.. SPDX-License-Identifier: GPL-2.0+
2.. Copyright (C) 2014, Simon Glass <sjg@chromium.org>
3.. Copyright (C) 2014, Bin Meng <bmeng.cn@gmail.com>
Bin Meng5dad97e2014-12-17 15:50:48 +08004
Bin Menga70e2ac2019-07-18 00:34:26 -07005x86
6===
Bin Meng5dad97e2014-12-17 15:50:48 +08007
8This document describes the information about U-Boot running on x86 targets,
9including supported boards, build instructions, todo list, etc.
10
11Status
12------
Bin Menga70e2ac2019-07-18 00:34:26 -070013U-Boot supports running as a `coreboot`_ payload on x86. So far only Link
14(Chromebook Pixel) and `QEMU`_ x86 targets have been tested, but it should
Bin Meng1ae5b782015-05-07 21:34:12 +080015work with minimal adjustments on other x86 boards since coreboot deals with
16most of the low-level details.
Bin Meng5dad97e2014-12-17 15:50:48 +080017
Andy Shevchenko495f3772017-07-06 14:41:53 +030018U-Boot is a main bootloader on Intel Edison board.
19
Stoppa, Igor28a85362015-08-13 16:43:35 +030020U-Boot also supports booting directly from x86 reset vector, without coreboot.
21In this case, known as bare mode, from the fact that it runs on the
Simon Glassf21069f2016-03-11 22:07:33 -070022'bare metal', U-Boot acts like a BIOS replacement. The following platforms
23are supported:
24
Bin Mengeda995a2016-05-07 07:46:36 -070025 - Bayley Bay CRB
Bin Mengeb457872017-08-15 22:42:02 -070026 - Cherry Hill CRB
Bin Mengeda995a2016-05-07 07:46:36 -070027 - Congatec QEVAL 2.0 & conga-QA3/E3845
Simon Glassf21069f2016-03-11 22:07:33 -070028 - Cougar Canyon 2 CRB
29 - Crown Bay CRB
30 - Galileo
31 - Link (Chromebook Pixel)
32 - Minnowboard MAX
33 - Samus (Chromebook Pixel 2015)
Bin Meng6feb2ff2018-10-13 20:52:03 -070034 - QEMU x86 (32-bit & 64-bit)
Bin Meng5dad97e2014-12-17 15:50:48 +080035
Simon Glass3a1a18f2015-01-27 22:13:47 -070036As for loading an OS, U-Boot supports directly booting a 32-bit or 64-bit
37Linux kernel as part of a FIT image. It also supports a compressed zImage.
Bin Meng3619e942015-10-07 20:19:20 -070038U-Boot supports loading an x86 VxWorks kernel. Please check README.vxworks
39for more details.
Bin Meng5dad97e2014-12-17 15:50:48 +080040
Stoppa, Igor28a85362015-08-13 16:43:35 +030041Build Instructions for U-Boot as BIOS replacement (bare mode)
42-------------------------------------------------------------
Simon Glass3a1a18f2015-01-27 22:13:47 -070043Building a ROM version of U-Boot (hereafter referred to as u-boot.rom) is a
Bin Meng5dad97e2014-12-17 15:50:48 +080044little bit tricky, as generally it requires several binary blobs which are not
45shipped in the U-Boot source tree. Due to this reason, the u-boot.rom build is
46not turned on by default in the U-Boot source tree. Firstly, you need turn it
Bin Menga70e2ac2019-07-18 00:34:26 -070047on by enabling the ROM build either via an environment variable::
Bin Meng5dad97e2014-12-17 15:50:48 +080048
Bin Menga70e2ac2019-07-18 00:34:26 -070049 $ export BUILD_ROM=y
Simon Glasseea0f112015-01-27 22:13:32 -070050
Bin Menga70e2ac2019-07-18 00:34:26 -070051or via configuration::
Heinrich Schuchardt871aa412017-10-16 18:08:38 +000052
Bin Menga70e2ac2019-07-18 00:34:26 -070053 CONFIG_BUILD_ROM=y
Heinrich Schuchardt871aa412017-10-16 18:08:38 +000054
55Both tell the Makefile to build u-boot.rom as a target.
Bin Meng5dad97e2014-12-17 15:50:48 +080056
Bin Meng5dad97e2014-12-17 15:50:48 +080057CPU Microcode
58-------------
Bin Menga70e2ac2019-07-18 00:34:26 -070059Modern CPUs usually require a special bit stream called `microcode`_ to be
Bin Meng5dad97e2014-12-17 15:50:48 +080060loaded on the processor after power up in order to function properly. U-Boot
61has already integrated these as hex dumps in the source tree.
62
Bin Meng1281a1f2015-06-23 12:18:53 +080063SMP Support
64-----------
65On a multicore system, U-Boot is executed on the bootstrap processor (BSP).
66Additional application processors (AP) can be brought up by U-Boot. In order to
67have an SMP kernel to discover all of the available processors, U-Boot needs to
68prepare configuration tables which contain the multi-CPUs information before
69loading the OS kernel. Currently U-Boot supports generating two types of tables
Bin Menga70e2ac2019-07-18 00:34:26 -070070for SMP, called Simple Firmware Interface (`SFI`_) and Multi-Processor (`MP`_)
71tables. The writing of these two tables are controlled by two Kconfig
Bin Meng7aaff9b2015-07-06 16:31:35 +080072options GENERATE_SFI_TABLE and GENERATE_MP_TABLE.
Bin Meng1281a1f2015-06-23 12:18:53 +080073
Bin Meng5dad97e2014-12-17 15:50:48 +080074Driver Model
75------------
Simon Glassf21069f2016-03-11 22:07:33 -070076x86 has been converted to use driver model for serial, GPIO, SPI, SPI flash,
77keyboard, real-time clock, USB. Video is in progress.
