drivers/cpufreq/cpufreq_conservative.c - linux/kernel/git/viro/vfs - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *  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>
  */

 #include <linux/slab.h>
 #include "cpufreq_governor.h"

 struct cs_policy_dbs_info {
 	struct policy_dbs_info policy_dbs;
 	unsigned int down_skip;
 	unsigned int requested_freq;
 };

 static inline struct cs_policy_dbs_info *to_dbs_info(struct policy_dbs_info *policy_dbs)
 {
 	return container_of(policy_dbs, struct cs_policy_dbs_info, policy_dbs);
 }

 struct cs_dbs_tuners {
 	unsigned int down_threshold;
 	unsigned int freq_step;
 };

 /* Conservative governor macros */
 #define DEF_FREQUENCY_UP_THRESHOLD		(80)
 #define DEF_FREQUENCY_DOWN_THRESHOLD		(20)
 #define DEF_FREQUENCY_STEP			(5)
 #define DEF_SAMPLING_DOWN_FACTOR		(1)
 #define MAX_SAMPLING_DOWN_FACTOR		(10)

 static inline unsigned int get_freq_step(struct cs_dbs_tuners *cs_tuners,
 					 struct cpufreq_policy *policy)
 {
 	unsigned int freq_step = (cs_tuners->freq_step * policy->max) / 100;

 	/* max freq cannot be less than 100. But who knows... */
 	if (unlikely(freq_step == 0))
 		freq_step = DEF_FREQUENCY_STEP;

 	return freq_step;
 }

 /*
  * 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
  *
  * Frequency updates happen at minimum steps of 5% (default) of maximum
  * frequency
  */
 static unsigned int cs_dbs_update(struct cpufreq_policy *policy)
 {
 	struct policy_dbs_info *policy_dbs = policy->governor_data;
 	struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs);
 	unsigned int requested_freq = dbs_info->requested_freq;
 	struct dbs_data *dbs_data = policy_dbs->dbs_data;
 	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
 	unsigned int load = dbs_update(policy);
 	unsigned int freq_step;

 	/*
 	 * break out if we 'cannot' reduce the speed as the user might
 	 * want freq_step to be zero
 	 */
 	if (cs_tuners->freq_step == 0)
 		goto out;

 	/*
 	 * If requested_freq is out of range, it is likely that the limits
 	 * changed in the meantime, so fall back to current frequency in that
 	 * case.
 	 */
 	if (requested_freq > policy->max || requested_freq < policy->min) {
 		requested_freq = policy->cur;
 		dbs_info->requested_freq = requested_freq;
 	}

 	freq_step = get_freq_step(cs_tuners, policy);

 	/*
 	 * Decrease requested_freq one freq_step for each idle period that
 	 * we didn't update the frequency.
 	 */
 	if (policy_dbs->idle_periods < UINT_MAX) {
 		unsigned int freq_steps = policy_dbs->idle_periods * freq_step;

 		if (requested_freq > policy->min + freq_steps)
 			requested_freq -= freq_steps;
 		else
 			requested_freq = policy->min;

 		policy_dbs->idle_periods = UINT_MAX;
 	}

 	/* Check for frequency increase */
 	if (load > dbs_data->up_threshold) {
 		dbs_info->down_skip = 0;

 		/* if we are already at full speed then break out early */
 		if (requested_freq == policy->max)
 			goto out;

 		requested_freq += freq_step;
 		if (requested_freq > policy->max)
 			requested_freq = policy->max;

 		__cpufreq_driver_target(policy, requested_freq,
 					CPUFREQ_RELATION_HE);
 		dbs_info->requested_freq = requested_freq;
 		goto out;
 	}

 	/* if sampling_down_factor is active break out early */
 	if (++dbs_info->down_skip < dbs_data->sampling_down_factor)
 		goto out;
 	dbs_info->down_skip = 0;

 	/* Check for frequency decrease */
 	if (load < cs_tuners->down_threshold) {
 		/*
 		 * if we cannot reduce the frequency anymore, break out early
 		 */
 		if (requested_freq == policy->min)
 			goto out;

 		if (requested_freq > freq_step)
 			requested_freq -= freq_step;
 		else
 			requested_freq = policy->min;

