[coreboot] v3 CAR/ROM area collision on C7 and Core2Duo

[JasonZhao at viatech.com.cn]

Hi Carl,
No VIA's datasheet tell about the location of C7 CAR, and I remember
once I used an address even lower than 0xFFBF0000 (NOT 0xc8000). Also I
tried 0xFFBF0000 on my current v2-coreboot just now, the result is ok.


> -----Original Message-----
> From: Carl-Daniel Hailfinger
[mailto:c-d.hailfinger.devel.2006 at gmx.net]
> Sent: Monday, November 24, 2008 10:51 AM
> To: Jason Zhao
> Cc: Coreboot
> Subject: Re: [coreboot] v3 CAR/ROM area collision on C7 and Core2Duo
> 
> Hi Jason,
> 
> do you know if the C7 CAR location is fixed at 0xFFEF0000? It would be
> great if we could move it to 0xFFBF0000. That way, the CAR area will
not
> collide with 4 MByte ROMs anymore.
> 
> Regards,
> Carl-Daniel
> 
> On 21.11.2008 16:47, Carl-Daniel Hailfinger wrote:
> > in v3 we enable full ROM decoding before initram. For VIA C7 and
Intel
> > Core 2 Duo, that means the CAR area is inside the mapped ROM
contents.
> >
> > The most obvious problem arising from that is having to make sure
> > fallback/initram and normal/initram end up in a place in ROM that is
> > _not_ behind CAR.
> >
> > One solution is to restrict the location of initram to the upper 1
MB of
> > the ROM chip. I can work with that, but we should definitely
document
> > these restrictions.
> >
> > Oh, and for chips which are behind some translation unit with
limited
> > window capabilities (like the IT8716 LPC->SPI translation) we need
to
> > have initram inside the decoded window anyway.
> >
> > Regards,
> > Carl-Daniel
> >
> >
> 
> 
> --
> http://www.hailfinger.org/