sb/intel/common/firmware: Enable me_cleaner for Nehalem

Recent patches in coreboot have fixed the freeze issues related to the
use of me_cleaner on Nehalem.

However, at least on the Lenovo X201, with me_cleaner some PCIe devices
(like the SATA and USB controllers) disappear. In particular, setting
the AltMeDisable bit ("-S" or "-s" flag) makes them disappear
completely, while unsetting it makes them disappear only during cold
boots.

This kind of behaviour was already observed by Youness Alaoui on the
Purism Librem laptops ([1]), and it seems related to some required
board-specific PCIe configuration in the ME's MFS partition.

For this reason, on the Lenovo X201, "-w EFFS" has been added to the
me_cleaner arguments, which whitelists the MFS-equivalent partition for
ME generation 2. This fixes all the issues, and the PCIe devices work as
expected.

[1] https://puri.sm/posts/deep-dive-into-intel-me-disablement/

Change-Id: Ie77a80d2cb4945cf1c984bdb0fb1cc2f18e82ebc
Signed-off-by: Nicola Corna <nicola@corna.info>
Reviewed-on: https://review.coreboot.org/27178
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/mainboard/lenovo/x201/Kconfig b/src/mainboard/lenovo/x201/Kconfig
index 235120915d..a689bbcd4d 100644
--- a/src/mainboard/lenovo/x201/Kconfig
+++ b/src/mainboard/lenovo/x201/Kconfig
@@ -48,4 +48,10 @@ config CPU_ADDR_BITS
 	int
 	default 36
 
+# Without the Intel ME's EFFS partition some PCIe devices (like the USB and SATA
+# controllers) don't work as expected
+config ME_CLEANER_ARGS
+	string
+	default "-S -w EFFS"
+
 endif