PM / QoS: Add support for MIN/MAX frequency constraints

This patch introduces the min-frequency and max-frequency device
constraints, which will be used by the cpufreq core to begin with.
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/qos.c

@@ -120,6 +120,14 @@ s32 dev_pm_qos_read_value(struct device *dev, enum dev_pm_qos_req_type type)
 		ret = IS_ERR_OR_NULL(qos) ? PM_QOS_RESUME_LATENCY_NO_CONSTRAINT
 			: pm_qos_read_value(&qos->resume_latency);
 		break;
+	case DEV_PM_QOS_MIN_FREQUENCY:
+		ret = IS_ERR_OR_NULL(qos) ? PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE
+			: pm_qos_read_value(&qos->min_frequency);
+		break;
+	case DEV_PM_QOS_MAX_FREQUENCY:
+		ret = IS_ERR_OR_NULL(qos) ? PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE
+			: pm_qos_read_value(&qos->max_frequency);
+		break;
 	default:
 		WARN_ON(1);
 		ret = 0;
@@ -161,6 +169,14 @@ static int apply_constraint(struct dev_pm_qos_request *req,
 			req->dev->power.set_latency_tolerance(req->dev, value);
 		}
 		break;
+	case DEV_PM_QOS_MIN_FREQUENCY:
+		ret = pm_qos_update_target(&qos->min_frequency,
+					   &req->data.pnode, action, value);
+		break;
+	case DEV_PM_QOS_MAX_FREQUENCY:
+		ret = pm_qos_update_target(&qos->max_frequency,
+					   &req->data.pnode, action, value);
+		break;
 	case DEV_PM_QOS_FLAGS:
 		ret = pm_qos_update_flags(&qos->flags, &req->data.flr,
 					  action, value);
@@ -189,12 +205,11 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
 	if (!qos)
 		return -ENOMEM;
 
-	n = kzalloc(sizeof(*n), GFP_KERNEL);
+	n = kzalloc(3 * sizeof(*n), GFP_KERNEL);
 	if (!n) {
 		kfree(qos);
 		return -ENOMEM;
 	}
-	BLOCKING_INIT_NOTIFIER_HEAD(n);
 
 	c = &qos->resume_latency;
 	plist_head_init(&c->list);
@@ -203,6 +218,7 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
 	c->no_constraint_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
 	c->type = PM_QOS_MIN;
 	c->notifiers = n;
+	BLOCKING_INIT_NOTIFIER_HEAD(n);
 
 	c = &qos->latency_tolerance;
 	plist_head_init(&c->list);
@@ -211,6 +227,24 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
 	c->no_constraint_value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT;
 	c->type = PM_QOS_MIN;
 
+	c = &qos->min_frequency;
+	plist_head_init(&c->list);
+	c->target_value = PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE;
+	c->default_value = PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE;
+	c->no_constraint_value = PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE;
+	c->type = PM_QOS_MAX;
+	c->notifiers = ++n;
+	BLOCKING_INIT_NOTIFIER_HEAD(n);
+
+	c = &qos->max_frequency;
+	plist_head_init(&c->list);
+	c->target_value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
+	c->default_value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
+	c->no_constraint_value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
+	c->type = PM_QOS_MIN;
+	c->notifiers = ++n;
+	BLOCKING_INIT_NOTIFIER_HEAD(n);
+
 	INIT_LIST_HEAD(&qos->flags.list);
 
 	spin_lock_irq(&dev->power.lock);
@@ -264,11 +298,25 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
 		apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
 		memset(req, 0, sizeof(*req));
 	}
+
 	c = &qos->latency_tolerance;
 	plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
 		apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
 		memset(req, 0, sizeof(*req));
 	}
+
+	c = &qos->min_frequency;
+	plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
+		apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE);
+		memset(req, 0, sizeof(*req));
+	}
+
+	c = &qos->max_frequency;
+	plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
+		apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
+		memset(req, 0, sizeof(*req));
+	}
+
 	f = &qos->flags;
 	list_for_each_entry_safe(req, tmp, &f->list, data.flr.node) {
 		apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
@@ -380,6 +428,8 @@ static int __dev_pm_qos_update_request(struct dev_pm_qos_request *req,
 	switch(req->type) {
 	case DEV_PM_QOS_RESUME_LATENCY:
 	case DEV_PM_QOS_LATENCY_TOLERANCE:
+	case DEV_PM_QOS_MIN_FREQUENCY:
+	case DEV_PM_QOS_MAX_FREQUENCY:
 		curr_value = req->data.pnode.prio;
 		break;
 	case DEV_PM_QOS_FLAGS:
@@ -492,9 +542,6 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
 {
 	int ret = 0;
 
-	if (WARN_ON(type != DEV_PM_QOS_RESUME_LATENCY))
-		return -EINVAL;
-
 	mutex_lock(&dev_pm_qos_mtx);
 
 	if (IS_ERR(dev->power.qos))
@@ -502,10 +549,28 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
 	else if (!dev->power.qos)
 		ret = dev_pm_qos_constraints_allocate(dev);
 
