-# SPDX-License-Identifier: GPL-2.0+
-#
-# Copyright (C) 2014, Simon Glass <sjg@chromium.org>
-# Copyright (C) 2014, Bin Meng <bmeng.cn@gmail.com>
-
-U-Boot on x86
-=============
-
-This document describes the information about U-Boot running on x86 targets,
-including supported boards, build instructions, todo list, etc.
-
-Status
-------
-U-Boot supports running as a coreboot [1] payload on x86. So far only Link
-(Chromebook Pixel) and QEMU [2] x86 targets have been tested, but it should
-work with minimal adjustments on other x86 boards since coreboot deals with
-most of the low-level details.
-
-U-Boot is a main bootloader on Intel Edison board.
-
-U-Boot also supports booting directly from x86 reset vector, without coreboot.
-In this case, known as bare mode, from the fact that it runs on the
-'bare metal', U-Boot acts like a BIOS replacement. The following platforms
-are supported:
-
- - Bayley Bay CRB
- - Cherry Hill CRB
- - Congatec QEVAL 2.0 & conga-QA3/E3845
- - Cougar Canyon 2 CRB
- - Crown Bay CRB
- - Galileo
- - Link (Chromebook Pixel)
- - Minnowboard MAX
- - Samus (Chromebook Pixel 2015)
- - QEMU x86 (32-bit & 64-bit)
-
-As for loading an OS, U-Boot supports directly booting a 32-bit or 64-bit
-Linux kernel as part of a FIT image. It also supports a compressed zImage.
-U-Boot supports loading an x86 VxWorks kernel. Please check README.vxworks
-for more details.
-
-Build Instructions for U-Boot as BIOS replacement (bare mode)
--------------------------------------------------------------
-Building a ROM version of U-Boot (hereafter referred to as u-boot.rom) is a
-little bit tricky, as generally it requires several binary blobs which are not
-shipped in the U-Boot source tree. Due to this reason, the u-boot.rom build is
-not turned on by default in the U-Boot source tree. Firstly, you need turn it
-on by enabling the ROM build either via an environment variable
-
- $ export BUILD_ROM=y
-
-or via configuration
-
- CONFIG_BUILD_ROM=y
-
-Both tell the Makefile to build u-boot.rom as a target.
-
----
-
-CPU Microcode
--------------
-Modern CPUs usually require a special bit stream called microcode [8] to be
-loaded on the processor after power up in order to function properly. U-Boot
-has already integrated these as hex dumps in the source tree.
-
-SMP Support
------------
-On a multicore system, U-Boot is executed on the bootstrap processor (BSP).
-Additional application processors (AP) can be brought up by U-Boot. In order to
-have an SMP kernel to discover all of the available processors, U-Boot needs to
-prepare configuration tables which contain the multi-CPUs information before
-loading the OS kernel. Currently U-Boot supports generating two types of tables
-for SMP, called Simple Firmware Interface (SFI) [9] and Multi-Processor (MP)
-[10] tables. The writing of these two tables are controlled by two Kconfig
-options GENERATE_SFI_TABLE and GENERATE_MP_TABLE.
-
-Driver Model
-------------
-x86 has been converted to use driver model for serial, GPIO, SPI, SPI flash,
-keyboard, real-time clock, USB. Video is in progress.
-
-Device Tree
------------
-x86 uses device tree to configure the board thus requires CONFIG_OF_CONTROL to
-be turned on. Not every device on the board is configured via device tree, but
-more and more devices will be added as time goes by. Check out the directory
-arch/x86/dts/ for these device tree source files.
-
-Useful Commands
----------------
-In keeping with the U-Boot philosophy of providing functions to check and
-adjust internal settings, there are several x86-specific commands that may be
-useful:
-
-fsp - Display information about Intel Firmware Support Package (FSP).
- This is only available on platforms which use FSP, mostly Atom.
-iod - Display I/O memory
-iow - Write I/O memory
-mtrr - List and set the Memory Type Range Registers (MTRR). These are used to
- tell the CPU whether memory is cacheable and if so the cache write
- mode to use. U-Boot sets up some reasonable values but you can
- adjust then with this command.
