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diff --git a/doc/README.qemu-mips b/doc/README.qemu-mips new file mode 100644 index 0000000..1fdfbab --- /dev/null +++ b/doc/README.qemu-mips @@ -0,0 +1,196 @@ +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) |