Bin Meng5dad97e2014-12-17 15:50:48 +080078
79Device Tree
80-----------
81x86 uses device tree to configure the board thus requires CONFIG_OF_CONTROL to
Bin Meng617b8672015-01-06 22:14:24 +080082be turned on. Not every device on the board is configured via device tree, but
Bin Meng5dad97e2014-12-17 15:50:48 +080083more and more devices will be added as time goes by. Check out the directory
84arch/x86/dts/ for these device tree source files.
85
Simon Glasscb3b2e62015-01-01 16:18:15 -070086Useful Commands
87---------------
Simon Glasscb3b2e62015-01-01 16:18:15 -070088In keeping with the U-Boot philosophy of providing functions to check and
89adjust internal settings, there are several x86-specific commands that may be
90useful:
91
Bin Menga70e2ac2019-07-18 00:34:26 -070092fsp
93 Display information about Intel Firmware Support Package (FSP).
94 This is only available on platforms which use FSP, mostly Atom.
95iod
96 Display I/O memory
97iow
98 Write I/O memory
99mtrr
100 List and set the Memory Type Range Registers (MTRR). These are used to
101 tell the CPU whether memory is cacheable and if so the cache write
102 mode to use. U-Boot sets up some reasonable values but you can
103 adjust then with this command.
Simon Glasscb3b2e62015-01-01 16:18:15 -0700104
Simon Glass7bea5272015-07-27 15:47:31 -0600105Booting Ubuntu
106--------------
107As an example of how to set up your boot flow with U-Boot, here are
108instructions for starting Ubuntu from U-Boot. These instructions have been
Bin Mengeda995a2016-05-07 07:46:36 -0700109tested on Minnowboard MAX with a SATA drive but are equally applicable on
110other platforms and other media. There are really only four steps and it's a
Simon Glass7bea5272015-07-27 15:47:31 -0600111very simple script, but a more detailed explanation is provided here for
112completeness.
113
114Note: It is possible to set up U-Boot to boot automatically using syslinux.
115It could also use the grub.cfg file (/efi/ubuntu/grub.cfg) to obtain the
116GUID. If you figure these out, please post patches to this README.
117
Bin Mengeda995a2016-05-07 07:46:36 -0700118Firstly, you will need Ubuntu installed on an available disk. It should be
Simon Glass7bea5272015-07-27 15:47:31 -0600119possible to make U-Boot start a USB start-up disk but for now let's assume
120that you used another boot loader to install Ubuntu.
121
122Use the U-Boot command line to find the UUID of the partition you want to
Bin Menga70e2ac2019-07-18 00:34:26 -0700123boot. For example our disk is SCSI device 0::
Simon Glass7bea5272015-07-27 15:47:31 -0600124
Bin Menga70e2ac2019-07-18 00:34:26 -0700125 => part list scsi 0
Simon Glass7bea5272015-07-27 15:47:31 -0600126
Bin Menga70e2ac2019-07-18 00:34:26 -0700127 Partition Map for SCSI device 0 -- Partition Type: EFI
Simon Glass7bea5272015-07-27 15:47:31 -0600128
Bin Menga70e2ac2019-07-18 00:34:26 -0700129 Part Start LBA End LBA Name
130 Attributes
131 Type GUID
132 Partition GUID
133 1 0x00000800 0x001007ff ""
134 attrs: 0x0000000000000000
135 type: c12a7328-f81f-11d2-ba4b-00a0c93ec93b
136 guid: 9d02e8e4-4d59-408f-a9b0-fd497bc9291c
137 2 0x00100800 0x037d8fff ""
138 attrs: 0x0000000000000000
139 type: 0fc63daf-8483-4772-8e79-3d69d8477de4
140 guid: 965c59ee-1822-4326-90d2-b02446050059
141 3 0x037d9000 0x03ba27ff ""
142 attrs: 0x0000000000000000
143 type: 0657fd6d-a4ab-43c4-84e5-0933c84b4f4f
144 guid: 2c4282bd-1e82-4bcf-a5ff-51dedbf39f17
145 =>
Simon Glass7bea5272015-07-27 15:47:31 -0600146
147This shows that your SCSI disk has three partitions. The really long hex
148strings are called Globally Unique Identifiers (GUIDs). You can look up the
Bin Menga70e2ac2019-07-18 00:34:26 -0700149'type' ones `here`_. On this disk the first partition is for EFI and is in
150VFAT format (DOS/Windows)::
Simon Glass7bea5272015-07-27 15:47:31 -0600151
152 => fatls scsi 0:1
153 efi/
154
155 0 file(s), 1 dir(s)
156
157
158Partition 2 is 'Linux filesystem data' so that will be our root disk. It is
Bin Menga70e2ac2019-07-18 00:34:26 -0700159in ext2 format::
Simon Glass7bea5272015-07-27 15:47:31 -0600160
161 => ext2ls scsi 0:2
162 <DIR> 4096 .
163 <DIR> 4096 ..
164 <DIR> 16384 lost+found
165 <DIR> 4096 boot
166 <DIR> 12288 etc
167 <DIR> 4096 media
168 <DIR> 4096 bin
169 <DIR> 4096 dev
170 <DIR> 4096 home
171 <DIR> 4096 lib
172 <DIR> 4096 lib64
173 <DIR> 4096 mnt
174 <DIR> 4096 opt
175 <DIR> 4096 proc
176 <DIR> 4096 root
177 <DIR> 4096 run
178 <DIR> 12288 sbin
179 <DIR> 4096 srv
180 <DIR> 4096 sys
181 <DIR> 4096 tmp
182 <DIR> 4096 usr
183 <DIR> 4096 var
184 <SYM> 33 initrd.img
185 <SYM> 30 vmlinuz
186 <DIR> 4096 cdrom
187 <SYM> 33 initrd.img.old
188 =>
189
Bin Menga70e2ac2019-07-18 00:34:26 -0700190and if you look in the /boot directory you will see the kernel::
Simon Glass7bea5272015-07-27 15:47:31 -0600191
192 => ext2ls scsi 0:2 /boot
193 <DIR> 4096 .
194 <DIR> 4096 ..
