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qemu-x86: Use config_distro_bootcmd 

Converts qemu x86 machines to boot using distro_config. The intent is to
allow u-boot in qemu to be maximally compatible with many boot methods
without having to change the config. Previously, u-boot would only boot
in a very limited set of circumstances where there was a /boot/vmlinuz
on scsi 0:3 with no ramdisk.

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: convert doc updates to reST]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
This commit is contained in:
Joshua Watt 2019-07-03 12:45:32 -05:00 committed by Bin Meng
parent 42ef707922
commit 00f237e226
4 changed files with 44 additions and 0 deletions
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1
configs/qemu-x86_64_defconfig
View File

@ -12,6 +12,7 @@ CONFIG_SMP=y
CONFIG_GENERATE_PIRQ_TABLE=y
CONFIG_GENERATE_MP_TABLE=y
CONFIG_GENERATE_ACPI_TABLE=y
CONFIG_DISTRO_DEFAULTS=y
CONFIG_BUILD_ROM=y
CONFIG_FIT=y
CONFIG_SPL_LOAD_FIT=y

1
configs/qemu-x86_defconfig
View File

@ -6,6 +6,7 @@ CONFIG_SMP=y
CONFIG_GENERATE_PIRQ_TABLE=y
CONFIG_GENERATE_MP_TABLE=y
CONFIG_GENERATE_ACPI_TABLE=y
CONFIG_DISTRO_DEFAULTS=y
CONFIG_BUILD_ROM=y
CONFIG_FIT=y
CONFIG_BOOTSTAGE=y

17
doc/board/emulation/qemu-x86.rst
View File

@ -54,6 +54,23 @@ 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.
U-Boot uses 'distro_bootcmd' by default when booting on x86 QEMU. This tries to
load a boot script, kernel, and ramdisk from several different interfaces. For
the default boot order, see 'qemu-x86.h'. For more information, see
'README.distro'. Most Linux distros can be booted by writing a uboot script.
For example, Debian (stretch) can be booted by creating a script file named
'boot.txt' with the contents::
setenv bootargs root=/dev/sda1 ro
load ${devtype} ${devnum}:${distro_bootpart} ${kernel_addr_r} /vmlinuz
load ${devtype} ${devnum}:${distro_bootpart} ${ramdisk_addr_r} /initrd.img
zboot ${kernel_addr_r} - ${ramdisk_addr_r} ${filesize}
Then compile and install it with::
$ apt install u-boot-tools && \
mkimage -T script -C none -n "Boot script" -d boot.txt /boot/boot.scr
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

25
include/configs/qemu-x86.h
View File

@ -10,8 +10,33 @@
#ifndef __CONFIG_H
#define __CONFIG_H
#include <linux/sizes.h>
#define BOOT_TARGET_DEVICES(func) \
func(USB, usb, 0) \
func(SCSI, scsi, 0) \
func(VIRTIO, virtio, 0) \
func(IDE, ide, 0) \
func(DHCP, dhcp, na)
#include <config_distro_bootcmd.h>
#include <configs/x86-common.h>
#undef CONFIG_ENV_SIZE
#define CONFIG_ENV_SIZE SZ_256K
#define CONFIG_PREBOOT "pci enum"
#undef CONFIG_EXTRA_ENV_SETTINGS
#define CONFIG_EXTRA_ENV_SETTINGS \
CONFIG_STD_DEVICES_SETTINGS \
"scriptaddr=0x7000000\0" \
"kernel_addr_r=0x1000000\0" \
"ramdisk_addr_r=0x4000000\0" \
"consoledev=ttyS0\0" \
CONFIG_OTHBOOTARGS \
BOOTENV
#define CONFIG_SYS_MONITOR_LEN (1 << 20)
#define CONFIG_STD_DEVICES_SETTINGS "stdin=serial,i8042-kbd\0" \