/*
* 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 <asm/cputime.h>
#include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/export.h>
#include <linux/kernel_stat.h>
#include <linux/mutex.h>
#include <linux/tick.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include "cpufreq_governor.h"
static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
{
u64 idle_time;
u64 cur_wall_time;
u64 busy_time;
cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
idle_time = cur_wall_time - busy_time;
if (wall)
*wall = cputime_to_usecs(cur_wall_time);
return cputime_to_usecs(idle_time);
}
u64 get_cpu_idle_time(unsigned int cpu, u64 *wall)
{
u64 idle_time = get_cpu_idle_time_us(cpu, NULL);
if (idle_time == -1ULL)
return get_cpu_idle_time_jiffy(cpu, wall);
else
idle_time += get_cpu_iowait_time_us(cpu, wall);
return idle_time;
}
EXPORT_SYMBOL_GPL(get_cpu_idle_time);
void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
{
struct cpu_dbs_common_info *cdbs = dbs_data->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 max_load = 0;
unsigned int ignore_nice;
unsigned int j;
if (dbs_data->governor == GOV_ONDEMAND)
ignore_nice = od_tuners->ignore_nice;
else
ignore_nice = cs_tuners->ignore_nice;
policy = cdbs->cur_policy;
/* Get Absolute Load (in terms of freq for ondemand gov) */
for_each_cpu(j, policy->cpus) {
struct cpu_dbs_common_info *j_cdbs;
u64 cur_wall_time, cur_idle_time, cur_iowait_time;
unsigned int idle_time, wall_time, iowait_time;
unsigned int load;
j_cdbs = dbs_data->get_cpu_cdbs(j);
cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
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 (dbs_data->governor == GOV_ONDEMAND) {
struct od_cpu_dbs_info_s *od_j_dbs_info =
dbs_data->get_cpu_dbs_info_s(cpu);
cur_iowait_time = get_cpu_iowait_time_us(j,
&cur_wall_time);
if (cur_iowait_time == -1ULL)
cur_iowait_time = 0;
iowait_time = (unsigned int) (cur_iowait_time -
od_j_dbs_info->prev_cpu_iowait);
od_j_dbs_info->prev_cpu_iowait = cur_iowait_time;
/*
* 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 subtract the
* iowait time from the cpu idle time.
*/
if (od_tuners->io_is_busy && idle_time >= iowait_time)
idle_time -= iowait_time;
}
if (unlikely(!wall_time || wall_time < idle_time))
continue;
load = 100 * (wall_time - idle_time) / wall_time;
if (dbs_data->governor == GOV_ONDEMAND) {
int freq_avg = __cpufreq_driver_getavg(policy, j);
if (freq_avg <= 0)
freq_avg = policy->cur;
load *= freq_avg;
}
if (load > max_load)
max_load = load;
}
dbs_data->gov_check_cpu(cpu, max_load);
}
EXPORT_SYMBOL_GPL(dbs_check_cpu);
static inline void dbs_timer_init(struct dbs_data *dbs_data,
struct cpu_dbs_common_info *cdbs, unsigned int sampling_rate)
{
int delay = delay_for_sampling_rate(sampling_rate);
INIT_DEFERRABLE_WORK(&cdbs->work, dbs_data->gov_dbs_timer);
schedule_delayed_work_on(cdbs->cpu, &cdbs->work, delay);
}
static inline void dbs_timer_exit(struct cpu_dbs_common_info *cdbs)
{
cancel_delayed_work_sync(&cdbs->work);
}
int cpufreq_governor_dbs(struct dbs_data *dbs_data,
struct cpufreq_policy *policy, unsigned int event)
{
struct od_cpu_dbs_info_s *od_dbs_info = NULL;
struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
