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Commit abe98ec2 authored by Jean Pihet's avatar Jean Pihet Committed by Rafael J. Wysocki
Browse files

PM QoS: Generalize and export constraints management code 



In preparation for the per-device constratins support:
 - rename update_target to pm_qos_update_target
 - generalize and export pm_qos_update_target for usage by the upcoming
   per-device latency constraints framework:
   * operate on struct pm_qos_constraints for constraints management,
   * introduce an 'action' parameter for constraints add/update/remove,
   * the return value indicates if the aggregated constraint value has
     changed,
 - update the internal code to operate on struct pm_qos_constraints
 - add a NULL pointer check in the API functions

Signed-off-by: default avatarJean Pihet <j-pihet@ti.com>
Reviewed-by: default avatarKevin Hilman <khilman@ti.com>
Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent 4e1779ba

include/linux/pm_qos.h

+14 −0
Original line number Diff line number Diff line
@@ -44,7 +44,16 @@ struct pm_qos_constraints { 
	struct blocking_notifier_head *notifiers;

};



/* Action requested to pm_qos_update_target */

enum pm_qos_req_action {

	PM_QOS_ADD_REQ,		/* Add a new request */

	PM_QOS_UPDATE_REQ,	/* Update an existing request */

	PM_QOS_REMOVE_REQ	/* Remove an existing request */

};



#ifdef CONFIG_PM

int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,

			 enum pm_qos_req_action action, int value);

void pm_qos_add_request(struct pm_qos_request *req, int pm_qos_class,

			s32 value);

void pm_qos_update_request(struct pm_qos_request *req,
@@ -56,6 +65,11 @@ int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier); 
int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier);

int pm_qos_request_active(struct pm_qos_request *req);

#else

static inline int pm_qos_update_target(struct pm_qos_constraints *c,

				       struct plist_node *node,

				       enum pm_qos_req_action action,

				       int value)

			{ return 0; }

static inline void pm_qos_add_request(struct pm_qos_request *req,

				      int pm_qos_class, s32 value)

			{ return; }

kernel/power/qos.c

+67 −56
Original line number Diff line number Diff line
@@ -122,17 +122,17 @@ static const struct file_operations pm_qos_power_fops = { 
};



/* unlocked internal variant */

static inline int pm_qos_get_value(struct pm_qos_object *o)

static inline int pm_qos_get_value(struct pm_qos_constraints *c)

{

	if (plist_head_empty(&o->constraints->list))

		return o->constraints->default_value;

	if (plist_head_empty(&c->list))

		return c->default_value;



	switch (o->constraints->type) {

	switch (c->type) {

	case PM_QOS_MIN:

		return plist_first(&o->constraints->list)->prio;

		return plist_first(&c->list)->prio;



	case PM_QOS_MAX:

		return plist_last(&o->constraints->list)->prio;

		return plist_last(&c->list)->prio;



	default:

		/* runtime check for not using enum */
@@ -140,47 +140,73 @@ static inline int pm_qos_get_value(struct pm_qos_object *o) 
	}

}



static inline s32 pm_qos_read_value(struct pm_qos_object *o)

static inline s32 pm_qos_read_value(struct pm_qos_constraints *c)

{

	return o->constraints->target_value;

	return c->target_value;

}



static inline void pm_qos_set_value(struct pm_qos_object *o, s32 value)

static inline void pm_qos_set_value(struct pm_qos_constraints *c, s32 value)

{

	o->constraints->target_value = value;

	c->target_value = value;

}



static void update_target(struct pm_qos_object *o, struct plist_node *node,

			  int del, int value)

/**

 * pm_qos_update_target - manages the constraints list and calls the notifiers

 *  if needed

 * @c: constraints data struct

 * @node: request to add to the list, to update or to remove

 * @action: action to take on the constraints list

 * @value: value of the request to add or update

 *

 * This function returns 1 if the aggregated constraint value has changed, 0

 *  otherwise.

 */

int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,

			 enum pm_qos_req_action action, int value)

{

	unsigned long flags;

	int prev_value, curr_value;

	int prev_value, curr_value, new_value;



	spin_lock_irqsave(&pm_qos_lock, flags);

	prev_value = pm_qos_get_value(o);

	/* PM_QOS_DEFAULT_VALUE is a signal that the value is unchanged */

	if (value != PM_QOS_DEFAULT_VALUE) {

	prev_value = pm_qos_get_value(c);

	if (value == PM_QOS_DEFAULT_VALUE)

		new_value = c->default_value;

	else

		new_value = value;



	switch (action) {

	case PM_QOS_REMOVE_REQ:

		plist_del(node, &c->list);

		break;

	case PM_QOS_UPDATE_REQ:

		/*

		 * to change the list, we atomically remove, reinit

		 * with new value and add, then see if the extremal

		 * changed

		 */

		plist_del(node, &o->constraints->list);

		plist_node_init(node, value);

		plist_add(node, &o->constraints->list);

	} else if (del) {

		plist_del(node, &o->constraints->list);