 		__cpufreq_driver_target(policy, requested_freq,
 					CPUFREQ_RELATION_LE);
 		dbs_info->requested_freq = requested_freq;
 	}

  out:
 	return dbs_data->sampling_rate;
 }

 /************************** sysfs interface ************************/

 static ssize_t sampling_down_factor_store(struct gov_attr_set *attr_set,
 					  const char *buf, size_t count)
 {
 	struct dbs_data *dbs_data = to_dbs_data(attr_set);
 	unsigned int input;
 	int ret;
 	ret = sscanf(buf, "%u", &input);

 	if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
 		return -EINVAL;

 	dbs_data->sampling_down_factor = input;
 	return count;
 }

 static ssize_t up_threshold_store(struct gov_attr_set *attr_set,
 				  const char *buf, size_t count)
 {
 	struct dbs_data *dbs_data = to_dbs_data(attr_set);
 	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;

 	dbs_data->up_threshold = input;
 	return count;
 }

 static ssize_t down_threshold_store(struct gov_attr_set *attr_set,
 				    const char *buf, size_t count)
 {
 	struct dbs_data *dbs_data = to_dbs_data(attr_set);
 	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
 	unsigned int input;
 	int ret;
 	ret = sscanf(buf, "%u", &input);

 	/* cannot be lower than 1 otherwise freq will not fall */
 	if (ret != 1 || input < 1 || input >= dbs_data->up_threshold)
 		return -EINVAL;

 	cs_tuners->down_threshold = input;
 	return count;
 }

 static ssize_t ignore_nice_load_store(struct gov_attr_set *attr_set,
 				      const char *buf, size_t count)
 {
 	struct dbs_data *dbs_data = to_dbs_data(attr_set);
 	unsigned int input;
 	int ret;

 	ret = sscanf(buf, "%u", &input);
 	if (ret != 1)
 		return -EINVAL;

 	if (input > 1)
 		input = 1;

 	if (input == dbs_data->ignore_nice_load) /* nothing to do */
 		return count;

 	dbs_data->ignore_nice_load = input;

 	/* we need to re-evaluate prev_cpu_idle */
 	gov_update_cpu_data(dbs_data);

 	return count;
 }

 static ssize_t freq_step_store(struct gov_attr_set *attr_set, const char *buf,
 			       size_t count)
 {
 	struct dbs_data *dbs_data = to_dbs_data(attr_set);
 	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;
 }

 gov_show_one_common(sampling_rate);
 gov_show_one_common(sampling_down_factor);
 gov_show_one_common(up_threshold);
 gov_show_one_common(ignore_nice_load);
 gov_show_one(cs, down_threshold);
 gov_show_one(cs, freq_step);

 gov_attr_rw(sampling_rate);
 gov_attr_rw(sampling_down_factor);
 gov_attr_rw(up_threshold);
 gov_attr_rw(ignore_nice_load);
 gov_attr_rw(down_threshold);
 gov_attr_rw(freq_step);

 static struct attribute *cs_attrs[] = {
 	&sampling_rate.attr,
 	&sampling_down_factor.attr,
 	&up_threshold.attr,
 	&down_threshold.attr,
 	&ignore_nice_load.attr,
 	&freq_step.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(cs);

 /************************** sysfs end ************************/

 static struct policy_dbs_info *cs_alloc(void)
 {
 	struct cs_policy_dbs_info *dbs_info;

 	dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL);
 	return dbs_info ? &dbs_info->policy_dbs : NULL;
 }

 static void cs_free(struct policy_dbs_info *policy_dbs)
 {
 	kfree(to_dbs_info(policy_dbs));
 }

 static int cs_init(struct dbs_data *dbs_data)
 {
 	struct cs_dbs_tuners *tuners;

 	tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
 	if (!tuners)
 		return -ENOMEM;

 	tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD;
 	tuners->freq_step = DEF_FREQUENCY_STEP;
 	dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
 	dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
 	dbs_data->ignore_nice_load = 0;
 	dbs_data->tuners = tuners;

 	return 0;
 }

 static void cs_exit(struct dbs_data *dbs_data)
 {
 	kfree(dbs_data->tuners);
 }

 static void cs_start(struct cpufreq_policy *policy)
 {
 	struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data);

 	dbs_info->down_skip = 0;
 	dbs_info->requested_freq = policy->cur;
 }

 static struct dbs_governor cs_governor = {
 	.gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("conservative"),
 	.kobj_type = { .default_groups = cs_groups },
 	.gov_dbs_update = cs_dbs_update,
 	.alloc = cs_alloc,
 	.free = cs_free,
 	.init = cs_init,
 	.exit = cs_exit,
 	.start = cs_start,
 };

 #define CPU_FREQ_GOV_CONSERVATIVE	(cs_governor.gov)

