[coreboot] [RFC] Here we go... the SLOF biosemu for coreboot-v3

Pattrick Hueper phueper at hueper.net
Fri Dec 12 21:58:22 CET 2008


i havent had time to look into seabios.
What i read/heard of seabios, it seems, that it is pretty much tied
with the x86 architecture, whereas the SLOF biosemu is designed to be
independent, and for me it has proven to be so by being ported from
OF/PPC to coreboot/x86 with reasonable effort.

Being architecture independent, i think the biosemu has to keep its
own set of Interrupt Vectors and virtual 1MB memory area (which is, by
the way currently hard coded to 16MB of real memory i think...)
That makes it possible to reenter biosemu e.g. for VBE calls (which we
did in SLOF, the code is initializing the card by running the Option
ROM first and later on reenters biosemu to switch to
framebuffer mode). Of course in a x86 coreboot this might need to be
redesigned... then again for a x86 coreboot, seabios or vm86 might be
the better / faster choices anyway.

I started working on porting v3 to qemu-ppc... once i have some serial
output, i will post patches. And i hope to hack qemu-ppc to use the
same cirrus
vga card and exprom and be able to initialize it in qemu-ppc though it
remains to be seen, wether that will work or wether it is already

And then i am still planning to try to get some other devices
(IDE/Ethernet) to work...

Also, would it be interesting for any of you if i tried to port biosemu to v2?

Regards, Pattrick

On Fri, Dec 12, 2008 at 7:57 PM, ron minnich <rminnich at gmail.com> wrote:
> On Fri, Dec 12, 2008 at 10:44 AM, Myles Watson <mylesgw at gmail.com> wrote:
>> So you'd rather that Pattrick and Kevin collaborate.  I'm fine with that.  I
>> didn't want to see a developer submitting working code that's ignored.
> The conclusion we reached is that vga/rom setup is getting very
> complex, and that seabios does a very good job of it. Further, in most
> cases we need the interrupt vectors to remain active after the ROM has
> been executed. We felt it made no sense to replicate that capability
> in two places. So, yes, I think it makes the most sense in seabios.
> thanks
> ron

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