	} else {

		plist_add(node, &o->constraints->list);

		plist_del(node, &c->list);

	case PM_QOS_ADD_REQ:

		plist_node_init(node, new_value);

		plist_add(node, &c->list);

		break;

	default:

		/* no action */

		;

	}

	curr_value = pm_qos_get_value(o);

	pm_qos_set_value(o, curr_value);



	curr_value = pm_qos_get_value(c);

	pm_qos_set_value(c, curr_value);



	spin_unlock_irqrestore(&pm_qos_lock, flags);



	if (prev_value != curr_value)

		blocking_notifier_call_chain(o->constraints->notifiers,

	if (prev_value != curr_value) {

		blocking_notifier_call_chain(c->notifiers,

					     (unsigned long)curr_value,

					     NULL);

		return 1;

	} else {

		return 0;

	}

}



/**
@@ -191,7 +217,7 @@ static void update_target(struct pm_qos_object *o, struct plist_node *node, 
 */

int pm_qos_request(int pm_qos_class)

{

	return pm_qos_read_value(pm_qos_array[pm_qos_class]);

	return pm_qos_read_value(pm_qos_array[pm_qos_class]->constraints);

}

EXPORT_SYMBOL_GPL(pm_qos_request);
@@ -217,20 +243,16 @@ EXPORT_SYMBOL_GPL(pm_qos_request_active); 
void pm_qos_add_request(struct pm_qos_request *req,

			int pm_qos_class, s32 value)

{

	struct pm_qos_object *o =  pm_qos_array[pm_qos_class];

	int new_value;

	if (!req) /*guard against callers passing in null */

		return;



	if (pm_qos_request_active(req)) {

		WARN(1, KERN_ERR "pm_qos_add_request() called for already added request\n");

		return;

	}

	if (value == PM_QOS_DEFAULT_VALUE)

		new_value = o->constraints->default_value;

	else

		new_value = value;

	plist_node_init(&req->node, new_value);

	req->pm_qos_class = pm_qos_class;

	update_target(o, &req->node, 0, PM_QOS_DEFAULT_VALUE);

	pm_qos_update_target(pm_qos_array[pm_qos_class]->constraints,

			     &req->node, PM_QOS_ADD_REQ, value);

}

EXPORT_SYMBOL_GPL(pm_qos_add_request);
@@ -247,9 +269,6 @@ EXPORT_SYMBOL_GPL(pm_qos_add_request); 
void pm_qos_update_request(struct pm_qos_request *req,

			   s32 new_value)

{

	s32 temp;

	struct pm_qos_object *o;



	if (!req) /*guard against callers passing in null */

		return;
@@ -258,15 +277,10 @@ void pm_qos_update_request(struct pm_qos_request *req, 
		return;

	}



	o = pm_qos_array[req->pm_qos_class];



	if (new_value == PM_QOS_DEFAULT_VALUE)

		temp = o->constraints->default_value;

	else

		temp = new_value;



	if (temp != req->node.prio)

		update_target(o, &req->node, 0, temp);

	if (new_value != req->node.prio)

		pm_qos_update_target(

			pm_qos_array[req->pm_qos_class]->constraints,

			&req->node, PM_QOS_UPDATE_REQ, new_value);

}

EXPORT_SYMBOL_GPL(pm_qos_update_request);
@@ -280,9 +294,7 @@ EXPORT_SYMBOL_GPL(pm_qos_update_request); 
 */

void pm_qos_remove_request(struct pm_qos_request *req)

{

	struct pm_qos_object *o;



	if (req == NULL)

	if (!req) /*guard against callers passing in null */

		return;

		/* silent return to keep pcm code cleaner */
@@ -291,8 +303,9 @@ void pm_qos_remove_request(struct pm_qos_request *req) 
		return;

	}



	o = pm_qos_array[req->pm_qos_class];

	update_target(o, &req->node, 1, PM_QOS_DEFAULT_VALUE);

	pm_qos_update_target(pm_qos_array[req->pm_qos_class]->constraints,

			     &req->node, PM_QOS_REMOVE_REQ,

			     PM_QOS_DEFAULT_VALUE);

	memset(req, 0, sizeof(*req));

}

EXPORT_SYMBOL_GPL(pm_qos_remove_request);
@@ -396,7 +409,6 @@ static ssize_t pm_qos_power_read(struct file *filp, char __user *buf, 
{

	s32 value;

	unsigned long flags;

	struct pm_qos_object *o;

	struct pm_qos_request *req = filp->private_data;



	if (!req)
@@ -404,9 +416,8 @@ static ssize_t pm_qos_power_read(struct file *filp, char __user *buf, 
	if (!pm_qos_request_active(req))

		return -EINVAL;



	o = pm_qos_array[req->pm_qos_class];

	spin_lock_irqsave(&pm_qos_lock, flags);

	value = pm_qos_get_value(o);

	value = pm_qos_get_value(pm_qos_array[req->pm_qos_class]->constraints);

	spin_unlock_irqrestore(&pm_qos_lock, flags);



	return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32));