 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
 struct cpufreq_governor *cpufreq_default_governor(void)
 {
 	return &CPU_FREQ_GOV_CONSERVATIVE;
 }
 #endif

 cpufreq_governor_init(CPU_FREQ_GOV_CONSERVATIVE);
 cpufreq_governor_exit(CPU_FREQ_GOV_CONSERVATIVE);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* 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>
	*/

	#include <linux/slab.h>
	#include "cpufreq_governor.h"

	struct cs_policy_dbs_info {
	struct policy_dbs_info policy_dbs;
	unsigned int down_skip;
	unsigned int requested_freq;
	};

	static inline struct cs_policy_dbs_info to_dbs_info(struct policy_dbs_info policy_dbs)
	{
	return container_of(policy_dbs, struct cs_policy_dbs_info, policy_dbs);
	}

	struct cs_dbs_tuners {
	unsigned int down_threshold;
	unsigned int freq_step;
	};

	/* Conservative governor macros */
	#define DEF_FREQUENCY_UP_THRESHOLD (80)
	#define DEF_FREQUENCY_DOWN_THRESHOLD (20)
	#define DEF_FREQUENCY_STEP (5)
	#define DEF_SAMPLING_DOWN_FACTOR (1)
	#define MAX_SAMPLING_DOWN_FACTOR (10)

	static inline unsigned int get_freq_step(struct cs_dbs_tuners *cs_tuners,
	struct cpufreq_policy *policy)
	{
	unsigned int freq_step = (cs_tuners->freq_step * policy->max) / 100;

	/* max freq cannot be less than 100. But who knows... */
	if (unlikely(freq_step == 0))
	freq_step = DEF_FREQUENCY_STEP;

	return freq_step;
	}

	/*
	* 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
	*
	* Frequency updates happen at minimum steps of 5% (default) of maximum
	* frequency
	*/
	static unsigned int cs_dbs_update(struct cpufreq_policy *policy)
	{
	struct policy_dbs_info *policy_dbs = policy->governor_data;
	struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs);
	unsigned int requested_freq = dbs_info->requested_freq;
	struct dbs_data *dbs_data = policy_dbs->dbs_data;
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	unsigned int load = dbs_update(policy);
	unsigned int freq_step;

	/*
	* break out if we 'cannot' reduce the speed as the user might
	* want freq_step to be zero
	*/
	if (cs_tuners->freq_step == 0)
	goto out;

	/*
	* If requested_freq is out of range, it is likely that the limits
	* changed in the meantime, so fall back to current frequency in that
	* case.
	*/
	if (requested_freq > policy->max \|\| requested_freq < policy->min) {
	requested_freq = policy->cur;
	dbs_info->requested_freq = requested_freq;
	}

	freq_step = get_freq_step(cs_tuners, policy);

	/*
	* Decrease requested_freq one freq_step for each idle period that
	* we didn't update the frequency.
	*/
	if (policy_dbs->idle_periods < UINT_MAX) {
	unsigned int freq_steps = policy_dbs->idle_periods * freq_step;

	if (requested_freq > policy->min + freq_steps)
	requested_freq -= freq_steps;
	else
	requested_freq = policy->min;

	policy_dbs->idle_periods = UINT_MAX;
	}

	/* Check for frequency increase */
	if (load > dbs_data->up_threshold) {
	dbs_info->down_skip = 0;

	/* if we are already at full speed then break out early */
	if (requested_freq == policy->max)
	goto out;

	requested_freq += freq_step;
	if (requested_freq > policy->max)
	requested_freq = policy->max;

	__cpufreq_driver_target(policy, requested_freq,
	CPUFREQ_RELATION_HE);
	dbs_info->requested_freq = requested_freq;
	goto out;
	}

	/* if sampling_down_factor is active break out early */
	if (++dbs_info->down_skip < dbs_data->sampling_down_factor)
	goto out;
	dbs_info->down_skip = 0;

	/* Check for frequency decrease */
	if (load < cs_tuners->down_threshold) {
	/*
	* if we cannot reduce the frequency anymore, break out early
	*/
	if (requested_freq == policy->min)
	goto out;

	if (requested_freq > freq_step)
	requested_freq -= freq_step;
	else
	requested_freq = policy->min;

