amd/pi: Add AgesaHeapRebase callout

Implement an optional callout for AgesaHeapRebase which allows AGESA
to override any internal hardcoded heap addresses.

Designate a region in CAR that may be used for pre-mem heap and return
that address before DRAM is configured.  After DRAM is up, the address
in cbmem is returned.

TEST=Boot grunt with patchstack and experimental blob

Change-Id: Ieda202a6064302b21707bd7ddfabc132cd85ed45
Signed-off-by: Marshall Dawson <>
Tested-by: build bot (Jenkins) <>
Reviewed-by: Martin Roth <>
4 files changed