tree 97ea42937aadc0d360e0d724504d93bfdbff428c
parent a96e9cb0b444e2d40c5ed625bbbe0e74bd510b1d
author Tim Wawrzynczak <twawrzynczak@chromium.org> 1624034049 -0600
committer Tim Wawrzynczak <twawrzynczak@chromium.org> 1625091563 +0000

soc/intel/common/block/cse: Add BWG error recovery to EOP failure

This patch adds functionality to attempt to allow booting in a secure
configuration (albeit with potentially reduced functionality) when the
CSE EOP message fails in any way. These steps come from the CSME BWG
(13.5, 15.0, 16.), and tell the CSE to disable the MEI bus, which
disables further communication from the host. This is followed by
requesting the PMC to disable the MEI devices. If these steps are
successful, then the boot firmware can continue to boot to the
OS. Otherwise, die() is called, prefering not to boot over leaving the
insecure MEI bus available.

BUG=b:191362590
TEST=Set FSP UPD to disable sending EOP; called this function from a
BS_PAYLOAD_LOAD, ON_ENTRY entry; observed that with just
cse_mei_bus_disable() called, Linux can no longer communicate over MEI:
[   16.198759] mei_me 0000:00:16.0: wait hw ready failed
[   16.204488] mei_me 0000:00:16.0: hw_start failed ret = -62
[   16.210804] mei_me 0000:00:16.0: H_RST is set = 0x80000031
[   18.245909] mei_me 0000:00:16.0: wait hw ready failed
[   18.251601] mei_me 0000:00:16.0: hw_start failed ret = -62
[   18.257785] mei_me 0000:00:16.0: reset: reached maximal consecutive..
[   18.267622] mei_me 0000:00:16.0: reset failed ret = -19
[   18.273580] mei_me 0000:00:16.0: link layer initialization failed.
[   18.280521] mei_me 0000:00:16.0: init hw failure.
[   18.285880] mei_me 0000:00:16.0: initialization failed.
Calling both error recovery functions causes all of the slot 16 devices
to fail to enumerate in the OS

Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Change-Id: I06abf36a9d9d8a5f2afba6002dd5695dd2107db1
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55675
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>