-
-Booting Ubuntu
---------------
-As an example of how to set up your boot flow with U-Boot, here are
-instructions for starting Ubuntu from U-Boot. These instructions have been
-tested on Minnowboard MAX with a SATA drive but are equally applicable on
-other platforms and other media. There are really only four steps and it's a
-very simple script, but a more detailed explanation is provided here for
-completeness.
-
-Note: It is possible to set up U-Boot to boot automatically using syslinux.
-It could also use the grub.cfg file (/efi/ubuntu/grub.cfg) to obtain the
-GUID. If you figure these out, please post patches to this README.
-
-Firstly, you will need Ubuntu installed on an available disk. It should be
-possible to make U-Boot start a USB start-up disk but for now let's assume
-that you used another boot loader to install Ubuntu.
-
-Use the U-Boot command line to find the UUID of the partition you want to
-boot. For example our disk is SCSI device 0:
-
-=> part list scsi 0
-
-Partition Map for SCSI device 0 -- Partition Type: EFI
-
- Part Start LBA End LBA Name
- Attributes
- Type GUID
- Partition GUID
- 1 0x00000800 0x001007ff ""
- attrs: 0x0000000000000000
- type: c12a7328-f81f-11d2-ba4b-00a0c93ec93b
- guid: 9d02e8e4-4d59-408f-a9b0-fd497bc9291c
- 2 0x00100800 0x037d8fff ""
- attrs: 0x0000000000000000
- type: 0fc63daf-8483-4772-8e79-3d69d8477de4
- guid: 965c59ee-1822-4326-90d2-b02446050059
- 3 0x037d9000 0x03ba27ff ""
- attrs: 0x0000000000000000
- type: 0657fd6d-a4ab-43c4-84e5-0933c84b4f4f
- guid: 2c4282bd-1e82-4bcf-a5ff-51dedbf39f17
- =>
-
-This shows that your SCSI disk has three partitions. The really long hex
-strings are called Globally Unique Identifiers (GUIDs). You can look up the
-'type' ones here [11]. On this disk the first partition is for EFI and is in
-VFAT format (DOS/Windows):
-
- => fatls scsi 0:1
- efi/
-
- 0 file(s), 1 dir(s)
-
-
-Partition 2 is 'Linux filesystem data' so that will be our root disk. It is
-in ext2 format:
-
- => ext2ls scsi 0:2
- <DIR> 4096 .
- <DIR> 4096 ..
- <DIR> 16384 lost+found
- <DIR> 4096 boot
- <DIR> 12288 etc
- <DIR> 4096 media
- <DIR> 4096 bin
- <DIR> 4096 dev
- <DIR> 4096 home
- <DIR> 4096 lib
- <DIR> 4096 lib64
- <DIR> 4096 mnt
- <DIR> 4096 opt
- <DIR> 4096 proc
- <DIR> 4096 root
- <DIR> 4096 run
- <DIR> 12288 sbin
- <DIR> 4096 srv
- <DIR> 4096 sys
- <DIR> 4096 tmp
- <DIR> 4096 usr
- <DIR> 4096 var
- <SYM> 33 initrd.img
- <SYM> 30 vmlinuz
- <DIR> 4096 cdrom
- <SYM> 33 initrd.img.old
- =>
-
-and if you look in the /boot directory you will see the kernel:
-
- => ext2ls scsi 0:2 /boot
- <DIR> 4096 .
- <DIR> 4096 ..
- <DIR> 4096 efi
- <DIR> 4096 grub
- 3381262 System.map-3.13.0-32-generic
- 1162712 abi-3.13.0-32-generic
- 165611 config-3.13.0-32-generic
- 176500 memtest86+.bin
- 178176 memtest86+.elf
- 178680 memtest86+_multiboot.bin
- 5798112 vmlinuz-3.13.0-32-generic
- 165762 config-3.13.0-58-generic
- 1165129 abi-3.13.0-58-generic
- 5823136 vmlinuz-3.13.0-58-generic
- 19215259 initrd.img-3.13.0-58-generic
- 3391763 System.map-3.13.0-58-generic
- 5825048 vmlinuz-3.13.0-58-generic.efi.signed
- 28304443 initrd.img-3.13.0-32-generic
- =>
-
-The 'vmlinuz' files contain a packaged Linux kernel. The format is a kind of
-self-extracting compressed file mixed with some 'setup' configuration data.
