[coreboot] EP80579 Mainboard support

[Ed Swierk]

On Tue, Jun 16, 2009 at 7:24 AM, Arnaud Maye<arnaud.maye at 4dsp.com> wrote:
> I've just received my UART dongle and I could see that indeed something has
> been sent over UART.
>
> The first error seen was about the fact only ECC DIMMs are allowed, in the
> devkit they provide
> non-ecc memory. Is it normal coreboot only supports ECC DIMMs?

No, but I never got around to implementing support for non-ECC DIMMs
in the EP80579 raminit code. It shouldn't be too hard--I think you
just need to note whether the DIMMs are ECC, and refrain from enabling
ECC mode if they are. (You may want to keep ECC disabled anyway during
debugging; until the DRAM is stable, ECC only makes the error behavior
more complicated.)

> I've then plugged some nice kingston DIMM with ecc and what I get then is an
> exception :
>
> Unexpected Exception: 13 @ 10:00002f08 - Halting
> Code: 4096 eflags: 00010282
> eax: 002163b6 ebx: 0000c000 ecx: 0000227e edx: fffffffe
> edi: 0000eb02 esi: 0000f444 ebp: 0000bebc esp: 0000bebc
>
> As soon I get this exception, the 7 segments display : FF
>
> I guess if this is the first thing I get, coreboot has a problem not the
> payload, right?
>
> Could you tell me which coreboot version from the 1.3 tree you have been
> using when you
> validated the port?

I did the work somewhere around revision 3650 of the coreboot-v2 tree.
However, I tested only a very limited number of DIMMs, and only at 667
speed, so I'm not surprised a random one doesn't work. Unfortunately
there's no substitute for spending some quality time with the
datasheet, beating the raminit settings into submission.

--Ed