8 files changed, 892 insertions, 6 deletions

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 56a6899..5cc1232 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -625,4 +625,21 @@ int opp_init_cpufreq_table(struct device *dev,
 
 	return 0;
 }
+
+/**
+ * opp_free_cpufreq_table() - free the cpufreq table
+ * @dev:	device for which we do this operation
+ * @table:	table to free
+ *
+ * Free up the table allocated by opp_init_cpufreq_table
+ */
+void opp_free_cpufreq_table(struct device *dev,
+				struct cpufreq_frequency_table **table)
+{
+	if (!table)
+		return;
+
+	kfree(*table);
+	*table = NULL;
+}
 #endif		/* CONFIG_CPU_FREQ */
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index 9fb8485..07711d1 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -99,6 +99,19 @@ config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
 	  Be aware that not all cpufreq drivers support the conservative
 	  governor. If unsure have a look at the help section of the
 	  driver. Fallback governor will be the performance governor.
+
+config CPU_FREQ_DEFAULT_GOV_HOTPLUG
+	bool "hotplug"
+	select CPU_FREQ_GOV_HOTPLUG
+	select CPU_FREQ_GOV_PERFORMANCE
+	help
+	  Use the CPUFreq governor 'hotplug' as default. This allows you
+	  to get a full dynamic frequency capable system with CPU
+	  hotplug support by simply loading your cpufreq low-level
+	  hardware driver.  Be aware that not all cpufreq drivers
+	  support the hotplug governor. If unsure have a look at
+	  the help section of the driver. Fallback governor will be the
+	  performance governor.
 endchoice
 
 config CPU_FREQ_GOV_PERFORMANCE
@@ -184,5 +197,25 @@ depends on X86
 source "drivers/cpufreq/Kconfig.x86"
 endmenu
 
+config CPU_FREQ_GOV_HOTPLUG
+	tristate "'hotplug' cpufreq governor"
+	depends on CPU_FREQ && NO_HZ && HOTPLUG_CPU
+	help
+	  'hotplug' - this driver mimics the frequency scaling behavior
+	  in 'ondemand', but with several key differences.  First is
+	  that frequency transitions use the CPUFreq table directly,
+	  instead of incrementing in a percentage of the maximum
+	  available frequency.  Second 'hotplug' will offline auxillary
+	  CPUs when the system is idle, and online those CPUs once the
+	  system becomes busy again.  This last feature is needed for
+	  architectures which transition to low power states when only
+	  the "master" CPU is online, or for thermally constrained
+	  devices.
+
+	  If you don't have one of these architectures or devices, use
+	  'ondemand' instead.
+
+	  If in doubt, say N.
+
 endif
 endmenu
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index e2fc2d2..6d6a35c 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_CPU_FREQ_GOV_POWERSAVE)	+= cpufreq_powersave.o
 obj-$(CONFIG_CPU_FREQ_GOV_USERSPACE)	+= cpufreq_userspace.o
 obj-$(CONFIG_CPU_FREQ_GOV_ONDEMAND)	+= cpufreq_ondemand.o
 obj-$(CONFIG_CPU_FREQ_GOV_CONSERVATIVE)	+= cpufreq_conservative.o
+obj-$(CONFIG_CPU_FREQ_GOV_HOTPLUG)	+= cpufreq_hotplug.o
 