-Despite its size (uncompressed it is >10MB) this only includes a basic set of
-device drivers, enough to boot on most hardware types.
-
-The 'initrd' files contain a RAM disk. This is something that can be loaded
-into RAM and will appear to Linux like a disk. Ubuntu uses this to hold lots
-of drivers for whatever hardware you might have. It is loaded before the
-real root disk is accessed.
-
-The numbers after the end of each file are the version. Here it is Linux
-version 3.13. You can find the source code for this in the Linux tree with
-the tag v3.13. The '.0' allows for additional Linux releases to fix problems,
-but normally this is not needed. The '-58' is used by Ubuntu. Each time they
-release a new kernel they increment this number. New Ubuntu versions might
-include kernel patches to fix reported bugs. Stable kernels can exist for
-some years so this number can get quite high.
-
-The '.efi.signed' kernel is signed for EFI's secure boot. U-Boot has its own
-secure boot mechanism - see [12] [13] and cannot read .efi files at present.
-
-To boot Ubuntu from U-Boot the steps are as follows:
-
-1. Set up the boot arguments. Use the GUID for the partition you want to
-boot:
-
- => setenv bootargs root=/dev/disk/by-partuuid/965c59ee-1822-4326-90d2-b02446050059 ro
-
-Here root= tells Linux the location of its root disk. The disk is specified
-by its GUID, using '/dev/disk/by-partuuid/', a Linux path to a 'directory'
-containing all the GUIDs Linux has found. When it starts up, there will be a
-file in that directory with this name in it. It is also possible to use a
-device name here, see later.
-
-2. Load the kernel. Since it is an ext2/4 filesystem we can do:
-
- => ext2load scsi 0:2 03000000 /boot/vmlinuz-3.13.0-58-generic
-
-The address 30000000 is arbitrary, but there seem to be problems with using
-small addresses (sometimes Linux cannot find the ramdisk). This is 48MB into
-the start of RAM (which is at 0 on x86).
-
-3. Load the ramdisk (to 64MB):
-
- => ext2load scsi 0:2 04000000 /boot/initrd.img-3.13.0-58-generic
-
-4. Start up the kernel. We need to know the size of the ramdisk, but can use
-a variable for that. U-Boot sets 'filesize' to the size of the last file it
-loaded.
-
- => zboot 03000000 0 04000000 ${filesize}
-
-Type 'help zboot' if you want to see what the arguments are. U-Boot on x86 is
-quite verbose when it boots a kernel. You should see these messages from
-U-Boot:
-
- Valid Boot Flag
- Setup Size = 0x00004400
- Magic signature found
- Using boot protocol version 2.0c
- Linux kernel version 3.13.0-58-generic (buildd@allspice) #97-Ubuntu SMP Wed Jul 8 02:56:15 UTC 2015
- Building boot_params at 0x00090000
- Loading bzImage at address 100000 (5805728 bytes)
- Magic signature found
- Initial RAM disk at linear address 0x04000000, size 19215259 bytes
- Kernel command line: "root=/dev/disk/by-partuuid/965c59ee-1822-4326-90d2-b02446050059 ro"
-
- Starting kernel ...
-
-U-Boot prints out some bootstage timing. This is more useful if you put the
-above commands into a script since then it will be faster.
