Commit 05d7ae15 authored by Leonard Crestez's avatar Leonard Crestez Committed by Chanwoo Choi
Browse files

PM / devfreq: Add PM QoS support 



Register notifiers with the PM QoS framework in order to respond to
requests for DEV_PM_QOS_MIN_FREQUENCY and DEV_PM_QOS_MAX_FREQUENCY.

No notifiers are added by this patch but PM QoS constraints can be
imposed externally (for example from other devices).

Signed-off-by: default avatarLeonard Crestez <leonard.crestez@nxp.com>
Acked-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: default avatarMatthias Kaehlcke <mka@chromium.org>
Tested-by: default avatarMatthias Kaehlcke <mka@chromium.org>
Signed-off-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
parent 42a6b25e

drivers/devfreq/devfreq.c

+77 −0
Original line number Diff line number Diff line
@@ -24,11 +24,14 @@ 
#include <linux/printk.h>

#include <linux/hrtimer.h>

#include <linux/of.h>

#include <linux/pm_qos.h>

#include "governor.h"



#define CREATE_TRACE_POINTS

#include <trace/events/devfreq.h>



#define HZ_PER_KHZ	1000



static struct class *devfreq_class;



/*
@@ -111,6 +114,7 @@ static void get_freq_range(struct devfreq *devfreq, 
			   unsigned long *max_freq)

{

	unsigned long *freq_table = devfreq->profile->freq_table;

	s32 qos_min_freq, qos_max_freq;



	lockdep_assert_held(&devfreq->lock);
@@ -127,6 +131,16 @@ static void get_freq_range(struct devfreq *devfreq, 
		*max_freq = freq_table[0];

	}



	/* Apply constraints from PM QoS */

	qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,

					     DEV_PM_QOS_MIN_FREQUENCY);

	qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,

					     DEV_PM_QOS_MAX_FREQUENCY);

	*min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq);

	if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE)

		*max_freq = min(*max_freq,

				(unsigned long)HZ_PER_KHZ * qos_max_freq);



	/* Apply constraints from sysfs */

	*min_freq = max(*min_freq, devfreq->min_freq);

	*max_freq = min(*max_freq, devfreq->max_freq);
@@ -626,6 +640,45 @@ out: 
	return NOTIFY_OK;

}



/**

 * qos_notifier_call() - Common handler for QoS constraints.

 * @devfreq:    the devfreq instance.

 */

static int qos_notifier_call(struct devfreq *devfreq)

{

	int err;



	mutex_lock(&devfreq->lock);

	err = update_devfreq(devfreq);

	mutex_unlock(&devfreq->lock);

	if (err)

		dev_err(devfreq->dev.parent,

			"failed to update frequency from PM QoS (%d)\n",

			err);



	return NOTIFY_OK;

}



/**

 * qos_min_notifier_call() - Callback for QoS min_freq changes.

 * @nb:		Should be devfreq->nb_min

 */

static int qos_min_notifier_call(struct notifier_block *nb,

					 unsigned long val, void *ptr)

{

	return qos_notifier_call(container_of(nb, struct devfreq, nb_min));

}



/**

 * qos_max_notifier_call() - Callback for QoS max_freq changes.

 * @nb:		Should be devfreq->nb_max

 */

static int qos_max_notifier_call(struct notifier_block *nb,

					 unsigned long val, void *ptr)

{

	return qos_notifier_call(container_of(nb, struct devfreq, nb_max));

}



/**

 * devfreq_dev_release() - Callback for struct device to release the device.

 * @dev:	the devfreq device
@@ -635,11 +688,23 @@ out: 
static void devfreq_dev_release(struct device *dev)

{

	struct devfreq *devfreq = to_devfreq(dev);

	int err;



	mutex_lock(&devfreq_list_lock);

	list_del(&devfreq->node);

	mutex_unlock(&devfreq_list_lock);



	err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,

					 DEV_PM_QOS_MAX_FREQUENCY);

	if (err && err != -ENOENT)

		dev_warn(dev->parent,

			"Failed to remove max_freq notifier: %d\n", err);

	err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,

					 DEV_PM_QOS_MIN_FREQUENCY);

	if (err && err != -ENOENT)

		dev_warn(dev->parent,

			"Failed to remove min_freq notifier: %d\n", err);



	if (devfreq->profile->exit)

		devfreq->profile->exit(devfreq->dev.parent);
@@ -762,6 +827,18 @@ struct devfreq *devfreq_add_device(struct device *dev, 


	mutex_unlock(&devfreq->lock);



	devfreq->nb_min.notifier_call = qos_min_notifier_call;

	err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_min,

				      DEV_PM_QOS_MIN_FREQUENCY);

	if (err)

		goto err_devfreq;



	devfreq->nb_max.notifier_call = qos_max_notifier_call;

	err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_max,

				      DEV_PM_QOS_MAX_FREQUENCY);

	if (err)

		goto err_devfreq;



	mutex_lock(&devfreq_list_lock);



	governor = try_then_request_governor(devfreq->governor_name);

include/linux/devfreq.h

+5 −0
Original line number Diff line number Diff line
@@ -136,6 +136,8 @@ struct devfreq_dev_profile { 
 * @time_in_state:	Statistics of devfreq states

 * @last_stat_updated:	The last time stat updated

 * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier

 * @nb_min:		Notifier block for DEV_PM_QOS_MIN_FREQUENCY

 * @nb_max:		Notifier block for DEV_PM_QOS_MAX_FREQUENCY

 *

 * This structure stores the devfreq information for a give device.

 *
@@ -178,6 +180,9 @@ struct devfreq { 
	unsigned long last_stat_updated;



	struct srcu_notifier_head transition_notifier_list;



	struct notifier_block nb_min;

	struct notifier_block nb_max;

};



struct devfreq_freqs {

CRA Git | Maintained and supported by SUSTech CRA and CCSE