[coreboot] [PATCH]tinybootblock

Myles Watson mylesgw at gmail.com
Tue Dec 22 23:17:35 CET 2009

On Tue, Dec 22, 2009 at 2:27 PM, Patrick Georgi <patrick at georgi-clan.de>wrote:

> - Provide a framework to build image selection logic
> In newconfig, most boards have their own code to select the image. The
> goal in this layout is to have generic decision routines to take care of
> that, and encourage their use.
Is it possible to have it be generic?  Won't we have to unify CMOS layouts
for that to happen?

> - Push as much as possible out of the bootblock
> The failover mechanism so far did CAR in the bootblock and raminit in
> the later stage. With tinybootblock, CAR is supposed to end up outside
> the bootblock. "Safe updates", once we provide them, will be able to
> update CAR support for new CPU types, too.
> Code flow in tinybootblock:
> - 16bit reset vector (0xfffffff0)
> - jump to 32bit mode
> - Do whatever is necessary to have the entire ROM around (C code,
> compiled with romcc)
I think it would be a mistake to bring romcc to targets that don't need it

> - Look up fallback/romstage in CBFS (this can be extended with selection
> logic if desired) ("selection logic" is C, compiled with romcc, lookup
> is assembly)
It's more important to me to avoid assembly than to have the absolute
minimum size bootblock.  Especially for K8 & Fam10, there's plenty of space
to not have to do this.

Picky detail:
Since CONFIG_TINY_BOOTBLOCK is referenced in a Makefile that isn't board
specific, the Kconfig entry for it should go there too (with a default n).
There should just be a "select" in qemu-x86/Kconfig

> Signed-off-by: Patrick Georgi <patrick.georgi at coresystems.de>

I think it's a good start, and since it doesn't break anything until it's

Acked-by: Myles Watson <mylesgw at gmail.com>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.coreboot.org/pipermail/coreboot/attachments/20091222/5f4618eb/attachment.html>

More information about the coreboot mailing list