How to use QEMU for learning ARM Linux kernel development?

Question

I want to learn it like developing some device driver etc and use QEMU for this because i have no hardware board for ARM like beagle board. What you guys suggest? Can i use Qemu simulator to learn Linux kernel on ARM targets? or any other option i should try ?

Answer 1

It depends on what you want to learn: hardware or software. If you really want to experiment with the different GPIO output to implement things like servo motor control, LED light blinking and display, a cheap board (eg, Raspberry Pi, about USD25) is much preferred.

But if you want to learn software in general, qemu is definitely much faster, and it lets you see the internal of what is happening. Experimenting with hardware will require oscilloscope etc. But experiment with software will depends on the error output of what others has implemented in their software.

As for drivers development, first version should be rapidly developed on QEMU. But testing which naturally involved hardware, should be done on the hardware.

Bottomline is: x86 is so much faster, that cross-crompilation is always done on x86 before it gets booted on the ARM board. Compiling on the board is too time consuming, and sometimes it may involved considerable amount of storage space for development libraries and source codes.

Answer 2

I used Qemu a while back to develop device drivers for an embedded programming class. It worked quite well. At the time we were learning device driver programming and then transitioning to Gumstix boards. I don't remember exactly what core we were using, but Qemu worked well.

I haven't done any ARM development, so I don't know if it is the best choice for learning ARM. But if you are new to drivers, it is probably a good place to start.

Answer 3

QEMU + Buildroot is great combination for ARM kernel development

Here is my setup that supports (mostly) both x86 and ARM: https://github.com/cirosantilli/linux-kernel-module-cheat

The kernel, toolchain, userland and QEMU are amazingly portable, that going from x86 to ARM is almost trivial.

Actually, you will seldom touch arch specifics, so you might as well start with x86.

I haven't played with ARM devices yet, only x86, but I bet it will be equally easy (i.e. not trivial due to lack of tutorials, but doable).