[coreboot] coreboot and embedded controllers, for example OLPC and its OpenEC code

Uwe Hermann uwe at hermann-uwe.de
Wed Jun 25 18:24:31 CEST 2008


On Thu, Jun 19, 2008 at 08:40:32AM +0200, Frieder Ferlemann wrote:
> > Me and Uwe ran into a desktop board with this SMSC superio..
> > 
> > 
> >> And OpenEC was written with portability in mind. While it
> >> specifically targets an ENE KB3700 (with its 8051 based core)
> >> the source is also compileable with gcc.
> > 
> > The superio included an 8051. The 8051 did not have it's own program
> > memory, it's program was stored in the BIOS flash.
> > 
> > When the board powered up, only the 8051 was running. It needed
> > software to do some stuff, and only then could it negotiate release
> > of the main CPU reset.
> This seems close to the EC on the XO.
> > We found some PDF files and it did seem within our reach to get the
> > 8051 to at least power up the CPU, but it was the heart of the
> > superio, so I believe most superio functions would be unavailable
> > until there was more 8051 code.
> On the XO both the host CPU (Geode) and the EC could access special
> function registers (those which were mapped into xdata space on the EC).
> (Access to these registers was later switched off for the host CPU due
> to security implications)
> Out of curiosity, which SMSC superio was it?

The SMSC FDC37N958FR, a datasheet is on the web. See
http://www.coreboot.org/Dell_Latitude_CPi_A366XT_Build_Tutorial for some
more (but not too many) details.

HTH, Uwe.
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