[coreboot-gerrit] Change in coreboot[master]: cpu/intel/model_206ax: Add overclocking support

[Angel Pons (Code Review)]

Angel Pons has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/42547 )

Change subject: cpu/intel/model_206ax: Add overclocking support
......................................................................

cpu/intel/model_206ax: Add overclocking support

Add a Kconfig option to force Turbo Ratio values to the maximum possible
value, which is the maximum non-turbo ratio plus the number of OC bins.

Tested on Asus P8Z77-V LX2 with an i5-3330, CPU now runs at 3.4 GHz.

Change-Id: I60bef32bfdde3c32a11f07afff64fc83d65fd3f1
Signed-off-by: Angel Pons 
---
M src/cpu/intel/model_206ax/Kconfig
M src/cpu/intel/model_206ax/model_206ax.h
M src/cpu/intel/model_206ax/model_206ax_init.c
3 files changed, 55 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/47/42547/1

diff --git a/src/cpu/intel/model_206ax/Kconfig b/src/cpu/intel/model_206ax/Kconfig
index c6a5020..df78524 100644
--- a/src/cpu/intel/model_206ax/Kconfig
+++ b/src/cpu/intel/model_206ax/Kconfig
@@ -38,4 +38,13 @@
    int
    default 8

+config FORCE_MAX_TURBO_RATIO
+	bool "Force turbo ratios to the maximum possible value"
+	default n
+	help
+	  By selecting this, all core turbo ratios will be set to the maximum possible value,
+	  which is the maximum non-turbo ratio of the CPU plus the number of overclocking bins
+	  by which the CPU can be overclocked. This is an overclocking option and therefore is
+	  dangerous to enable, especially on mobile platforms with a limited cooling solution!
+
 endif
diff --git a/src/cpu/intel/model_206ax/model_206ax.h b/src/cpu/intel/model_206ax/model_206ax.h
index e24993c..7ac3ec9 100644
--- a/src/cpu/intel/model_206ax/model_206ax.h
+++ b/src/cpu/intel/model_206ax/model_206ax.h
@@ -18,6 +18,7 @@
 #define MSR_PIC_MSG_CONTROL		0x2e
 #define MSR_PLATFORM_INFO		0xce
 #define  PLATFORM_INFO_SET_TDP		(1 << 29)
+#define  PLATFORM_INFO_RATIO_LIMIT	(1 << 28)

#define MSR_MISC_PWR_MGMT		0x1aa
 #define  MISC_PWR_MGMT_EIST_HW_DIS	(1 << 0)
diff --git a/src/cpu/intel/model_206ax/model_206ax_init.c b/src/cpu/intel/model_206ax/model_206ax_init.c
index e69d4fa..de4392d 100644
--- a/src/cpu/intel/model_206ax/model_206ax_init.c
+++ b/src/cpu/intel/model_206ax/model_206ax_init.c
@@ -14,6 +14,7 @@
 #include <cpu/intel/turbo.h>
 #include <cpu/x86/cache.h>
 #include <cpu/x86/name.h>
+#include <stdint.h>
 #include "model_206ax.h"
 #include "chip.h"
 #include <cpu/intel/smm_reloc.h>
@@ -439,6 +440,47 @@
    printk(BIOS_INFO, "CPU: VT %ssupported\n", mode[vt]);
 }

+static void xe_init(void)
+{
+	msr_t msr;
+
+	/* If not enabled, do not touch anything */
+	if (!CONFIG(FORCE_MAX_TURBO_RATIO)) {
+		printk(BIOS_DEBUG, "XE: not overriding Turbo Ratio limits\n");
+		return;
+	}
+
+	/* Get the number of OC bins */
+	msr = rdmsr(MSR_FLEX_RATIO);
+	const uint8_t oc_bins = (msr.lo >> 17) & 0x7;
+
+	/* Ensure that the preconditions for XE are true */
+	msr = rdmsr(MSR_PLATFORM_INFO);
+	if (!(cpuid_eax(1) >= 0x206a3 && (msr.lo & PLATFORM_INFO_RATIO_LIMIT) && oc_bins)) {
+
+		printk(BIOS_WARNING, "XE: Cannot configure XE on a non-XE processor\n");
+		return;
+	}
+
+	/* Obtain maximum non-turbo ratio from MSR_PLATFORM_INFO */
+	const uint8_t max_non_turbo = (msr.lo >> 8) & 0xff;
+
+	/* Now do the deed */
+	msr = rdmsr(MSR_TURBO_RATIO_LIMIT);
+
+	msr.lo  = 0;
+	msr.lo |= (max_non_turbo + oc_bins) <<  0;
+	msr.lo |= (max_non_turbo + oc_bins) <<  8;
+	msr.lo |= (max_non_turbo + oc_bins) << 16;
+	msr.lo |= (max_non_turbo + oc_bins) << 24;
+
+	printk(BIOS_NOTICE, "XE: Setting Turbo Ratio to %d... ", max_non_turbo + oc_bins);
+
+	wrmsr(MSR_TURBO_RATIO_LIMIT, msr);
+
+	printk(BIOS_NOTICE, "done.\n");
+}
+
 static void model_206ax_init(struct device *cpu)
 {

@@ -481,6 +523,9 @@

/* Enable Turbo */
    enable_turbo();
+
+	/* Crank up the turbo ratio, if possible and desired */
+	xe_init();
 }

/* MP initialization support. */