1 files changed, 414 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c
new file mode 100644
index 000000000..9a76965fa
--- /dev/null
+++ b/drivers/cpufreq/cpufreq_conservative.c
@@ -0,0 +1,414 @@
+/*
+ *  drivers/cpufreq/cpufreq_conservative.c
+ *
+ *  Copyright (C)  2001 Russell King
+ *            (C)  2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
+ *                      Jun Nakajima <jun.nakajima@intel.com>
+ *            (C)  2009 Alexander Clouter <alex@digriz.org.uk>
+ *
+ * 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/slab.h>
+#include "cpufreq_governor.h"
+
+/* Conservative governor macros */
+#ifdef CONFIG_SCHED_BFS
+#define DEF_FREQUENCY_UP_THRESHOLD		(63)
+#define DEF_FREQUENCY_DOWN_THRESHOLD		(26)
+#else
+#define DEF_FREQUENCY_UP_THRESHOLD		(80)
+#define DEF_FREQUENCY_DOWN_THRESHOLD		(20)
+#endif
+
+#define DEF_FREQUENCY_STEP			(5)
+#define DEF_SAMPLING_DOWN_FACTOR		(1)
+#define MAX_SAMPLING_DOWN_FACTOR		(10)
+
+static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info);
+
+static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners,
+					   struct cpufreq_policy *policy)
+{
+	unsigned int freq_target = (cs_tuners->freq_step * policy->max) / 100;
+
+	/* max freq cannot be less than 100. But who knows... */
+	if (unlikely(freq_target == 0))
+		freq_target = DEF_FREQUENCY_STEP;
+
+	return freq_target;
+}
+
+/*
+ * Every sampling_rate, we check, if current idle time is less than 20%
+ * (default), then we try to increase frequency. Every sampling_rate *
+ * sampling_down_factor, we check, if current idle time is more than 80%
+ * (default), then we try to decrease frequency
+ *
+ * Any frequency increase takes it to the maximum frequency. Frequency reduction
+ * happens at minimum steps of 5% (default) of maximum frequency
+ */
+static void cs_check_cpu(int cpu, unsigned int load)
+{
+	struct cs_cpu_dbs_info_s *dbs_info = &per_cpu(cs_cpu_dbs_info, cpu);
+	struct cpufreq_policy *policy = dbs_info->cdbs.cur_policy;
+	struct dbs_data *dbs_data = policy->governor_data;
+	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+
+	/*
+	 * break out if we 'cannot' reduce the speed as the user might
+	 * want freq_step to be zero
+	 */
+	if (cs_tuners->freq_step == 0)
+		return;
+
+	/* Check for frequency increase */
+	if (load > cs_tuners->up_threshold) {
+		dbs_info->down_skip = 0;
+
+		/* if we are already at full speed then break out early */
+		if (dbs_info->requested_freq == policy->max)
+			return;
+
+		dbs_info->requested_freq += get_freq_target(cs_tuners, policy);
+
+		if (dbs_info->requested_freq > policy->max)
+			dbs_info->requested_freq = policy->max;
+
+		__cpufreq_driver_target(policy, dbs_info->requested_freq,
+			CPUFREQ_RELATION_H);
+		return;
+	}
+
+	/* if sampling_down_factor is active break out early */
+	if (++dbs_info->down_skip < cs_tuners->sampling_down_factor)
+		return;
+	dbs_info->down_skip = 0;
+
+	/* Check for frequency decrease */
+	if (load < cs_tuners->down_threshold) {
+		unsigned int freq_target;
+		/*
+		 * if we cannot reduce the frequency anymore, break out early
+		 */
+		if (policy->cur == policy->min)
+			return;
+
+		freq_target = get_freq_target(cs_tuners, policy);
+		if (dbs_info->requested_freq > freq_target)
+			dbs_info->requested_freq -= freq_target;
+		else
+			dbs_info->requested_freq = policy->min;
+
+		__cpufreq_driver_target(policy, dbs_info->requested_freq,
+				CPUFREQ_RELATION_L);
+		return;
+	}
+}
+
+static void cs_dbs_timer(struct work_struct *work)
+{
+	struct cs_cpu_dbs_info_s *dbs_info = container_of(work,
+			struct cs_cpu_dbs_info_s, cdbs.work.work);
+	unsigned int cpu = dbs_info->cdbs.cur_policy->cpu;
+	struct cs_cpu_dbs_info_s *core_dbs_info = &per_cpu(cs_cpu_dbs_info,
+			cpu);
+	struct dbs_data *dbs_data = dbs_info->cdbs.cur_policy->governor_data;
+	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+	int delay = delay_for_sampling_rate(cs_tuners->sampling_rate);