 # CPUfreq cross-arch helpers
 obj-$(CONFIG_CPU_FREQ_TABLE)		+= freq_table.o
diff --git a/drivers/cpufreq/cpufreq_hotplug.c b/drivers/cpufreq/cpufreq_hotplug.c
new file mode 100644
index 0000000..85aa6d2
--- /dev/null
+++ b/drivers/cpufreq/cpufreq_hotplug.c
@@ -0,0 +1,705 @@
+/*
+ * CPUFreq hotplug governor
+ *
+ * Copyright (C) 2010 Texas Instruments, Inc.
+ *   Mike Turquette <mturquette@ti.com>
+ *   Santosh Shilimkar <santosh.shilimkar@ti.com>
+ *
+ * Based on ondemand governor
+ * Copyright (C)  2001 Russell King
+ *           (C)  2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>,
+ *                     Jun Nakajima <jun.nakajima@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/cpu.h>
+#include <linux/jiffies.h>
+#include <linux/kernel_stat.h>
+#include <linux/mutex.h>
+#include <linux/hrtimer.h>
+#include <linux/tick.h>
+#include <linux/ktime.h>
+#include <linux/sched.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+
+/* greater than 80% avg load across online CPUs increases frequency */
+#define DEFAULT_UP_FREQ_MIN_LOAD			(80)
+
+/* less than 20% avg load across online CPUs decreases frequency */
+#define DEFAULT_DOWN_FREQ_MAX_LOAD			(20)
+
+/* default sampling period (uSec) is bogus; 10x ondemand's default for x86 */
+#define DEFAULT_SAMPLING_PERIOD				(100000)
+
+/* default number of sampling periods to average before hotplug-in decision */
+#define DEFAULT_HOTPLUG_IN_SAMPLING_PERIODS		(5)
+
+/* default number of sampling periods to average before hotplug-out decision */
+#define DEFAULT_HOTPLUG_OUT_SAMPLING_PERIODS		(20)
+
+static void do_dbs_timer(struct work_struct *work);
+static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
+		unsigned int event);
+
+#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_HOTPLUG
+static
+#endif
+struct cpufreq_governor cpufreq_gov_hotplug = {
+       .name                   = "hotplug",
+       .governor               = cpufreq_governor_dbs,
+       .owner                  = THIS_MODULE,
+};
+
+struct cpu_dbs_info_s {
+	cputime64_t prev_cpu_idle;
+	cputime64_t prev_cpu_wall;
+	cputime64_t prev_cpu_nice;
+	struct cpufreq_policy *cur_policy;
+	struct delayed_work work;
+	struct cpufreq_frequency_table *freq_table;
+	int cpu;
+	/*
+	 * percpu mutex that serializes governor limit change with
+	 * do_dbs_timer invocation. We do not want do_dbs_timer to run
+	 * when user is changing the governor or limits.
+	 */
+	struct mutex timer_mutex;
+};
+static DEFINE_PER_CPU(struct cpu_dbs_info_s, hp_cpu_dbs_info);
+
+static unsigned int dbs_enable;	/* number of CPUs using this policy */
+
+/*
+ * dbs_mutex protects data in dbs_tuners_ins from concurrent changes on
+ * different CPUs. It protects dbs_enable in governor start/stop.
+ */
+static DEFINE_MUTEX(dbs_mutex);
+
+static struct workqueue_struct	*khotplug_wq;
+
+static struct dbs_tuners {
+	unsigned int sampling_rate;
+	unsigned int up_threshold;
+	unsigned int down_threshold;
+	unsigned int hotplug_in_sampling_periods;
+	unsigned int hotplug_out_sampling_periods;
+	unsigned int hotplug_load_index;
+	unsigned int *hotplug_load_history;
+	unsigned int ignore_nice;
+	unsigned int io_is_busy;
+} dbs_tuners_ins = {
+	.sampling_rate =		DEFAULT_SAMPLING_PERIOD,
+	.up_threshold =			DEFAULT_UP_FREQ_MIN_LOAD,
+	.down_threshold =		DEFAULT_DOWN_FREQ_MAX_LOAD,
+	.hotplug_in_sampling_periods =	DEFAULT_HOTPLUG_IN_SAMPLING_PERIODS,
+	.hotplug_out_sampling_periods =	DEFAULT_HOTPLUG_OUT_SAMPLING_PERIODS,
+	.hotplug_load_index =		0,
+	.ignore_nice =			0,
+	.io_is_busy =			0,
+};
+
+/*
+ * A corner case exists when switching io_is_busy at run-time: comparing idle
+ * times from a non-io_is_busy period to an io_is_busy period (or vice-versa)
+ * will misrepresent the actual change in system idleness.  We ignore this
+ * corner case: enabling io_is_busy might cause freq increase and disabling
+ * might cause freq decrease, which probably matches the original intent.
+ */
+static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
+{
+        u64 idle_time;
+        u64 iowait_time;
+
+        /* cpufreq-hotplug always assumes CONFIG_NO_HZ */
