|
|
|
|
By Vlad Lungu vlad.lungu@windriver.com 2007-Oct-01
|
|
|
|
|
----------------------------------------
|
|
|
|
|
Qemu is a full system emulator. See
|
|
|
|
|
|
|
|
|
|
http://www.nongnu.org/qemu/
|
|
|
|
|
|
|
|
|
|
Limitations & comments
|
|
|
|
|
----------------------
|
|
|
|
|
Supports the "-M mips" configuration of qemu: serial,NE2000,IDE.
|
|
|
|
|
Supports little and big endian as well as 32 bit and 64 bit.
|
|
|
|
|
Derived from au1x00 with a lot of things cut out.
|
|
|
|
|
|
|
|
|
|
Supports emulated flash (patch Jean-Christophe PLAGNIOL-VILLARD) with
|
|
|
|
|
recent qemu versions. When using emulated flash, launch with
|
|
|
|
|
-pflash <filename> and erase mips_bios.bin.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Notes for the Qemu MIPS port
|
|
|
|
|
----------------------------
|
|
|
|
|
|
|
|
|
|
I) Example usage:
|
|
|
|
|
|
|
|
|
|
Using u-boot.bin as ROM (replaces Qemu monitor):
|
|
|
|
|
|
|
|
|
|
32 bit, big endian:
|
|
|
|
|
# make qemu_mips
|
|
|
|
|
# qemu-system-mips -M mips -bios u-boot.bin -nographic
|
|
|
|
|
|
|
|
|
|
32 bit, little endian:
|
|
|
|
|
# make qemu_mipsel
|
|
|
|
|
# qemu-system-mipsel -M mips -bios u-boot.bin -nographic
|
|
|
|
|
|
|
|
|
|
64 bit, big endian:
|
|
|
|
|
# make qemu_mips64
|
|
|
|
|
# qemu-system-mips64 -cpu MIPS64R2-generic -M mips -bios u-boot.bin -nographic
|
|
|
|
|
|
|
|
|
|
64 bit, little endian:
|
|
|
|
|
# make qemu_mips64el
|
|
|
|
|
# qemu-system-mips64el -cpu MIPS64R2-generic -M mips -bios u-boot.bin -nographic
|
|
|
|
|
|
|
|
|
|
or using u-boot.bin from emulated flash:
|
|
|
|
|
|
|
|
|
|
if you use a qemu version after commit 4224
|
|
|
|
|
|
|
|
|
|
create image:
|
|
|
|
|
# dd of=flash bs=1k count=4k if=/dev/zero
|
|
|
|
|
# dd of=flash bs=1k conv=notrunc if=u-boot.bin
|
|
|
|
|
start it (see above):
|
|
|
|
|
# qemu-system-mips[64][el] [-cpu MIPS64R2-generic] -M mips -pflash flash -nographic
|
|
|
|
|
|
|
|
|
|
2) Download kernel + initrd
|
|
|
|
|
|
|
|
|
|
On ftp://ftp.denx.de/pub/contrib/Jean-Christophe_Plagniol-Villard/qemu_mips/
|
|
|
|
|
you can downland
|
|
|
|
|
|
|
|
|
|
#config to build the kernel
|
|
|
|
|
qemu_mips_defconfig
|
|
|
|
|
#patch to fix mips interrupt init on 2.6.24.y kernel
|
|
|
|
|
qemu_mips_kernel.patch
|
|
|
|
|
initrd.gz
|
|
|
|
|
vmlinux
|
|
|
|
|
vmlinux.bin
|
|
|
|
|
System.map
|
|
|
|
|
|
|
|
|
|
4) Generate uImage
|
|
|
|
|
|
|
|
|
|
# tools/mkimage -A mips -O linux -T kernel -C gzip -a 0x80010000 -e 0x80245650 -n "Linux 2.6.24.y" -d vmlinux.bin.gz uImage
|
|
|
|
|
|
|
|
|
|
5) Copy uImage to Flash
|
|
|
|
|
# dd if=uImage bs=1k conv=notrunc seek=224 of=flash
|
|
|
|
|
|
|
|
|
|
6) Generate Ide Disk
|
|
|
|
|
|
|
|
|
|
# dd of=ide bs=1k cout=100k if=/dev/zero
|
|
|
|
|
|
|
|
|
|
# sfdisk -C 261 -d ide
|
|
|
|
|
# partition table of ide
|
|
|
|
|
unit: sectors
|
|
|
|
|
|
|
|
|
|
