arm: tegra: whistler/ventana: dynamic cpufreq governor

To improve the power consumption situation for MP3 playback
the scaling governor is set to conservative when display
is turned off and the default governor is saved. The governor
is restored when display is turned on.

Bug 817727

(cherry picked from commit 4c0e831af450f0e5af65e8d09c8d347d23073b65)
(cherry picked from http://git-master/r/35000)

Change-Id: I73fc9e2851eae36c488e17cb97423c44101e1ba5
Reviewed-on: http://git-master/r/37187
Reviewed-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Tested-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

4 files changed, 178 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/board-ventana-panel.c b/arch/arm/mach-tegra/board-ventana-panel.c
index 66bea3b0a9c7..0194ebfa036c 100644
--- a/arch/arm/mach-tegra/board-ventana-panel.c
+++ b/arch/arm/mach-tegra/board-ventana-panel.c
@@ -32,6 +32,7 @@
 #include <mach/iomap.h>
 #include <mach/dc.h>
 #include <mach/fb.h>
+#include <mach/tegra_cpufreq.h>
 
 #include "devices.h"
 #include "gpio-names.h"
@@ -336,12 +337,22 @@ static void ventana_panel_early_suspend(struct early_suspend *h)
 {
 	if (num_registered_fb > 0)
 		fb_blank(registered_fb[0], FB_BLANK_POWERDOWN);
+#ifdef CONFIG_CPU_FREQ
+	cpufreq_save_default_governor();
+	cpufreq_set_conservative_governor();
+	cpufreq_set_conservative_governor_param(
+		SET_CONSERVATIVE_GOVERNOR_UP_THRESHOLD,
+		SET_CONSERVATIVE_GOVERNOR_DOWN_THRESHOLD);
+#endif
 }
 
 static void ventana_panel_late_resume(struct early_suspend *h)
 {
 	if (num_registered_fb > 0)
 		fb_blank(registered_fb[0], FB_BLANK_UNBLANK);
+#ifdef CONFIG_CPU_FREQ
+	cpufreq_restore_default_governor();
+#endif
 }
 #endif
 
diff --git a/arch/arm/mach-tegra/board-whistler-panel.c b/arch/arm/mach-tegra/board-whistler-panel.c
index 9cc797739149..fdf3960d4684 100644
--- a/arch/arm/mach-tegra/board-whistler-panel.c
+++ b/arch/arm/mach-tegra/board-whistler-panel.c
@@ -25,6 +25,7 @@
 #include <asm/mach-types.h>
 #include <linux/platform_device.h>
 #include <linux/earlysuspend.h>
+#include <linux/kernel.h>
 #include <linux/pwm_backlight.h>
 #include <linux/tegra_pwm_bl.h>
 #include <mach/nvhost.h>
@@ -33,6 +34,7 @@
 #include <mach/iomap.h>
 #include <mach/dc.h>
 #include <mach/fb.h>
+#include <mach/tegra_cpufreq.h>
 
 #include "devices.h"
 #include "gpio-names.h"
@@ -299,6 +301,13 @@ static void whistler_panel_early_suspend(struct early_suspend *h)
 	unsigned i;
 	for (i = 0; i < num_registered_fb; i++)
 		fb_blank(registered_fb[i], FB_BLANK_POWERDOWN);
+#ifdef CONFIG_CPU_FREQ
+	cpufreq_save_default_governor();
+	cpufreq_set_conservative_governor();
+	cpufreq_set_conservative_governor_param(
+		SET_CONSERVATIVE_GOVERNOR_UP_THRESHOLD,
+		SET_CONSERVATIVE_GOVERNOR_DOWN_THRESHOLD);
+#endif
 }
 
 static void whistler_panel_late_resume(struct early_suspend *h)
@@ -306,6 +315,9 @@ static void whistler_panel_late_resume(struct early_suspend *h)
 	unsigned i;
 	for (i = 0; i < num_registered_fb; i++)
 		fb_blank(registered_fb[i], FB_BLANK_UNBLANK);
+#ifdef CONFIG_CPU_FREQ
+	cpufreq_restore_default_governor();
+#endif
 }
 #endif
 
diff --git a/arch/arm/mach-tegra/common.c b/arch/arm/mach-tegra/common.c
index e36af7691fc3..51aa082a45dd 100644
--- a/arch/arm/mach-tegra/common.c
+++ b/arch/arm/mach-tegra/common.c
@@ -36,6 +36,7 @@
 #include <mach/dma.h>
 #include <mach/powergate.h>
 #include <mach/system.h>
+#include <mach/tegra_cpufreq.h>
 
