Initial import

1 files changed, 449 insertions, 0 deletions

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
new file mode 100644
index 000000000..1b44496b2
--- /dev/null
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -0,0 +1,449 @@
+/*
+ * drivers/cpufreq/cpufreq_governor.c
+ *
+ * CPUFREQ governors common code
+ *
+ * Copyright	(C) 2001 Russell King
+ *		(C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
+ *		(C) 2003 Jun Nakajima <jun.nakajima@intel.com>
+ *		(C) 2009 Alexander Clouter <alex@digriz.org.uk>
+ *		(c) 2012 Viresh Kumar <viresh.kumar@linaro.org>
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/export.h>
+#include <linux/kernel_stat.h>
+#include <linux/slab.h>
+
+#include "cpufreq_governor.h"
+
+static struct attribute_group *get_sysfs_attr(struct dbs_data *dbs_data)
+{
+	if (have_governor_per_policy())
+		return dbs_data->cdata->attr_group_gov_pol;
+	else
+		return dbs_data->cdata->attr_group_gov_sys;
+}
+
+void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
+{
+	struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
+	struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+	struct cpufreq_policy *policy;
+	unsigned int sampling_rate;
+	unsigned int max_load = 0;
+	unsigned int ignore_nice;
+	unsigned int j;
+
+	if (dbs_data->cdata->governor == GOV_ONDEMAND) {
+		struct od_cpu_dbs_info_s *od_dbs_info =
+				dbs_data->cdata->get_cpu_dbs_info_s(cpu);
+
+		/*
+		 * Sometimes, the ondemand governor uses an additional
+		 * multiplier to give long delays. So apply this multiplier to
+		 * the 'sampling_rate', so as to keep the wake-up-from-idle
+		 * detection logic a bit conservative.
+		 */
+		sampling_rate = od_tuners->sampling_rate;
+		sampling_rate *= od_dbs_info->rate_mult;
+
+		ignore_nice = od_tuners->ignore_nice_load;
+	} else {
+		sampling_rate = cs_tuners->sampling_rate;
+		ignore_nice = cs_tuners->ignore_nice_load;
+	}
+
+	policy = cdbs->cur_policy;
+
+	/* Get Absolute Load */
+	for_each_cpu(j, policy->cpus) {
+		struct cpu_dbs_common_info *j_cdbs;
+		u64 cur_wall_time, cur_idle_time;
+		unsigned int idle_time, wall_time;
+		unsigned int load;
+		int io_busy = 0;
+
+		j_cdbs = dbs_data->cdata->get_cpu_cdbs(j);
+
+		/*
+		 * For the purpose of ondemand, waiting for disk IO is
+		 * an indication that you're performance critical, and
+		 * not that the system is actually idle. So do not add
+		 * the iowait time to the cpu idle time.
+		 */
+		if (dbs_data->cdata->governor == GOV_ONDEMAND)
+			io_busy = od_tuners->io_is_busy;
+		cur_idle_time = get_cpu_idle_time(j, &cur_wall_time, io_busy);
+
+		wall_time = (unsigned int)
+			(cur_wall_time - j_cdbs->prev_cpu_wall);
+		j_cdbs->prev_cpu_wall = cur_wall_time;
+
+		idle_time = (unsigned int)
+			(cur_idle_time - j_cdbs->prev_cpu_idle);
+		j_cdbs->prev_cpu_idle = cur_idle_time;
+
+		if (ignore_nice) {
+			u64 cur_nice;
+			unsigned long cur_nice_jiffies;
+
+			cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] -
+					 cdbs->prev_cpu_nice;
+			/*
+			 * Assumption: nice time between sampling periods will
+			 * be less than 2^32 jiffies for 32 bit sys
+			 */
+			cur_nice_jiffies = (unsigned long)
+					cputime64_to_jiffies64(cur_nice);
+
+			cdbs->prev_cpu_nice =
+				kcpustat_cpu(j).cpustat[CPUTIME_NICE];
+			idle_time += jiffies_to_usecs(cur_nice_jiffies);
+		}
+
+		if (unlikely(!wall_time || wall_time < idle_time))
+			continue;
+
+		/*
+		 * If the CPU had gone completely idle, and a task just woke up
+		 * on this CPU now, it would be unfair to calculate 'load' the
+		 * usual way for this elapsed time-window, because it will show
+		 * near-zero load, irrespective of how CPU intensive that task
+		 * actually is. This is undesirable for latency-sensitive bursty
+		 * workloads.
