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Commit e33df1d2 authored by Javi Merino's avatar Javi Merino Committed by Eduardo Valentin
Browse files

thermal: let governors have private data for each thermal zone 



A governor may need to store its current state between calls to
throttle().  That state depends on the thermal zone, so store it as
private data in struct thermal_zone_device.

The governors may have two new ops: bind_to_tz() and unbind_from_tz().
When provided, these functions let governors do some initialization
and teardown when they are bound/unbound to a tz and possibly store that
information in the governor_data field of the struct
thermal_zone_device.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: default avatarJavi Merino <javi.merino@arm.com>
Signed-off-by: default avatarEduardo Valentin <edubezval@gmail.com>
parent c610afaa

drivers/thermal/thermal_core.c

+75 −8
Original line number Diff line number Diff line
@@ -75,6 +75,58 @@ static struct thermal_governor *__find_governor(const char *name) 
	return NULL;

}



/**

 * bind_previous_governor() - bind the previous governor of the thermal zone

 * @tz:		a valid pointer to a struct thermal_zone_device

 * @failed_gov_name:	the name of the governor that failed to register

 *

 * Register the previous governor of the thermal zone after a new

 * governor has failed to be bound.

 */

static void bind_previous_governor(struct thermal_zone_device *tz,

				   const char *failed_gov_name)

{

	if (tz->governor && tz->governor->bind_to_tz) {

		if (tz->governor->bind_to_tz(tz)) {

			dev_err(&tz->device,

				"governor %s failed to bind and the previous one (%s) failed to bind again, thermal zone %s has no governor\n",

				failed_gov_name, tz->governor->name, tz->type);

			tz->governor = NULL;

		}

	}

}



/**

 * thermal_set_governor() - Switch to another governor

 * @tz:		a valid pointer to a struct thermal_zone_device

 * @new_gov:	pointer to the new governor

 *

 * Change the governor of thermal zone @tz.

 *

 * Return: 0 on success, an error if the new governor's bind_to_tz() failed.

 */

static int thermal_set_governor(struct thermal_zone_device *tz,

				struct thermal_governor *new_gov)

{

	int ret = 0;



	if (tz->governor && tz->governor->unbind_from_tz)

		tz->governor->unbind_from_tz(tz);



	if (new_gov && new_gov->bind_to_tz) {

		ret = new_gov->bind_to_tz(tz);

		if (ret) {

			bind_previous_governor(tz, new_gov->name);



			return ret;

		}

	}



	tz->governor = new_gov;



	return ret;

}



int thermal_register_governor(struct thermal_governor *governor)

{

	int err;
@@ -107,8 +159,15 @@ int thermal_register_governor(struct thermal_governor *governor) 


		name = pos->tzp->governor_name;



		if (!strncasecmp(name, governor->name, THERMAL_NAME_LENGTH))

			pos->governor = governor;

		if (!strncasecmp(name, governor->name, THERMAL_NAME_LENGTH)) {

			int ret;



			ret = thermal_set_governor(pos, governor);

			if (ret)

				dev_err(&pos->device,

					"Failed to set governor %s for thermal zone %s: %d\n",

					governor->name, pos->type, ret);

		}

	}



	mutex_unlock(&thermal_list_lock);
@@ -134,7 +193,7 @@ void thermal_unregister_governor(struct thermal_governor *governor) 
	list_for_each_entry(pos, &thermal_tz_list, node) {

		if (!strncasecmp(pos->governor->name, governor->name,

						THERMAL_NAME_LENGTH))

			pos->governor = NULL;

			thermal_set_governor(pos, NULL);

	}



	mutex_unlock(&thermal_list_lock);
@@ -770,7 +829,8 @@ policy_store(struct device *dev, struct device_attribute *attr, 
	if (!gov)

		goto exit;



	tz->governor = gov;

	ret = thermal_set_governor(tz, gov);

	if (!ret)

		ret = count;



exit:
@@ -1512,6 +1572,7 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type, 
	int result;

	int count;

	int passive = 0;

	struct thermal_governor *governor;



	if (type && strlen(type) >= THERMAL_NAME_LENGTH)

		return ERR_PTR(-EINVAL);
@@ -1602,9 +1663,15 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type, 
	mutex_lock(&thermal_governor_lock);



	if (tz->tzp)

		tz->governor = __find_governor(tz->tzp->governor_name);

		governor = __find_governor(tz->tzp->governor_name);

	else

		tz->governor = def_governor;

		governor = def_governor;



	result = thermal_set_governor(tz, governor);

	if (result) {

		mutex_unlock(&thermal_governor_lock);

		goto unregister;

	}



	mutex_unlock(&thermal_governor_lock);
@@ -1693,7 +1760,7 @@ void thermal_zone_device_unregister(struct thermal_zone_device *tz) 
		device_remove_file(&tz->device, &dev_attr_mode);

	device_remove_file(&tz->device, &dev_attr_policy);

	remove_trip_attrs(tz);

	tz->governor = NULL;

	thermal_set_governor(tz, NULL);



	thermal_remove_hwmon_sysfs(tz);

	release_idr(&thermal_tz_idr, &thermal_idr_lock, tz->id);

include/linux/thermal.h

+9 −0
Original line number Diff line number Diff line
@@ -165,6 +165,7 @@ struct thermal_attr { 
 * @ops:	operations this &thermal_zone_device supports

 * @tzp:	thermal zone parameters

 * @governor:	pointer to the governor for this thermal zone

 * @governor_data:	private pointer for governor data

 * @thermal_instances:	list of &struct thermal_instance of this thermal zone

 * @idr:	&struct idr to generate unique id for this zone's cooling

 *		devices
@@ -191,6 +192,7 @@ struct thermal_zone_device { 
	struct thermal_zone_device_ops *ops;

	const struct thermal_zone_params *tzp;

	struct thermal_governor *governor;

	void *governor_data;

	struct list_head thermal_instances;

	struct idr idr;

	struct mutex lock;
@@ -201,12 +203,19 @@ struct thermal_zone_device { 
/**

 * struct thermal_governor - structure that holds thermal governor information

 * @name:	name of the governor

 * @bind_to_tz: callback called when binding to a thermal zone.  If it

 *		returns 0, the governor is bound to the thermal zone,

 *		otherwise it fails.

 * @unbind_from_tz:	callback called when a governor is unbound from a

 *			thermal zone.

 * @throttle:	callback called for every trip point even if temperature is

 *		below the trip point temperature

 * @governor_list:	node in thermal_governor_list (in thermal_core.c)

 */

struct thermal_governor {

	char name[THERMAL_NAME_LENGTH];

	int (*bind_to_tz)(struct thermal_zone_device *tz);

	void (*unbind_from_tz)(struct thermal_zone_device *tz);

	int (*throttle)(struct thermal_zone_device *tz, int trip);

	struct list_head	governor_list;

};