[coreboot-gerrit] Change in coreboot[master]: cpu/intel/turbo: Add option to disable turbo

[Subrata Banik (Code Review)]

Subrata Banik has uploaded a new change for review. ( https://review.coreboot.org/19674 )

Change subject: cpu/intel/turbo: Add option to disable turbo
......................................................................

cpu/intel/turbo: Add option to disable turbo

disable_turbo function use to disable turbo mode
on each processor by settings MSR 0x1A0 bit 38.

This option will help to perform some quick test
without enabling turbo mode.

Change-Id: If3e387e16e9fa6f63cb0ffff6ab2759b447e7c5c
Signed-off-by: Subrata Banik <subrata.banik at intel.com>
---
M src/cpu/intel/turbo/turbo.c
M src/include/cpu/intel/turbo.h
2 files changed, 20 insertions(+), 0 deletions(-)


  git pull ssh://review.coreboot.org:29418/coreboot refs/changes/74/19674/1

diff --git a/src/cpu/intel/turbo/turbo.c b/src/cpu/intel/turbo/turbo.c
index ac66273..3fae3f0 100644
--- a/src/cpu/intel/turbo/turbo.c
+++ b/src/cpu/intel/turbo/turbo.c
@@ -106,3 +106,20 @@
 		printk(BIOS_INFO, "Turbo has been enabled\n");
 	}
 }
+
+/*
+ * Try to disable Turbo mode.
+ */
+void disable_turbo(void)
+{
+	msr_t msr;
+
+	/* Set Turbo Disable bit in Misc Enables */
+	msr = rdmsr(MSR_IA32_MISC_ENABLES);
+	msr.hi |= H_MISC_DISABLE_TURBO;
+	wrmsr(MSR_IA32_MISC_ENABLES, msr);
+
+	/* Update cached turbo state */
+	set_global_turbo_state(TURBO_UNAVAILABLE);
+	printk(BIOS_INFO, "Turbo has been disabled\n");
+}
diff --git a/src/include/cpu/intel/turbo.h b/src/include/cpu/intel/turbo.h
index 6626cb1..58f4831 100644
--- a/src/include/cpu/intel/turbo.h
+++ b/src/include/cpu/intel/turbo.h
@@ -39,4 +39,7 @@
 /* Enable turbo */
 void enable_turbo(void);
 
+/* Disable turbo */
+void disable_turbo(void);
+
 #endif

-- 
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Gerrit-MessageType: newchange
Gerrit-Change-Id: If3e387e16e9fa6f63cb0ffff6ab2759b447e7c5c
Gerrit-PatchSet: 1
Gerrit-Project: coreboot
Gerrit-Branch: master
Gerrit-Owner: Subrata Banik <subrata.banik at intel.com>