--- /dev/null
+/*
+ * 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)
+
+/* Keep 10% of idle under the up threshold when decreasing the frequency */
+#define DEFAULT_FREQ_DOWN_DIFFERENTIAL (10)
+
+/* less than 35% avg load across online CPUs decreases frequency */
+#define DEFAULT_DOWN_FREQ_MAX_LOAD (35)
+
+/* 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_differential;
+ 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_differential = DEFAULT_FREQ_DOWN_DIFFERENTIAL,
+ .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_differential, down_differential);
+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_differential(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_differential = 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_differential);
+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_differential.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 percentage*/
+ unsigned int max_load = 0;
+ /* largest CPU load in terms of frequency */
+ unsigned int max_load_freq = 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 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;
+ }
+
+ /* use the max load in the OPP freq change policy */
+ max_load_freq = max_load * policy->cur;
+
+ /* 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 if auxiliary CPU is needed based on avg_load */
+ 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;
+ }
+ }
+
+ /* check for frequency increase based on max_load */
+ if (max_load > dbs_tuners_ins.up_threshold) {
+ /* 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;
+ }
+ }
+
+ /*
+ * go down to the lowest frequency which can sustain the load by
+ * keeping 30% of idle in order to not cross the up_threshold
+ */
+ if ((max_load_freq <
+ (dbs_tuners_ins.up_threshold - dbs_tuners_ins.down_differential) *
+ policy->cur) && (policy->cur > policy->min)) {
+ unsigned int freq_next;
+ freq_next = max_load_freq /
+ (dbs_tuners_ins.up_threshold -
+ dbs_tuners_ins.down_differential);
+
+ if (freq_next < policy->min)
+ freq_next = policy->min;
+
+ __cpufreq_driver_target(policy, freq_next,
+ 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);
projects / firefly-linux-kernel-4.4.55.git / commitdiff