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skylake: Set Pkg Power clamping bit in Power Limit MSR 

Setting the Package Power clamping bits in Power Limit MSR
(MSR_PKG_POWER_LIMIT 0x610) Allows going below the OS requested
P or T state for the time window specified for PL1 or PL2.

BRANCH=none
BUG=chrome-os-partner:47041
TEST=Built and boot on kunimitsu, load the system with Aquarium WebGL,
	change the power limit value from default (TDP or 15W) to any lower value
	note that the Pkg power comes down and also the CPU frequency is lowered.

Change-Id: I9c0dd90a6660214ae142418aae8b8c5f6a739896
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: b0b527991c2d26da5772700a22ff101eaf9993ef
Original-Change-Id: Ia59fcfe2a14cd7f8b1e1b8e967073e67eb452f42
Original-Signed-off-by: Rizwan Qureshi <rizwan.qureshi@intel.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/309556
Original-Tested-by: Charulatha Varadarajan <charuprasanna@gmail.com>
Original-Tested-by: Charulatha Varadarajan <charulatha.varadarajan@intel.com>
Original-Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/12257
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
This commit is contained in:
Rizwan Qureshi 2015-10-15 21:38:21 +05:30 committed by Patrick Georgi
parent f86d035105
commit 0dd72e8b1d
1 changed files with 5 additions and 0 deletions
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5
src/soc/intel/skylake/cpu.c
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@ -152,6 +152,10 @@ void set_power_limits(u8 power_limit_1_time)
/* Set long term power limit to TDP */
limit.lo = 0;
limit.lo |= tdp & PKG_POWER_LIMIT_MASK;
/* Set PL1 Pkg Power clamp bit */
limit.lo |= PKG_POWER_LIMIT_CLAMP;
limit.lo |= PKG_POWER_LIMIT_EN;
limit.lo |= (power_limit_1_val & PKG_POWER_LIMIT_TIME_MASK) <<
PKG_POWER_LIMIT_TIME_SHIFT;
@ -159,6 +163,7 @@ void set_power_limits(u8 power_limit_1_time)
/* Set short term power limit to 1.25 * TDP */
limit.hi = 0;
limit.hi |= ((tdp * 125) / 100) & PKG_POWER_LIMIT_MASK;
limit.hi |= PKG_POWER_LIMIT_CLAMP;
limit.hi |= PKG_POWER_LIMIT_EN;
/* Power limit 2 time is only programmable on server SKU */