[U-Boot-Users] Microcode patches for mpc8xx

[Vladimir A. Gurevich]

Hello Wolfgang,

Wolfgang Denk wrote:

>This is a neglected area  in  U-Boot;  usually  U-Boot  needs  little
>resources  and  uCode patches are needed at all. actually none of the
>existing configurations seems to use the code.
>  
>
Yes, I noticed that too and was a little suprised. At least SMC1/SCC3 or 
SPI/SCC2 combinations should not be that uncommon...

Does that mean it's OK to mess up cpu/mpc8xx/upatch.c? How would you 
like to ifdef the original code?

I think that CFG_{SPI,I2C}_UCODE_PATCH config variables  make little 
sense. Instead, we should rely on CFG_{I2C,SPI}_DPMEM_OFFSET (and add 
another one for SMC) as well as the CPU type to decide whether a patch 
is needed and if yes, which one. Also, the code in the corresponding 
drivers will be changed to use RPBASE based not on the  fact that patch 
is there, but on whether the feature is supported. This will take care 
of MPC852T, that doesn't need a patch for SPI/I2C, but still needs one 
for SMC1. Is that OK?

>You are right. See how it's implemented in our Linux tree.
>  
>
I should've probably asked that on linuxppc-embedded, but since we are 
on this topic here: look like SMC relocation is explicitly not supported 
and I can't see the SPI driver as well (unless it reuses 8260 driver). 
So, while the ucode support seems to be more elaborate, I am not sure I 
understand how it is used. I am talking about linuxppc_2_4_devel tree 
here. Am I missing something?

>This is what it's doing at the moment. One can ague if this is a good idea or not.
>  
>
That's probably the safest way, though probably not the most efficient 
or elegant one.

Thanks,
Vladimir