Change in coreboot[master]: soc/amd/cezanne: Start loading APOB asynchronously

[Raul Rangel (Code Review)]

Attention is currently required from: Jason Glenesk, Marshall Dawson, Felix Held.
Hello build bot (Jenkins), Jason Glenesk, Marshall Dawson, Eric Peers, Felix Held,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/56234

to look at the new patch set (#4).

Change subject: soc/amd/cezanne: Start loading APOB asynchronously
......................................................................

soc/amd/cezanne: Start loading APOB asynchronously

This enables COOP_MULTITASKING (i.e., multiple stacks single CPU). This
will allow the APOB to start loading while ramstage progresses
through the state machine.

BUG=b:179699789
TEST=Boot guybrush and verify APOB read timestamp has dropped from 10ms
to a few uS.

Starting APOB preload
APOB thread running
spi_dma_readat_dma: start: dest: 0xcb7aa640, offset: 0x0, size: 65536
 took 0 us to acquire mutex
start_spi_dma_transaction: dest: 0xcb7aa640, offset: 0x0, remaining: 65536

<ramstage doing work>

spi_dma_readat_dma: end: dest: 0xcb7aa640, offset: 0x0, size: 65536, remaining: 0

<more work..>

waiting for thread
 took 0 us
APOB valid copy is already in flash

Signed-off-by: Raul E Rangel 
Change-Id: I4b5c1ef4cad571d1cbca33b1aff017a3cedc1bea
---
M src/soc/amd/cezanne/Kconfig
M src/soc/amd/cezanne/fsp_s_params.c
2 files changed, 7 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/34/56234/4