2 Notes for the Qemu MIPS port
6 # ln -s u-boot.bin mips_bios.bin
8 qemu-system-mips -L . /dev/null -nographic
12 if you use a qemu version after commit 4224
15 # dd of=flash bs=1k count=4k if=/dev/zero
16 # dd of=flash bs=1k conv=notrunc if=u-boot.bin
18 # qemu-system-mips -M mips -pflash flash -monitor null -nographic
20 2) Download kernel + initrd
22 On ftp://ftp.denx.de/pub/contrib/Jean-Christophe_Plagniol-Villard/qemu_mips/
25 #config to build the kernel
27 #patch to fix mips interrupt init on 2.6.24.y kernel
28 qemu_mips_kernel.patch
36 # 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
38 5) Copy uImage to Flash
39 # dd if=uImage bs=1k conv=notrunc seek=224 of=flash
43 # dd of=ide bs=1k cout=100k if=/dev/zero
45 # sfdisk -C 261 -d ide
46 # partition table of ide
49 ide1 : start= 63, size= 32067, Id=83
50 ide2 : start= 32130, size= 32130, Id=83
51 ide3 : start= 64260, size= 4128705, Id=83
52 ide4 : start= 0, size= 0, Id= 0
56 # dd if=uImage bs=512 conv=notrunc seek=63 of=ide
58 8) Generate ext2 on part 2 on Copy uImage and initrd.gz
60 # Attached as loop device ide offset = 32130 * 512
61 # losetup -o 16450560 -f ide
62 # Format as ext2 ( arg2 : nb blocks)
63 # mke2fs /dev/loop0 16065
64 # losetup -d /dev/loop0
65 # Mount and copy uImage and initrd.gz to it
66 # mount -o loop,offset=16450560 -t ext2 ide /mnt
68 # cp {initrd.gz,uImage} /mnt/boot/
74 setenv rd_start 0x80800000
75 setenv rd_size 2663940
76 setenv kernel BFC38000
77 setenv oad_addr 80500000
78 setenv load_addr2 80F00000
79 setenv kernel_flash BFC38000
80 setenv load_addr_hello 80200000
81 setenv bootargs 'root=/dev/ram0 init=/bin/sh'
82 setenv load_rd_ext2 'ide res; ext2load ide 0:2 ${rd_start} /boot/initrd.gz'
83 setenv load_rd_tftp 'tftp ${rd_start} /initrd.gz'
84 setenv load_kernel_hda 'ide res; diskboot ${load_addr} 0:2'
85 setenv load_kernel_ext2 'ide res; ext2load ide 0:2 ${load_addr} /boot/uImage'
86 setenv load_kernel_tftp 'tftp ${load_addr} /qemu_mips/uImage'
87 setenv boot_ext2_ext2 'run load_rd_ext2; run load_kernel_ext2; run addmisc; bootm ${load_addr}'
88 setenv boot_ext2_flash 'run load_rd_ext2; run addmisc; bootm ${kernel_flash}'
89 setenv boot_ext2_hda 'run load_rd_ext2; run load_kernel_hda; run addmisc; bootm ${load_addr}'
90 setenv boot_ext2_tftp 'run load_rd_ext2; run load_kernel_tftp; run addmisc; bootm ${load_addr}'
91 setenv boot_tftp_hda 'run load_rd_tftp; run load_kernel_hda; run addmisc; bootm ${load_addr}'
92 setenv boot_tftp_ext2 'run load_rd_tftp; run load_kernel_ext2; run addmisc; bootm ${load_addr}'
93 setenv boot_tftp_flash 'run load_rd_tftp; run addmisc; bootm ${kernel_flash}'
94 setenv boot_tftp_tftp 'run load_rd_tftp; run load_kernel_tftp; run addmisc; bootm ${load_addr}'
95 setenv load_hello_tftp 'tftp ${load_addr_hello} /examples/hello_world.bin'
96 setenv go_tftp 'run load_hello_tftp; go ${load_addr_hello}'
97 setenv addmisc 'setenv bootargs ${bootargs} console=ttyS0,${baudrate} rd_start=${rd_start} rd_size=${rd_size} ethaddr=${ethaddr}'
98 setenv bootcmd 'run boot_tftp_flash'
100 10) Now you can boot from flash, ide, ide+ext2 and tfp
102 # qemu-system-mips -M mips -pflash flash -monitor null -nographic -net nic -net user -tftp `pwd` -hda ide
104 II) How to debug U-Boot
106 In order to debug U-Boot you need to start qemu with gdb server support (-s)
107 and waiting the connection to start the CPU (-S)
109 # qemu-system-mips -S -s -M mips -pflash flash -monitor null -nographic -net nic -net user -tftp `pwd` -hda ide
111 in an other console you start gdb
113 1) Debugging of U-Boot Before Relocation
115 Before relocation, the addresses in the ELF file can be used without any problems
116 by connecting to the gdb server localhost:1234
118 # mipsel-unknown-linux-gnu-gdb u-boot
120 Copyright (C) 2006 Free Software Foundation, Inc.
121 GDB is free software, covered by the GNU General Public License, and you are
122 welcome to change it and/or distribute copies of it under certain conditions.
123 Type "show copying" to see the conditions.
124 There is absolutely no warranty for GDB. Type "show warranty" for details.
125 This GDB was configured as "--host=i486-linux-gnu --target=mipsel-unknown-linux-gnu"...
126 (gdb) target remote localhost:1234
127 Remote debugging using localhost:1234
128 _start () at start.S:64
129 64 RVECENT(reset,0) /* U-boot entry point */
130 Current language: auto; currently asm
132 Breakpoint 1 at 0xbfc00cc8: file board.c, line 289.
136 Breakpoint 1, board_init_f (bootflag=<value optimized out>) at board.c:290
137 290 relocate_code (addr_sp, id, addr);
138 Current language: auto; currently c
142 2) Debugging of U-Boot After Relocation
144 For debugging U-Boot after relocation we need to know the address to which
145 U-Boot relocates itself to 0x87fa0000 by default.
146 And replace the symbol table to this offset.
149 Discard symbol table from `/private/u-boot-arm/u-boot'? (y or n) y
150 Error in re-setting breakpoint 1:
151 No symbol table is loaded. Use the "file" command.
153 (gdb) add-symbol-file u-boot 0x87fa0000
154 add symbol table from file "u-boot" at
155 .text_addr = 0x87fa0000
157 Reading symbols from /private/u-boot-arm/u-boot...done.
158 Breakpoint 1 at 0x87fa0cc8: file board.c, line 289.
162 Program received signal SIGINT, Interrupt.
163 0xffffffff87fa0de4 in udelay (usec=<value optimized out>) at time.c:78
164 78 while ((tmo - read_c0_count()) < 0x7fffffff)