+	bool modify_all = true;
+
+	mutex_lock(&core_dbs_info->cdbs.timer_mutex);
+	if (!need_load_eval(&core_dbs_info->cdbs, cs_tuners->sampling_rate))
+		modify_all = false;
+	else
+		dbs_check_cpu(dbs_data, cpu);
+
+	gov_queue_work(dbs_data, dbs_info->cdbs.cur_policy, delay, modify_all);
+	mutex_unlock(&core_dbs_info->cdbs.timer_mutex);
+}
+
+static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
+		void *data)
+{
+	struct cpufreq_freqs *freq = data;
+	struct cs_cpu_dbs_info_s *dbs_info =
+					&per_cpu(cs_cpu_dbs_info, freq->cpu);
+	struct cpufreq_policy *policy;
+
+	if (!dbs_info->enable)
+		return 0;
+
+	policy = dbs_info->cdbs.cur_policy;
+
+	/*
+	 * we only care if our internally tracked freq moves outside the 'valid'
+	 * ranges of frequency available to us otherwise we do not change it
+	*/
+	if (dbs_info->requested_freq > policy->max
+			|| dbs_info->requested_freq < policy->min)
+		dbs_info->requested_freq = freq->new;
+
+	return 0;
+}
+
+/************************** sysfs interface ************************/
+static struct common_dbs_data cs_dbs_cdata;
+
+static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data,
+		const char *buf, size_t count)
+{
+	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+	unsigned int input;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+
+	if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
+		return -EINVAL;
+
+	cs_tuners->sampling_down_factor = input;
+	return count;
+}
+
+static ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
+		size_t count)
+{
+	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+	unsigned int input;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+
+	if (ret != 1)
+		return -EINVAL;
+
+	cs_tuners->sampling_rate = max(input, dbs_data->min_sampling_rate);
+	return count;
+}
+
+static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf,
+		size_t count)
+{
+	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+	unsigned int input;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+
+	if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold)
+		return -EINVAL;
+
+	cs_tuners->up_threshold = input;
+	return count;
+}
+
+static ssize_t store_down_threshold(struct dbs_data *dbs_data, const char *buf,
+		size_t count)
+{
+	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+	unsigned int input;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+
+	/* cannot be lower than 11 otherwise freq will not fall */
+	if (ret != 1 || input < 11 || input > 100 ||
+			input >= cs_tuners->up_threshold)
+		return -EINVAL;
+
+	cs_tuners->down_threshold = input;
+	return count;
+}
+
+static ssize_t store_ignore_nice_load(struct dbs_data *dbs_data,
+		const char *buf, size_t count)
+{
+	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+	unsigned int input, j;
+	int ret;
+
+	ret = sscanf(buf, "%u", &input);
+	if (ret != 1)
+		return -EINVAL;
+
+	if (input > 1)
+		input = 1;
+
+	if (input == cs_tuners->ignore_nice_load) /* nothing to do */
+		return count;
+
+	cs_tuners->ignore_nice_load = input;
+
+	/* we need to re-evaluate prev_cpu_idle */
+	for_each_online_cpu(j) {
+		struct cs_cpu_dbs_info_s *dbs_info;
+		dbs_info = &per_cpu(cs_cpu_dbs_info, j);
+		dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
+					&dbs_info->cdbs.prev_cpu_wall, 0);
+		if (cs_tuners->ignore_nice_load)
+			dbs_info->cdbs.prev_cpu_nice =
+				kcpustat_cpu(j).cpustat[CPUTIME_NICE];
+	}
+	return count;
+}
+
+static ssize_t store_freq_step(struct dbs_data *dbs_data, const char *buf,
+		size_t count)
+{
+	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+	unsigned int input;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+
+	if (ret != 1)
+		return -EINVAL;
+
+	if (input > 100)
+		input = 100;
+
+	/*
+	 * no need to test here if freq_step is zero as the user might actually
+	 * want this, they would be crazy though :)
+	 */
+	cs_tuners->freq_step = input;