ide1 : start= 63, size= 32067, Id=83
|
|
|
|
|
ide2 : start= 32130, size= 32130, Id=83
|
|
|
|
|
ide3 : start= 64260, size= 4128705, Id=83
|
|
|
|
|
ide4 : start= 0, size= 0, Id= 0
|
|
|
|
|
|
|
|
|
|
7) Copy to ide
|
|
|
|
|
|
|
|
|
|
# dd if=uImage bs=512 conv=notrunc seek=63 of=ide
|
|
|
|
|
|
|
|
|
|
8) Generate ext2 on part 2 on Copy uImage and initrd.gz
|
|
|
|
|
|
|
|
|
|
# Attached as loop device ide offset = 32130 * 512
|
|
|
|
|
# losetup -o 16450560 -f ide
|
|
|
|
|
# Format as ext2 ( arg2 : nb blocks)
|
|
|
|
|
# mke2fs /dev/loop0 16065
|
|
|
|
|
# losetup -d /dev/loop0
|
|
|
|
|
# Mount and copy uImage and initrd.gz to it
|
|
|
|
|
# mount -o loop,offset=16450560 -t ext2 ide /mnt
|
|
|
|
|
# mkdir /mnt/boot
|
|
|
|
|
# cp {initrd.gz,uImage} /mnt/boot/
|
|
|
|
|
# Umount it
|
|
|
|
|
# umount /mnt
|
|
|
|
|
|
|
|
|
|
9) Set Environment
|
|
|
|
|
|
|
|
|
|
setenv rd_start 0x80800000
|
|
|
|
|
setenv rd_size 2663940
|
|
|
|
|
setenv kernel BFC38000
|
|
|
|
|
setenv oad_addr 80500000
|
|
|
|
|
setenv load_addr2 80F00000
|
|
|
|
|
setenv kernel_flash BFC38000
|
|
|
|
|
setenv load_addr_hello 80200000
|
|
|
|
|
setenv bootargs 'root=/dev/ram0 init=/bin/sh'
|
|
|
|
|
setenv load_rd_ext2 'ide res; ext2load ide 0:2 ${rd_start} /boot/initrd.gz'
|
|
|
|
|
setenv load_rd_tftp 'tftp ${rd_start} /initrd.gz'
|
|
|
|
|
setenv load_kernel_hda 'ide res; diskboot ${load_addr} 0:2'
|
|
|
|
|
setenv load_kernel_ext2 'ide res; ext2load ide 0:2 ${load_addr} /boot/uImage'
|
|
|
|
|
setenv load_kernel_tftp 'tftp ${load_addr} /qemu_mips/uImage'
|
|
|
|
|
setenv boot_ext2_ext2 'run load_rd_ext2; run load_kernel_ext2; run addmisc; bootm ${load_addr}'
|
|
|
|
|
setenv boot_ext2_flash 'run load_rd_ext2; run addmisc; bootm ${kernel_flash}'
|
|
|
|
|
setenv boot_ext2_hda 'run load_rd_ext2; run load_kernel_hda; run addmisc; bootm ${load_addr}'
|
|
|
|
|
setenv boot_ext2_tftp 'run load_rd_ext2; run load_kernel_tftp; run addmisc; bootm ${load_addr}'
|
|
|
|
|
setenv boot_tftp_hda 'run load_rd_tftp; run load_kernel_hda; run addmisc; bootm ${load_addr}'
|
|
|
|
|
setenv boot_tftp_ext2 'run load_rd_tftp; run load_kernel_ext2; run addmisc; bootm ${load_addr}'
|
|
|
|
|
setenv boot_tftp_flash 'run load_rd_tftp; run addmisc; bootm ${kernel_flash}'
|
|
|
|
|
setenv boot_tftp_tftp 'run load_rd_tftp; run load_kernel_tftp; run addmisc; bootm ${load_addr}'
|
|
|
|
|
setenv load_hello_tftp 'tftp ${load_addr_hello} /examples/hello_world.bin'
|
|
|
|
|
setenv go_tftp 'run load_hello_tftp; go ${load_addr_hello}'
|
|
|
|
|
setenv addmisc 'setenv bootargs ${bootargs} console=ttyS0,${baudrate} rd_start=${rd_start} rd_size=${rd_size} ethaddr=${ethaddr}'
|
|
|
|
|
setenv bootcmd 'run boot_tftp_flash'
|
|
|
|
|
|
|
|
|
|
10) Now you can boot from flash, ide, ide+ext2 and tfp
|
|
|
|
|
|
|
|
|
|
# qemu-system-mips -M mips -pflash flash -monitor null -nographic -net nic -net user -tftp `pwd` -hda ide
|