195 <DIR> 4096 efi
196 <DIR> 4096 grub
197 3381262 System.map-3.13.0-32-generic
198 1162712 abi-3.13.0-32-generic
199 165611 config-3.13.0-32-generic
200 176500 memtest86+.bin
201 178176 memtest86+.elf
202 178680 memtest86+_multiboot.bin
203 5798112 vmlinuz-3.13.0-32-generic
204 165762 config-3.13.0-58-generic
205 1165129 abi-3.13.0-58-generic
206 5823136 vmlinuz-3.13.0-58-generic
207 19215259 initrd.img-3.13.0-58-generic
208 3391763 System.map-3.13.0-58-generic
209 5825048 vmlinuz-3.13.0-58-generic.efi.signed
210 28304443 initrd.img-3.13.0-32-generic
211 =>
212
213The 'vmlinuz' files contain a packaged Linux kernel. The format is a kind of
214self-extracting compressed file mixed with some 'setup' configuration data.
215Despite its size (uncompressed it is >10MB) this only includes a basic set of
216device drivers, enough to boot on most hardware types.
217
218The 'initrd' files contain a RAM disk. This is something that can be loaded
219into RAM and will appear to Linux like a disk. Ubuntu uses this to hold lots
220of drivers for whatever hardware you might have. It is loaded before the
221real root disk is accessed.
222
223The numbers after the end of each file are the version. Here it is Linux
224version 3.13. You can find the source code for this in the Linux tree with
225the tag v3.13. The '.0' allows for additional Linux releases to fix problems,
226but normally this is not needed. The '-58' is used by Ubuntu. Each time they
227release a new kernel they increment this number. New Ubuntu versions might
228include kernel patches to fix reported bugs. Stable kernels can exist for
229some years so this number can get quite high.
230
231The '.efi.signed' kernel is signed for EFI's secure boot. U-Boot has its own
Bin Menga70e2ac2019-07-18 00:34:26 -0700232secure boot mechanism - see `this`_ & `that`_. It cannot read .efi files
233at present.
Simon Glass7bea5272015-07-27 15:47:31 -0600234
235To boot Ubuntu from U-Boot the steps are as follows:
236
Bin Menga70e2ac2019-07-18 00:34:26 -07002371. Set up the boot arguments. Use the GUID for the partition you want to boot::
Simon Glass7bea5272015-07-27 15:47:31 -0600238
239 => setenv bootargs root=/dev/disk/by-partuuid/965c59ee-1822-4326-90d2-b02446050059 ro
240
241Here root= tells Linux the location of its root disk. The disk is specified
242by its GUID, using '/dev/disk/by-partuuid/', a Linux path to a 'directory'
243containing all the GUIDs Linux has found. When it starts up, there will be a
244file in that directory with this name in it. It is also possible to use a
245device name here, see later.
246
Bin Menga70e2ac2019-07-18 00:34:26 -07002472. Load the kernel. Since it is an ext2/4 filesystem we can do::
Simon Glass7bea5272015-07-27 15:47:31 -0600248
249 => ext2load scsi 0:2 03000000 /boot/vmlinuz-3.13.0-58-generic
250
251The address 30000000 is arbitrary, but there seem to be problems with using
252small addresses (sometimes Linux cannot find the ramdisk). This is 48MB into
253the start of RAM (which is at 0 on x86).
254
Bin Menga70e2ac2019-07-18 00:34:26 -07002553. Load the ramdisk (to 64MB)::
Simon Glass7bea5272015-07-27 15:47:31 -0600256
257 => ext2load scsi 0:2 04000000 /boot/initrd.img-3.13.0-58-generic
258
2594. Start up the kernel. We need to know the size of the ramdisk, but can use
Bin Menga70e2ac2019-07-18 00:34:26 -0700260 a variable for that. U-Boot sets 'filesize' to the size of the last file it
261 loaded::
Simon Glass7bea5272015-07-27 15:47:31 -0600262
263 => zboot 03000000 0 04000000 ${filesize}
264
265Type 'help zboot' if you want to see what the arguments are. U-Boot on x86 is
266quite verbose when it boots a kernel. You should see these messages from
Bin Menga70e2ac2019-07-18 00:34:26 -0700267U-Boot::
Simon Glass7bea5272015-07-27 15:47:31 -0600268
269 Valid Boot Flag
270 Setup Size = 0x00004400
271 Magic signature found
272 Using boot protocol version 2.0c
273 Linux kernel version 3.13.0-58-generic (buildd@allspice) #97-Ubuntu SMP Wed Jul 8 02:56:15 UTC 2015
274 Building boot_params at 0x00090000
275 Loading bzImage at address 100000 (5805728 bytes)
276 Magic signature found
277 Initial RAM disk at linear address 0x04000000, size 19215259 bytes
Bin Mengeda995a2016-05-07 07:46:36 -0700278 Kernel command line: "root=/dev/disk/by-partuuid/965c59ee-1822-4326-90d2-b02446050059 ro"
Simon Glass7bea5272015-07-27 15:47:31 -0600279
280 Starting kernel ...
281
282U-Boot prints out some bootstage timing. This is more useful if you put the
Bin Menga70e2ac2019-07-18 00:34:26 -0700283above commands into a script since then it will be faster::
Simon Glass7bea5272015-07-27 15:47:31 -0600284
285 Timer summary in microseconds:
286 Mark Elapsed Stage
287 0 0 reset
288 241,535 241,535 board_init_r
289 2,421,611 2,180,076 id=64
290 2,421,790 179 id=65
291 2,428,215 6,425 main_loop
292 48,860,584 46,432,369 start_kernel
293
294 Accumulated time:
295 240,329 ahci
296 1,422,704 vesa display
297
Bin Menga70e2ac2019-07-18 00:34:26 -0700298Now the kernel actually starts (if you want to examine kernel boot up message on
299the serial console, append "console=ttyS0,115200" to the kernel command line)::
Simon Glass7bea5272015-07-27 15:47:31 -0600300
301 [ 0.000000] Initializing cgroup subsys cpuset
302 [ 0.000000] Initializing cgroup subsys cpu
303 [ 0.000000] Initializing cgroup subsys cpuacct
304 [ 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)
Bin Mengeda995a2016-05-07 07:46:36 -0700305 [ 0.000000] Command line: root=/dev/disk/by-partuuid/965c59ee-1822-4326-90d2-b02446050059 ro console=ttyS0,115200
Simon Glass7bea5272015-07-27 15:47:31 -0600306
307It continues for a long time. Along the way you will see it pick up your
Bin Menga70e2ac2019-07-18 00:34:26 -0700308ramdisk::
Simon Glass7bea5272015-07-27 15:47:31 -0600309
310 [ 0.000000] RAMDISK: [mem 0x04000000-0x05253fff]
Bin Menga70e2ac2019-07-18 00:34:26 -0700311 ...