	__cpufreq_driver_target(policy, requested_freq,
	CPUFREQ_RELATION_LE);
	dbs_info->requested_freq = requested_freq;
	}

	out:
	return dbs_data->sampling_rate;
	}

	/************************ sysfs interface **********************/

	static ssize_t sampling_down_factor_store(struct gov_attr_set *attr_set,
	const char *buf, size_t count)
	{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	unsigned int input;
	int ret;
	ret = sscanf(buf, "%u", &input);

	if (ret != 1 \|\| input > MAX_SAMPLING_DOWN_FACTOR \|\| input < 1)
	return -EINVAL;

	dbs_data->sampling_down_factor = input;
	return count;
	}

	static ssize_t up_threshold_store(struct gov_attr_set *attr_set,
	const char *buf, size_t count)
	{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	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;

	dbs_data->up_threshold = input;
	return count;
	}

	static ssize_t down_threshold_store(struct gov_attr_set *attr_set,
	const char *buf, size_t count)
	{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	unsigned int input;
	int ret;
	ret = sscanf(buf, "%u", &input);

	/* cannot be lower than 1 otherwise freq will not fall */
	if (ret != 1 \|\| input < 1 \|\| input >= dbs_data->up_threshold)
	return -EINVAL;

	cs_tuners->down_threshold = input;
	return count;
	}

	static ssize_t ignore_nice_load_store(struct gov_attr_set *attr_set,
	const char *buf, size_t count)
	{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	unsigned int input;
	int ret;

	ret = sscanf(buf, "%u", &input);
	if (ret != 1)
	return -EINVAL;

	if (input > 1)
	input = 1;

	if (input == dbs_data->ignore_nice_load) /* nothing to do */
	return count;

	dbs_data->ignore_nice_load = input;

	/* we need to re-evaluate prev_cpu_idle */
	gov_update_cpu_data(dbs_data);

	return count;
	}

	static ssize_t freq_step_store(struct gov_attr_set attr_set, const char buf,
	size_t count)
	{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	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;
	}

	gov_show_one_common(sampling_rate);
	gov_show_one_common(sampling_down_factor);
	gov_show_one_common(up_threshold);
	gov_show_one_common(ignore_nice_load);
	gov_show_one(cs, down_threshold);
	gov_show_one(cs, freq_step);

	gov_attr_rw(sampling_rate);
	gov_attr_rw(sampling_down_factor);
	gov_attr_rw(up_threshold);
	gov_attr_rw(ignore_nice_load);
	gov_attr_rw(down_threshold);
	gov_attr_rw(freq_step);

	static struct attribute *cs_attrs[] = {
	&sampling_rate.attr,
	&sampling_down_factor.attr,
	&up_threshold.attr,
	&down_threshold.attr,
	&ignore_nice_load.attr,
	&freq_step.attr,
	NULL
	};
	ATTRIBUTE_GROUPS(cs);

	/************************ sysfs end **********************/

	static struct policy_dbs_info *cs_alloc(void)
	{
	struct cs_policy_dbs_info *dbs_info;

	dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL);
	return dbs_info ? &dbs_info->policy_dbs : NULL;
	}

	static void cs_free(struct policy_dbs_info *policy_dbs)
	{
	kfree(to_dbs_info(policy_dbs));
	}

	static int cs_init(struct dbs_data *dbs_data)
	{
	struct cs_dbs_tuners *tuners;

	tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
	if (!tuners)
	return -ENOMEM;

	tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD;
	tuners->freq_step = DEF_FREQUENCY_STEP;
	dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
	dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
	dbs_data->ignore_nice_load = 0;
	dbs_data->tuners = tuners;

	return 0;
	}

	static void cs_exit(struct dbs_data *dbs_data)
	{
	kfree(dbs_data->tuners);
	}

	static void cs_start(struct cpufreq_policy *policy)
	{
	struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data);

	dbs_info->down_skip = 0;
	dbs_info->requested_freq = policy->cur;
	}

	static struct dbs_governor cs_governor = {
	.gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("conservative"),
	.kobj_type = { .default_groups = cs_groups },
	.gov_dbs_update = cs_dbs_update,
	.alloc = cs_alloc,
	.free = cs_free,
	.init = cs_init,
	.exit = cs_exit,
	.start = cs_start,
	};

	#define CPU_FREQ_GOV_CONSERVATIVE (cs_governor.gov)

	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
	struct cpufreq_governor *cpufreq_default_governor(void)
	{
	return &CPU_FREQ_GOV_CONSERVATIVE;
	}
	#endif

	cpufreq_governor_init(CPU_FREQ_GOV_CONSERVATIVE);
	cpufreq_governor_exit(CPU_FREQ_GOV_CONSERVATIVE);