+		 *
+		 * To avoid this, we reuse the 'load' from the previous
+		 * time-window and give this task a chance to start with a
+		 * reasonably high CPU frequency. (However, we shouldn't over-do
+		 * this copy, lest we get stuck at a high load (high frequency)
+		 * for too long, even when the current system load has actually
+		 * dropped down. So we perform the copy only once, upon the
+		 * first wake-up from idle.)
+		 *
+		 * Detecting this situation is easy: the governor's deferrable
+		 * timer would not have fired during CPU-idle periods. Hence
+		 * an unusually large 'wall_time' (as compared to the sampling
+		 * rate) indicates this scenario.
+		 *
+		 * prev_load can be zero in two cases and we must recalculate it
+		 * for both cases:
+		 * - during long idle intervals
+		 * - explicitly set to zero
+		 */
+		if (unlikely(wall_time > (2 * sampling_rate) &&
+			     j_cdbs->prev_load)) {
+			load = j_cdbs->prev_load;
+
+			/*
+			 * Perform a destructive copy, to ensure that we copy
+			 * the previous load only once, upon the first wake-up
+			 * from idle.
+			 */
+			j_cdbs->prev_load = 0;
+		} else {
+			load = 100 * (wall_time - idle_time) / wall_time;
+			j_cdbs->prev_load = load;
+		}
+
+		if (load > max_load)
+			max_load = load;
+	}
+
+	dbs_data->cdata->gov_check_cpu(cpu, max_load);
+}
+EXPORT_SYMBOL_GPL(dbs_check_cpu);
+
+static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data,
+		unsigned int delay)
+{
+	struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
+
+	mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay);
+}
+
+void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
+		unsigned int delay, bool all_cpus)
+{
+	int i;
+
+	mutex_lock(&cpufreq_governor_lock);
+	if (!policy->governor_enabled)
+		goto out_unlock;
+
+	if (!all_cpus) {
+		/*
+		 * Use raw_smp_processor_id() to avoid preemptible warnings.
+		 * We know that this is only called with all_cpus == false from
+		 * works that have been queued with *_work_on() functions and
+		 * those works are canceled during CPU_DOWN_PREPARE so they
+		 * can't possibly run on any other CPU.
+		 */
+		__gov_queue_work(raw_smp_processor_id(), dbs_data, delay);
+	} else {
+		for_each_cpu(i, policy->cpus)
+			__gov_queue_work(i, dbs_data, delay);
+	}
+
+out_unlock:
+	mutex_unlock(&cpufreq_governor_lock);
+}
+EXPORT_SYMBOL_GPL(gov_queue_work);
+
+static inline void gov_cancel_work(struct dbs_data *dbs_data,
+		struct cpufreq_policy *policy)
+{
+	struct cpu_dbs_common_info *cdbs;
+	int i;
+
+	for_each_cpu(i, policy->cpus) {
+		cdbs = dbs_data->cdata->get_cpu_cdbs(i);
+		cancel_delayed_work_sync(&cdbs->work);
+	}
+}
+
+/* Will return if we need to evaluate cpu load again or not */
+bool need_load_eval(struct cpu_dbs_common_info *cdbs,
+		unsigned int sampling_rate)
+{
+	if (policy_is_shared(cdbs->cur_policy)) {
+		ktime_t time_now = ktime_get();
+		s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp);
+
+		/* Do nothing if we recently have sampled */
+		if (delta_us < (s64)(sampling_rate / 2))
+			return false;
+		else
+			cdbs->time_stamp = time_now;
+	}
