[coreboot] Saved SeaBIOS configuration options for mainboards.

[Martin Roth]

I recently posted a patch that would allow the coreboot build to use a
saved SeaBIOS .config file stored in the mainboard directory.  The
initial reason for this was to replace one existing SeaBIOS
configuration option that was in coreboot's Kconfig, and to remove the
need for a second option that was about to be added.

The intention behind this is not to add full config files, but to add
individual options that are required for the platforms.  That said,
saving a full config will almost certainly happen at some point since
this change doesn't prevent this.  I'm not sure how big an issue this
really is, other than creating some maintenance problems.

Another side effect of this is that a user could point to a saved
.config outside of the coreboot tree, to customize the SeaBIOS.  I
don't think this should present a problem, as the .config file for
SeaBIOS is getting saved in CBFS.  If we want to minimize this, the
prompt in Kconfig can be removed, preventing the option from showing
up in menuconfig (or your favorite config method).

It was requested that I post this change to the mailing list for
thoughts and review.


The patches in question are here:

payloads/external/SeaBIOS: Add option for saved SeaBIOS .config
https://review.coreboot.org/#/c/12568

intel/mohonpeak: Change SEABIOS_MALLOC_UPPERMEMORY to config_seabios
https://review.coreboot.org/#/c/12569

SeaBIOS/Kconfig: Remove SEABIOS_MALLOC_UPPERMEMORY option
https://review.coreboot.org/#/c/12570

payloads/Seabios: add SEABIOS_NO_HARDWARE_IRQ symbol
https://review.coreboot.org/#/c/12534/

Thoughts?  Review?  Downsides I didn't think of?

Martin