-
- Timer summary in microseconds:
- Mark Elapsed Stage
- 0 0 reset
- 241,535 241,535 board_init_r
- 2,421,611 2,180,076 id=64
- 2,421,790 179 id=65
- 2,428,215 6,425 main_loop
- 48,860,584 46,432,369 start_kernel
-
- Accumulated time:
- 240,329 ahci
- 1,422,704 vesa display
-
-Now the kernel actually starts: (if you want to examine kernel boot up message
-on the serial console, append "console=ttyS0,115200" to the kernel command line)
-
- [ 0.000000] Initializing cgroup subsys cpuset
- [ 0.000000] Initializing cgroup subsys cpu
- [ 0.000000] Initializing cgroup subsys cpuacct
- [ 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)
- [ 0.000000] Command line: root=/dev/disk/by-partuuid/965c59ee-1822-4326-90d2-b02446050059 ro console=ttyS0,115200
-
-It continues for a long time. Along the way you will see it pick up your
-ramdisk:
-
- [ 0.000000] RAMDISK: [mem 0x04000000-0x05253fff]
-...
- [ 0.788540] Trying to unpack rootfs image as initramfs...
- [ 1.540111] Freeing initrd memory: 18768K (ffff880004000000 - ffff880005254000)
-...
-
-Later it actually starts using it:
-
- Begin: Running /scripts/local-premount ... done.
-
-You should also see your boot disk turn up:
-
- [ 4.357243] scsi 1:0:0:0: Direct-Access ATA ADATA SP310 5.2 PQ: 0 ANSI: 5
- [ 4.366860] sd 1:0:0:0: [sda] 62533296 512-byte logical blocks: (32.0 GB/29.8 GiB)
- [ 4.375677] sd 1:0:0:0: Attached scsi generic sg0 type 0
- [ 4.381859] sd 1:0:0:0: [sda] Write Protect is off
- [ 4.387452] sd 1:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
- [ 4.399535] sda: sda1 sda2 sda3
-
-Linux has found the three partitions (sda1-3). Mercifully it doesn't print out
-the GUIDs. In step 1 above we could have used:
-
- setenv bootargs root=/dev/sda2 ro
-
-instead of the GUID. However if you add another drive to your board the
-numbering may change whereas the GUIDs will not. So if your boot partition
-becomes sdb2, it will still boot. For embedded systems where you just want to
-boot the first disk, you have that option.
-
-The last thing you will see on the console is mention of plymouth (which
-displays the Ubuntu start-up screen) and a lot of 'Starting' messages:
-
- * Starting Mount filesystems on boot [ OK ]
-
-After a pause you should see a login screen on your display and you are done.
-
-If you want to put this in a script you can use something like this:
-
- setenv bootargs root=UUID=b2aaf743-0418-4d90-94cc-3e6108d7d968 ro
- setenv boot zboot 03000000 0 04000000 \${filesize}
- 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"
- saveenv
-
-The \ is to tell the shell not to evaluate ${filesize} as part of the setenv
-command.
-
-You can also bake this behaviour into your build by hard-coding the
-environment variables if you add this to minnowmax.h:
-
-#undef CONFIG_BOOTCOMMAND
-#define CONFIG_BOOTCOMMAND \
- "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"
-
-#undef CONFIG_EXTRA_ENV_SETTINGS
-#define CONFIG_EXTRA_ENV_SETTINGS "boot=zboot 03000000 0 04000000 ${filesize}"
-
-and change CONFIG_BOOTARGS value in configs/minnowmax_defconfig to:
-
-CONFIG_BOOTARGS="root=/dev/sda2 ro"
-
-Test with SeaBIOS
------------------
-SeaBIOS [14] is an open source implementation of a 16-bit x86 BIOS. It can run
-in an emulator or natively on x86 hardware with the use of U-Boot. With its
-help, we can boot some OSes that require 16-bit BIOS services like Windows/DOS.
-
-As U-Boot, we have to manually create a table where SeaBIOS gets various system
-information (eg: E820) from. The table unfortunately has to follow the coreboot
-table format as SeaBIOS currently supports booting as a coreboot payload.
-
-To support loading SeaBIOS, U-Boot should be built with CONFIG_SEABIOS on.
-Booting SeaBIOS is done via U-Boot's bootelf command, like below:
-
- => tftp bios.bin.elf;bootelf
- Using e1000#0 device
- TFTP from server 10.10.0.100; our IP address is 10.10.0.108
- ...
- Bytes transferred = 122124 (1dd0c hex)
- ## Starting application at 0x000ff06e ...
- SeaBIOS (version rel-1.9.0)
- ...