+        idle_time = get_cpu_idle_time_us(cpu, wall);
+
+	/* add time spent doing I/O to idle time */
+        if (dbs_tuners_ins.io_is_busy) {
+                iowait_time = get_cpu_iowait_time_us(cpu, wall);
+                /* cpufreq-hotplug always assumes CONFIG_NO_HZ */
+                if (iowait_time != -1ULL && idle_time >= iowait_time)
+                        idle_time -= iowait_time;
+        }
+
+        return idle_time;
+}
+
+/************************** sysfs interface ************************/
+
+/* XXX look at global sysfs macros in cpufreq.h, can those be used here? */
+
+/* cpufreq_hotplug Governor Tunables */
+#define show_one(file_name, object)					\
+static ssize_t show_##file_name						\
+(struct kobject *kobj, struct attribute *attr, char *buf)		\
+{									\
+	return sprintf(buf, "%u\n", dbs_tuners_ins.object);		\
+}
+show_one(sampling_rate, sampling_rate);
+show_one(up_threshold, up_threshold);
+show_one(down_threshold, down_threshold);
+show_one(hotplug_in_sampling_periods, hotplug_in_sampling_periods);
+show_one(hotplug_out_sampling_periods, hotplug_out_sampling_periods);
+show_one(ignore_nice_load, ignore_nice);
+show_one(io_is_busy, io_is_busy);
+
+static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b,
+				   const char *buf, size_t count)
+{
+	unsigned int input;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+	if (ret != 1)
+		return -EINVAL;
+
+	mutex_lock(&dbs_mutex);
+	dbs_tuners_ins.sampling_rate = input;
+	mutex_unlock(&dbs_mutex);
+
+	return count;
+}
+
+static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
+				  const char *buf, size_t count)
+{
+	unsigned int input;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+
+	if (ret != 1 || input <= dbs_tuners_ins.down_threshold) {
+		return -EINVAL;
+	}
+
+	mutex_lock(&dbs_mutex);
+	dbs_tuners_ins.up_threshold = input;
+	mutex_unlock(&dbs_mutex);
+
+	return count;
+}
+
+static ssize_t store_down_threshold(struct kobject *a, struct attribute *b,
+				  const char *buf, size_t count)
+{
+	unsigned int input;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+
+	if (ret != 1 || input >= dbs_tuners_ins.up_threshold) {
+		return -EINVAL;
+	}
+
+	mutex_lock(&dbs_mutex);
+	dbs_tuners_ins.down_threshold = input;
+	mutex_unlock(&dbs_mutex);
+
+	return count;
+}
+
+static ssize_t store_hotplug_in_sampling_periods(struct kobject *a,
+		struct attribute *b, const char *buf, size_t count)
+{
+	unsigned int input;
+	unsigned int *temp;
+	unsigned int max_windows;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+
+	if (ret != 1)
+		return -EINVAL;
+
+	/* already using this value, bail out */
+	if (input == dbs_tuners_ins.hotplug_in_sampling_periods)
+		return count;
+
+	mutex_lock(&dbs_mutex);
+	ret = count;
+	max_windows = max(dbs_tuners_ins.hotplug_in_sampling_periods,
+			dbs_tuners_ins.hotplug_out_sampling_periods);
+
+	/* no need to resize array */
+	if (input <= max_windows) {
+		dbs_tuners_ins.hotplug_in_sampling_periods = input;
+		goto out;
+	}
+
+	/* resize array */
+	temp = kmalloc((sizeof(unsigned int) * input), GFP_KERNEL);
+
+	if (!temp || IS_ERR(temp)) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	memcpy(temp, dbs_tuners_ins.hotplug_load_history,
+			(max_windows * sizeof(unsigned int)));
+	kfree(dbs_tuners_ins.hotplug_load_history);
+
+	/* replace old buffer, old number of sampling periods & old index */
+	dbs_tuners_ins.hotplug_load_history = temp;
+	dbs_tuners_ins.hotplug_in_sampling_periods = input;
+	dbs_tuners_ins.hotplug_load_index = max_windows;
+out:
+	mutex_unlock(&dbs_mutex);
+
+	return ret;
+}
+
+static ssize_t store_hotplug_out_sampling_periods(struct kobject *a,
+		struct attribute *b, const char *buf, size_t count)
+{
+	unsigned int input;
+	unsigned int *temp;
+	unsigned int max_windows;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+
+	if (ret != 1)
+		return -EINVAL;
+
+	/* already using this value, bail out */
+	if (input == dbs_tuners_ins.hotplug_out_sampling_periods)
+		return count;
+
+	mutex_lock(&dbs_mutex);
+	ret = count;
+	max_windows = max(dbs_tuners_ins.hotplug_in_sampling_periods,
