Re: [coreboot] fallback/normal support [PATCH]Remove non-CBFS

[Tom Sylla]

Peter Stuge wrote:
> Patrick Georgi wrote:
> > What I don't know is, do we require any chipset setup to _reach_
> > CMOS?
>
> It's not generally in the CPU, so some setup may be needed. On the
> other hand, maybe 70/71 are decoded correctly on power up, just like
> flash access?

It's not like there is a spec or anything, but most of the PC AT junk in 
IO space will be accessible from first fetch. Disassemble the early 
portions of some AMI or Phoenix BIOSes, and you'll see accesses to 
things like CMOS in the first few instructions. Legacy accesses have to 
die somewhere subtractively, and the RTC usually is in that path.

Tom