[LinuxBIOS] SPD Logical and Physical Banks

[Corey Osgood]

Uwe Hermann wrote:
> On Tue, May 15, 2007 at 04:45:53AM -0400, Corey Osgood wrote:
>> joe at smittys.pointclark.net wrote:
>>> Hello,
>>> Can someone please explain to me the difference between Logical and  
>>> Physical Banks on SDRAM? I am looking for a quick and dirty way to  
>>> determine if the SDRAM module is single sided or double sided through  
>>> SPD. Would I use the Logical (SPD Byte 17) or Physical (SPD Byte 5)  
>>> Bank for that?
>>>
>>> Thanks - Joe
>>>
>> Well, in the best case, neither. Read the Intel SPD standard
>> (http://www.intel.com/design/chipsets/memory/spdsd12a.pdf), I've checked
>> several PC66, 100, and 133 dimms, and all of them so far support it.
>> Check out bytes 126 and 127. If that doesn't work out though, you're
>> looking for byte 5.
> 
> Just to prevent unnecessary duplicated work: please don't write
> SPD-related functions for 440BX. I'm about to finish a patch which moves
> all generic SPD-related functions into src/sdram/spd.c where all
> chipsets can use them.
> 
> The SPD-only stuff should be chipset-independent, only the
> chipset-specific stuff should be handled in the respective raminit.c.
> 
> 
> Uwe.

That figures. Just finished a ton of SPD stuff for the 440bx last night.
Any luck on getting cache-as-ram going? I'm running out of registers
with my code, perhaps yours is more register-friendly.

-Corey