[coreboot] ram init help on the i82830

Corey Osgood corey.osgood at gmail.com
Fri May 30 17:07:00 CEST 2008


On Fri, May 30, 2008 at 11:00 AM, Joseph Smith <joe at settoplinux.org> wrote:
>
> On Fri, 30 May 2008 00:54:01 -0400, "Corey Osgood" <corey.osgood at gmail.com>
> wrote:
>> It's double sided?
> Yes, remember the slot is DIMMO and the single-sided onboard is DIMM1
>
> 512MB PC133 so-dimm
> DRB 0x60 = 0x08 x 32 = 256MB
> DRB 0x61 = 0x10 x 32 = 512MB
>
> 64MB PC133 single-sided onboard memory
> DRB 0x62 = 0x12 x 32 = 576MB
> DRB 0x63 = 0x12 x 32 = 576MB
>
> 60: 08 10 12 12 12 12 00 00 00 00 00 00 00 00 00 00
>
> So, I have a few questions abot the read32().
> Is this supposed to just read32() the begining (+ addr_offset) of each
> dimm???
>
> Or, is it to do a read32() at the begining and then another read32() at the
> end???
>
> Or, is it just supposed to do a read32() the begining (+ addr_offset) of
> each side of each dimm???
>
> I'm really confused about this part, is there any jedec docs I can read on
> how this is supposed to work???

The SDRAM specification, from either Intel or JEDEC, explains it. But
all you really need to know is, you have to do a read from the
beginning of the dimm at each step, except of course for MRS when you
read from the addr_offset.

-Corey


>
> --
> Thanks,
> Joseph Smith
> Set-Top-Linux
> www.settoplinux.org
>
>




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