|
|
|
|
|
|
|
|
|
II) How to debug U-Boot
|
|
|
|
|
|
|
|
|
|
In order to debug U-Boot you need to start qemu with gdb server support (-s)
|
|
|
|
|
and waiting the connection to start the CPU (-S)
|
|
|
|
|
|
|
|
|
|
# qemu-system-mips -S -s -M mips -pflash flash -monitor null -nographic -net nic -net user -tftp `pwd` -hda ide
|
|
|
|
|
|
|
|
|
|
in an other console you start gdb
|
|
|
|
|
|
|
|
|
|
1) Debugging of U-Boot Before Relocation
|
|
|
|
|
|
|
|
|
|
Before relocation, the addresses in the ELF file can be used without any problems
|
|
|
|
|
by connecting to the gdb server localhost:1234
|
|
|
|
|
|
|
|
|
|
# mipsel-unknown-linux-gnu-gdb u-boot
|
|
|
|
|
GNU gdb 6.6
|
|
|
|
|
Copyright (C) 2006 Free Software Foundation, Inc.
|
|
|
|
|
GDB is free software, covered by the GNU General Public License, and you are
|
|
|
|
|
welcome to change it and/or distribute copies of it under certain conditions.
|
|
|
|
|
Type "show copying" to see the conditions.
|
|
|
|
|
There is absolutely no warranty for GDB. Type "show warranty" for details.
|
|
|
|
|
This GDB was configured as "--host=i486-linux-gnu --target=mipsel-unknown-linux-gnu"...
|
|
|
|
|
(gdb) target remote localhost:1234
|
|
|
|
|
Remote debugging using localhost:1234
|
|
|
|
|
_start () at start.S:64
|
|
|
|
|
64 RVECENT(reset,0) /* U-Boot entry point */
|
|
|
|
|
Current language: auto; currently asm
|
|
|
|
|
(gdb) b board.c:289
|
|
|
|
|
Breakpoint 1 at 0xbfc00cc8: file board.c, line 289.
|
|
|
|
|
(gdb) c
|
|
|
|
|
Continuing.
|
|
|
|
|
|
|
|
|
|
Breakpoint 1, board_init_f (bootflag=<value optimized out>) at board.c:290
|
|
|
|
|
290 relocate_code (addr_sp, id, addr);
|
|
|
|
|
Current language: auto; currently c
|
|
|
|
|
(gdb) p/x addr
|
|
|
|
|
$1 = 0x87fa0000
|
|
|
|
|
|
|
|
|
|
2) Debugging of U-Boot After Relocation
|
|
|
|
|
|
|
|
|
|
For debugging U-Boot after relocation we need to know the address to which
|
|
|
|
|
U-Boot relocates itself to 0x87fa0000 by default.
|
|
|
|
|
And replace the symbol table to this offset.
|
|
|
|
|
|
|
|
|
|
(gdb) symbol-file
|
|
|
|
|
Discard symbol table from `/private/u-boot-arm/u-boot'? (y or n) y
|
|
|
|
|
Error in re-setting breakpoint 1:
|
|
|
|
|
No symbol table is loaded. Use the "file" command.
|
|
|
|
|
No symbol file now.
|
|
|
|
|
(gdb) add-symbol-file u-boot 0x87fa0000
|
|
|
|
|
add symbol table from file "u-boot" at
|
|
|
|
|
.text_addr = 0x87fa0000
|
|
|
|
|
(y or n) y
|
|
|
|
|
Reading symbols from /private/u-boot-arm/u-boot...done.
|
|
|
|
|
Breakpoint 1 at 0x87fa0cc8: file board.c, line 289.
|
|
|
|
|
(gdb) c
|
|
|
|
|
Continuing.
|
|
|
|
|
|
|
|
|
|
Program received signal SIGINT, Interrupt.
|
|
|
|
|
0xffffffff87fa0de4 in udelay (usec=<value optimized out>) at time.c:78
|
|
|
|
|
78 while ((tmo - read_c0_count()) < 0x7fffffff)
|