-
-bios.bin.elf is the SeaBIOS image built from SeaBIOS source tree.
-Make sure it is built as follows:
-
- $ make menuconfig
-
-Inside the "General Features" menu, select "Build for coreboot" as the
-"Build Target". Inside the "Debugging" menu, turn on "Serial port debugging"
-so that we can see something as soon as SeaBIOS boots. Leave other options
-as in their default state. Then,
-
- $ make
- ...
- Total size: 121888 Fixed: 66496 Free: 9184 (used 93.0% of 128KiB rom)
- Creating out/bios.bin.elf
-
-Currently this is tested on QEMU x86 target with U-Boot chain-loading SeaBIOS
-to install/boot a Windows XP OS (below for example command to install Windows).
-
- # Create a 10G disk.img as the virtual hard disk
- $ qemu-img create -f qcow2 disk.img 10G
-
- # Install a Windows XP OS from an ISO image 'winxp.iso'
- $ qemu-system-i386 -serial stdio -bios u-boot.rom -hda disk.img -cdrom winxp.iso -smp 2 -m 512
-
- # Boot a Windows XP OS installed on the virutal hard disk
- $ qemu-system-i386 -serial stdio -bios u-boot.rom -hda disk.img -smp 2 -m 512
-
-This is also tested on Intel Crown Bay board with a PCIe graphics card, booting
-SeaBIOS then chain-loading a GRUB on a USB drive, then Linux kernel finally.
-
-If you are using Intel Integrated Graphics Device (IGD) as the primary display
-device on your board, SeaBIOS needs to be patched manually to get its VGA ROM
-loaded and run by SeaBIOS. SeaBIOS locates VGA ROM via the PCI expansion ROM
-register, but IGD device does not have its VGA ROM mapped by this register.
-Its VGA ROM is packaged as part of u-boot.rom at a configurable flash address
-which is unknown to SeaBIOS. An example patch is needed for SeaBIOS below:
-
-diff --git a/src/optionroms.c b/src/optionroms.c
-index 65f7fe0..c7b6f5e 100644
---- a/src/optionroms.c
-+++ b/src/optionroms.c
-@@ -324,6 +324,8 @@ init_pcirom(struct pci_device *pci, int isvga, u64 *sources)
- rom = deploy_romfile(file);
- else if (RunPCIroms > 1 || (RunPCIroms == 1 && isvga))
- rom = map_pcirom(pci);
-+ if (pci->bdf == pci_to_bdf(0, 2, 0))
-+ rom = (struct rom_header *)0xfff90000;
- if (! rom)
- // No ROM present.
- return;
-
-Note: the patch above expects IGD device is at PCI b.d.f 0.2.0 and its VGA ROM
-is at 0xfff90000 which corresponds to CONFIG_VGA_BIOS_ADDR on Minnowboard MAX.
-Change these two accordingly if this is not the case on your board.
-
-Development Flow
-----------------
-These notes are for those who want to port U-Boot to a new x86 platform.
-
-Since x86 CPUs boot from SPI flash, a SPI flash emulator is a good investment.
-The Dediprog em100 can be used on Linux. The em100 tool is available here:
-
- http://review.coreboot.org/p/em100.git
-
-On Minnowboard Max the following command line can be used:
-
- sudo em100 -s -p LOW -d u-boot.rom -c W25Q64DW -r
-
-A suitable clip for connecting over the SPI flash chip is here:
-
- http://www.dediprog.com/pd/programmer-accessories/EM-TC-8
-
-This allows you to override the SPI flash contents for development purposes.
-Typically you can write to the em100 in around 1200ms, considerably faster
-than programming the real flash device each time. The only important
-limitation of the em100 is that it only supports SPI bus speeds up to 20MHz.
-This means that images must be set to boot with that speed. This is an
-Intel-specific feature - e.g. tools/ifttool has an option to set the SPI
-speed in the SPI descriptor region.
-
-If your chip/board uses an Intel Firmware Support Package (FSP) it is fairly
-easy to fit it in. You can follow the Minnowboard Max implementation, for
-example. Hopefully you will just need to create new files similar to those
-in arch/x86/cpu/baytrail which provide Bay Trail support.
