[XS] Change in coreboot[master]: mb/google/skyrim/: Set system_configuration to 3 to avoid SMU call

[Jason Glenesk (Code Review)]

Jason Glenesk has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/76096?usp=email )

Change subject: mb/google/skyrim/: Set system_configuration to 3 to avoid SMU call
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mb/google/skyrim/: Set system_configuration to 3 to avoid SMU call

Update system_configuration to 3 for 15W. Specification "FT6
Infrastructure Roadmap #57316" incorrectly lists system config index of
4 for 15W. Setting to 4 will cause an additional call to the SMU that is
not needed and will add boot delay. Both SMU and FSP interpret configs >
3 as 3.

BUG=b:267294958
TEST=Confirm extra message "Service Request 0x5F" not in log.

Change-Id: Ib12c73f95030625b52e26f86e932ee2aaa6ea522
Signed-off-by: Jason Glenesk 
---
M src/mainboard/google/skyrim/variants/winterhold/overridetree.cb
1 file changed, 4 insertions(+), 2 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/96/76096/1

diff --git a/src/mainboard/google/skyrim/variants/winterhold/overridetree.cb b/src/mainboard/google/skyrim/variants/winterhold/overridetree.cb
index 57e2cab..490b415 100644
--- a/src/mainboard/google/skyrim/variants/winterhold/overridetree.cb
+++ b/src/mainboard/google/skyrim/variants/winterhold/overridetree.cb
@@ -11,8 +11,10 @@
    # Set DPTC multi-profile common parameters

# Refer the spec "FT6 Infrastructure Roadmap"#57316
-	# Set system_configuration to 4 for 15W
-	register "system_configuration" = "4"
+	# Set system_configuration to 3 for 15W. Spec lists 4 for 15W,
+	# however, setting to 3 will avoid an additional communication
+	# with the SMU and save boot time.
+	register "system_configuration" = "3"
    register "thermctl_limit_degreeC" = "97"

register "stt_control" = "1"