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

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?

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?

Is anyone else interested in such a port?

Any suggestions and comments are welcome.

Sincerely,

Ken Fuchs

[Carl-Daniel Hailfinger]

Hi Ken,

On 03.05.2008 00:56, [e-mail] 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

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

> Ken Fuchs wrote:
> > Any suggestions and comments are welcome.

Thanks Carl-Daniel for your opinions on porting coreboot to the
Atom/Poulsbo, but I'd like to address your suggestion of AMD as
alternative first.

Carl-Daniel Hailfinger wrote:
> 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.

I really do like this suggestion for the reasons mentioned.  I have
also found that AMD is much easier to work with than Intel.  When AMD
sees a business opportunity they turn the information facet on full for
you.  With Intel, you seem to have to ask for each individual piece of
information, leaving you wonder when the next drop (of information)
will fall.

Thanks for the great suggestion, but AMD doesn't seem to have a low
power embedded "platform" like the Silverthorne/Poulsbo combo which
uses only 5W maximum total at the highest clock for these parts.  I
understand that the Poulsbo is 2.7 W at all speeds and Atom ranges
from 1.6 W to a maximum of 2.3 W based on clock speed of the part.

One of the hardware engineers on our project claims that AMD doesn't
have any processor using less than 30 W, but I couldn't believe that.
I searched for an AMD processor with low wattage requirements, but the
best I could find was this Sempron at 25 W (for just the processor).

http://products.amd.com/en-us/NotebookCPUDetail.aspx?id=14

AMD must have processors with lower wattage requirements, right?

Maybe some as yet unreleased product?

Sincerely,

Ken Fuchs

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

[Peter Stuge]

On Wed, May 07, 2008 at 02:54:43PM -0500, [e-mail] wrote:
> One of the hardware engineers on our project claims that AMD doesn't
> have any processor using less than 30 W, but I couldn't believe that.
> I searched for an AMD processor with low wattage requirements, but the
> best I could find was this Sempron at 25 W (for just the processor).
>
> http://products.amd.com/en-us/NotebookCPUDetail.aspx?id=14
>
> AMD must have processors with lower wattage requirements, right?

I don't know what frequency you want, but I suppose the Geode LX
could contend regarding power consumption?

//Peter

[Marc Jones]

Peter Stuge wrote:
> On Wed, May 07, 2008 at 02:54:43PM -0500, [e-mail] wrote:
> > One of the hardware engineers on our project claims that AMD doesn't
> > have any processor using less than 30 W, but I couldn't believe that.
> > I searched for an AMD processor with low wattage requirements, but the
> > best I could find was this Sempron at 25 W (for just the processor).
> >
> > http://products.amd.com/en-us/NotebookCPUDetail.aspx?id=14
> >
> > AMD must have processors with lower wattage requirements, right?
>
> I don't know what frequency you want, but I suppose the Geode LX
> could contend regarding power consumption?

Peter is correct. Depending on the performance envelope, Geode LX might 
fit your needs.

Check out the embedded website.
http://www.amd.com/embedded

Marc