-
-If you are not using an FSP you have more freedom and more responsibility.
-The ivybridge support works this way, although it still uses a ROM for
-graphics and still has binary blobs containing Intel code. You should aim to
-support all important peripherals on your platform including video and storage.
-Use the device tree for configuration where possible.
-
-For the microcode you can create a suitable device tree file using the
-microcode tool:
-
- ./tools/microcode-tool -d microcode.dat -m <model> create
-
-or if you only have header files and not the full Intel microcode.dat database:
-
- ./tools/microcode-tool -H BAY_TRAIL_FSP_KIT/Microcode/M0130673322.h \
- -H BAY_TRAIL_FSP_KIT/Microcode/M0130679901.h \
- -m all create
-
-These are written to arch/x86/dts/microcode/ by default.
-
-Note that it is possible to just add the micrcode for your CPU if you know its
-model. U-Boot prints this information when it starts
-
- CPU: x86_64, vendor Intel, device 30673h
-
-so here we can use the M0130673322 file.
-
-If you platform can display POST codes on two little 7-segment displays on
-the board, then you can use post_code() calls from C or assembler to monitor
-boot progress. This can be good for debugging.
-
-If not, you can try to get serial working as early as possible. The early
-debug serial port may be useful here. See setup_internal_uart() for an example.
-
-During the U-Boot porting, one of the important steps is to write correct PIRQ
-routing information in the board device tree. Without it, device drivers in the
-Linux kernel won't function correctly due to interrupt is not working. Please
-refer to U-Boot doc [15] for the device tree bindings of Intel interrupt router.
-Here we have more details on the intel,pirq-routing property below.
-
- intel,pirq-routing = <
- PCI_BDF(0, 2, 0) INTA PIRQA
- ...
- >;
-
-As you see each entry has 3 cells. For the first one, we need describe all pci
-devices mounted on the board. For SoC devices, normally there is a chapter on
-the chipset datasheet which lists all the available PCI devices. For example on
-Bay Trail, this is chapter 4.3 (PCI configuration space). For the second one, we
-can get the interrupt pin either from datasheet or hardware via U-Boot shell.
-The reliable source is the hardware as sometimes chipset datasheet is not 100%
-up-to-date. Type 'pci header' plus the device's pci bus/device/function number
-from U-Boot shell below.
-
- => pci header 0.1e.1
- vendor ID = 0x8086
- device ID = 0x0f08
- ...
- interrupt line = 0x09
- interrupt pin = 0x04
- ...
-
-It shows this PCI device is using INTD pin as it reports 4 in the interrupt pin
-register. Repeat this until you get interrupt pins for all the devices. The last
-cell is the PIRQ line which a particular interrupt pin is mapped to. On Intel
-chipset, the power-up default mapping is INTA/B/C/D maps to PIRQA/B/C/D. This
-can be changed by registers in LPC bridge. So far Intel FSP does not touch those
-registers so we can write down the PIRQ according to the default mapping rule.
-
-Once we get the PIRQ routing information in the device tree, the interrupt
-allocation and assignment will be done by U-Boot automatically. Now you can
-enable CONFIG_GENERATE_PIRQ_TABLE for testing Linux kernel using i8259 PIC and
-CONFIG_GENERATE_MP_TABLE for testing Linux kernel using local APIC and I/O APIC.
-
-This script might be useful. If you feed it the output of 'pci long' from
-U-Boot then it will generate a device tree fragment with the interrupt
-configuration for each device (note it needs gawk 4.0.0):
-
- $ cat console_output |awk '/PCI/ {device=$4} /interrupt line/ {line=$4} \
- /interrupt pin/ {pin = $4; if (pin != "0x00" && pin != "0xff") \
- {patsplit(device, bdf, "[0-9a-f]+"); \
- printf "PCI_BDF(%d, %d, %d) INT%c PIRQ%c\n", strtonum("0x" bdf[1]), \
- strtonum("0x" bdf[2]), bdf[3], strtonum(pin) + 64, 64 + strtonum(pin)}}'
-
-Example output:
- PCI_BDF(0, 2, 0) INTA PIRQA
- PCI_BDF(0, 3, 0) INTA PIRQA
-...
