Hi, I did some progress porting this kernel to Raspberry Pi 5.
https://github.com/kindermax/rust-raspberrypi-OS
You can look at commit history on master branch.

However I've stuck on implementing MMU, in particular after the lastisb barrier it just hangs or the uart stops working - anyway, i can not see any logs.

I tried to replaceisb withdsb barrier, and something works (kindermax@ffff330) but later inexceptions chapter in themain.rs where we are trying to access some out of range memory, it does not throws an exception, so my guess that MMU is not working properly.

Also since RPI 5 has all the peripherals on Southbridge RP1 chip, I can not use PL011 uart drivers the usual way without setting up PCIe driver first. Instead I use so calledearly uart which means that some uarts already configured by firmware and are ready to use, no need for driver initialization.
One such uart is debug uart which is 3pin uart, other uart on gpio pins (similar to rpi3/4) can be used with special address (see memory.rs::mmio). In practice I use both uarts so i can load kernel via one uart and debug via another uart

I would like to receive some help/advice so I can move forward)