Change in coreboot[master]: mb/google/brya: Disable C1-state auto demotion for Brya & Brask

[Nick Vaccaro (Code Review)]

Nick Vaccaro has submitted this change. ( https://review.coreboot.org/c/coreboot/+/62630 )

Change subject: mb/google/brya: Disable C1-state auto demotion for Brya & Brask
......................................................................

mb/google/brya: Disable C1-state auto demotion for Brya & Brask

C1-state auto demotion feature allows hardware to determine C1-state as
per platform policy. Since Brya sets performance policy to balanced from
hardware, auto demotion can be disabled without performance impact.

Also, disabling this feature results in 110 mW power savings during
video playback.

Note that C1state Autodemotion feature is not applicable for ADL-P SoC.
Hence recommendation is to keep it disabled.

BUG=b:221876248
BRANCH=firmware-brya-14505.B
TEST=Code compiles and correct value of c1-state auto demotion is passed
to FSP. Also power and performance impact has been measure by respective
teams.

Change-Id: I41eea916cdfe4a86e4d263e3191f5cb40fa33a90
Signed-off-by: Maulik V Vaghela 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62630
Tested-by: build bot (Jenkins) 
Reviewed-by: Nick Vaccaro 
Reviewed-by: Tim Wawrzynczak 
Reviewed-by: Subrata Banik 
Reviewed-by: Sridhar Siricilla 
---
M src/mainboard/google/brya/variants/baseboard/brask/devicetree.cb
M src/mainboard/google/brya/variants/baseboard/brya/devicetree.cb
2 files changed, 6 insertions(+), 0 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Nick Vaccaro: Looks good to me, approved
  Tim Wawrzynczak: Looks good to me, approved
  Sridhar Siricilla: Looks good to me, but someone else must approve
  Subrata Banik: Looks good to me, approved

diff --git a/src/mainboard/google/brya/variants/baseboard/brask/devicetree.cb b/src/mainboard/google/brya/variants/baseboard/brask/devicetree.cb
index a57289b..0d60a57 100644
--- a/src/mainboard/google/brya/variants/baseboard/brask/devicetree.cb
+++ b/src/mainboard/google/brya/variants/baseboard/brask/devicetree.cb
@@ -76,6 +76,9 @@
    # FIVR RFI Spread Spectrum 1.5%
    register "fivr_spread_spectrum" = "FIVR_SS_1_5"

+	# Disable C state auto-demotion for all brask baseboards
+	register "disable_c1_state_auto_demotion" = "1"
+
    # Intel Common SoC Config
    #+-------------------+---------------------------+
    #| Field             |  Value                    |
diff --git a/src/mainboard/google/brya/variants/baseboard/brya/devicetree.cb b/src/mainboard/google/brya/variants/baseboard/brya/devicetree.cb
index 9ceda11..c75f321 100644
--- a/src/mainboard/google/brya/variants/baseboard/brya/devicetree.cb
+++ b/src/mainboard/google/brya/variants/baseboard/brya/devicetree.cb
@@ -72,6 +72,9 @@
    # FIVR RFI Spread Spectrum 1.5%
    register "fivr_spread_spectrum" = "FIVR_SS_1_5"

+	# Disable C state auto-demotion for all brya baseboards
+	register "disable_c1_state_auto_demotion" = "1"
+
    # Intel Common SoC Config
    #+-------------------+---------------------------+
    #| Field             |  Value                    |

13 is the latest approved patch-set.
No files were changed between the latest approved patch-set and the submitted one.