Embedded Linux emulation with QEMU (on LPC313X by NXP)

Question

I'm starting to work with Embedded Linux and I've got a LPC313x based board (Embedded Artists). I've built apex and kernel with ELDK (as suggested here: http://www.lpclinux.com/LPC313x/LPC313xGettingstartedELDK). The kernel is built correctly (apparently no error occurs) with the default settings, and I am using a pre-made ramdisk, provided at the same link.

Now I want to use QEMU to emulate my system prior to load all the stuff in the physical board. To do that, I'm using the command:

qemu-system-arm -kernel kernel/work_2.6.28.2/arch/arm/boot/zImage -initrd ../eldk42/arm/images/ramdisk_image.gz

I cannot get it work! QEMU starts but the emulator screen remains black, nothing happens. What am I missing here?

Answer 1

Try this:

qemu-system-arm -kernel kernel/work_2.6.28.2/arch/arm/boot/zImage -initrd ../eldk42/arm/images/ramdisk_image.gz -append "root=/dev/ram"

Try with -m:

qemu-system-arm -m 128 -kernel kernel/work_2.6.28.2/arch/arm/boot/zImage -initrd ../eldk42/arm/images/ramdisk_image.gz -append "root=/dev/ram"

Try with -M:

qemu-system-arm -M versatilepb -m 128 -kernel kernel/work_2.6.28.2/arch/arm/boot/zImage -initrd ../eldk42/arm/images/ramdisk_image.gz -append "root=/dev/ram"

You are basically making /dev/ram (which you provide with -initrd argument) as your system's root directory. You can find more information here.

Answer 2

You board is not supported by Qemu. You have to write your own Board Support Package, if you can't find one on the Internet. Try checking the kernel source tree, you might find one there. Plus you have to know the exact internal details of your SoC and board.

Answer 3

You're probably interested in the linux option console=ttyS0 which you can add to -append of qemu.