[coreboot] libgfxinit quick starter guide

[Michal Zygowski]

Hi coreboot folks,

For some time I have been interested in libgfxinit and I wondered how it
works (like in developer details).

Particularly I would like to implement Braswell support for native
graphics init with libgfxinit. I see the programming manuals from Intel
are in place:
https://01.org/linuxgraphics/documentation/hardware-specification-prms

What do I need to implement a new microarchitecture in libgfxinit? Where
to start and what should I focus on?

tl;dr;
Haven't written anything in SPARK/Ada yet. It will be a new adventure
for me.

Regards,