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(need_load_eval);
+
+static void set_sampling_rate(struct dbs_data *dbs_data,
+		unsigned int sampling_rate)
+{
+	if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
+		struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+		cs_tuners->sampling_rate = sampling_rate;
+	} else {
+		struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+		od_tuners->sampling_rate = sampling_rate;
+	}
+}
+
+int cpufreq_governor_dbs(struct cpufreq_policy *policy,
+		struct common_dbs_data *cdata, unsigned int event)
+{
+	struct dbs_data *dbs_data;
+	struct od_cpu_dbs_info_s *od_dbs_info = NULL;
+	struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
+	struct od_ops *od_ops = NULL;
+	struct od_dbs_tuners *od_tuners = NULL;
+	struct cs_dbs_tuners *cs_tuners = NULL;
+	struct cpu_dbs_common_info *cpu_cdbs;
+	unsigned int sampling_rate, latency, ignore_nice, j, cpu = policy->cpu;
+	int io_busy = 0;
+	int rc;
+
+	if (have_governor_per_policy())
+		dbs_data = policy->governor_data;
+	else
+		dbs_data = cdata->gdbs_data;
+
+	WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT));
+
+	switch (event) {
+	case CPUFREQ_GOV_POLICY_INIT:
+		if (have_governor_per_policy()) {
+			WARN_ON(dbs_data);
+		} else if (dbs_data) {
+			dbs_data->usage_count++;
+			policy->governor_data = dbs_data;
+			return 0;
+		}
+
+		dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
+		if (!dbs_data) {
+			pr_err("%s: POLICY_INIT: kzalloc failed\n", __func__);
+			return -ENOMEM;
+		}
+
+		dbs_data->cdata = cdata;
+		dbs_data->usage_count = 1;
+		rc = cdata->init(dbs_data);
+		if (rc) {
+			pr_err("%s: POLICY_INIT: init() failed\n", __func__);
+			kfree(dbs_data);
+			return rc;
+		}
+
+		if (!have_governor_per_policy())
+			WARN_ON(cpufreq_get_global_kobject());
+
+		rc = sysfs_create_group(get_governor_parent_kobj(policy),
+				get_sysfs_attr(dbs_data));
+		if (rc) {
+			cdata->exit(dbs_data);
+			kfree(dbs_data);
+			return rc;
+		}
+
+		policy->governor_data = dbs_data;
+
+		/* policy latency is in ns. Convert it to us first */
+		latency = policy->cpuinfo.transition_latency / 1000;
+		if (latency == 0)
+			latency = 1;
+
+		/* Bring kernel and HW constraints together */
+		dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
+				MIN_LATENCY_MULTIPLIER * latency);
+		set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate,
+					latency * LATENCY_MULTIPLIER));
+
+		if ((cdata->governor == GOV_CONSERVATIVE) &&
+				(!policy->governor->initialized)) {
+			struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
+
+			cpufreq_register_notifier(cs_ops->notifier_block,
+					CPUFREQ_TRANSITION_NOTIFIER);
+		}
+
+		if (!have_governor_per_policy())
+			cdata->gdbs_data = dbs_data;
+
+		return 0;
+	case CPUFREQ_GOV_POLICY_EXIT:
+		if (!--dbs_data->usage_count) {
+			sysfs_remove_group(get_governor_parent_kobj(policy),
+					get_sysfs_attr(dbs_data));
+
+			if (!have_governor_per_policy())
+				cpufreq_put_global_kobject();
+
+			if ((dbs_data->cdata->governor == GOV_CONSERVATIVE) &&
+				(policy->governor->initialized == 1)) {
+				struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
