mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-01 17:10:11 +00:00
80 lines
2.5 KiB
Text
80 lines
2.5 KiB
Text
|
|
Notes for the Qemu MIPS port
|
|
|
|
I) Example usage:
|
|
|
|
# ln -s u-boot.bin mips_bios.bin
|
|
start it:
|
|
qemu-system-mips -L . /dev/null -nographic
|
|
|
|
or
|
|
|
|
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:
|
|
# qemu-system-mips -M mips -pflash flash -monitor null -nographic
|
|
|
|
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
|
|
|
|
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
|
|
buy 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)
|