[S] Change in coreboot[main]: cpu/intel/model_206ax: Allow package power limit clamping

[Nico Huber (Code Review)]

Nico Huber has submitted this change. ( https://review.coreboot.org/c/coreboot/+/83270?usp=email )

Change subject: cpu/intel/model_206ax: Allow package power limit clamping
......................................................................

cpu/intel/model_206ax: Allow package power limit clamping

Setting the clamp bit allows the CPU to operate below the highest
non-turbo frequency in order to obey the power limit.

Tested on ThinkPad T420 with the i7-3940XM.

Change-Id: Id0c0aedc29aca121d0fd1d8f8826089e13a026be
Signed-off-by: Anastasios Koutian 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83270
Tested-by: build bot (Jenkins) 
Reviewed-by: Nico Huber 
---
M src/cpu/intel/model_206ax/chip.h
M src/cpu/intel/model_206ax/model_206ax_init.c
2 files changed, 12 insertions(+), 0 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Nico Huber: Looks good to me, approved

diff --git a/src/cpu/intel/model_206ax/chip.h b/src/cpu/intel/model_206ax/chip.h
index f26fa61..1102cfe 100644
--- a/src/cpu/intel/model_206ax/chip.h
+++ b/src/cpu/intel/model_206ax/chip.h
@@ -3,6 +3,8 @@
 #ifndef __CPU_INTEL_MODEL_206AX_CHIP_H__
 #define __CPU_INTEL_MODEL_206AX_CHIP_H__

+#include "stdbool.h"
+
 /* Keep this in sync with acpi.c */
 enum cpu_acpi_level {
    CPU_ACPI_DISABLED = 0,
@@ -44,7 +46,9 @@
    int tcc_offset;		/* TCC Activation Offset */

unsigned int pl1_mw; /* Long-term power limit in milliwatts */
+	bool pl1_clamp; /* Long-term power limit clamping limitation */
    unsigned int pl2_mw; /* Short-term power limit in milliwatts */
+	bool pl2_clamp; /* Short-term power limit clamping limitation */

int pp0_current_limit;	/* Primary Plane Current Limit (Icc) in Amps */
    int pp1_current_limit;	/* Secondary Plane Current Limit (IAXG) in Amps */
diff --git a/src/cpu/intel/model_206ax/model_206ax_init.c b/src/cpu/intel/model_206ax/model_206ax_init.c
index aafb4dc..0d0e3f7 100644
--- a/src/cpu/intel/model_206ax/model_206ax_init.c
+++ b/src/cpu/intel/model_206ax/model_206ax_init.c
@@ -141,6 +141,10 @@
    	/* Set long term power limit to TDP */
    	limit.lo |= tdp & PKG_POWER_LIMIT_MASK;
    }
+	if (conf->pl2_clamp) {
+		printk(BIOS_DEBUG, "Enabling PL1 clamping limitation\n");
+		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;
@@ -153,6 +157,10 @@
    	/* Set short term power limit to 1.25 * TDP */
    	limit.hi |= ((tdp * 125) / 100) & PKG_POWER_LIMIT_MASK;
    }
+	if (conf->pl2_clamp) {
+		printk(BIOS_DEBUG, "Enabling PL2 clamping limitation\n");
+		limit.hi |= PKG_POWER_LIMIT_CLAMP;
+	}
    limit.hi |= PKG_POWER_LIMIT_EN;
    /* Power limit 2 time is only programmable on SNB EP/EX */