Simon Glass7bea5272015-07-27 15:47:31 -0600312 [ 0.788540] Trying to unpack rootfs image as initramfs...
313 [ 1.540111] Freeing initrd memory: 18768K (ffff880004000000 - ffff880005254000)
Bin Menga70e2ac2019-07-18 00:34:26 -0700314 ...
Simon Glass7bea5272015-07-27 15:47:31 -0600315
Bin Menga70e2ac2019-07-18 00:34:26 -0700316Later it actually starts using it::
Simon Glass7bea5272015-07-27 15:47:31 -0600317
318 Begin: Running /scripts/local-premount ... done.
319
Bin Menga70e2ac2019-07-18 00:34:26 -0700320You should also see your boot disk turn up::
Simon Glass7bea5272015-07-27 15:47:31 -0600321
322 [ 4.357243] scsi 1:0:0:0: Direct-Access ATA ADATA SP310 5.2 PQ: 0 ANSI: 5
323 [ 4.366860] sd 1:0:0:0: [sda] 62533296 512-byte logical blocks: (32.0 GB/29.8 GiB)
324 [ 4.375677] sd 1:0:0:0: Attached scsi generic sg0 type 0
325 [ 4.381859] sd 1:0:0:0: [sda] Write Protect is off
326 [ 4.387452] sd 1:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
327 [ 4.399535] sda: sda1 sda2 sda3
328
329Linux has found the three partitions (sda1-3). Mercifully it doesn't print out
Bin Menga70e2ac2019-07-18 00:34:26 -0700330the GUIDs. In step 1 above we could have used::
Simon Glass7bea5272015-07-27 15:47:31 -0600331
332 setenv bootargs root=/dev/sda2 ro
333
334instead of the GUID. However if you add another drive to your board the
335numbering may change whereas the GUIDs will not. So if your boot partition
336becomes sdb2, it will still boot. For embedded systems where you just want to
337boot the first disk, you have that option.
338
339The last thing you will see on the console is mention of plymouth (which
Bin Menga70e2ac2019-07-18 00:34:26 -0700340displays the Ubuntu start-up screen) and a lot of 'Starting' messages::
Simon Glass7bea5272015-07-27 15:47:31 -0600341
Bin Menga70e2ac2019-07-18 00:34:26 -0700342 * Starting Mount filesystems on boot [ OK ]
Simon Glass7bea5272015-07-27 15:47:31 -0600343
344After a pause you should see a login screen on your display and you are done.
345
Bin Menga70e2ac2019-07-18 00:34:26 -0700346If you want to put this in a script you can use something like this::
Simon Glass7bea5272015-07-27 15:47:31 -0600347
348 setenv bootargs root=UUID=b2aaf743-0418-4d90-94cc-3e6108d7d968 ro
349 setenv boot zboot 03000000 0 04000000 \${filesize}
350 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"
351 saveenv
352
353The \ is to tell the shell not to evaluate ${filesize} as part of the setenv
354command.
355
Simon Glass7bea5272015-07-27 15:47:31 -0600356You can also bake this behaviour into your build by hard-coding the
357environment variables if you add this to minnowmax.h:
358
Bin Menga70e2ac2019-07-18 00:34:26 -0700359.. code-block:: c
Simon Glass7bea5272015-07-27 15:47:31 -0600360
Bin Menga70e2ac2019-07-18 00:34:26 -0700361 #undef CONFIG_BOOTCOMMAND
362 #define CONFIG_BOOTCOMMAND \
363 "ext2load scsi 0:2 03000000 /boot/vmlinuz-3.13.0-58-generic; " \
364 "ext2load scsi 0:2 04000000 /boot/initrd.img-3.13.0-58-generic; " \
365 "run boot"
Simon Glass7bea5272015-07-27 15:47:31 -0600366
Bin Menga70e2ac2019-07-18 00:34:26 -0700367 #undef CONFIG_EXTRA_ENV_SETTINGS
368 #define CONFIG_EXTRA_ENV_SETTINGS "boot=zboot 03000000 0 04000000 ${filesize}"
Sam Protsenko5abc1a42017-08-14 20:22:17 +0300369
Bin Menga70e2ac2019-07-18 00:34:26 -0700370and change CONFIG_BOOTARGS value in configs/minnowmax_defconfig to::
371
372 CONFIG_BOOTARGS="root=/dev/sda2 ro"
Sam Protsenko5abc1a42017-08-14 20:22:17 +0300373
Bin Meng2e9ae222016-02-28 23:54:52 -0800374Test with SeaBIOS
375-----------------
Bin Menga70e2ac2019-07-18 00:34:26 -0700376`SeaBIOS`_ is an open source implementation of a 16-bit x86 BIOS. It can run
Bin Meng2e9ae222016-02-28 23:54:52 -0800377in an emulator or natively on x86 hardware with the use of U-Boot. With its
378help, we can boot some OSes that require 16-bit BIOS services like Windows/DOS.
379
380As U-Boot, we have to manually create a table where SeaBIOS gets various system
381information (eg: E820) from. The table unfortunately has to follow the coreboot
382table format as SeaBIOS currently supports booting as a coreboot payload.