+			dbs_tuners_ins.hotplug_out_sampling_periods);
+
+	/* no need to resize array */
+	if (input <= max_windows) {
+		dbs_tuners_ins.hotplug_out_sampling_periods = input;
+		goto out;
+	}
+
+	/* resize array */
+	temp = kmalloc((sizeof(unsigned int) * input), GFP_KERNEL);
+
+	if (!temp || IS_ERR(temp)) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	memcpy(temp, dbs_tuners_ins.hotplug_load_history,
+			(max_windows * sizeof(unsigned int)));
+	kfree(dbs_tuners_ins.hotplug_load_history);
+
+	/* replace old buffer, old number of sampling periods & old index */
+	dbs_tuners_ins.hotplug_load_history = temp;
+	dbs_tuners_ins.hotplug_out_sampling_periods = input;
+	dbs_tuners_ins.hotplug_load_index = max_windows;
+out:
+	mutex_unlock(&dbs_mutex);
+
+	return ret;
+}
+
+static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b,
+				      const char *buf, size_t count)
+{
+	unsigned int input;
+	int ret;
+
+	unsigned int j;
+
+	ret = sscanf(buf, "%u", &input);
+	if (ret != 1)
+		return -EINVAL;
+
+	if (input > 1)
+		input = 1;
+
+	mutex_lock(&dbs_mutex);
+	if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */
+		mutex_unlock(&dbs_mutex);
+		return count;
+	}
+	dbs_tuners_ins.ignore_nice = input;
+
+	/* we need to re-evaluate prev_cpu_idle */
+	for_each_online_cpu(j) {
+		struct cpu_dbs_info_s *dbs_info;
+		dbs_info = &per_cpu(hp_cpu_dbs_info, j);
+		dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
+						&dbs_info->prev_cpu_wall);
+		if (dbs_tuners_ins.ignore_nice)
+			dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
+
+	}
+	mutex_unlock(&dbs_mutex);
+
+	return count;
+}
+
+static ssize_t store_io_is_busy(struct kobject *a, struct attribute *b,
+				   const char *buf, size_t count)
+{
+	unsigned int input;
+	int ret;
+
+	ret = sscanf(buf, "%u", &input);
+	if (ret != 1)
+		return -EINVAL;
+
+	mutex_lock(&dbs_mutex);
+	dbs_tuners_ins.io_is_busy = !!input;
+	mutex_unlock(&dbs_mutex);
+
+	return count;
+}
+
+define_one_global_rw(sampling_rate);
+define_one_global_rw(up_threshold);
+define_one_global_rw(down_threshold);
+define_one_global_rw(hotplug_in_sampling_periods);
+define_one_global_rw(hotplug_out_sampling_periods);
+define_one_global_rw(ignore_nice_load);
+define_one_global_rw(io_is_busy);
+
+static struct attribute *dbs_attributes[] = {
+	&sampling_rate.attr,
+	&up_threshold.attr,
+	&down_threshold.attr,
+	&hotplug_in_sampling_periods.attr,
+	&hotplug_out_sampling_periods.attr,
+	&ignore_nice_load.attr,
+	&io_is_busy.attr,
+	NULL
+};
+
+static struct attribute_group dbs_attr_group = {
+	.attrs = dbs_attributes,
+	.name = "hotplug",
+};
+
+/************************** sysfs end ************************/
+
+static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
+{
+	/* combined load of all enabled CPUs */
+	unsigned int total_load = 0;
+	/* single largest CPU load */
+	unsigned int max_load = 0;
+	/* average load across all enabled CPUs */
+	unsigned int avg_load = 0;
+	/* average load across multiple sampling periods for hotplug events */
+	unsigned int hotplug_in_avg_load = 0;
+	unsigned int hotplug_out_avg_load = 0;
+	/* number of sampling periods averaged for hotplug decisions */
+	unsigned int periods;
+
+	struct cpufreq_policy *policy;
+	unsigned int index = 0;
+	unsigned int i, j;
+
+	policy = this_dbs_info->cur_policy;
+
+	/*
+	 * cpu load accounting
+	 * get highest load, total load and average load across all CPUs
+	 */
+	for_each_cpu(j, policy->cpus) {
+		unsigned int load;
+		unsigned int idle_time, wall_time;
+		cputime64_t cur_wall_time, cur_idle_time;
+		struct cpu_dbs_info_s *j_dbs_info;
+
+		j_dbs_info = &per_cpu(hp_cpu_dbs_info, j);
+
+		/* update both cur_idle_time and cur_wall_time */
+		cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
+
+		/* how much wall time has passed since last iteration? */
+		wall_time = (unsigned int) cputime64_sub(cur_wall_time,
+				j_dbs_info->prev_cpu_wall);
+		j_dbs_info->prev_cpu_wall = cur_wall_time;
+
+		/* how much idle time has passed since last iteration? */
+		idle_time = (unsigned int) cputime64_sub(cur_idle_time,
+				j_dbs_info->prev_cpu_idle);
+		j_dbs_info->prev_cpu_idle = cur_idle_time;
