1 files changed, 90 insertions, 0 deletions
diff --git a/src/cpu/intel/turbo/turbo.c b/src/cpu/intel/turbo/turbo.c
new file mode 100644
index 0000000000..779550e26b
--- /dev/null
+++ b/src/cpu/intel/turbo/turbo.c
@@ -0,0 +1,90 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2011 The ChromiumOS Authors. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; version 2 of
+ * the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#include <console/console.h>
+#include <cpu/intel/turbo.h>
+#include <cpu/x86/msr.h>
+#include <arch/cpu.h>
+
+static int turbo_state = TURBO_UNKNOWN;
+
+static const char *turbo_state_desc[] = {
+	[TURBO_UNKNOWN]		= "unknown",
+	[TURBO_UNAVAILABLE]	= "unavailable",
+	[TURBO_DISABLED]	= "available but hidden",
+	[TURBO_ENABLED]		= "available and visible"
+};
+
+/*
+ * Determine the current state of Turbo and cache it for later.
+ * Turbo is a package level config so it does not need to be
+ * enabled on every core.
+ */
+int get_turbo_state(void)
+{
+	struct cpuid_result cpuid_regs;
+	int turbo_en, turbo_cap;
+	msr_t msr;
+
+	/* Return cached state if available */
+	if (turbo_state != TURBO_UNKNOWN)
+		return turbo_state;
+
+	cpuid_regs = cpuid(CPUID_LEAF_PM);
+	turbo_cap = !!(cpuid_regs.eax & PM_CAP_TURBO_MODE);
+
+	msr = rdmsr(MSR_IA32_MISC_ENABLES);
+	turbo_en = !(msr.hi & H_MISC_DISABLE_TURBO);
+
+	if (!turbo_cap && turbo_en) {
+		/* Unavailable */
+		turbo_state = TURBO_UNAVAILABLE;
+	} else if (!turbo_cap && !turbo_en) {
+		/* Available but disabled */
+		turbo_state = TURBO_DISABLED;
+	} else if (turbo_cap && turbo_en) {
+		/* Available */
+		turbo_state = TURBO_ENABLED;
+	}
+
+	printk(BIOS_INFO, "Turbo is %s\n", turbo_state_desc[turbo_state]);
+	return turbo_state;
+}
+
+/*
+ * Try to enable Turbo mode.
+ */
+void enable_turbo(void)
+{
+	msr_t msr;
+
+	/* Only possible if turbo is available but hidden */
+	if (get_turbo_state() == TURBO_DISABLED) {
+		/* Clear 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 */
+		turbo_state = TURBO_ENABLED;
+		printk(BIOS_INFO, "Turbo has been enabled\n");
+	}
+}