New subject: New patch to review for coreboot: 77a6780 Add support for Intel Turbo feature

2 Apr 2012

Stefan Reinauer (stefan.reinauer@coreboot.org) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/844
-gerrit
commit 77a6780c39fbea5ccd89663cb65e80f95bde7310
Author: Stefan Reinauer reinauer@chromium.org
Date:   Mon Apr 2 13:35:09 2012 -0700
Add support for Intel Turbo feature
Change-Id: I166ead7c219083006c2b05859eb18749c6fbe832
    Signed-off-by: Duncan Laurie dlaurie@google.com
    Signed-off-by: Stefan Reinauer reinauer@google.com
---
 src/cpu/intel/turbo/Makefile.inc |    1 +
 src/cpu/intel/turbo/turbo.c      |   90 ++++++++++++++++++++++++++++++++++++++
 src/include/cpu/intel/turbo.h    |   44 ++++++++++++++++++
 3 files changed, 135 insertions(+), 0 deletions(-)

diff --git a/src/cpu/intel/turbo/Makefile.inc b/src/cpu/intel/turbo/Makefile.inc
new file mode 100644
index 0000000..48ec55d
--- /dev/null
+++ b/src/cpu/intel/turbo/Makefile.inc
@@ -0,0 +1 @@
+ramstage-y += turbo.c
diff --git a/src/cpu/intel/turbo/turbo.c b/src/cpu/intel/turbo/turbo.c
new file mode 100644
index 0000000..779550e
--- /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");
+	}
+}
diff --git a/src/include/cpu/intel/turbo.h b/src/include/cpu/intel/turbo.h
new file mode 100644
index 0000000..b60c8cf
--- /dev/null
+++ b/src/include/cpu/intel/turbo.h
@@ -0,0 +1,44 @@
+/*
+ * 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
+ */
+
+#ifndef _CPU_INTEL_TURBO_H
+#define _CPU_INTEL_TURBO_H
+
+#define CPUID_LEAF_PM		6
+#define PM_CAP_TURBO_MODE	(1 << 1)
+
+#define MSR_IA32_MISC_ENABLES	0x1a0
+#define H_MISC_DISABLE_TURBO	(1 << 6)
+
+enum {
+	TURBO_UNKNOWN,
+	TURBO_UNAVAILABLE,
+	TURBO_DISABLED,
+	TURBO_ENABLED,
+};
+
+/* Return current turbo state */
+int get_turbo_state(void);
+
+/* Enable turbo */
+void enable_turbo(void);
+
+#endif

    