+	return count;
+}
+
+show_store_one(cs, sampling_rate);
+show_store_one(cs, sampling_down_factor);
+show_store_one(cs, up_threshold);
+show_store_one(cs, down_threshold);
+show_store_one(cs, ignore_nice_load);
+show_store_one(cs, freq_step);
+declare_show_sampling_rate_min(cs);
+
+gov_sys_pol_attr_rw(sampling_rate);
+gov_sys_pol_attr_rw(sampling_down_factor);
+gov_sys_pol_attr_rw(up_threshold);
+gov_sys_pol_attr_rw(down_threshold);
+gov_sys_pol_attr_rw(ignore_nice_load);
+gov_sys_pol_attr_rw(freq_step);
+gov_sys_pol_attr_ro(sampling_rate_min);
+
+static struct attribute *dbs_attributes_gov_sys[] = {
+	&sampling_rate_min_gov_sys.attr,
+	&sampling_rate_gov_sys.attr,
+	&sampling_down_factor_gov_sys.attr,
+	&up_threshold_gov_sys.attr,
+	&down_threshold_gov_sys.attr,
+	&ignore_nice_load_gov_sys.attr,
+	&freq_step_gov_sys.attr,
+	NULL
+};
+
+static struct attribute_group cs_attr_group_gov_sys = {
+	.attrs = dbs_attributes_gov_sys,
+	.name = "conservative",
+};
+
+static struct attribute *dbs_attributes_gov_pol[] = {
+	&sampling_rate_min_gov_pol.attr,
+	&sampling_rate_gov_pol.attr,
+	&sampling_down_factor_gov_pol.attr,
+	&up_threshold_gov_pol.attr,
+	&down_threshold_gov_pol.attr,
+	&ignore_nice_load_gov_pol.attr,
+	&freq_step_gov_pol.attr,
+	NULL
+};
+
+static struct attribute_group cs_attr_group_gov_pol = {
+	.attrs = dbs_attributes_gov_pol,
+	.name = "conservative",
+};
+
+/************************** sysfs end ************************/
+
+static int cs_init(struct dbs_data *dbs_data)
+{
+	struct cs_dbs_tuners *tuners;
+
+	tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
+	if (!tuners) {
+		pr_err("%s: kzalloc failed\n", __func__);
+		return -ENOMEM;
+	}
+
+	tuners->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
+	tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD;
+	tuners->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
+	tuners->ignore_nice_load = 0;
+	tuners->freq_step = DEF_FREQUENCY_STEP;
+
+	dbs_data->tuners = tuners;
+	dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
+		jiffies_to_usecs(10);
+	mutex_init(&dbs_data->mutex);
+	return 0;
+}
+
+static void cs_exit(struct dbs_data *dbs_data)
+{
+	kfree(dbs_data->tuners);
+}
+
+define_get_cpu_dbs_routines(cs_cpu_dbs_info);
+
+static struct notifier_block cs_cpufreq_notifier_block = {
+	.notifier_call = dbs_cpufreq_notifier,
+};
+
+static struct cs_ops cs_ops = {
+	.notifier_block = &cs_cpufreq_notifier_block,
+};
+
+static struct common_dbs_data cs_dbs_cdata = {
+	.governor = GOV_CONSERVATIVE,
+	.attr_group_gov_sys = &cs_attr_group_gov_sys,
+	.attr_group_gov_pol = &cs_attr_group_gov_pol,
+	.get_cpu_cdbs = get_cpu_cdbs,
+	.get_cpu_dbs_info_s = get_cpu_dbs_info_s,
+	.gov_dbs_timer = cs_dbs_timer,
+	.gov_check_cpu = cs_check_cpu,
+	.gov_ops = &cs_ops,
+	.init = cs_init,
+	.exit = cs_exit,
+};
+
+static int cs_cpufreq_governor_dbs(struct cpufreq_policy *policy,
+				   unsigned int event)
+{
+	return cpufreq_governor_dbs(policy, &cs_dbs_cdata, event);
+}
+
+#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
+static
+#endif
+struct cpufreq_governor cpufreq_gov_conservative = {
+	.name			= "conservative",
+	.governor		= cs_cpufreq_governor_dbs,
+	.max_transition_latency	= TRANSITION_LATENCY_LIMIT,
+	.owner			= THIS_MODULE,
+};
+
+static int __init cpufreq_gov_dbs_init(void)
+{
+	return cpufreq_register_governor(&cpufreq_gov_conservative);
+}
+
+static void __exit cpufreq_gov_dbs_exit(void)
+{
+	cpufreq_unregister_governor(&cpufreq_gov_conservative);
+}
+
+MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
+MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
+		"Low Latency Frequency Transition capable processors "
+		"optimised for use in a battery environment");
+MODULE_LICENSE("GPL");
+
+#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
+fs_initcall(cpufreq_gov_dbs_init);
+#else
+module_init(cpufreq_gov_dbs_init);
+#endif
+module_exit(cpufreq_gov_dbs_exit);