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

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Sun May 4 17:10:07 CEST 2008

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.


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