383
384To support loading SeaBIOS, U-Boot should be built with CONFIG_SEABIOS on.
Bin Menga70e2ac2019-07-18 00:34:26 -0700385Booting SeaBIOS is done via U-Boot's bootelf command, like below::
Bin Meng2e9ae222016-02-28 23:54:52 -0800386
387 => tftp bios.bin.elf;bootelf
388 Using e1000#0 device
389 TFTP from server 10.10.0.100; our IP address is 10.10.0.108
390 ...
391 Bytes transferred = 122124 (1dd0c hex)
392 ## Starting application at 0x000ff06e ...
393 SeaBIOS (version rel-1.9.0)
394 ...
395
396bios.bin.elf is the SeaBIOS image built from SeaBIOS source tree.
Bin Menga70e2ac2019-07-18 00:34:26 -0700397Make sure it is built as follows::
Bin Meng2e9ae222016-02-28 23:54:52 -0800398
399 $ make menuconfig
400
401Inside the "General Features" menu, select "Build for coreboot" as the
402"Build Target". Inside the "Debugging" menu, turn on "Serial port debugging"
403so that we can see something as soon as SeaBIOS boots. Leave other options
Bin Menga70e2ac2019-07-18 00:34:26 -0700404as in their default state. Then::
Bin Meng2e9ae222016-02-28 23:54:52 -0800405
406 $ make
407 ...
408 Total size: 121888 Fixed: 66496 Free: 9184 (used 93.0% of 128KiB rom)
409 Creating out/bios.bin.elf
410
411Currently this is tested on QEMU x86 target with U-Boot chain-loading SeaBIOS
412to install/boot a Windows XP OS (below for example command to install Windows).
413
Bin Menga70e2ac2019-07-18 00:34:26 -0700414.. code-block:: none
415
Bin Meng2e9ae222016-02-28 23:54:52 -0800416 # Create a 10G disk.img as the virtual hard disk
417 $ qemu-img create -f qcow2 disk.img 10G
418
419 # Install a Windows XP OS from an ISO image 'winxp.iso'
420 $ qemu-system-i386 -serial stdio -bios u-boot.rom -hda disk.img -cdrom winxp.iso -smp 2 -m 512
421
422 # Boot a Windows XP OS installed on the virutal hard disk
423 $ qemu-system-i386 -serial stdio -bios u-boot.rom -hda disk.img -smp 2 -m 512
424
425This is also tested on Intel Crown Bay board with a PCIe graphics card, booting
426SeaBIOS then chain-loading a GRUB on a USB drive, then Linux kernel finally.
427
Bin Meng5a6a2c72016-05-11 07:45:06 -0700428If you are using Intel Integrated Graphics Device (IGD) as the primary display
429device on your board, SeaBIOS needs to be patched manually to get its VGA ROM
430loaded and run by SeaBIOS. SeaBIOS locates VGA ROM via the PCI expansion ROM
431register, but IGD device does not have its VGA ROM mapped by this register.
432Its VGA ROM is packaged as part of u-boot.rom at a configurable flash address
433which is unknown to SeaBIOS. An example patch is needed for SeaBIOS below:
434
Bin Menga70e2ac2019-07-18 00:34:26 -0700435.. code-block:: none
436
437 diff --git a/src/optionroms.c b/src/optionroms.c
438 index 65f7fe0..c7b6f5e 100644
439 --- a/src/optionroms.c
440 +++ b/src/optionroms.c
441 @@ -324,6 +324,8 @@ init_pcirom(struct pci_device *pci, int isvga, u64 *sources)
442 rom = deploy_romfile(file);
443 else if (RunPCIroms > 1 || (RunPCIroms == 1 && isvga))
444 rom = map_pcirom(pci);
445 + if (pci->bdf == pci_to_bdf(0, 2, 0))
446 + rom = (struct rom_header *)0xfff90000;
447 if (! rom)
448 // No ROM present.
449 return;
Bin Meng5a6a2c72016-05-11 07:45:06 -0700450
451Note: the patch above expects IGD device is at PCI b.d.f 0.2.0 and its VGA ROM
452is at 0xfff90000 which corresponds to CONFIG_VGA_BIOS_ADDR on Minnowboard MAX.
453Change these two accordingly if this is not the case on your board.
Simon Glass7bea5272015-07-27 15:47:31 -0600454
Simon Glass00bdd952015-01-27 22:13:46 -0700455Development Flow
456----------------
Simon Glass00bdd952015-01-27 22:13:46 -0700457These notes are for those who want to port U-Boot to a new x86 platform.
458
459Since x86 CPUs boot from SPI flash, a SPI flash emulator is a good investment.
Bin Menga70e2ac2019-07-18 00:34:26 -0700460The Dediprog em100 can be used on Linux.
Simon Glass00bdd952015-01-27 22:13:46 -0700461
Bin Menga70e2ac2019-07-18 00:34:26 -0700462The em100 tool is available here: http://review.coreboot.org/p/em100.git
Simon Glass00bdd952015-01-27 22:13:46 -0700463
Bin Menga70e2ac2019-07-18 00:34:26 -0700464On Minnowboard Max the following command line can be used::
Simon Glass00bdd952015-01-27 22:13:46 -0700465
466 sudo em100 -s -p LOW -d u-boot.rom -c W25Q64DW -r
467
468A suitable clip for connecting over the SPI flash chip is here:
Bin Menga70e2ac2019-07-18 00:34:26 -0700469http://www.dediprog.com/pd/programmer-accessories/EM-TC-8.
Simon Glass00bdd952015-01-27 22:13:46 -0700470
471This allows you to override the SPI flash contents for development purposes.
472Typically you can write to the em100 in around 1200ms, considerably faster
473than programming the real flash device each time. The only important
474limitation of the em100 is that it only supports SPI bus speeds up to 20MHz.
475This means that images must be set to boot with that speed. This is an
476Intel-specific feature - e.g. tools/ifttool has an option to set the SPI
477speed in the SPI descriptor region.
