[GSoC] Help needed for the continuation of project RPi4B

Noor Aman nooraman5718 at gmail.com
Mon Jul 11 16:12:12 UTC 2022

Hello, I wanted some help on my project and what do I need to do next.
Here is a summary of what I have done so far.

---- TESTING ----
- Tested bare-metal from https://rpi4os.com, worked good
- (Suggested by Alan) Tested VxWorks from
https://www.windriver.com/products/vxworks, it worked fine too.
- Tested the A72-qemu-bsp on the rpi4b, modified the linkercmds to point at
address 0x200000, 0x80000 and 0xFE000000 (Tried all three of them), loaded
it using openocd, it was getting stuck at the

arm_pl011_write_polled (base=<optimized out>, c=13 '\r') at
while ((regs->uartfr & PL011_UARTFR_TXFF) != 0)

after manually adding serial uart address through GDB, the code jumps to

---- CODE -----
- Made a basic abi.yml, bsp*.yml, linkercmds.yml for rpi4b under
- copied some of the files from a72 like bspstarthooks.c and tm27.h into

---- ANOMALIES ----
- Some registers are failing to show in the gdb, some of them are ESR_EL1,
ELR_EL2 and SPSR_EL3, are they required?
- So in order to cross check, I'm trying to use RPi4B qemu build (Custom
fork). Not tested yet. I'm planning to do this in a qemu machine. Any other
- trying to use u-boot. One thing to note is that even with U-boot, you'll
have to use the bootcode.bin from the 1.20200212 tag. This is mentioned in
the VxWorks README. Alan once mentioned about not being able to boot the
RPI zero 2, because of this issue. Is there any problem using old
- tested the christinaa/rpi-open-firmware, didnt work as expected

---- QUESTIONS ----
- Would there be any gain from using U-boot? As this is just a Second stage
- What should be my next step?
- Any recommendations which will help me for the project?

I know I'm a bit slow in this project. My sincere apologies for that. My
college is still open and we are at the end of the semester so it's a bit
inconvenient to adjust my time for both. Semester time was reduced from 6
months to 4 months. I think we might not get vacation this year in order to
adjust the timing like it was before Covid. So please bear with me a bit :)
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