-
-Porting Hints
--------------
-
-Quark-specific considerations:
-
-To port U-Boot to other boards based on the Intel Quark SoC, a few things need
-to be taken care of. The first important part is the Memory Reference Code (MRC)
-parameters. Quark MRC supports memory-down configuration only. All these MRC
-parameters are supplied via the board device tree. To get started, first copy
-the MRC section of arch/x86/dts/galileo.dts to your board's device tree, then
-change these values by consulting board manuals or your hardware vendor.
-Available MRC parameter values are listed in include/dt-bindings/mrc/quark.h.
-The other tricky part is with PCIe. Quark SoC integrates two PCIe root ports,
-but by default they are held in reset after power on. In U-Boot, PCIe
-initialization is properly handled as per Quark's firmware writer guide.
-In your board support codes, you need provide two routines to aid PCIe
-initialization, which are board_assert_perst() and board_deassert_perst().
-The two routines need implement a board-specific mechanism to assert/deassert
-PCIe PERST# pin. Care must be taken that in those routines that any APIs that
-may trigger PCI enumeration process are strictly forbidden, as any access to
-PCIe root port's configuration registers will cause system hang while it is
-held in reset. For more details, check how they are implemented by the Intel
-Galileo board support codes in board/intel/galileo/galileo.c.
-
-coreboot:
-
-See scripts/coreboot.sed which can assist with porting coreboot code into
-U-Boot drivers. It will not resolve all build errors, but will perform common
-transformations. Remember to add attribution to coreboot for new files added
-to U-Boot. This should go at the top of each file and list the coreboot
-filename where the code originated.
-
-Debugging ACPI issues with Windows:
-
-Windows might cache system information and only detect ACPI changes if you
-modify the ACPI table versions. So tweak them liberally when debugging ACPI
-issues with Windows.
-
-ACPI Support Status
--------------------
-Advanced Configuration and Power Interface (ACPI) [16] aims to establish
-industry-standard interfaces enabling OS-directed configuration, power
-management, and thermal management of mobile, desktop, and server platforms.
-
-Linux can boot without ACPI with "acpi=off" command line parameter, but
-with ACPI the kernel gains the capabilities to handle power management.
-For Windows, ACPI is a must-have firmware feature since Windows Vista.
-CONFIG_GENERATE_ACPI_TABLE is the config option to turn on ACPI support in
-U-Boot. This requires Intel ACPI compiler to be installed on your host to
-compile ACPI DSDT table written in ASL format to AML format. You can get
-the compiler via "apt-get install iasl" if you are on Ubuntu or download
-the source from [17] to compile one by yourself.
-
-Current ACPI support in U-Boot is basically complete. More optional features
-can be added in the future. The status as of today is:
-
- * Support generating RSDT, XSDT, FACS, FADT, MADT, MCFG tables.
- * Support one static DSDT table only, compiled by Intel ACPI compiler.
- * Support S0/S3/S4/S5, reboot and shutdown from OS.
- * Support booting a pre-installed Ubuntu distribution via 'zboot' command.
- * Support installing and booting Ubuntu 14.04 (or above) from U-Boot with
- the help of SeaBIOS using legacy interface (non-UEFI mode).
- * Support installing and booting Windows 8.1/10 from U-Boot with the help
- of SeaBIOS using legacy interface (non-UEFI mode).
- * Support ACPI interrupts with SCI only.
-
-Features that are optional:
- * Dynamic AML bytecodes insertion at run-time. We may need this to support
- SSDT table generation and DSDT fix up.
- * SMI support. Since U-Boot is a modern bootloader, we don't want to bring
- those legacy stuff into U-Boot. ACPI spec allows a system that does not
- support SMI (a legacy-free system).
-
-ACPI was initially enabled on BayTrail based boards. Testing was done by booting
-a pre-installed Ubuntu 14.04 from a SATA drive. Installing Ubuntu 14.04 and
-Windows 8.1/10 to a SATA drive and booting from there is also tested. Most
-devices seem to work correctly and the board can respond a reboot/shutdown
-command from the OS.