478
479If your chip/board uses an Intel Firmware Support Package (FSP) it is fairly
480easy to fit it in. You can follow the Minnowboard Max implementation, for
481example. Hopefully you will just need to create new files similar to those
482in arch/x86/cpu/baytrail which provide Bay Trail support.
483
484If you are not using an FSP you have more freedom and more responsibility.
485The ivybridge support works this way, although it still uses a ROM for
486graphics and still has binary blobs containing Intel code. You should aim to
487support all important peripherals on your platform including video and storage.
488Use the device tree for configuration where possible.
489
490For the microcode you can create a suitable device tree file using the
Bin Menga70e2ac2019-07-18 00:34:26 -0700491microcode tool::
Simon Glass00bdd952015-01-27 22:13:46 -0700492
Bin Menga70e2ac2019-07-18 00:34:26 -0700493 ./tools/microcode-tool -d microcode.dat -m <model> create
Simon Glass00bdd952015-01-27 22:13:46 -0700494
Bin Menga70e2ac2019-07-18 00:34:26 -0700495or if you only have header files and not the full Intel microcode.dat database::
Simon Glass00bdd952015-01-27 22:13:46 -0700496
Bin Menga70e2ac2019-07-18 00:34:26 -0700497 ./tools/microcode-tool -H BAY_TRAIL_FSP_KIT/Microcode/M0130673322.h \
498 -H BAY_TRAIL_FSP_KIT/Microcode/M0130679901.h -m all create
Simon Glass00bdd952015-01-27 22:13:46 -0700499
500These are written to arch/x86/dts/microcode/ by default.
501
502Note that it is possible to just add the micrcode for your CPU if you know its
Bin Menga70e2ac2019-07-18 00:34:26 -0700503model. U-Boot prints this information when it starts::
Simon Glass00bdd952015-01-27 22:13:46 -0700504
505 CPU: x86_64, vendor Intel, device 30673h
506
507so here we can use the M0130673322 file.
508
509If you platform can display POST codes on two little 7-segment displays on
510the board, then you can use post_code() calls from C or assembler to monitor
511boot progress. This can be good for debugging.
512
513If not, you can try to get serial working as early as possible. The early
Stefan Roesed5211972016-01-19 14:24:12 +0100514debug serial port may be useful here. See setup_internal_uart() for an example.
Simon Glass00bdd952015-01-27 22:13:46 -0700515
Bin Meng12c75102015-08-02 20:33:35 -0700516During the U-Boot porting, one of the important steps is to write correct PIRQ
517routing information in the board device tree. Without it, device drivers in the
518Linux kernel won't function correctly due to interrupt is not working. Please
Bin Menga70e2ac2019-07-18 00:34:26 -0700519refer to U-Boot `doc <doc/device-tree-bindings/misc/intel,irq-router.txt>`_ for
520the device tree bindings of Intel interrupt router. Here we have more details
521on the intel,pirq-routing property below.
522
523.. code-block:: none
Bin Meng12c75102015-08-02 20:33:35 -0700524
525 intel,pirq-routing = <
526 PCI_BDF(0, 2, 0) INTA PIRQA
527 ...
528 >;
529
530As you see each entry has 3 cells. For the first one, we need describe all pci
531devices mounted on the board. For SoC devices, normally there is a chapter on
532the chipset datasheet which lists all the available PCI devices. For example on
533Bay Trail, this is chapter 4.3 (PCI configuration space). For the second one, we
534can get the interrupt pin either from datasheet or hardware via U-Boot shell.
535The reliable source is the hardware as sometimes chipset datasheet is not 100%
536up-to-date. Type 'pci header' plus the device's pci bus/device/function number
Bin Menga70e2ac2019-07-18 00:34:26 -0700537from U-Boot shell below::
Bin Meng12c75102015-08-02 20:33:35 -0700538
539 => pci header 0.1e.1
540 vendor ID = 0x8086
541 device ID = 0x0f08
542 ...
543 interrupt line = 0x09
544 interrupt pin = 0x04
545 ...
546
547It shows this PCI device is using INTD pin as it reports 4 in the interrupt pin
548register. Repeat this until you get interrupt pins for all the devices. The last
549cell is the PIRQ line which a particular interrupt pin is mapped to. On Intel
550chipset, the power-up default mapping is INTA/B/C/D maps to PIRQA/B/C/D. This
551can be changed by registers in LPC bridge. So far Intel FSP does not touch those
552registers so we can write down the PIRQ according to the default mapping rule.
553
554Once we get the PIRQ routing information in the device tree, the interrupt
555allocation and assignment will be done by U-Boot automatically. Now you can
556enable CONFIG_GENERATE_PIRQ_TABLE for testing Linux kernel using i8259 PIC and
557CONFIG_GENERATE_MP_TABLE for testing Linux kernel using local APIC and I/O APIC.
558
Simon Glass590870e2015-08-13 10:36:17 -0600559This script might be useful. If you feed it the output of 'pci long' from
560U-Boot then it will generate a device tree fragment with the interrupt
Bin Menga70e2ac2019-07-18 00:34:26 -0700561configuration for each device (note it needs gawk 4.0.0)::
Simon Glass590870e2015-08-13 10:36:17 -0600562
563 $ cat console_output |awk '/PCI/ {device=$4} /interrupt line/ {line=$4} \
564 /interrupt pin/ {pin = $4; if (pin != "0x00" && pin != "0xff") \
565 {patsplit(device, bdf, "[0-9a-f]+"); \
566 printf "PCI_BDF(%d, %d, %d) INT%c PIRQ%c\n", strtonum("0x" bdf[1]), \
567 strtonum("0x" bdf[2]), bdf[3], strtonum(pin) + 64, 64 + strtonum(pin)}}'
568
Bin Menga70e2ac2019-07-18 00:34:26 -0700569Example output::
570
Simon Glass590870e2015-08-13 10:36:17 -0600571 PCI_BDF(0, 2, 0) INTA PIRQA
572 PCI_BDF(0, 3, 0) INTA PIRQA
Bin Menga70e2ac2019-07-18 00:34:26 -0700573 ...
