Change in coreboot[master]: mb/google/poppy/variants/nami: Enable mbox command for ISL VR c-state...

[Shelley Chen (Code Review)]

Shelley Chen has uploaded this change for review. ( https://review.coreboot.org/27780

Change subject: mb/google/poppy/variants/nami: Enable mbox command for ISL VR c-state issue
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mb/google/poppy/variants/nami: Enable mbox command for ISL VR c-state issue

There is a potential IMVP8 issue for KBL that affects Intersil VRs
Nami is using one of the affected parts. The fix is to use an updated
microcode and also send a mailbox box command from FSP.

BUG=b:112081534
BRANCH=None
TEST=Build and boot Nami
     Verify that suspend/resume and consecutive reboots are working

Change-Id: I6ec18a4c3fae6a66cf8a95685d91a8ba51e2697c
Signed-off-by: Shelley Chen 
---
M src/mainboard/google/poppy/variants/nami/devicetree.cb
1 file changed, 4 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/80/27780/1

diff --git a/src/mainboard/google/poppy/variants/nami/devicetree.cb b/src/mainboard/google/poppy/variants/nami/devicetree.cb
index 54d989f..fe105cb 100644
--- a/src/mainboard/google/poppy/variants/nami/devicetree.cb
+++ b/src/mainboard/google/poppy/variants/nami/devicetree.cb
@@ -59,6 +59,10 @@
    register "PmTimerDisabled" = "1"
    register "VmxEnable" = "1"

+	# Intersil VR c-state issue workaround
+	# send VR mailbox command for IA/GT/SA rails
+	register "IslVrCmd" = "2"
+
    register "pirqa_routing" = "PCH_IRQ11"
    register "pirqb_routing" = "PCH_IRQ10"
    register "pirqc_routing" = "PCH_IRQ11"