[coreboot] YABEL and images in LAR files

[Myles Watson]

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.


Yes.


> 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.

Thanks,
Myles
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