Simon Glass590870e2015-08-13 10:36:17 -0600574
Bin Meng448719c2015-09-09 23:20:29 -0700575Porting Hints
576-------------
577
Bin Menga70e2ac2019-07-18 00:34:26 -0700578Quark-specific considerations
579^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Bin Meng448719c2015-09-09 23:20:29 -0700580
581To port U-Boot to other boards based on the Intel Quark SoC, a few things need
582to be taken care of. The first important part is the Memory Reference Code (MRC)
583parameters. Quark MRC supports memory-down configuration only. All these MRC
584parameters are supplied via the board device tree. To get started, first copy
585the MRC section of arch/x86/dts/galileo.dts to your board's device tree, then
586change these values by consulting board manuals or your hardware vendor.
587Available MRC parameter values are listed in include/dt-bindings/mrc/quark.h.
588The other tricky part is with PCIe. Quark SoC integrates two PCIe root ports,
589but by default they are held in reset after power on. In U-Boot, PCIe
590initialization is properly handled as per Quark's firmware writer guide.
591In your board support codes, you need provide two routines to aid PCIe
592initialization, which are board_assert_perst() and board_deassert_perst().
593The two routines need implement a board-specific mechanism to assert/deassert
594PCIe PERST# pin. Care must be taken that in those routines that any APIs that
595may trigger PCI enumeration process are strictly forbidden, as any access to
596PCIe root port's configuration registers will cause system hang while it is
597held in reset. For more details, check how they are implemented by the Intel
598Galileo board support codes in board/intel/galileo/galileo.c.
599
Bin Menga70e2ac2019-07-18 00:34:26 -0700600coreboot
601^^^^^^^^
Simon Glasse28fcb22016-03-06 19:28:17 -0700602
603See scripts/coreboot.sed which can assist with porting coreboot code into
604U-Boot drivers. It will not resolve all build errors, but will perform common
605transformations. Remember to add attribution to coreboot for new files added
606to U-Boot. This should go at the top of each file and list the coreboot
607filename where the code originated.
608
Bin Menga70e2ac2019-07-18 00:34:26 -0700609Debugging ACPI issues with Windows
610^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Bin Mengefd4be42016-05-11 07:45:12 -0700611
612Windows might cache system information and only detect ACPI changes if you
613modify the ACPI table versions. So tweak them liberally when debugging ACPI
614issues with Windows.
615
Bin Meng49d929b2016-05-07 07:46:37 -0700616ACPI Support Status
617-------------------
Bin Menga70e2ac2019-07-18 00:34:26 -0700618Advanced Configuration and Power Interface (`ACPI`_) aims to establish
Bin Meng49d929b2016-05-07 07:46:37 -0700619industry-standard interfaces enabling OS-directed configuration, power
620management, and thermal management of mobile, desktop, and server platforms.
621
622Linux can boot without ACPI with "acpi=off" command line parameter, but
623with ACPI the kernel gains the capabilities to handle power management.
624For Windows, ACPI is a must-have firmware feature since Windows Vista.
625CONFIG_GENERATE_ACPI_TABLE is the config option to turn on ACPI support in
626U-Boot. This requires Intel ACPI compiler to be installed on your host to
627compile ACPI DSDT table written in ASL format to AML format. You can get
628the compiler via "apt-get install iasl" if you are on Ubuntu or download
Bin Menga70e2ac2019-07-18 00:34:26 -0700629the source from https://www.acpica.org/downloads to compile one by yourself.
Bin Meng49d929b2016-05-07 07:46:37 -0700630
Bin Meng13c9d842017-04-21 07:24:49 -0700631Current ACPI support in U-Boot is basically complete. More optional features
632can be added in the future. The status as of today is:
Bin Meng49d929b2016-05-07 07:46:37 -0700633
634 * Support generating RSDT, XSDT, FACS, FADT, MADT, MCFG tables.
635 * Support one static DSDT table only, compiled by Intel ACPI compiler.
Bin Meng13c9d842017-04-21 07:24:49 -0700636 * Support S0/S3/S4/S5, reboot and shutdown from OS.
Bin Meng49d929b2016-05-07 07:46:37 -0700637 * Support booting a pre-installed Ubuntu distribution via 'zboot' command.
Bin Meng206a3a42016-05-11 07:45:08 -0700638 * Support installing and booting Ubuntu 14.04 (or above) from U-Boot with
639 the help of SeaBIOS using legacy interface (non-UEFI mode).
640 * Support installing and booting Windows 8.1/10 from U-Boot with the help
641 of SeaBIOS using legacy interface (non-UEFI mode).
Bin Meng49d929b2016-05-07 07:46:37 -0700642 * Support ACPI interrupts with SCI only.
643
Bin Meng49d929b2016-05-07 07:46:37 -0700644Features that are optional:
Bin Menga70e2ac2019-07-18 00:34:26 -0700645
Bin Meng49d929b2016-05-07 07:46:37 -0700646 * Dynamic AML bytecodes insertion at run-time. We may need this to support
647 SSDT table generation and DSDT fix up.
648 * SMI support. Since U-Boot is a modern bootloader, we don't want to bring
649 those legacy stuff into U-Boot. ACPI spec allows a system that does not
650 support SMI (a legacy-free system).
651
Bin Menge6ddb6b2016-05-25 19:19:12 -0700652ACPI was initially enabled on BayTrail based boards. Testing was done by booting
Bin Meng206a3a42016-05-11 07:45:08 -0700653a pre-installed Ubuntu 14.04 from a SATA drive. Installing Ubuntu 14.04 and
654Windows 8.1/10 to a SATA drive and booting from there is also tested. Most
655devices seem to work correctly and the board can respond a reboot/shutdown
656command from the OS.
Simon Glasse28fcb22016-03-06 19:28:17 -0700657
Bin Menge6ddb6b2016-05-25 19:19:12 -0700658For other platform boards, ACPI support status can be checked by examining their
659board defconfig files to see if CONFIG_GENERATE_ACPI_TABLE is set to y.