-
-For other platform boards, ACPI support status can be checked by examining their
-board defconfig files to see if CONFIG_GENERATE_ACPI_TABLE is set to y.
-
-The S3 sleeping state is a low wake latency sleeping state defined by ACPI
-spec where all system context is lost except system memory. To test S3 resume
-with a Linux kernel, simply run "echo mem > /sys/power/state" and kernel will
-put the board to S3 state where the power is off. So when the power button is
-pressed again, U-Boot runs as it does in cold boot and detects the sleeping
-state via ACPI register to see if it is S3, if yes it means we are waking up.
-U-Boot is responsible for restoring the machine state as it is before sleep.
-When everything is done, U-Boot finds out the wakeup vector provided by OSes
-and jump there. To determine whether ACPI S3 resume is supported, check to
-see if CONFIG_HAVE_ACPI_RESUME is set for that specific board.
-
-Note for testing S3 resume with Windows, correct graphics driver must be
-installed for your platform, otherwise you won't find "Sleep" option in
-the "Power" submenu from the Windows start menu.
-
-EFI Support
------------
-U-Boot supports booting as a 32-bit or 64-bit EFI payload, e.g. with UEFI.
-This is enabled with CONFIG_EFI_STUB to boot from both 32-bit and 64-bit
-UEFI BIOS. U-Boot can also run as an EFI application, with CONFIG_EFI_APP.
-The CONFIG_EFI_LOADER option, where U-Boot provides an EFI environment to
-the kernel (i.e. replaces UEFI completely but provides the same EFI run-time
-services) is supported too. For example, we can even use 'bootefi' command
-to load a 'u-boot-payload.efi', see below test logs on QEMU.
-
- => load ide 0 3000000 u-boot-payload.efi
- 489787 bytes read in 138 ms (3.4 MiB/s)
- => bootefi 3000000
- Scanning disk ide.blk#0...
- Found 2 disks
- WARNING: booting without device tree
- ## Starting EFI application at 03000000 ...
- U-Boot EFI Payload
-
-
- U-Boot 2018.07-rc2 (Jun 23 2018 - 17:12:58 +0800)
-
- CPU: x86_64, vendor AMD, device 663h
- DRAM: 2 GiB
- MMC:
- Video: 1024x768x32
- Model: EFI x86 Payload
- Net: e1000: 52:54:00:12:34:56
-
- Warning: e1000#0 using MAC address from ROM
- eth0: e1000#0
- No controllers found
- Hit any key to stop autoboot: 0
-
-See README.u-boot_on_efi and README.uefi for details of EFI support in U-Boot.
-
-TODO List
----------
-- Audio
-- Chrome OS verified boot
-
-References
-----------
-[1] http://www.coreboot.org
-[2] http://www.qemu.org
-[3] http://www.coreboot.org/~stepan/pci8086,0166.rom
-[4] http://www.intel.com/content/www/us/en/embedded/design-tools/evaluation-platforms/atom-e660-eg20t-development-kit.html
-[5] http://www.intel.com/fsp
-[6] http://www.intel.com/content/www/us/en/secure/intelligent-systems/privileged/e6xx-35-b1-cmc22211.html
-[7] http://www.ami.com/products/bios-uefi-tools-and-utilities/bios-uefi-utilities/
-[8] http://en.wikipedia.org/wiki/Microcode
-[9] http://simplefirmware.org
-[10] http://www.intel.com/design/archives/processors/pro/docs/242016.htm
-[11] https://en.wikipedia.org/wiki/GUID_Partition_Table
-[12] http://events.linuxfoundation.org/sites/events/files/slides/chromeos_and_diy_vboot_0.pdf
-[13] http://events.linuxfoundation.org/sites/events/files/slides/elce-2014.pdf
-[14] http://www.seabios.org/SeaBIOS
-[15] doc/device-tree-bindings/misc/intel,irq-router.txt
-[16] http://www.acpi.info
-[17] https://www.acpica.org/downloads
projects / oweals / u-boot.git / commitdiff