[coreboot] YABEL and images in LAR files

Myles Watson mylesgw at gmail.com
Fri Dec 19 20:37:48 CET 2008

On Fri, Dec 19, 2008 at 11:57 AM, Pattrick Hueper <phueper at hueper.net>wrote:

> Hi,
> well following the BIOS spec (i think its somewhere in the PNP BIOS
> spec... i have to check... ) the BIOS copies the ROM to RAM... since
> YABEL uses its own "virtual" memory it _has_ to copy the ROM to its
> RAM...

Yes.  Right now there's just a redundant copy, since Coreboot copies it to
RAM too.

> also some of the cards i have used do actually modify the
> memory where the ROM is stored, so it has to be in the virtual RAM.
> Currently, the ROM is always copied from the Expansion ROM bar of PCI
> devices.... i havent had to initialize any onboard devices. If there
> is a parameter to run_bios that points to the location of the Option
> ROM i could pass that parameter to YABEL and only use the Expansion
> ROM BAR if that parameter is not set (null?).

That's what I was thinking.

> But IIRC i still have to
> copy it to the virtual memory.


> If it helps coreboot to know where the Option ROM image is after
> execution of the ROM, i guess YABEL could return the location of the
> ROM (the length which could be changed during execution is part of the
> ROM, so coreboot could figure out how much to copy back if it decides
> to do so.

I don't think Coreboot cares after the card is initialized.

> I am thinking of buying a x86 board to do coreboot development, i am
> wondering which one would be a good choice with regards to YABEL and
> maybe SEABIOS development? Any recommendations?

> My requirements:
> coreboot-v3 and preferably v2 "compatible"
> PCI and PCIe slots
> since Myles mentioned onboard devices with ROM in LAR that would be
> very interesting too...

You can test even with an add-in card if you "pretend" its onboard.  Then
you can have coreboot give you a pointer to it and initialize it.

> "affordable"
> I am really unsure what else to look for... Flash Chip Types? Processor?

Socketed flash chip. Preferably compatible with a BIOS savior.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.coreboot.org/pipermail/coreboot/attachments/20081219/ba3d4412/attachment.html>

More information about the coreboot mailing list