660
Bin Meng13c9d842017-04-21 07:24:49 -0700661The S3 sleeping state is a low wake latency sleeping state defined by ACPI
662spec where all system context is lost except system memory. To test S3 resume
663with a Linux kernel, simply run "echo mem > /sys/power/state" and kernel will
664put the board to S3 state where the power is off. So when the power button is
665pressed again, U-Boot runs as it does in cold boot and detects the sleeping
666state via ACPI register to see if it is S3, if yes it means we are waking up.
667U-Boot is responsible for restoring the machine state as it is before sleep.
668When everything is done, U-Boot finds out the wakeup vector provided by OSes
669and jump there. To determine whether ACPI S3 resume is supported, check to
670see if CONFIG_HAVE_ACPI_RESUME is set for that specific board.
671
672Note for testing S3 resume with Windows, correct graphics driver must be
673installed for your platform, otherwise you won't find "Sleep" option in
674the "Power" submenu from the Windows start menu.
675
Simon Glass007adbc2016-07-17 01:23:45 -0600676EFI Support
677-----------
678U-Boot supports booting as a 32-bit or 64-bit EFI payload, e.g. with UEFI.
Bin Meng9efeb3f2018-06-12 08:36:13 -0700679This is enabled with CONFIG_EFI_STUB to boot from both 32-bit and 64-bit
680UEFI BIOS. U-Boot can also run as an EFI application, with CONFIG_EFI_APP.
Bin Meng73149162018-06-27 20:38:05 -0700681The CONFIG_EFI_LOADER option, where U-Boot provides an EFI environment to
Bin Meng9efeb3f2018-06-12 08:36:13 -0700682the kernel (i.e. replaces UEFI completely but provides the same EFI run-time
Bin Meng73149162018-06-27 20:38:05 -0700683services) is supported too. For example, we can even use 'bootefi' command
684to load a 'u-boot-payload.efi', see below test logs on QEMU.
685
Bin Menga70e2ac2019-07-18 00:34:26 -0700686.. code-block:: none
687
Bin Meng73149162018-06-27 20:38:05 -0700688 => load ide 0 3000000 u-boot-payload.efi
689 489787 bytes read in 138 ms (3.4 MiB/s)
690 => bootefi 3000000
691 Scanning disk ide.blk#0...
692 Found 2 disks
693 WARNING: booting without device tree
694 ## Starting EFI application at 03000000 ...
695 U-Boot EFI Payload
696
697
698 U-Boot 2018.07-rc2 (Jun 23 2018 - 17:12:58 +0800)
699
700 CPU: x86_64, vendor AMD, device 663h
701 DRAM: 2 GiB
702 MMC:
703 Video: 1024x768x32
704 Model: EFI x86 Payload
705 Net: e1000: 52:54:00:12:34:56
706
707 Warning: e1000#0 using MAC address from ROM
708 eth0: e1000#0
709 No controllers found
710 Hit any key to stop autoboot: 0
Simon Glass007adbc2016-07-17 01:23:45 -0600711
Heinrich Schuchardt0c4a0e62019-08-15 21:20:56 +0200712See :doc:`../uefi/u-boot_on_efi` and :doc:`../uefi/uefi` for details of
713EFI support in U-Boot.
Simon Glass007adbc2016-07-17 01:23:45 -0600714
Simon Glass24915462020-04-26 09:13:01 -0600715Chain-loading
716-------------
717U-Boot can be chain-loaded from another bootloader, such as coreboot or
718Slim Bootloader. Typically this is done by building for targets 'coreboot' or
719'slimbootloader'.
720
721For example, at present we have a 'coreboot' target but this runs very
722different code from the bare-metal targets, such as coral. There is very little
723in common between them.
724
725It is useful to be able to boot the same U-Boot on a device, with or without a
726first-stage bootloader. For example, with chromebook_coral, it is helpful for
727testing to be able to boot the same U-Boot (complete with FSP) on bare metal
728and from coreboot. It allows checking of things like CPU speed, comparing
729registers, ACPI tables and the like.
730
731To do this you can use ll_boot_init() in appropriate places to skip init that
732has already been done by the previous stage. This works by setting a
733GD_FLG_NO_LL_INIT flag when U-Boot detects that it is running from another
734bootloader.
735
736With this feature, you can build a bare-metal target and boot it from
737coreboot, for example.
738
739Note that this is a development feature only. It is not intended for use in
740production environments. Also it is not currently part of the automated tests
741so may break in the future.
742
Simon Glassf9696532020-11-05 06:32:10 -0700743SMBIOS tables
744-------------
745
746To generate SMBIOS tables in U-Boot, for use by the OS, enable the
747CONFIG_GENERATE_SMBIOS_TABLE option. The easiest way to provide the values to
748use is via the device tree. For details see
749device-tree-bindings/sysinfo/smbios.txt
750
Bin Meng5dad97e2014-12-17 15:50:48 +0800751TODO List
752---------
Bin Meng5dad97e2014-12-17 15:50:48 +0800753- Audio
754- Chrome OS verified boot
Bin Meng5dad97e2014-12-17 15:50:48 +0800755
Bin Menga70e2ac2019-07-18 00:34:26 -0700756.. _coreboot: http://www.coreboot.org
757.. _QEMU: http://www.qemu.org
758.. _microcode: http://en.wikipedia.org/wiki/Microcode
759.. _SFI: http://simplefirmware.org
760.. _MP: http://www.intel.com/design/archives/processors/pro/docs/242016.htm
761.. _here: https://en.wikipedia.org/wiki/GUID_Partition_Table
762.. _this: http://events.linuxfoundation.org/sites/events/files/slides/chromeos_and_diy_vboot_0.pdf
763.. _that: http://events.linuxfoundation.org/sites/events/files/slides/elce-2014.pdf
764.. _SeaBIOS: http://www.seabios.org/SeaBIOS
765.. _ACPI: http://www.acpi.info