rtems-boot-image tool: Raspberry Pi

[Chris Johns]

On 22/2/20 1:45 am, G. S. Niteesh wrote:
> Hi,
> 
> This is regarding adding RPi support to the boot image generation tool.
> 
> The boot process for Raspberry Pi is very unconventional. The GPU starts
> first, initializes RAM, other hardware, loads the bootloaders and then starts
> the ARM CPU.
> 
> The minimum files that are required to boot an RPi are
> bootcode.bin, startx.elf, fixup.dat, kernel.img, config.txt
> There are also other variants of startx.elf and fixup.dat.
> Please have a look
> at https://www.raspberrypi.org/documentation/configuration/config-txt/boot.md
> for information on the variants.
> 
> From what I have tried on my Rpi3 model b v1.2 the minimum files that are
> required are start_x.elf, fixup_x.dat, bootcode.bin, kernel.img, config.txt
> But for this to work, we must add start_x=1 to config.txt because by default
> start.elf is loaded.

I would have look at how the tool maps to RPi to know if it needs more work :)

> 
> So, what should be the values for the first and second stages in rtems-boot.ini
> for Rpi?

Would this be bootcode.bin?

> And also wouldn't it be nice if we could add a files field, which will copy the
> specified files to the image? This would save a lot of typing in case of RPi

Do you have an example?

Chris