forked from Minki/linux
0dd25a0d12
The devfreq governor is able to have the specific flag as follows in order to implement the specific feature. For example, devfreq allows user to change the governors on runtime via sysfs interface. But, if devfreq device uses 'passive' governor, don't allow user to change the governor. For this case, define the DEVFREQ_GOV_FLAG_IMMUTABLE and set it to flag of passive governor. [Definition for governor flag] - DEVFREQ_GOV_FLAG_IMMUTABLE : If immutable flag is set, governor is never changeable to other governors. - DEVFREQ_GOV_FLAG_IRQ_DRIVEN : Devfreq core won't schedule polling work for this governor if value is set. [Table of governor flag for devfreq governors] ------------------------------------------------------------------------------ | simple | perfor | power | user | passive | tegra30 | ondemand | mance | save | space| | ------------------------------------------------------------------------------ immutable | X | X | X | X | O | O interrupt_driven | X(polling)| X | X | X | X | O (irq) ------------------------------------------------------------------------------ Reviewed-by: Dmitry Osipenko <digetx@gmail.com> Tested-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
186 lines
4.9 KiB
C
186 lines
4.9 KiB
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/device.h>
|
|
#include <linux/devfreq.h>
|
|
#include "governor.h"
|
|
|
|
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;
|
|
struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
|
|
unsigned long child_freq = ULONG_MAX;
|
|
struct dev_pm_opp *opp;
|
|
int i, count, ret = 0;
|
|
|
|
/*
|
|
* 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) {
|
|
ret = p_data->get_target_freq(devfreq, freq);
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* If the parent and passive devfreq device uses the OPP table,
|
|
* get the next frequency by using the OPP table.
|
|
*/
|
|
|
|
/*
|
|
* - parent devfreq device uses the governors except for passive.
|
|
* - passive devfreq device uses the passive governor.
|
|
*
|
|
* Each devfreq has the OPP table. After deciding the new frequency
|
|
* from the governor of parent devfreq device, the passive governor
|
|
* need to get the index of new frequency on OPP table of parent
|
|
* device. And then the index is used for getting the suitable
|
|
* new frequency for passive devfreq device.
|
|
*/
|
|
if (!devfreq->profile || !devfreq->profile->freq_table
|
|
|| devfreq->profile->max_state <= 0)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* The passive governor have to get the correct frequency from OPP
|
|
* list of parent device. Because in this case, *freq is temporary
|
|
* value which is decided by ondemand governor.
|
|
*/
|
|
opp = devfreq_recommended_opp(parent_devfreq->dev.parent, freq, 0);
|
|
if (IS_ERR(opp)) {
|
|
ret = PTR_ERR(opp);
|
|
goto out;
|
|
}
|
|
|
|
dev_pm_opp_put(opp);
|
|
|
|
/*
|
|
* Get the OPP table's index of decided freqeuncy by governor
|
|
* of parent device.
|
|
*/
|
|
for (i = 0; i < parent_devfreq->profile->max_state; i++)
|
|
if (parent_devfreq->profile->freq_table[i] == *freq)
|
|
break;
|
|
|
|
if (i == parent_devfreq->profile->max_state) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* Get the suitable frequency by using index of parent device. */
|
|
if (i < devfreq->profile->max_state) {
|
|
child_freq = devfreq->profile->freq_table[i];
|
|
} else {
|
|
count = devfreq->profile->max_state;
|
|
child_freq = devfreq->profile->freq_table[count - 1];
|
|
}
|
|
|
|
/* Return the suitable frequency for passive device. */
|
|
*freq = child_freq;
|
|
|
|
out:
|
|
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_event_handler(struct devfreq *devfreq,
|
|
unsigned int event, void *data)
|
|
{
|
|
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;
|
|
int ret = 0;
|
|
|
|
if (!parent)
|
|
return -EPROBE_DEFER;
|
|
|
|
switch (event) {
|
|
case DEVFREQ_GOV_START:
|
|
if (!p_data->this)
|
|
p_data->this = devfreq;
|
|
|
|
nb->notifier_call = devfreq_passive_notifier_call;
|
|
ret = devfreq_register_notifier(parent, nb,
|
|
DEVFREQ_TRANSITION_NOTIFIER);
|
|
break;
|
|
case DEVFREQ_GOV_STOP:
|
|
WARN_ON(devfreq_unregister_notifier(parent, nb,
|
|
DEVFREQ_TRANSITION_NOTIFIER));
|
|
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");
|