+
+		if (unlikely(!wall_time || wall_time < idle_time))
+			continue;
+
+		/* load is the percentage of time not spent in idle */
+		load = 100 * (wall_time - idle_time) / wall_time;
+
+		/* keep track of combined load across all CPUs */
+		total_load += load;
+
+		/* keep track of highest single load across all CPUs */
+		if (load > max_load)
+			max_load = load;
+	}
+
+	/* calculate the average load across all related CPUs */
+	avg_load = total_load / num_online_cpus();
+
+
+	/*
+	 * hotplug load accounting
+	 * average load over multiple sampling periods
+	 */
+
+	/* how many sampling periods do we use for hotplug decisions? */
+	periods = max(dbs_tuners_ins.hotplug_in_sampling_periods,
+			dbs_tuners_ins.hotplug_out_sampling_periods);
+
+	/* store avg_load in the circular buffer */
+	dbs_tuners_ins.hotplug_load_history[dbs_tuners_ins.hotplug_load_index]
+		= avg_load;
+
+	/* compute average load across in & out sampling periods */
+	for (i = 0, j = dbs_tuners_ins.hotplug_load_index;
+			i < periods; i++, j--) {
+		if (i < dbs_tuners_ins.hotplug_in_sampling_periods)
+			hotplug_in_avg_load +=
+				dbs_tuners_ins.hotplug_load_history[j];
+		if (i < dbs_tuners_ins.hotplug_out_sampling_periods)
+			hotplug_out_avg_load +=
+				dbs_tuners_ins.hotplug_load_history[j];
+
+		if (j == 0)
+			j = periods;
+	}
+
+	hotplug_in_avg_load = hotplug_in_avg_load /
+		dbs_tuners_ins.hotplug_in_sampling_periods;
+
+	hotplug_out_avg_load = hotplug_out_avg_load /
+		dbs_tuners_ins.hotplug_out_sampling_periods;
+
+	/* return to first element if we're at the circular buffer's end */
+	if (++dbs_tuners_ins.hotplug_load_index == periods)
+		dbs_tuners_ins.hotplug_load_index = 0;
+
+	/* check for frequency increase */
+	if (avg_load > dbs_tuners_ins.up_threshold) {
+		/* should we enable auxillary CPUs? */
+		if (num_online_cpus() < 2 && hotplug_in_avg_load >
+				dbs_tuners_ins.up_threshold) {
+			/* hotplug with cpufreq is nasty
+			 * a call to cpufreq_governor_dbs may cause a lockup.
+			 * wq is not running here so its safe.
+			 */
+			mutex_unlock(&this_dbs_info->timer_mutex);
+			cpu_up(1);
+			mutex_lock(&this_dbs_info->timer_mutex);
+			goto out;
+		}
+
+		/* increase to highest frequency supported */
+		if (policy->cur < policy->max)
+			__cpufreq_driver_target(policy, policy->max,
+					CPUFREQ_RELATION_H);
+
+		goto out;
+	}
+
+	/* check for frequency decrease */
+	if (avg_load < dbs_tuners_ins.down_threshold) {
+		/* are we at the minimum frequency already? */
+		if (policy->cur == policy->min) {
+			/* should we disable auxillary CPUs? */
+			if (num_online_cpus() > 1 && hotplug_out_avg_load <
+					dbs_tuners_ins.down_threshold) {
+				mutex_unlock(&this_dbs_info->timer_mutex);
+				cpu_down(1);
+				mutex_lock(&this_dbs_info->timer_mutex);
+			}
+			goto out;
+		}
+
+		/* bump down to the next lowest frequency in the table */
+		if (cpufreq_frequency_table_next_lowest(policy,
+					this_dbs_info->freq_table, &index)) {
+			pr_err("%s: failed to get next lowest frequency\n",
+					__func__);
+			goto out;
+		}
+
+		__cpufreq_driver_target(policy,
+				this_dbs_info->freq_table[index].frequency,
+				CPUFREQ_RELATION_L);
+	}
+out:
+	return;
+}
+
+static void do_dbs_timer(struct work_struct *work)
+{
+	struct cpu_dbs_info_s *dbs_info =
+		container_of(work, struct cpu_dbs_info_s, work.work);
+	unsigned int cpu = dbs_info->cpu;
+
+	/* We want all related CPUs to do sampling nearly on same jiffy */
+	int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
+
+	mutex_lock(&dbs_info->timer_mutex);
+	dbs_check_cpu(dbs_info);
+	queue_delayed_work_on(cpu, khotplug_wq, &dbs_info->work, delay);
+	mutex_unlock(&dbs_info->timer_mutex);
+}
+
+static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
+{
+	/* We want all related CPUs to do sampling nearly on same jiffy */
+	int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
+	delay -= jiffies % delay;
+
+	INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
+	queue_delayed_work_on(dbs_info->cpu, khotplug_wq, &dbs_info->work,
+		delay);
+}
+
+static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