-	if (!ret)
+	if (ret)
+		goto unlock;
+
+	switch (type) {
+	case DEV_PM_QOS_RESUME_LATENCY:
 		ret = blocking_notifier_chain_register(dev->power.qos->resume_latency.notifiers,
 						       notifier);
+		break;
+	case DEV_PM_QOS_MIN_FREQUENCY:
+		ret = blocking_notifier_chain_register(dev->power.qos->min_frequency.notifiers,
+						       notifier);
+		break;
+	case DEV_PM_QOS_MAX_FREQUENCY:
+		ret = blocking_notifier_chain_register(dev->power.qos->max_frequency.notifiers,
+						       notifier);
+		break;
+	default:
+		WARN_ON(1);
+		ret = -EINVAL;
+	}
 
+unlock:
 	mutex_unlock(&dev_pm_qos_mtx);
 	return ret;
 }
@@ -526,20 +591,35 @@ int dev_pm_qos_remove_notifier(struct device *dev,
 			       struct notifier_block *notifier,
 			       enum dev_pm_qos_req_type type)
 {
-	int retval = 0;
-
-	if (WARN_ON(type != DEV_PM_QOS_RESUME_LATENCY))
-		return -EINVAL;
+	int ret = 0;
 
 	mutex_lock(&dev_pm_qos_mtx);
 
 	/* Silently return if the constraints object is not present. */
-	if (!IS_ERR_OR_NULL(dev->power.qos))
-		retval = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers,
-							    notifier);
+	if (IS_ERR_OR_NULL(dev->power.qos))
+		goto unlock;
+
+	switch (type) {
+	case DEV_PM_QOS_RESUME_LATENCY:
+		ret = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers,
+							 notifier);
+		break;
+	case DEV_PM_QOS_MIN_FREQUENCY:
+		ret = blocking_notifier_chain_unregister(dev->power.qos->min_frequency.notifiers,
+							 notifier);
+		break;
+	case DEV_PM_QOS_MAX_FREQUENCY:
+		ret = blocking_notifier_chain_unregister(dev->power.qos->max_frequency.notifiers,
+							 notifier);
+		break;
+	default:
+		WARN_ON(1);
+		ret = -EINVAL;
+	}
 
+unlock:
 	mutex_unlock(&dev_pm_qos_mtx);
-	return retval;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier);
 
@@ -599,6 +679,9 @@ static void __dev_pm_qos_drop_user_request(struct device *dev,
 		req = dev->power.qos->flags_req;
 		dev->power.qos->flags_req = NULL;
 		break;
+	default:
+		WARN_ON(1);
+		return;
 	}
 	__dev_pm_qos_remove_request(req);
 	kfree(req);

include/linux/pm_qos.h

@@ -40,6 +40,8 @@ enum pm_qos_flags_status {
 #define PM_QOS_RESUME_LATENCY_NO_CONSTRAINT	PM_QOS_LATENCY_ANY
 #define PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS	PM_QOS_LATENCY_ANY_NS
 #define PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE	0
+#define PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE	0
+#define PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE	(-1)
 #define PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT	(-1)
 
 #define PM_QOS_FLAG_NO_POWER_OFF	(1 << 0)
@@ -58,6 +60,8 @@ struct pm_qos_flags_request {
 enum dev_pm_qos_req_type {
 	DEV_PM_QOS_RESUME_LATENCY = 1,
 	DEV_PM_QOS_LATENCY_TOLERANCE,
+	DEV_PM_QOS_MIN_FREQUENCY,
+	DEV_PM_QOS_MAX_FREQUENCY,
 	DEV_PM_QOS_FLAGS,
 };
 
@@ -99,10 +103,14 @@ struct pm_qos_flags {
 struct dev_pm_qos {
 	struct pm_qos_constraints resume_latency;
 	struct pm_qos_constraints latency_tolerance;
+	struct pm_qos_constraints min_frequency;
+	struct pm_qos_constraints max_frequency;
 	struct pm_qos_flags flags;
 	struct dev_pm_qos_request *resume_latency_req;
 	struct dev_pm_qos_request *latency_tolerance_req;
 	struct dev_pm_qos_request *flags_req;
+	struct dev_pm_qos_request *min_frequency_req;
+	struct dev_pm_qos_request *max_frequency_req;
 };
 
 /* Action requested to pm_qos_update_target */
@@ -197,6 +205,10 @@ static inline s32 dev_pm_qos_read_value(struct device *dev,
 	switch (type) {
 	case DEV_PM_QOS_RESUME_LATENCY:
 		return PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
+	case DEV_PM_QOS_MIN_FREQUENCY:
+		return PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE;
+	case DEV_PM_QOS_MAX_FREQUENCY:
+		return PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
 	default:
 		WARN_ON(1);
 		return 0;