+# SPDX-License-Identifier: GPL-2.0+
#
# Copyright (C) 2014, Simon Glass <sjg@chromium.org>
# Copyright (C) 2014, Bin Meng <bmeng.cn@gmail.com>
-#
-# SPDX-License-Identifier: GPL-2.0+
-#
U-Boot on x86
=============
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
Building U-Boot as a coreboot payload is just like building U-Boot for targets
on other architectures, like below:
-$ make coreboot-x86_defconfig
+$ make coreboot_defconfig
$ make all
Note this default configuration will build a U-Boot payload for the QEMU board.
to point to a new board. You can also change the Cache-As-RAM (CAR) related
settings here if the default values do not fit your new board.
+Build Instructions for U-Boot as main bootloader
+------------------------------------------------
+
+Intel Edison instructions:
+
+Simple you can build U-Boot and obtain u-boot.bin
+
+$ make edison_defconfig
+$ make all
+
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:
+on by enabling the ROM build either via an environment variable
+
+ $ export BUILD_ROM=y
-$ export BUILD_ROM=y
+or via configuration
-This tells the Makefile to build u-boot.rom as a target.
+ CONFIG_BUILD_ROM=y
+
+Both tell the Makefile to build u-boot.rom as a target.
---
6ef000 Environment CONFIG_ENV_OFFSET
6f0000 MRC cache CONFIG_ENABLE_MRC_CACHE
700000 u-boot-dtb.bin CONFIG_SYS_TEXT_BASE
-790000 vga.bin CONFIG_VGA_BIOS_ADDR
+7b0000 vga.bin CONFIG_VGA_BIOS_ADDR
7c0000 fsp.bin CONFIG_FSP_ADDR
7f8000 <spare> (depends on size of fsp.bin)
7ff800 U-Boot 16-bit boot CONFIG_SYS_X86_START16
---
+Intel Cherry Hill specific instructions for bare mode:
+
+This uses Intel FSP for Braswell platform. Download it from Intel FSP website,
+put the .fd file to the board directory and rename it to fsp.bin.
+
+Extract descriptor.bin and me.bin from the original BIOS on the board using
+ifdtool and put them to the board directory as well.
+
+Note the FSP package for Braswell does not ship a traditional legacy VGA BIOS
+image for the integrated graphics device. Instead a new binary called Video
+BIOS Table (VBT) is shipped. Put it to the board directory and rename it to
+vbt.bin if you want graphics support in U-Boot.
+
+Now you can build U-Boot and obtain u-boot.rom
+
+$ make cherryhill_defconfig
+$ make all
+
+An important note for programming u-boot.rom to the on-board SPI flash is that
+you need make sure the SPI flash's 'quad enable' bit in its status register
+matches the settings in the descriptor.bin, otherwise the board won't boot.
+
+For the on-board SPI flash MX25U6435F, this can be done by writing 0x40 to the
+status register by DediProg in: Config > Modify Status Register > Write Status
+Register(s) > Register1 Value(Hex). This is is a one-time change. Once set, it
+persists in SPI flash part regardless of the u-boot.rom image burned.
+
+---
+
Intel Galileo instructions for bare mode:
Only one binary blob is needed for Remote Management Unit (RMU) within Intel
=> zboot 01000000 - 04000000 1b1ab50
+Updating U-Boot on Edison
+-------------------------
+By default Intel Edison boards are shipped with preinstalled heavily
+patched U-Boot v2014.04. Though it supports DFU which we may be able to
+use.
+
+1. Prepare u-boot.bin as described in chapter above. You still need one
+more step (if and only if you have original U-Boot), i.e. run the
+following command:
+
+$ truncate -s %4096 u-boot.bin
+
+2. Run your board and interrupt booting to U-Boot console. In the console
+call:
+
+ => run do_force_flash_os
+
+3. Wait for few seconds, it will prepare environment variable and runs
+DFU. Run DFU command from the host system:
+
+$ dfu-util -v -d 8087:0a99 --alt u-boot0 -D u-boot.bin
+
+4. Return to U-Boot console and following hint. i.e. push Ctrl+C, and
+reset the board:
+
+ => reset
+
CPU Microcode
-------------
Modern CPUs usually require a special bit stream called microcode [8] to be
You can also bake this behaviour into your build by hard-coding the
environment variables if you add this to minnowmax.h:
-#undef CONFIG_BOOTARGS
#undef CONFIG_BOOTCOMMAND
-
-#define CONFIG_BOOTARGS \
- "root=/dev/sda2 ro"
#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; " \
#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
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 not complete. More features will be added
-in the future. The status as of today is:
+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/S5, reboot and shutdown from OS.
+ * 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).
of SeaBIOS using legacy interface (non-UEFI mode).
* Support ACPI interrupts with SCI only.
-Features not supported so far (to make it a complete ACPI solution):
- * S3 (Suspend to RAM), S4 (Suspend to Disk).
-
Features that are optional:
* Dynamic AML bytecodes insertion at run-time. We may need this to support
SSDT table generation and DSDT fix up.
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.
projects / platform / kernel / u-boot.git / blobdiff