commit 63278ab07d684f90804065a6351e0d138f09b507
author Gaggery Tsai <gaggery.tsai@intel.com> Mon Jan 22 11:17:28 2018 +0800
committer Stefan Reinauer <stefan.reinauer@coreboot.org> Wed Jan 24 00:44:30 2018 +0000
tree 7d8aa7dd74bdacaf5770b7e1972d52b331307095
parent 94ef4a8a476a66931eb2b2f7f8573fed52956d0f

mb/google/fizz: Add AC/DC loadline settings

This patch adds AC and DC loadline settings since vr_config_enable is
set. Without correct AD/DC loadline settings, VRs reported incorrect
VID values which caused CPU freqency clipping. The clipping reason
could be retrieved from MSR 0x64F. From VRTT report, the AC/DC
loadline resistances are within spec, we can use default value defined
in Table 6-1, doc #543977.

BUG=b:70646304
BRANCH=None
TEST=emerge-fizz coreboot chromeos-bootimage & Read AC/DC loadline
     settings from DCI to ensure the values were programmed correctly.

Change-Id: Id0ce29fa5726ca3711aa4c822fb123e2de7bc48f
Signed-off-by: Gaggery Tsai <gaggery.tsai@intel.com>
Reviewed-on: https://review.coreboot.org/23349
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/fizz/devicetree.cb

diff --git a/src/mainboard/google/fizz/devicetree.cb b/src/mainboard/google/fizz/devicetree.cb
index 8cf4e52..9fb366d 100644
--- a/src/mainboard/google/fizz/devicetree.cb
+++ b/src/mainboard/google/fizz/devicetree.cb
@@ -116,6 +116,8 @@
 	#| ImonOffset     | 0     | 0     | 0     | 0     |
 	#| IccMax         | 7A    | 34A   | 35A   | 35A   |
 	#| VrVoltageLimit | 1.52V | 1.52V | 1.52V | 1.52V |
+	#| AcLoadline(ohm)| 10.3m | 2.4m  | 3.1m  | 3.1m  |
+	#| DcLoadline(ohm)| 10.3m | 2.4m  | 3.1m  | 3.1m  |
 	#+----------------+-------+-------+-------+-------+
 	#Note: IccMax settings are moved to SoC code
 	register "domain_vr_config[VR_SYSTEM_AGENT]" = "{
@@ -128,6 +130,8 @@
 		.imon_slope = 0x0,
 		.imon_offset = 0x0,
 		.voltage_limit = 1520,
+		.ac_loadline = 1030,
+		.dc_loadline = 1030,
 	}"
 
 	register "domain_vr_config[VR_IA_CORE]" = "{
@@ -140,6 +144,8 @@
 		.imon_slope = 0x0,
 		.imon_offset = 0x0,
 		.voltage_limit = 1520,
+		.ac_loadline = 240,
+		.dc_loadline = 240,
 	}"
 
 	register "domain_vr_config[VR_GT_UNSLICED]" = "{
@@ -152,6 +158,8 @@
 		.imon_slope = 0x0,
 		.imon_offset = 0x0,
 		.voltage_limit = 1520,
+		.ac_loadline = 310,
+		.dc_loadline = 310,
 	}"
 
 	register "domain_vr_config[VR_GT_SLICED]" = "{
@@ -164,6 +172,8 @@
 		.imon_slope = 0x0,
 		.imon_offset = 0x0,
 		.voltage_limit = 1520,
+		.ac_loadline = 310,
+		.dc_loadline = 310,
 	}"
 
 	# Enable Root port 3(x1) for LAN.