struct od_dbs_tuners *od_tuners = dbs_data->tuners;
struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
struct cpu_dbs_common_info *cpu_cdbs;
unsigned int *sampling_rate, latency, ignore_nice, j, cpu = policy->cpu;
int rc;
cpu_cdbs = dbs_data->get_cpu_cdbs(cpu);
if (dbs_data->governor == GOV_CONSERVATIVE) {
cs_dbs_info = dbs_data->get_cpu_dbs_info_s(cpu);
sampling_rate = &cs_tuners->sampling_rate;
ignore_nice = cs_tuners->ignore_nice;
} else {
od_dbs_info = dbs_data->get_cpu_dbs_info_s(cpu);
sampling_rate = &od_tuners->sampling_rate;
ignore_nice = od_tuners->ignore_nice;
}
switch (event) {
case CPUFREQ_GOV_START:
if ((!cpu_online(cpu)) || (!policy->cur))
return -EINVAL;
mutex_lock(&dbs_data->mutex);
dbs_data->enable++;
cpu_cdbs->cpu = cpu;
for_each_cpu(j, policy->cpus) {
struct cpu_dbs_common_info *j_cdbs;
j_cdbs = dbs_data->get_cpu_cdbs(j);
j_cdbs->cur_policy = policy;
j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
&j_cdbs->prev_cpu_wall);
if (ignore_nice)
j_cdbs->prev_cpu_nice =
kcpustat_cpu(j).cpustat[CPUTIME_NICE];
}
/*
* Start the timerschedule work, when this governor is used for
* first time
*/
if (dbs_data->enable != 1)
goto second_time;
rc = sysfs_create_group(cpufreq_global_kobject,
dbs_data->attr_group);
if (rc) {
mutex_unlock(&dbs_data->mutex);
return rc;
}
/* policy latency is in nS. Convert it to uS first */
latency = policy->cpuinfo.transition_latency / 1000;
if (latency == 0)
latency = 1;
/*
* conservative does not implement micro like ondemand
* governor, thus we are bound to jiffes/HZ
*/
if (dbs_data->governor == GOV_CONSERVATIVE) {
struct cs_ops *ops = dbs_data->gov_ops;
cpufreq_register_notifier(ops->notifier_block,
CPUFREQ_TRANSITION_NOTIFIER);
dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
jiffies_to_usecs(10);
} else {
struct od_ops *ops = dbs_data->gov_ops;
od_tuners->io_is_busy = ops->io_busy();
}
/* Bring kernel and HW constraints together */
dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
MIN_LATENCY_MULTIPLIER * latency);
*sampling_rate = max(dbs_data->min_sampling_rate, latency *
LATENCY_MULTIPLIER);
second_time:
if (dbs_data->governor == GOV_CONSERVATIVE) {
cs_dbs_info->down_skip = 0;
cs_dbs_info->enable = 1;
cs_dbs_info->requested_freq = policy->cur;
} else {
struct od_ops *ops = dbs_data->gov_ops;
od_dbs_info->rate_mult = 1;
od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
ops->powersave_bias_init_cpu(cpu);
}
mutex_unlock(&dbs_data->mutex);
mutex_init(&cpu_cdbs->timer_mutex);
dbs_timer_init(dbs_data, cpu_cdbs, *sampling_rate);
break;
case CPUFREQ_GOV_STOP:
if (dbs_data->governor == GOV_CONSERVATIVE)
cs_dbs_info->enable = 0;
dbs_timer_exit(cpu_cdbs);
mutex_lock(&dbs_data->mutex);
mutex_destroy(&cpu_cdbs->timer_mutex);
dbs_data->enable--;
if (!dbs_data->enable) {
struct cs_ops *ops = dbs_data->gov_ops;
sysfs_remove_group(cpufreq_global_kobject,
dbs_data->attr_group);
if (dbs_data->governor == GOV_CONSERVATIVE)
cpufreq_unregister_notifier(ops->notifier_block,
CPUFREQ_TRANSITION_NOTIFIER);
}
mutex_unlock(&dbs_data->mutex);
break;
case CPUFREQ_GOV_LIMITS:
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);
break;
}
return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);
