[U-Boot] mpc512x: Trouble migrating from 2012.07 to 2013.01

[Mats Kärrman]

Dear Wolfgang Denk,

>> Found that it was looping endlessly in arch/powerpc/lib/ticks.S::wait_ticks(). Reverting commit "ppc: Create a stack frame for wait_ticks()" made everything work again.
> 
> This makes no sense to me  - especially as it works on all other
> systems.

If you say it works, it makes no sense to me either. I thought it might be some subtle difference in the way the e300c4 core or GCC works compared to other PPC cores. If there are no such differences, then a patch with no intended functional difference beyond keeping gdb happy should not make any difference, good or bad.

> Well, you mentioned you were using a MPC5125 processor which is not
> supported in mainline U-Boot, and which is known to have enough
> differences in it's register layout that anything might be the cause
> for such issues.
>
> Is it correct to assume that you have a _lot_ of local modifiucations
> in your tree?  I bet the problem lies there...

I wouldn't say a lot. I'm using only the serial console to be able to download and flash images (using CFI flash) and to boot Linux so the primary patches are the serial driver and the DRAM initialization. On top of that there are some minimal I/O initialization and of course I went through and updated the register mappings for the relevant peripherals. It worked fine with 2009.03 and with 2012.07 but of course I might have overlooked something.

I will report back when / if I find out something more.
I'm not much for betting though ;)

Best regards,
Mats