[flashrom] AMD - SP5100 - take SPI ownership (1/2)

[Stefan Tauner]

On Wed, 03 Apr 2013 00:35:09 +0200
Rudolf Marek <r.marek at assembler.cz> wrote:

> So... This is going to be complicated. Can you please send me in private both 
> images? Or paste URL where i can get ami bios image.
> 
> I will check if IMC firmware is there or not (I guess none in coreboot). What we 
> could possibly do is to re-add a firmware to coreboot image. But we would have 
> to override the straps and activate the imc. There is also 
> BuildParameters.ImcEnableOverWrite in SB800 CIMX.
> 
> What is your goal here anyway? To have smooth transition to coreboot? Or you 
> just reported this issue?
> 
> I guess we need to implement some safety checks that if IMC strap is always 
> enabled then IMC firmware must exist and ideally be same as in flash.
> 
> But first we need to know what CIMX is doing.
> 
> if
> 1) EC is disabled and it is re-enabled by soft strap
> 
> This seems not to be the case, because
> 
>    if (validateImcFirmware (pConfig)) {
>        softwareToggleImcStrapping (pConfig);
> 
> It will enable the IMC only if valid firmware is found. And for CIMX800 we are 
> not doing this, only hudson has AMD firmware.
> 
> 2) if it is enabled by some hardware strap
> 
> This could be detected most likely by getChipSysMode() in this case we need to 
> disallow write of firmware which has no IMC code. Here are couple of problems, 
> what to do if firmware is there, but different for example... Or with coreboot 
> may happen it is on different location. Franly I don't know how to deal with 
> that because for this I would need detailed knowledge of the firmware itself. I 
> only disassembled that and I can see it just spins in memory when 0xb4 is 
> invoked and waits for 0xb5 (and I have seen sometimes for 0xb6)
> 
> And this gets worse because Hudson has USB firmware and Gigabit ethernet 
> firmware. Which are are same PITA.

I am not completely sure if I understood everything you wrote, but all
of that is only relevant for "wrong" images, right? So the current
patch* does improve the overall usability of flashrom on AMD boards and
only users that try to move from an image with active IMC to an image
w/o or improper IMC firmware will run into problems?

http://patchwork.coreboot.org/patch/3894/
-- 
Kind regards/Mit freundlichen Grüßen, Stefan Tauner