+{
+	cancel_delayed_work_sync(&dbs_info->work);
+}
+
+static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
+				   unsigned int event)
+{
+	unsigned int cpu = policy->cpu;
+	struct cpu_dbs_info_s *this_dbs_info;
+	unsigned int i, j, max_periods;
+	int rc;
+
+	this_dbs_info = &per_cpu(hp_cpu_dbs_info, cpu);
+
+	switch (event) {
+	case CPUFREQ_GOV_START:
+		if ((!cpu_online(cpu)) || (!policy->cur))
+			return -EINVAL;
+
+		mutex_lock(&dbs_mutex);
+		dbs_enable++;
+		for_each_cpu(j, policy->cpus) {
+			struct cpu_dbs_info_s *j_dbs_info;
+			j_dbs_info = &per_cpu(hp_cpu_dbs_info, j);
+			j_dbs_info->cur_policy = policy;
+
+			j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
+						&j_dbs_info->prev_cpu_wall);
+			if (dbs_tuners_ins.ignore_nice) {
+				j_dbs_info->prev_cpu_nice =
+						kstat_cpu(j).cpustat.nice;
+			}
+
+			max_periods = max(DEFAULT_HOTPLUG_IN_SAMPLING_PERIODS,
+					DEFAULT_HOTPLUG_OUT_SAMPLING_PERIODS);
+			dbs_tuners_ins.hotplug_load_history = kmalloc(
+					(sizeof(unsigned int) * max_periods),
+					GFP_KERNEL);
+			if (!dbs_tuners_ins.hotplug_load_history) {
+				WARN_ON(1);
+				return -ENOMEM;
+			}
+			for (i = 0; i < max_periods; i++)
+				dbs_tuners_ins.hotplug_load_history[i] = 50;
+		}
+		this_dbs_info->cpu = cpu;
+		this_dbs_info->freq_table = cpufreq_frequency_get_table(cpu);
+		/*
+		 * Start the timerschedule work, when this governor
+		 * is used for first time
+		 */
+		if (dbs_enable == 1) {
+			rc = sysfs_create_group(cpufreq_global_kobject,
+						&dbs_attr_group);
+			if (rc) {
+				mutex_unlock(&dbs_mutex);
+				return rc;
+			}
+		}
+		mutex_unlock(&dbs_mutex);
+
+		mutex_init(&this_dbs_info->timer_mutex);
+		dbs_timer_init(this_dbs_info);
+		break;
+
+	case CPUFREQ_GOV_STOP:
+		dbs_timer_exit(this_dbs_info);
+
+		mutex_lock(&dbs_mutex);
+		mutex_destroy(&this_dbs_info->timer_mutex);
+		dbs_enable--;
+		mutex_unlock(&dbs_mutex);
+		if (!dbs_enable)
+			sysfs_remove_group(cpufreq_global_kobject,
+					   &dbs_attr_group);
+		kfree(dbs_tuners_ins.hotplug_load_history);
+		/*
+		 * XXX BIG CAVEAT: Stopping the governor with CPU1 offline
+		 * will result in it remaining offline until the user onlines
+		 * it again.  It is up to the user to do this (for now).
+		 */
+		break;
+
+	case CPUFREQ_GOV_LIMITS:
+		mutex_lock(&this_dbs_info->timer_mutex);
+		if (policy->max < this_dbs_info->cur_policy->cur)
+			__cpufreq_driver_target(this_dbs_info->cur_policy,
+				policy->max, CPUFREQ_RELATION_H);
+		else if (policy->min > this_dbs_info->cur_policy->cur)
+			__cpufreq_driver_target(this_dbs_info->cur_policy,
+				policy->min, CPUFREQ_RELATION_L);
+		mutex_unlock(&this_dbs_info->timer_mutex);
+		break;
+	}
+	return 0;
+}
+
+static int __init cpufreq_gov_dbs_init(void)
+{
+	int err;
+	cputime64_t wall;
+	u64 idle_time;
+	int cpu = get_cpu();
+
+	idle_time = get_cpu_idle_time_us(cpu, &wall);
+	put_cpu();
+	if (idle_time != -1ULL) {
+		dbs_tuners_ins.up_threshold = DEFAULT_UP_FREQ_MIN_LOAD;
+	} else {
+		pr_err("cpufreq-hotplug: %s: assumes CONFIG_NO_HZ\n",
+				__func__);
+		return -EINVAL;
+	}
+
+	khotplug_wq = create_workqueue("khotplug");
+	if (!khotplug_wq) {
+		pr_err("Creation of khotplug failed\n");
+		return -EFAULT;
+	}
+	err = cpufreq_register_governor(&cpufreq_gov_hotplug);
+	if (err)
+		destroy_workqueue(khotplug_wq);
+
+	return err;
+}
+
+static void __exit cpufreq_gov_dbs_exit(void)
+{
+	cpufreq_unregister_governor(&cpufreq_gov_hotplug);
+	destroy_workqueue(khotplug_wq);
+}
+
+MODULE_AUTHOR("Mike Turquette <mturquette@ti.com>");
+MODULE_DESCRIPTION("'cpufreq_hotplug' - cpufreq governor for dynamic frequency scaling and CPU hotplugging");
+MODULE_LICENSE("GPL");
+
+#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_HOTPLUG
+fs_initcall(cpufreq_gov_dbs_init);
+#else
+module_init(cpufreq_gov_dbs_init);
+#endif
+module_exit(cpufreq_gov_dbs_exit);
diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
index 90431cb..54c4de4 100644
--- a/drivers/cpufreq/freq_table.c
+++ b/drivers/cpufreq/freq_table.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/cpufreq.h>
+#include <linux/err.h>
 
