mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-09-12 15:53:21 +09:00
![Bin Meng](/assets/img/avatar_default.png)
This extracts QEMU x86 board specific information from README.x86, converts plain text documentation to reST format and adds it to Sphinx TOC tree. No essential content change. Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
102 lines
4.0 KiB
ReStructuredText
102 lines
4.0 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+
|
|
.. sectionauthor:: Bin Meng <bmeng.cn@gmail.com>
|
|
|
|
QEMU x86
|
|
========
|
|
|
|
Build instructions for bare mode
|
|
--------------------------------
|
|
|
|
To build u-boot.rom for QEMU x86 targets, just simply run::
|
|
|
|
$ make qemu-x86_defconfig (for 32-bit)
|
|
$ make qemu-x86_64_defconfig (for 64-bit)
|
|
$ make all
|
|
|
|
Note this default configuration will build a U-Boot for the QEMU x86 i440FX
|
|
board. To build a U-Boot against QEMU x86 Q35 board, you can change the build
|
|
configuration during the 'make menuconfig' process like below::
|
|
|
|
Device Tree Control --->
|
|
...
|
|
(qemu-x86_q35) Default Device Tree for DT control
|
|
|
|
Test with QEMU for bare mode
|
|
----------------------------
|
|
|
|
QEMU is a fancy emulator that can enable us to test U-Boot without access to
|
|
a real x86 board. Please make sure your QEMU version is 2.3.0 or above test
|
|
U-Boot. 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.
|
|
|
|
QEMU emulates a graphic card which U-Boot supports. Removing '-nographic' will
|
|
show QEMU's VGA console window. Note this will disable QEMU's serial output.
|
|
If you want to check both consoles, use '-serial stdio'.
|
|
|
|
Multicore is also supported by QEMU via '-smp n' where n is the number of cores
|
|
to instantiate. Note, the maximum supported CPU number in QEMU is 255.
|
|
|
|
The fw_cfg interface in QEMU also provides information about kernel data,
|
|
initrd, command-line arguments and more. U-Boot supports directly accessing
|
|
these informtion from fw_cfg interface, which saves the time of loading them
|
|
from hard disk or network again, through emulated devices. To use it , simply
|
|
providing them in QEMU command line::
|
|
|
|
$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -m 1024 \
|
|
-kernel /path/to/bzImage -append 'root=/dev/ram console=ttyS0' \
|
|
-initrd /path/to/initrd -smp 8
|
|
|
|
Note: -initrd and -smp are both optional
|
|
|
|
Then start QEMU, in U-Boot command line use the following U-Boot command to
|
|
setup kernel::
|
|
|
|
=> qfw
|
|
qfw - QEMU firmware interface
|
|
|
|
Usage:
|
|
qfw <command>
|
|
- list : print firmware(s) currently loaded
|
|
- cpus : print online cpu number
|
|
- load <kernel addr> <initrd addr> : load kernel and initrd (if any) and setup for zboot
|
|
|
|
=> qfw load
|
|
loading kernel to address 01000000 size 5d9d30 initrd 04000000 size 1b1ab50
|
|
|
|
Here the kernel (bzImage) is loaded to 01000000 and initrd is to 04000000. Then,
|
|
'zboot' can be used to boot the kernel::
|
|
|
|
=> zboot 01000000 - 04000000 1b1ab50
|
|
|
|
To run 64-bit U-Boot, qemu-system-x86_64 should be used instead, e.g.::
|
|
|
|
$ qemu-system-x86_64 -nographic -bios path/to/u-boot.rom
|
|
|
|
A specific CPU can be specified via the '-cpu' parameter but please make
|
|
sure the specified CPU supports 64-bit like '-cpu core2duo'. Conversely
|
|
'-cpu pentium' won't work for obvious reasons that the processor only
|
|
supports 32-bit.
|
|
|
|
Note 64-bit support is very preliminary at this point. Lots of features
|
|
are missing in the 64-bit world. One notable feature is the VGA console
|
|
support which is currently missing, so that you must specify '-nographic'
|
|
to get 64-bit U-Boot up and running.
|