https://github.com/torvalds/linux
Tip revision: 58720809f52779dc0f08e53e54b014209d13eebb authored by Linus Torvalds on 15 October 2023, 20:34:39 UTC
Linux 6.6-rc6
Linux 6.6-rc6
Tip revision: 5872080
governor_passive.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/drivers/devfreq/governor_passive.c
*
* Copyright (C) 2016 Samsung Electronics
* Author: Chanwoo Choi <cw00.choi@samsung.com>
* Author: MyungJoo Ham <myungjoo.ham@samsung.com>
*/
#include <linux/module.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/devfreq.h>
#include <linux/units.h>
#include "governor.h"
static struct devfreq_cpu_data *
get_parent_cpu_data(struct devfreq_passive_data *p_data,
struct cpufreq_policy *policy)
{
struct devfreq_cpu_data *parent_cpu_data;
if (!p_data || !policy)
return NULL;
list_for_each_entry(parent_cpu_data, &p_data->cpu_data_list, node)
if (parent_cpu_data->first_cpu == cpumask_first(policy->related_cpus))
return parent_cpu_data;
return NULL;
}
static void delete_parent_cpu_data(struct devfreq_passive_data *p_data)
{
struct devfreq_cpu_data *parent_cpu_data, *tmp;
list_for_each_entry_safe(parent_cpu_data, tmp, &p_data->cpu_data_list, node) {
list_del(&parent_cpu_data->node);
if (parent_cpu_data->opp_table)
dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
kfree(parent_cpu_data);
}
}
static unsigned long get_target_freq_by_required_opp(struct device *p_dev,
struct opp_table *p_opp_table,
struct opp_table *opp_table,
unsigned long *freq)
{
struct dev_pm_opp *opp = NULL, *p_opp = NULL;
unsigned long target_freq;
if (!p_dev || !p_opp_table || !opp_table || !freq)
return 0;
p_opp = devfreq_recommended_opp(p_dev, freq, 0);
if (IS_ERR(p_opp))
return 0;
opp = dev_pm_opp_xlate_required_opp(p_opp_table, opp_table, p_opp);
dev_pm_opp_put(p_opp);
if (IS_ERR(opp))
return 0;
target_freq = dev_pm_opp_get_freq(opp);
dev_pm_opp_put(opp);
return target_freq;
}
static int get_target_freq_with_cpufreq(struct devfreq *devfreq,
unsigned long *target_freq)
{
struct devfreq_passive_data *p_data =
(struct devfreq_passive_data *)devfreq->data;
struct devfreq_cpu_data *parent_cpu_data;
struct cpufreq_policy *policy;
unsigned long cpu, cpu_cur, cpu_min, cpu_max, cpu_percent;
unsigned long dev_min, dev_max;
unsigned long freq = 0;
int ret = 0;
for_each_online_cpu(cpu) {
policy = cpufreq_cpu_get(cpu);
if (!policy) {
ret = -EINVAL;
continue;
}
parent_cpu_data = get_parent_cpu_data(p_data, policy);
if (!parent_cpu_data) {
cpufreq_cpu_put(policy);
continue;
}
/* Get target freq via required opps */
cpu_cur = parent_cpu_data->cur_freq * HZ_PER_KHZ;
freq = get_target_freq_by_required_opp(parent_cpu_data->dev,
parent_cpu_data->opp_table,
devfreq->opp_table, &cpu_cur);
if (freq) {
*target_freq = max(freq, *target_freq);
cpufreq_cpu_put(policy);
continue;
}
/* Use interpolation if required opps is not available */
devfreq_get_freq_range(devfreq, &dev_min, &dev_max);
cpu_min = parent_cpu_data->min_freq;
cpu_max = parent_cpu_data->max_freq;
cpu_cur = parent_cpu_data->cur_freq;
cpu_percent = ((cpu_cur - cpu_min) * 100) / (cpu_max - cpu_min);
freq = dev_min + mult_frac(dev_max - dev_min, cpu_percent, 100);
*target_freq = max(freq, *target_freq);
cpufreq_cpu_put(policy);
}
return ret;
}
static int get_target_freq_with_devfreq(struct devfreq *devfreq,
unsigned long *freq)
{
struct devfreq_passive_data *p_data
= (struct devfreq_passive_data *)devfreq->data;
struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
unsigned long child_freq = ULONG_MAX;
int i, count;
/* Get target freq via required opps */
child_freq = get_target_freq_by_required_opp(parent_devfreq->dev.parent,
parent_devfreq->opp_table,
devfreq->opp_table, freq);
if (child_freq)
goto out;
/* Use interpolation if required opps is not available */
for (i = 0; i < parent_devfreq->max_state; i++)
if (parent_devfreq->freq_table[i] == *freq)
break;
if (i == parent_devfreq->max_state)
return -EINVAL;
if (i < devfreq->max_state) {
child_freq = devfreq->freq_table[i];
} else {
count = devfreq->max_state;
child_freq = devfreq->freq_table[count - 1];
}
out:
*freq = child_freq;
return 0;
}
static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
unsigned long *freq)
{
struct devfreq_passive_data *p_data =
(struct devfreq_passive_data *)devfreq->data;
int ret;
if (!p_data)
return -EINVAL;
/*
* If the devfreq device with passive governor has the specific method
* to determine the next frequency, should use the get_target_freq()
* of struct devfreq_passive_data.
