Change in coreboot[master]: soc/amd/common/block/espi_util: Work around in-band reset race condition

[Raul Rangel (Code Review)]

Attention is currently required from: Marshall Dawson, Paul Menzel, Karthik Ramasubramanian, Felix Held.
Hello build bot (Jenkins), Jason Glenesk, Furquan Shaikh, Marshall Dawson, Paul Menzel, Rob Barnes, Karthik Ramasubramanian, Felix Held,

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

https://review.coreboot.org/c/coreboot/+/54070

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

Change subject: soc/amd/common/block/espi_util: Work around in-band reset race condition
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soc/amd/common/block/espi_util: Work around in-band reset race condition

When performing an in-band reset the host controller and the
peripheral can have mismatched IO configs.

i.e., The eSPI peripheral can be in IO-4 mode while, the
eSPI host will be in IO-1. This results in the peripheral
getting invalid packets and thus not responding. This causes the
NO_RESPONSE status bit to be set and cause eSPI init to fail.

If the peripheral is alerting when we perform an in-band
reset, there is a race condition in espi_send_command.
1) espi_send_command clears the interrupt status.
2) eSPI host controller hardware notices the alert and sends
   a GET_STATUS.
3) espi_send_command writes the in-band reset command.
4) eSPI hardware enqueues the in-band reset until GET_STATUS
   is complete.
5) GET_STATUS fails with NO_RESPONSE and sets the interrupt
   status.
6) eSPI hardware performs in-band reset.
7) espi_send_command checks the status and sees a
   NO_RESPONSE bit.

As a workaround we allow the NO_RESPONSE status code when
we perform an in-band reset.

BUG=b:186135022
TEST=suspend_stress_test and S5->S0 tests on guybrush and zork.

Signed-off-by: Raul E Rangel 
Change-Id: I71271377f20eaf29032214be98794e1645d9b70a
---
M src/soc/amd/common/block/lpc/espi_util.c
1 file changed, 30 insertions(+), 2 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/70/54070/4