embedded - Can ARM qemu system emulator boot from card image without kernel param? -


i've seen lot of examples how run qemu arm board emulator. in every case, besides sd card image param, qemu supplied kernel param, i.e.:

qemu-system-arm -m versatilepb \                 -kernel vmlinuz-2.6.18-6-versatile \ #kernel param here                 -initrd initrd.gz \                 -hda hda.img -append "root=/dev/ram"

i palying bootloaders , want create own bootable sd card, don't have real board yet , want learn emulated one. however, if run described above, qemu skips bootloader stage , runs kernel.

so should emulate full boot sequence on qemu executes bootloader? should rom dump , pass -bios param?

you can feeding uboot image. never used rom dump.

qemu boot sqeuqnce:

  • on real, physical boards boot process involves non-volatile memory (e.g. flash) containing boot-loader , operating system. on power on, core loads , runs boot-loader, in turn loads , runs operating system.

  • qemu has possibility emulate flash memory on many platforms, not on versatilepb. there patches ad procedures available can add flash support, wanted leave qemu is.

  • qemu can load linux kernel using -kernel , -initrd options; @ low level, these options have effect of loading 2 binary files emulated memory: kernel binary @ address 0x10000 (64kib) , ramdisk binary @ address 0x800000 (8mib).

  • then qemu prepares kernel arguments , jumps @ 0x10000 (64kib) execute linux. wanted recreate same situation using u-boot, , keep situation similar real 1 wanted create single binary image containing whole system, having flash on board. -kernel option in qemu used load flash binary emulated memory, , means starting address of binary image 0x10000 (64kib).

this example based of arm versatilepb board

make cross_compile=arm-none-eabi- versatilepb_config make cross_compile=arm-none-eabi-

creating flash image * download u-boot-xxx.x source tree , extract * cd source tree directory , build it

mkimage -a arm -c none -o linux -t kernel -d zimage -a 0x00010000 -e 0x00010000 zimage.uimg mkimage -a arm -c none -o linux -t ramdisk -d rootfs.img.gz -a 0x00800000 -e 0x00800000 rootfs.uimg dd if=/dev/zero of=flash.bin bs=1 count=6m dd if=u-boot.bin of=flash.bin conv=notrunc bs=1 dd if=zimage.uimg of=flash.bin conv=notrunc bs=1 seek=2m dd if=rootfs.uimg of=flash.bin conv=notrunc bs=1 seek=4m

booting linux

to boot linux can call:

qemu-system-arm -m versatilepb -m 128m -kernel flash.bin -serial stdio

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