*/
if (p_data->get_target_freq)
return p_data->get_target_freq(devfreq, freq);
switch (p_data->parent_type) {
case DEVFREQ_PARENT_DEV:
ret = get_target_freq_with_devfreq(devfreq, freq);
break;
case CPUFREQ_PARENT_DEV:
ret = get_target_freq_with_cpufreq(devfreq, freq);
break;
default:
ret = -EINVAL;
dev_err(&devfreq->dev, "Invalid parent type\n");
break;
}
return ret;
}
static int cpufreq_passive_notifier_call(struct notifier_block *nb,
unsigned long event, void *ptr)
{
struct devfreq_passive_data *p_data =
container_of(nb, struct devfreq_passive_data, nb);
struct devfreq *devfreq = (struct devfreq *)p_data->this;
struct devfreq_cpu_data *parent_cpu_data;
struct cpufreq_freqs *freqs = ptr;
unsigned int cur_freq;
int ret;
if (event != CPUFREQ_POSTCHANGE || !freqs)
return 0;
parent_cpu_data = get_parent_cpu_data(p_data, freqs->policy);
if (!parent_cpu_data || parent_cpu_data->cur_freq == freqs->new)
return 0;
cur_freq = parent_cpu_data->cur_freq;
parent_cpu_data->cur_freq = freqs->new;
mutex_lock(&devfreq->lock);
ret = devfreq_update_target(devfreq, freqs->new);
mutex_unlock(&devfreq->lock);
if (ret) {
parent_cpu_data->cur_freq = cur_freq;
dev_err(&devfreq->dev, "failed to update the frequency.\n");
return ret;
}
return 0;
}
static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
{
struct devfreq_passive_data *p_data
= (struct devfreq_passive_data *)devfreq->data;
int ret;
if (p_data->nb.notifier_call) {
ret = cpufreq_unregister_notifier(&p_data->nb,
CPUFREQ_TRANSITION_NOTIFIER);
if (ret < 0)
return ret;
}
delete_parent_cpu_data(p_data);
return 0;
}
static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
{
struct devfreq_passive_data *p_data
= (struct devfreq_passive_data *)devfreq->data;
struct device *dev = devfreq->dev.parent;
struct opp_table *opp_table = NULL;
struct devfreq_cpu_data *parent_cpu_data;
struct cpufreq_policy *policy;
struct device *cpu_dev;
unsigned int cpu;
int ret;
p_data->cpu_data_list
= (struct list_head)LIST_HEAD_INIT(p_data->cpu_data_list);
p_data->nb.notifier_call = cpufreq_passive_notifier_call;
ret = cpufreq_register_notifier(&p_data->nb, CPUFREQ_TRANSITION_NOTIFIER);
if (ret) {
dev_err(dev, "failed to register cpufreq notifier\n");
p_data->nb.notifier_call = NULL;
goto err;
}
for_each_possible_cpu(cpu) {
policy = cpufreq_cpu_get(cpu);
if (!policy) {
ret = -EPROBE_DEFER;
goto err;
}
parent_cpu_data = get_parent_cpu_data(p_data, policy);
if (parent_cpu_data) {
cpufreq_cpu_put(policy);
continue;
}
parent_cpu_data = kzalloc(sizeof(*parent_cpu_data),
GFP_KERNEL);
if (!parent_cpu_data) {
ret = -ENOMEM;
goto err_put_policy;
}
cpu_dev = get_cpu_device(cpu);
if (!cpu_dev) {
dev_err(dev, "failed to get cpu device\n");
ret = -ENODEV;
goto err_free_cpu_data;
}
opp_table = dev_pm_opp_get_opp_table(cpu_dev);
if (IS_ERR(opp_table)) {
dev_err(dev, "failed to get opp_table of cpu%d\n", cpu);
ret = PTR_ERR(opp_table);
goto err_free_cpu_data;
}
parent_cpu_data->dev = cpu_dev;
parent_cpu_data->opp_table = opp_table;
parent_cpu_data->first_cpu = cpumask_first(policy->related_cpus);
parent_cpu_data->cur_freq = policy->cur;
parent_cpu_data->min_freq = policy->cpuinfo.min_freq;
parent_cpu_data->max_freq = policy->cpuinfo.max_freq;
list_add_tail(&parent_cpu_data->node, &p_data->cpu_data_list);
cpufreq_cpu_put(policy);
}
mutex_lock(&devfreq->lock);