+
+				cpufreq_unregister_notifier(cs_ops->notifier_block,
+						CPUFREQ_TRANSITION_NOTIFIER);
+			}
+
+			cdata->exit(dbs_data);
+			kfree(dbs_data);
+			cdata->gdbs_data = NULL;
+		}
+
+		policy->governor_data = NULL;
+		return 0;
+	}
+
+	cpu_cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
+
+	if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
+		cs_tuners = dbs_data->tuners;
+		cs_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
+		sampling_rate = cs_tuners->sampling_rate;
+		ignore_nice = cs_tuners->ignore_nice_load;
+	} else {
+		od_tuners = dbs_data->tuners;
+		od_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
+		sampling_rate = od_tuners->sampling_rate;
+		ignore_nice = od_tuners->ignore_nice_load;
+		od_ops = dbs_data->cdata->gov_ops;
+		io_busy = od_tuners->io_is_busy;
+	}
+
+	switch (event) {
+	case CPUFREQ_GOV_START:
+		if (!policy->cur)
+			return -EINVAL;
+
+		mutex_lock(&dbs_data->mutex);
+
+		for_each_cpu(j, policy->cpus) {
+			struct cpu_dbs_common_info *j_cdbs =
+				dbs_data->cdata->get_cpu_cdbs(j);
+			unsigned int prev_load;
+
+			j_cdbs->cpu = j;
+			j_cdbs->cur_policy = policy;
+			j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
+					       &j_cdbs->prev_cpu_wall, io_busy);
+
+			prev_load = (unsigned int)
+				(j_cdbs->prev_cpu_wall - j_cdbs->prev_cpu_idle);
+			j_cdbs->prev_load = 100 * prev_load /
+					(unsigned int) j_cdbs->prev_cpu_wall;
+
+			if (ignore_nice)
+				j_cdbs->prev_cpu_nice =
+					kcpustat_cpu(j).cpustat[CPUTIME_NICE];
+
+			mutex_init(&j_cdbs->timer_mutex);
+			INIT_DEFERRABLE_WORK(&j_cdbs->work,
+					     dbs_data->cdata->gov_dbs_timer);
+		}
+
+		if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
+			cs_dbs_info->down_skip = 0;
+			cs_dbs_info->enable = 1;
+			cs_dbs_info->requested_freq = policy->cur;
+		} else {
+			od_dbs_info->rate_mult = 1;
+			od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
+			od_ops->powersave_bias_init_cpu(cpu);
+		}
+
+		mutex_unlock(&dbs_data->mutex);
+
+		/* Initiate timer time stamp */
+		cpu_cdbs->time_stamp = ktime_get();
+
+		gov_queue_work(dbs_data, policy,
+				delay_for_sampling_rate(sampling_rate), true);
+		break;
+
+	case CPUFREQ_GOV_STOP:
+		if (dbs_data->cdata->governor == GOV_CONSERVATIVE)
+			cs_dbs_info->enable = 0;
+
+		gov_cancel_work(dbs_data, policy);
+
+		mutex_lock(&dbs_data->mutex);
+		mutex_destroy(&cpu_cdbs->timer_mutex);
+		cpu_cdbs->cur_policy = NULL;
+
+		mutex_unlock(&dbs_data->mutex);
+
+		break;
+
+	case CPUFREQ_GOV_LIMITS:
+		mutex_lock(&dbs_data->mutex);
+		if (!cpu_cdbs->cur_policy) {
+			mutex_unlock(&dbs_data->mutex);
+			break;
+		}
+		mutex_lock(&cpu_cdbs->timer_mutex);
+		if (policy->max < cpu_cdbs->cur_policy->cur)
+			__cpufreq_driver_target(cpu_cdbs->cur_policy,
+					policy->max, CPUFREQ_RELATION_H);
+		else if (policy->min > cpu_cdbs->cur_policy->cur)
+			__cpufreq_driver_target(cpu_cdbs->cur_policy,
+					policy->min, CPUFREQ_RELATION_L);
+		dbs_check_cpu(dbs_data, cpu);
+		mutex_unlock(&cpu_cdbs->timer_mutex);
+		mutex_unlock(&dbs_data->mutex);
+		break;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);