[coreboot] Geode LX: SDRAM initialization with no DIMMs

[Marc Jones]

llandre wrote:
> Hi all,
>
> I'm porting coreboot to custom hardware (Geode LX-based).
> The system is equipped with on-board DDR chips (no DIMMs). Since OLPC 
> platform has similar SDRAM configuration, I was thinking about using 
> the mainboard/olpc/btest/auto.c file as a starting point. However this 
> file includes GX2 stuff
> #include "northbridge/amd/gx2/raminit.c"
> so it seems it refers to old version of hardware.
>
> Which LX-based platform do you suggest to use as starting point instead?
>
>
> TIA,
> llandre
>
> DAVE Electronics System House - R&D Department
> web:   http://www.dave.eu
> email: r&d2 at dave-tech.it
>
>   
I recommend that you look at the way it was done in the dbe61 mainboard 
inv2 or the dbe62 in v3. You will need to make adjustments based on the 
memory configuration and speed. You need to make a virtual spd for the 
memory init code to use. If you need to reverse engineer the settings 
the MSRs to look at are the following:

0x20000018
0x20000019
0x2000001a
0x2000001f
0x2000001d
0x20000020
0x4c000014

Marc

-- 
Marc Jones
Senior Firmware Engineer
(970) 226-9684 Office
mailto:Marc.Jones at amd.com
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