EPIA-M SPD progress [PMX:#]

[Dave Ashley]

src/sdram/smbus_pcibus.inc has some smbus code, I was able to compile it
into the epia-m tree and do some test SMBUS_READ_BYTE calls that actually
read out values from the ddr eeprom. I had to #if out the section that
actually does the dram configuration to get it to compile.

I'm in a bad way for experimenting with this, I have to physically remove
the BIOS and plug in a new one if something goes bad, and do the reverse
to recover. I've fried 2 motherboards with my pliers rubbing out traces
under the flashrom socket (good luck fixing that!).

If the dram settings are wrong it might make the product flaky. We're
trying to field some units for in situ testing real soon, and the system
has to be solid. We can probably hardcode the dram configuration for our
known good ddr module that we're using mostly. However I'd like the system
to function the right way. I'll keep messing with it for now.

-Dave


>some SPD roms have incorrect information. You have to take care with SPD. 
>
>Overall, SPD is better. However, if you are on a short fuse and need to 
>deliver soon, I would go with probing for now and restrict the type of ram 
>you use. 
>
>Longer term, we want to do SPD.
>
>ron
>