[coreboot] The default value of TOM (MSRC001_001A) just after Power-On

Marc Jones marcj303 at gmail.com
Thu Jan 21 21:37:24 CET 2010

On Wed, Jan 20, 2010 at 2:13 AM, Darmawan Salihun
<darmawan.salihun at gmail.com> wrote:
> The default value of MSRC001_001A (Top of Memory below the 4GB limit)
> according to BKDG for AMD Fam 10h rev. 3.06 is undefined (after
> Reset/power-on).
> However, AMD64 Architecture Programmer's Manual Volume 2: System
> Programming Rev. 3.14 states that the value of MSRC001_001A
> after Reset or power on is: 0000_0000_0400_0000h
> Which one of this information is correct?
> I need to know it because I want to know what is the default MMIO range
> after reset.

Hi Darmawan,

I think that the BKDG is correct.  I get 000_0001F_7780_0000 on a K8.
You can take a look at cpu/amd/car/cache_as_ram.inc for the initial



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