ret = devfreq_update_target(devfreq, 0L);
mutex_unlock(&devfreq->lock);
if (ret)
dev_err(dev, "failed to update the frequency\n");
return ret;
err_free_cpu_data:
kfree(parent_cpu_data);
err_put_policy:
cpufreq_cpu_put(policy);
err:
return ret;
}
static int devfreq_passive_notifier_call(struct notifier_block *nb,
unsigned long event, void *ptr)
{
struct devfreq_passive_data *data
= container_of(nb, struct devfreq_passive_data, nb);
struct devfreq *devfreq = (struct devfreq *)data->this;
struct devfreq *parent = (struct devfreq *)data->parent;
struct devfreq_freqs *freqs = (struct devfreq_freqs *)ptr;
unsigned long freq = freqs->new;
int ret = 0;
mutex_lock_nested(&devfreq->lock, SINGLE_DEPTH_NESTING);
switch (event) {
case DEVFREQ_PRECHANGE:
if (parent->previous_freq > freq)
ret = devfreq_update_target(devfreq, freq);
break;
case DEVFREQ_POSTCHANGE:
if (parent->previous_freq < freq)
ret = devfreq_update_target(devfreq, freq);
break;
}
mutex_unlock(&devfreq->lock);
if (ret < 0)
dev_warn(&devfreq->dev,
"failed to update devfreq using passive governor\n");
return NOTIFY_DONE;
}
static int devfreq_passive_unregister_notifier(struct devfreq *devfreq)
{
struct devfreq_passive_data *p_data
= (struct devfreq_passive_data *)devfreq->data;
struct devfreq *parent = (struct devfreq *)p_data->parent;
struct notifier_block *nb = &p_data->nb;
return devfreq_unregister_notifier(parent, nb, DEVFREQ_TRANSITION_NOTIFIER);
}
static int devfreq_passive_register_notifier(struct devfreq *devfreq)
{
struct devfreq_passive_data *p_data
= (struct devfreq_passive_data *)devfreq->data;
struct devfreq *parent = (struct devfreq *)p_data->parent;
struct notifier_block *nb = &p_data->nb;
if (!parent)
return -EPROBE_DEFER;
nb->notifier_call = devfreq_passive_notifier_call;
return devfreq_register_notifier(parent, nb, DEVFREQ_TRANSITION_NOTIFIER);
}
static int devfreq_passive_event_handler(struct devfreq *devfreq,
unsigned int event, void *data)
{
struct devfreq_passive_data *p_data
= (struct devfreq_passive_data *)devfreq->data;
int ret = 0;
if (!p_data)
return -EINVAL;
p_data->this = devfreq;
switch (event) {
case DEVFREQ_GOV_START:
if (p_data->parent_type == DEVFREQ_PARENT_DEV)
ret = devfreq_passive_register_notifier(devfreq);
else if (p_data->parent_type == CPUFREQ_PARENT_DEV)
ret = cpufreq_passive_register_notifier(devfreq);
break;
case DEVFREQ_GOV_STOP:
if (p_data->parent_type == DEVFREQ_PARENT_DEV)
WARN_ON(devfreq_passive_unregister_notifier(devfreq));
else if (p_data->parent_type == CPUFREQ_PARENT_DEV)
WARN_ON(cpufreq_passive_unregister_notifier(devfreq));
break;
default:
break;
}
return ret;
}
static struct devfreq_governor devfreq_passive = {
.name = DEVFREQ_GOV_PASSIVE,
.flags = DEVFREQ_GOV_FLAG_IMMUTABLE,
.get_target_freq = devfreq_passive_get_target_freq,
.event_handler = devfreq_passive_event_handler,
};
static int __init devfreq_passive_init(void)
{
return devfreq_add_governor(&devfreq_passive);
}
subsys_initcall(devfreq_passive_init);
static void __exit devfreq_passive_exit(void)
{
int ret;
ret = devfreq_remove_governor(&devfreq_passive);
if (ret)
pr_err("%s: failed remove governor %d\n", __func__, ret);
}
module_exit(devfreq_passive_exit);
MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
MODULE_DESCRIPTION("DEVFREQ Passive governor");
MODULE_LICENSE("GPL v2");