Previously the SPI mirroring was using the SMM default
region. If the payload exceeds the SMM default region size
the mirroring won't happen. This causes a slow down. Instead
find a region to mirror into below 4GiB that is marked as
available ram.
Prior to this change 60ms payload times were observed with
current depthcharge builds. With this change the load time is
24ms - 32ms depending on boot type.
BUG=chrome-os-partner:25385
BRANCH=baytrail
TEST=Booted and noted timing.
Change-Id: I201f0fd6cf82f4521e5cb7fafac6ece27951995d
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/188715
Reviewed-by: Marc Jones <marc.jones@se-eng.com>