Re: [coreboot] ram init help on the i82830

[Joseph Smith]

On Fri, 30 May 2008 00:54:01 -0400, "Corey Osgood" 
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???

ram init help on the i82830

[Corey Osgood]

On Fri, May 30, 2008 at 11:00 AM, Joseph Smith  wrote:
> On Fri, 30 May 2008 00:54:01 -0400, "Corey Osgood" 
> 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
>

ram init help on the i82830

[Joseph Smith]

Well,
Just for the heck of it I hardcoded the do_ram_command() and then I had to
hardcode set_dram_row_attributes() just to see if I could get it to boot
with the 512MB chip. Horray, it boots! But now there is a very strange
Kernel panic everytime I try to boot Linux (see attached bootlog):

BUG: unable to handle kernel paging request at virtual address b71f2410

Well at least I now have some hope, and something to work towards:-)