Re: [coreboot] sourcing 128MB flash chips for an X60 with coreboot

[Carl-Daniel Hailfinger]

Hi,

On 29.10.2014 05:17, Charles Devereaux via coreboot wrote:
> On Tue, Oct 28, 2014 at 8:56 PM, Kyösti Mälkki <[e-mail]>
> wrote:
> > For the i82801gx part in x60, I am not sure if it will support 16MB SPI
> > parts as datasheet specifies decode registers for the top 8MB only.
> >
> > Or was there already a proof-of-concept it works?
> >
> > FWH_DEC_EN1—Firmware Hub Decode Enable Register.
> > Oops. you may be right. I just picked up 16 MB since it was the largest
> > size SPI would support. For the moment, I guess I will have to restrict the
> > images to 8MB

What does FWH_DEC_EN1 have to to with SPI flash? AFAICS it's for FWH
flash, a totally different beast.
Or put another way, why would that register restrict SPI flash size in
any way?

Regards,
Carl-Daniel

sourcing 128MB flash chips for an X60 with coreboot

[Kyösti Mälkki]

On Thu, Oct 30, 2014 at 12:18 AM, Carl-Daniel Hailfinger 
<[e-mail]> wrote:
> Hi,
>
> On 29.10.2014 05:17, Charles Devereaux via coreboot wrote:
> > On Tue, Oct 28, 2014 at 8:56 PM, Kyösti Mälkki <[e-mail]>
> > wrote:
> > > For the i82801gx part in x60, I am not sure if it will support 16MB SPI
> > > parts as datasheet specifies decode registers for the top 8MB only.
> > >
> > > Or was there already a proof-of-concept it works?
> > >
> > > FWH_DEC_EN1—Firmware Hub Decode Enable Register.
> > > Oops. you may be right. I just picked up 16 MB since it was the largest
> > > size SPI would support. For the moment, I guess I will have to restrict
> > > the
> > > images to 8MB
>
> What does FWH_DEC_EN1 have to to with SPI flash? AFAICS it's for FWH
> flash, a totally different beast.
> Or put another way, why would that register restrict SPI flash size in
> any way?

Carl-Daniel,

In the datasheet, register has a bottom note as stated below.

   This register effects the BIOS decode regardless of whether the BIOS
   is resident on LPC or SPI (Desktop and Mobile Only). The concept of
   Feature Space does not apply to SPI-based flash. The ICH7 simply
   decodes these ranges as memory accesses when enabled for the SPI
   flash interface.

Go figure. Better just try with flashrom, you do not need a 16MB flash 
part installed to see if these take effect on SPI.

Kyösti