[coreboot] [RFC] Porting coreboot to Intel Atom (Silverthorne) & SCH US15W (Poulsbo) chipset

[Carl-Daniel Hailfinger]

Hi Ken,

On 03.05.2008 00:56, Ken.Fuchs at bench.com wrote:
> Intel Atom:
>
> http://en.wikipedia.org/wiki/Silverthorne_(CPU)
>
> http://download.intel.com/design/chipsets/embedded/prodbrf/319544.pdf
>
> http://download.intel.com/design/chipsets/embedded/datashts/319535.pdf
>
> Intel SCH US15W (combined northbridge, southbridge and graphics):
>
> http://download.intel.com/design/chipsets/embedded/prodbrf/319545.pdf
>
> http://download.intel.com/design/chipsets/embedded/datashts/319537.pdf
>
> Intel's "reference design" for these two is called the
> "Menlow" platform.  For more Intel codename definitions
> concerning Mobile Internet Devices (MID), see:
>
> http://softwareblogs.intel.com/2008/04/01/atom-101-deciphering-the-intel
> -codewords-around-mids/
>
> Comments:
>
> Assuming that technical documentation is available for
> Atom/Poulsbo, is it feasible to port coreboot (aka
> LinuxBIOS) to Atom/Poulsbo?
>   

Yes, if real technical documentation is available. The northbridge
datasheet you posted mentions nothing about RAM init, so while we could
bring up the processor and possibly a serial console, RAM init will be
impossible unless you find actual RAM init documentation. Intel has such
documentation, but they only give it to you if you have a very good
business case (and even then it could take a year until you get the docs).

> Given that this port will support both a new processor
> and a new single support chip (as opposed to a northbridge
> and southbridge chipset), what kind of development effort
> might be required?
>   

To be honest, I fear that doing the whole package (if you have all the
needed docs) can take you roughly six months or more, depending on your
firmware experience.

> Is anyone else interested in such a port?
>   

We (coreboot developers) are certainly interested in such a port and the
EEEPC guys are interested in Intel mobile stuff as well.

> Any suggestions and comments are welcome.
>   

My first suggestion would be to investigate if you can find a matching
platform from AMD. While Intel docs are difficult to get and sometimes
even wrong, AMD provides fast access to good documentation and they even
employ a few excellent engineers who work on coreboot and contribute all
of their code (they contributed Barcelona processor support at the time
it became available commercially).
That's why I recommend AMD.
Besides that, saying "we chose AMD because of coreboot" helps those nice
AMD guys to justify and strengthen the development effort they invest
into coreboot and everyone benefits.

Regards,
Carl-Daniel