[coreboot] Any intro available for adding cbmem support to an old platform?

[Keith Hui]

Hi (again) coreboot:

My original question got lost in the list probably because of a bad
subject, so I'm asking again with a better one.

I read that after 4.7 we are going to drop older platforms without
"cbmem support in romstage", and that includes one that I brought into
coreboot. I am interested in bringing this platform up to standard.
Where can I read up on adding this cbmem support?

I just checked out the master from git in case they are part of the readings.

Thanks
Keith