Commit 3aa173b8 authored by Nishanth Menon's avatar Nishanth Menon Committed by MyungJoo Ham
Browse files

PM / devfreq: provide hooks for governors to be registered 



Add devfreq_add_governor and devfreq_remove_governor which
can be invoked by governors to register with devfreq.

This sets up the stage to dynamically switch governors and
allow governors to be dynamically loaded as well.

Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Kevin Hilman <khilman@ti.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

Signed-off-by: default avatarNishanth Menon <nm@ti.com>
Acked-by: default avatarMyungJoo Ham <myungjoo.ham@samsung.com>
parent 2df5021f

drivers/devfreq/devfreq.c

+91 −0
Original line number Diff line number Diff line
@@ -36,6 +36,8 @@ static struct class *devfreq_class; 
 */

static struct workqueue_struct *devfreq_wq;



/* The list of all device-devfreq governors */

static LIST_HEAD(devfreq_governor_list);

/* The list of all device-devfreq */

static LIST_HEAD(devfreq_list);

static DEFINE_MUTEX(devfreq_list_lock);
@@ -111,6 +113,32 @@ static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) 
	return 0;

}



/**

 * find_devfreq_governor() - find devfreq governor from name

 * @name:	name of the governor

 *

 * Search the list of devfreq governors and return the matched

 * governor's pointer. devfreq_list_lock should be held by the caller.

 */

static struct devfreq_governor *find_devfreq_governor(const char *name)

{

	struct devfreq_governor *tmp_governor;



	if (unlikely(IS_ERR_OR_NULL(name))) {

		pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);

		return ERR_PTR(-EINVAL);

	}

	WARN(!mutex_is_locked(&devfreq_list_lock),

	     "devfreq_list_lock must be locked.");



	list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {

		if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))

			return tmp_governor;

	}



	return ERR_PTR(-ENODEV);

}



/* Load monitoring helper functions for governors use */



/**
@@ -515,6 +543,69 @@ int devfreq_resume_device(struct devfreq *devfreq) 
}

EXPORT_SYMBOL(devfreq_resume_device);



/**

 * devfreq_add_governor() - Add devfreq governor

 * @governor:	the devfreq governor to be added

 */

int devfreq_add_governor(struct devfreq_governor *governor)

{

	struct devfreq_governor *g;

	int err = 0;



	if (!governor) {

		pr_err("%s: Invalid parameters.\n", __func__);

		return -EINVAL;

	}



	mutex_lock(&devfreq_list_lock);

	g = find_devfreq_governor(governor->name);

	if (!IS_ERR(g)) {

		pr_err("%s: governor %s already registered\n", __func__,

		       g->name);

		err = -EINVAL;

		goto err_out;

	}



	list_add(&governor->node, &devfreq_governor_list);



err_out:

	mutex_unlock(&devfreq_list_lock);



	return err;

}

EXPORT_SYMBOL(devfreq_add_governor);



/**

 * devfreq_remove_device() - Remove devfreq feature from a device.

 * @governor:	the devfreq governor to be removed

 */

int devfreq_remove_governor(struct devfreq_governor *governor)

{

	struct devfreq_governor *g;

	int err = 0;



	if (!governor) {

		pr_err("%s: Invalid parameters.\n", __func__);

		return -EINVAL;

	}



	mutex_lock(&devfreq_list_lock);

	g = find_devfreq_governor(governor->name);

	if (IS_ERR(g)) {

		pr_err("%s: governor %s not registered\n", __func__,

		       g->name);

		err = -EINVAL;

		goto err_out;

	}



	list_del(&governor->node);

err_out:

	mutex_unlock(&devfreq_list_lock);



	return err;

}

EXPORT_SYMBOL(devfreq_remove_governor);



static ssize_t show_governor(struct device *dev,

			     struct device_attribute *attr, char *buf)

{

drivers/devfreq/governor.h

+4 −0
Original line number Diff line number Diff line
@@ -34,4 +34,8 @@ extern void devfreq_monitor_suspend(struct devfreq *devfreq); 
extern void devfreq_monitor_resume(struct devfreq *devfreq);

extern void devfreq_interval_update(struct devfreq *devfreq,

					unsigned int *delay);



extern int devfreq_add_governor(struct devfreq_governor *governor);

extern int devfreq_remove_governor(struct devfreq_governor *governor);



#endif /* _GOVERNOR_H */

include/linux/devfreq.h

+3 −0
Original line number Diff line number Diff line
@@ -92,6 +92,7 @@ struct devfreq_dev_profile { 


/**

 * struct devfreq_governor - Devfreq policy governor

 * @node:		list node - contains registered devfreq governors

 * @name:		Governor's name

 * @get_target_freq:	Returns desired operating frequency for the device.

 *			Basically, get_target_freq will run
@@ -107,6 +108,8 @@ struct devfreq_dev_profile { 
 * Note that the callbacks are called with devfreq->lock locked by devfreq.

 */

struct devfreq_governor {

	struct list_head node;



	const char name[DEVFREQ_NAME_LEN];

	int (*get_target_freq)(struct devfreq *this, unsigned long *freq);

	int (*event_handler)(struct devfreq *devfreq,

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