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x86: Update README.x86 for QEMU support

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Document how to build and test U-Boot with QEMU.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
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Bin Meng 2015-05-07 21:34:12 +08:00 committed by Simon Glass
parent b28c147569
commit 1ae5b78c45
1 changed files with 48 additions and 17 deletions
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@ -14,12 +14,13 @@ 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) has been tested, but it should work with minimal adjustments
on other x86 boards since coreboot deals with most of the low-level details.
(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 also supports booting directly from x86 reset vector without coreboot,
aka raw support or bare support. Currently Link, Intel Crown Bay, Intel
Minnowboard Max and Intel Galileo support running U-Boot 'bare metal'.
aka raw support or bare support. Currently Link, QEMU x86 targets and all
Intel boards support running U-Boot 'bare metal'.
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.
@ -32,15 +33,15 @@ on other architectures, like below:
$ make coreboot-x86_defconfig
$ make all
Note this default configuration will build a U-Boot payload for the Link board.
Note this default configuration will build a U-Boot payload for the QEMU board.
To build a coreboot payload against another board, you can change the build
configuration during the 'make menuconfig' process.
x86 architecture --->
...
(chromebook_link) Board configuration file
(chromebook_link) Board Device Tree Source (dts) file
(0x19200000) Board specific Cache-As-RAM (CAR) address
(qemu-x86) Board configuration file
(qemu-x86) Board Device Tree Source (dts) file
(0x01920000) Board specific Cache-As-RAM (CAR) address
(0x4000) Board specific Cache-As-RAM (CAR) size
Change the 'Board configuration file' and 'Board Device Tree Source (dts) file'
@ -78,7 +79,7 @@ Find the following files:
* ./northbridge/intel/sandybridge/systemagent-r6.bin
The 3rd one should be renamed to mrc.bin.
As for the video ROM, you can get it here [2].
As for the video ROM, you can get it here [3].
Make sure all these binary blobs are put in the board directory.
Now you can build U-Boot and obtain u-boot.rom:
@ -88,8 +89,8 @@ $ make all
Intel Crown Bay specific instructions:
U-Boot support of Intel Crown Bay board [3] relies on a binary blob called
Firmware Support Package [4] to perform all the necessary initialization steps
U-Boot support of Intel Crown Bay board [4] relies on a binary blob called
Firmware Support Package [5] to perform all the necessary initialization steps
as documented in the BIOS Writer Guide, including initialization of the CPU,
memory controller, chipset and certain bus interfaces.
@ -178,6 +179,13 @@ Now you can build U-Boot and obtain u-boot.rom
$ make galileo_defconfig
$ make all
QEMU x86 target instructions:
To build u-boot.rom for QEMU x86 targets, just simply run
$ make qemu-x86_defconfig
$ make all
Test with coreboot
------------------
For testing U-Boot as the coreboot payload, there are things that need be paid
@ -207,10 +215,33 @@ At present it seems that for Minnowboard Max, coreboot does not pass through
the video information correctly (it always says the resolution is 0x0). This
works correctly for link though.
Test with QEMU
--------------
QEMU is a fancy emulator that can enable us to test U-Boot without access to
a real x86 board. To launch QEMU with u-boot.rom, call QEMU as follows:
$ qemu-system-i386 -nographic -bios path/to/u-boot.rom
This will instantiate an emulated x86 board with i440FX and PIIX chipset. QEMU
also supports emulating an x86 board with Q35 and ICH9 based chipset, which is
also supported by U-Boot. To instantiate such a machine, call QEMU with:
$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -M q35
Note by default QEMU instantiated boards only have 128 MiB system memory. But
it is enough to have U-Boot boot and function correctly. You can increase the
system memory by pass '-m' parameter to QEMU if you want more memory:
$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -m 1024
This creates a board with 1 GiB system memory. Currently U-Boot for QEMU only
supports 3 GiB maximum system memory and reserves the last 1 GiB address space
for PCI device memory-mapped I/O and other stuff, so the maximum value of '-m'
would be 3072.
CPU Microcode
-------------
Modern CPUs usually require a special bit stream called microcode [5] to be
Modern CPUs usually require a special bit stream called microcode [6] 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.
@ -227,7 +258,6 @@ 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:
@ -314,7 +344,8 @@ TODO List
References
----------
[1] http://www.coreboot.org
[2] http://www.coreboot.org/~stepan/pci8086,0166.rom
[3] http://www.intel.com/content/www/us/en/embedded/design-tools/evaluation-platforms/atom-e660-eg20t-development-kit.html
[4] http://www.intel.com/fsp
[5] http://en.wikipedia.org/wiki/Microcode
[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://en.wikipedia.org/wiki/Microcode