 /*********************************************************************
  *                     FREQUENCY TABLE HELPERS                       *
@@ -171,6 +172,78 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 }
 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
 
+int cpufreq_frequency_table_next_lowest(struct cpufreq_policy *policy,
+		struct cpufreq_frequency_table *table, int *index)
+{
+	unsigned int cur_freq;
+	unsigned int next_lowest_freq;
+	int optimal_index = -1;
+	int i = 0;
+
+	if (!policy || IS_ERR(policy) || !table || IS_ERR(table) ||
+			!index || IS_ERR(index))
+		return -ENOMEM;
+
+	cur_freq = policy->cur;
+	next_lowest_freq = policy->min;
+
+	/* we're at the lowest frequency in the table already, bail out */
+	if (cur_freq == policy->min)
+		return -EINVAL;
+
+	/* walk the list, find closest freq to cur_freq that is below it */
+	while(table[i].frequency != CPUFREQ_TABLE_END) {
+		if (table[i].frequency < cur_freq &&
+				table[i].frequency >= next_lowest_freq) {
+			next_lowest_freq = table[i].frequency;
+			optimal_index = table[i].index;
+		}
+
+		i++;
+	}
+
+	*index = optimal_index;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cpufreq_frequency_table_next_lowest);
+
+int cpufreq_frequency_table_next_highest(struct cpufreq_policy *policy,
+		struct cpufreq_frequency_table *table, int *index)
+{
+	unsigned int cur_freq;
+	unsigned int next_higher_freq;
+	int optimal_index = -1;
+	int i = 0;
+
+	if (!policy || IS_ERR(policy) || !table || IS_ERR(table) ||
+			!index || IS_ERR(index))
+		return -ENOMEM;
+
+	cur_freq = policy->cur;
+	next_higher_freq = policy->max;
+
+	/* we're at the highest frequency in the table already, bail out */
+	if (cur_freq == policy->max)
+		return -EINVAL;
+
+	/* walk the list, find closest freq to cur_freq that is above it */
+	while(table[i].frequency != CPUFREQ_TABLE_END) {
+		if (table[i].frequency > cur_freq &&
+				table[i].frequency <= next_higher_freq) {
+			next_higher_freq = table[i].frequency;
+			optimal_index = table[i].index;
+		}
+
+		i++;
+	}
+
+	*index = optimal_index;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cpufreq_frequency_table_next_highest);
+
 static DEFINE_PER_CPU(struct cpufreq_frequency_table *, cpufreq_show_table);
 /**
  * show_available_freqs - show available frequencies for the specified CPU
diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index 01f74a8..13ca564 100644
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -73,6 +73,8 @@ struct omap3_gpio_regs {
 static struct omap3_gpio_regs gpio_context[OMAP34XX_NR_GPIOS];
 #endif
 