 #include "apbio.h"
 #include "board.h"
@@ -496,3 +497,124 @@ void __init tegra_reserve(unsigned long carveout_size, unsigned long fb_size,
 		tegra_carveout_start,
 		tegra_carveout_start + tegra_carveout_size - 1);
 }
+
+#if defined CONFIG_HAS_EARLYSUSPEND && defined CONFIG_CPU_FREQ
+static char cpufreq_gov_default[32];
+static char *cpufreq_gov_conservative = "conservative";
+static char *cpufreq_sysfs_place_holder="/sys/devices/system/cpu/cpu%i/cpufreq/scaling_governor";
+static char *cpufreq_gov_conservative_param="/sys/devices/system/cpu/cpufreq/conservative/%s";
+
+static void cpufreq_set_governor(char *governor)
+{
+	struct file *scaling_gov = NULL;
+	char    buf[128];
+	int i;
+	loff_t offset = 0;
+
+	if (governor == NULL)
+		return;
+
+	for_each_cpu(i, cpu_present_mask) {
+		sprintf(buf, cpufreq_sysfs_place_holder, i);
+		scaling_gov = filp_open(buf, O_RDWR, 0);
+		if (scaling_gov != NULL) {
+			if (scaling_gov->f_op != NULL &&
+				scaling_gov->f_op->write != NULL)
+				scaling_gov->f_op->write(scaling_gov,
+						governor,
+						strlen(governor),
+						&offset);
+			else
+				pr_err("f_op might be null\n");
+
+			filp_close(scaling_gov, NULL);
+		} else {
+			pr_err("%s. Can't open %s\n", __func__, buf);
+		}
+	}
+}
+
+void cpufreq_save_default_governor(void)
+{
+	struct file *scaling_gov = NULL;
+	char    buf[128];
+	loff_t offset = 0;
+
+	buf[127] = 0;
+	sprintf(buf, cpufreq_sysfs_place_holder,0);
+	scaling_gov = filp_open(buf, O_RDONLY, 0);
+	if (scaling_gov != NULL) {
+		if (scaling_gov->f_op != NULL &&
+			scaling_gov->f_op->read != NULL)
+			scaling_gov->f_op->read(scaling_gov,
+					cpufreq_gov_default,
+					32,
+					&offset);
+		else
+			pr_err("f_op might be null\n");
+
+		filp_close(scaling_gov, NULL);
+	} else {
+		pr_err("%s. Can't open %s\n", __func__, buf);
+	}
+}
+
+void cpufreq_restore_default_governor(void)
+{
+	cpufreq_set_governor(cpufreq_gov_default);
+}
+
+void cpufreq_set_conservative_governor_param(int up_th, int down_th)
+{
+	struct file *gov_param = NULL;
+	static char buf[128],parm[8];
+	loff_t offset = 0;
+
+	if (up_th <= down_th) {
+		printk(KERN_ERR "%s: up_th(%d) is lesser than down_th(%d)\n",
+			__func__, up_th, down_th);
+		return;
+	}
+
+	sprintf(parm, "%d", up_th);
+	sprintf(buf, cpufreq_gov_conservative_param ,"up_threshold");
+	gov_param = filp_open(buf, O_RDONLY, 0);
+	if (gov_param != NULL) {
+		if (gov_param->f_op != NULL &&
+			gov_param->f_op->write != NULL)
+			gov_param->f_op->write(gov_param,
+					parm,
+					strlen(parm),
+					&offset);
+		else
+			pr_err("f_op might be null\n");
+
+		filp_close(gov_param, NULL);
+	} else {
+		pr_err("%s. Can't open %s\n", __func__, buf);
+	}
+
+	sprintf(parm, "%d", down_th);
+	sprintf(buf, cpufreq_gov_conservative_param ,"down_threshold");
+	gov_param = filp_open(buf, O_RDONLY, 0);
+	if (gov_param != NULL) {
+		if (gov_param->f_op != NULL &&
+			gov_param->f_op->write != NULL)
+			gov_param->f_op->write(gov_param,
+					parm,
+					strlen(parm),
+					&offset);
+		else
+			pr_err("f_op might be null\n");
+
+		filp_close(gov_param, NULL);
+	} else {
+		pr_err("%s. Can't open %s\n", __func__, buf);
+	}
+}
+
+void cpufreq_set_conservative_governor(void)
+{
+	cpufreq_set_governor(cpufreq_gov_conservative);
+}
+#endif
diff --git a/arch/arm/mach-tegra/include/mach/tegra_cpufreq.h b/arch/arm/mach-tegra/include/mach/tegra_cpufreq.h
new file mode 100644
index 000000000000..2812926c6ecd
--- /dev/null
+++ b/arch/arm/mach-tegra/include/mach/tegra_cpufreq.h
@@ -0,0 +1,33 @@
+/*
+ * arch/arm/mach-tegra/include/mach/fb.h
+ *
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * Author:
+ *	Erik Gilling <konkers@google.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+#ifndef __MACH_TEGRA_CPUFREQ_H
+#define __MACH_TEGRA_CPUFREQ_H
+
+#if defined CONFIG_HAS_EARLYSUSPEND && defined CONFIG_CPU_FREQ
+#define SET_CONSERVATIVE_GOVERNOR_UP_THRESHOLD 95
+#define SET_CONSERVATIVE_GOVERNOR_DOWN_THRESHOLD 50
+
+void cpufreq_save_default_governor(void);
+void cpufreq_restore_default_governor(void);
+void cpufreq_set_conservative_governor(void);
+void cpufreq_set_conservative_governor_param(int up_th, int down_th);
+#endif
+
+#endif