[coreboot] ast2400 / ast2500

[Andrey Korolyov]

> 4. Using same firmware on x86 and bmc means, what ever infra we develop for
> board bring up and ops (as coreboot payload) works on both.
> 5. Same thing for secure booting.
>

While I borrow not much expertise there, these points are applicable
at this moment only if you are planning to run UEFI on both ARM and
x86 devices at once, all other things are pretty less generic and not
replaceable. UEFI is mentioned, but it could be u-boot or something
else which works as cross-platform bootloader and could be inserted
within a boot sequence stack on both IMC and host - on certain
hardware you would manage to get identical software stack on different
architectures for a small effort but for most times this is not true
and significant work needs to be done.

The second major point is a lack of host board signaling unification,
you would not even have a guarantee that same BMC-side GPIO pins are
responsible for same action types across boards of a single vendor
(true for generations of Supermicro removable BMCs), so each board or
board family would probably need additional work to create signaling
descriptions. I`m not sure if coreboot is an appropriate replacement
for OpenBMC efforts right there, as it was said before in this thread
because real positive outcome is barely imaginable from this
description.