+#include <plat/omap_device.h>
+
 /*
  * TODO: Cleanup gpio_bank usage as it is having information
  * related to all instances of the device
@@ -1748,6 +1750,7 @@ void omap2_gpio_prepare_for_idle(int off_mode)
 {
 	int i, c = 0;
 	int min = 0;
+	struct platform_device *pdev;
 
 	if (cpu_is_omap34xx())
 		min = 1;
@@ -1760,6 +1763,9 @@ void omap2_gpio_prepare_for_idle(int off_mode)
 		for (j = 0; j < hweight_long(bank->dbck_enable_mask); j++)
 			clk_disable(bank->dbck);
 
+		 pdev = to_platform_device(bank->dev);
+		 omap_device_idle(pdev);
+
 		if (!off_mode)
 			continue;
 
@@ -1817,6 +1823,7 @@ void omap2_gpio_resume_after_idle(void)
 {
 	int i;
 	int min = 0;
+	struct platform_device *pdev;
 
 	if (cpu_is_omap34xx())
 		min = 1;
@@ -1825,6 +1832,9 @@ void omap2_gpio_resume_after_idle(void)
 		u32 l = 0, gen, gen0, gen1;
 		int j;
 
+		pdev = to_platform_device(bank->dev);
+		omap_device_enable(pdev);
+
 		for (j = 0; j < hweight_long(bank->dbck_enable_mask); j++)
 			clk_enable(bank->dbck);
 
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 58a58c7..ab9833b 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -1142,18 +1142,16 @@ omap_i2c_remove(struct platform_device *pdev)
 #ifdef CONFIG_SUSPEND
 static int omap_i2c_suspend(struct device *dev)
 {
-	if (!pm_runtime_suspended(dev))
-		if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend)
-			dev->bus->pm->runtime_suspend(dev);
+	if (dev->power.runtime_auto == false)
+		pm_runtime_put_sync(dev);
 
 	return 0;
 }
 
 static int omap_i2c_resume(struct device *dev)
 {
-	if (!pm_runtime_suspended(dev))
-		if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_resume)
-			dev->bus->pm->runtime_resume(dev);
+	if (dev->power.runtime_auto == false)
+		pm_runtime_get_sync(dev);
 
 	return 0;
 }
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 47cadf4..0275c28 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1335,6 +1335,55 @@ static struct platform_driver serial_omap_driver = {
 	},
 };
 
+int omap_uart_active(int num, u32 timeout)
+{
+	struct uart_omap_port *up = ui[num];
+	struct circ_buf *xmit;
+	unsigned int status;
+
+	if(num >= OMAP_MAX_HSUART_PORTS)
+		return 0;
+
+	/* Though when UART's initialised this can never happen,
+	 * but during initialisation, it can happen the "ui"
+	 * structure is not initialized and the timer kicks
+	 * in. This would result in a NULL value, resulting
+	 * in crash.
+	 */
+	up = ui[num];
+	if (up == NULL)
+		return 0;
+
+	if (!up->port_activity)
+		return 1;
+
+	/* Check for recent driver activity. If time delta from now
+	 * to last activty < "uart idle timeout" second keep clocks on.
+	 */
+	if (((jiffies - up->port_activity) < timeout))
+		return 1;
+
+	xmit = &up->port.state->xmit;
+	if (!(uart_circ_empty(xmit) || uart_tx_stopped(&up->port)))
+		return 1;
+
+	status = serial_in(up, UART_LSR);
+	/* TX hardware not empty */
+	if (!(status & (UART_LSR_TEMT | UART_LSR_THRE)))
+		return 1;
+
+	/* Any rx activity? */
+	if (status & UART_LSR_DR)
+		return 1;
+
+	/* Check if DMA channels are active */
+	if (up->use_dma && (up->uart_dma.rx_dma_channel != OMAP_UART_DMA_CH_FREE ||
+		up->uart_dma.tx_dma_channel != OMAP_UART_DMA_CH_FREE))
+		return 1;
+	return 0;
+}
+EXPORT_SYMBOL(omap_uart_active);
+
 static int __init serial_omap_init(void)
 {
 	int ret;