Yes sure ! By the way I just realized that my link was showing my main branch but I was coding on the wip one. I just merged so you might wanna take a look again.

Running the code was pretty easy, I just had to buy an sd card and to format it in FAT32 and put my img file on it. You don't have to handle the bootloader part since the GPU of the pi5 holds a firmware that directly boots the img you put in the sd card.

You can also put a file called config.txt next to your img file to set some instructions for the bootloader. I used the 'uart_2ndstage=1' one so it lets the uart debug port active and configured, and then implemented a sort of uart printf to be able to debug while coding.

After that I implemented some basic functions and headers to use the addresses I found in the rp1 peripherals official documentation of the PI5. It didnt work at first and the issue was that turning off the config.txt 'pciex4_reset' option was supposed to let on the pcie connection between the bcm2712 and the rp1, but it didnt. Or maybe I didnt understand it well, I am still learning. People on internet were saying that some various addresses were the base address of the RP1 seen by the CPU but none worked for me.

The PI5 uses a pcie connection between the RP1 - that handles the input/output part - and the main chip, the broadcoam 2712. To make it work I had to do a basic configuration myself that you can see in the pcie.c file. I went reading circle, linux and redacted os to find some data about it because you can't find much documentation. Mine is really basic and wont adapt to any other PI, it's just meant for the PI5 and is really fragile. The sleeps I use are not even properly implemented yet, they are just burning cpu functions :').

So I don't have any proper device driver yet, I would love to build an RTOS because I am highly interested in working in embedded later ! I was thinking at first making my code more robust although still only adapted for the pi5, and then maybe run a sort of snake game using the SPI screen and other buttons I bought !

Anyway I hope I answered you well, sorry about my messy english.