Raspberry Pi bare metal code.

qemu-raspi2

name
framebuffer01	draw framebuffer
int01	uart rx interrupt handling
timer01	arm generic timer every 1 secnod

qemu-raspi3

name
dma01	dma memory to meory
framebuffer01	draw framebuffer
int01	uart rx interrupt handling
int02	mini uart rx interrupt handling
sdhost01	sdhost initialize
sdhost02	sdhost readblock
task01	task create
task02	task switch
timer01	arm generic timer every 1 secnod
usb01	usb host : usb device detect
usb02	usb host : control transfer
usb03	usb host : enumuration

$ sudo apt install gcc-arm-none-eabi

$ sudo apt install gcc-aarch64-linux-gnu

I use QEMU 4.2 raspi3 model and raspi2 model.

$ qemu-system-aarch64 -m 128 -M raspi3 -nographic -kernel kernel.elf

$ qemu-system-arm -m 128 -M raspi2 -nographic -kernel kernel.elf