PM / QoS: Restore DEV_PM_QOS_MIN/MAX_FREQUENCY

Support for adding per-device frequency limits was removed in
commit 2aac8bdf ("PM: QoS: Drop frequency QoS types from device PM QoS")
after cpufreq switched to use a new "freq_constraints" construct.

Restore support for per-device freq limits but base this upon
freq_constraints. This is primarily meant to be used by the devfreq
subsystem.

This removes the "static" marking on freq_qos_apply but does not export
it for modules.
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/qos.c

@@ -115,10 +115,20 @@ s32 dev_pm_qos_read_value(struct device *dev, enum dev_pm_qos_req_type type)
 
 	spin_lock_irqsave(&dev->power.lock, flags);
 
-	if (type == DEV_PM_QOS_RESUME_LATENCY) {
+	switch (type) {
+	case DEV_PM_QOS_RESUME_LATENCY:
 		ret = IS_ERR_OR_NULL(qos) ? PM_QOS_RESUME_LATENCY_NO_CONSTRAINT
 			: pm_qos_read_value(&qos->resume_latency);
-	} else {
+		break;
+	case DEV_PM_QOS_MIN_FREQUENCY:
+		ret = IS_ERR_OR_NULL(qos) ? PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE
+			: freq_qos_read_value(&qos->freq, FREQ_QOS_MIN);
+		break;
+	case DEV_PM_QOS_MAX_FREQUENCY:
+		ret = IS_ERR_OR_NULL(qos) ? PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE
+			: freq_qos_read_value(&qos->freq, FREQ_QOS_MAX);
+		break;
+	default:
 		WARN_ON(1);
 		ret = 0;
 	}
@@ -159,6 +169,10 @@ 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:
+	case DEV_PM_QOS_MAX_FREQUENCY:
+		ret = freq_qos_apply(&req->data.freq, action, value);
+		break;
 	case DEV_PM_QOS_FLAGS:
 		ret = pm_qos_update_flags(&qos->flags, &req->data.flr,
 					  action, value);
@@ -209,6 +223,8 @@ 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;
 
+	freq_constraints_init(&qos->freq);
+
 	INIT_LIST_HEAD(&qos->flags.list);
 
 	spin_lock_irq(&dev->power.lock);
@@ -269,6 +285,20 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
 		memset(req, 0, sizeof(*req));
 	}
 
+	c = &qos->freq.min_freq;
+	plist_for_each_entry_safe(req, tmp, &c->list, data.freq.pnode) {
+		apply_constraint(req, PM_QOS_REMOVE_REQ,
+				 PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE);
+		memset(req, 0, sizeof(*req));
+	}
+
+	c = &qos->freq.max_freq;
+	plist_for_each_entry_safe(req, tmp, &c->list, data.freq.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);
@@ -314,11 +344,22 @@ static int __dev_pm_qos_add_request(struct device *dev,
 		ret = dev_pm_qos_constraints_allocate(dev);
 
 	trace_dev_pm_qos_add_request(dev_name(dev), type, value);
-	if (!ret) {
+	if (ret)
+		return ret;
+
 	req->dev = dev;
 	req->type = type;
+	if (req->type == DEV_PM_QOS_MIN_FREQUENCY)
+		ret = freq_qos_add_request(&dev->power.qos->freq,
+					   &req->data.freq,
+					   FREQ_QOS_MIN, value);
+	else if (req->type == DEV_PM_QOS_MAX_FREQUENCY)
+		ret = freq_qos_add_request(&dev->power.qos->freq,
+					   &req->data.freq,
+					   FREQ_QOS_MAX, value);
+	else
 		ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
-	}
+
 	return ret;
 }
 
@@ -382,6 +423,10 @@ static int __dev_pm_qos_update_request(struct dev_pm_qos_request *req,
 	case DEV_PM_QOS_LATENCY_TOLERANCE:
 		curr_value = req->data.pnode.prio;
 		break;
+	case DEV_PM_QOS_MIN_FREQUENCY:
+	case DEV_PM_QOS_MAX_FREQUENCY:
+		curr_value = req->data.freq.pnode.prio;
+		break;
 	case DEV_PM_QOS_FLAGS:
 		curr_value = req->data.flr.flags;
 		break;
@@ -507,6 +552,14 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
 		ret = blocking_notifier_chain_register(dev->power.qos->resume_latency.notifiers,
 						       notifier);
 		break;
+	case DEV_PM_QOS_MIN_FREQUENCY:
+		ret = freq_qos_add_notifier(&dev->power.qos->freq,
+					    FREQ_QOS_MIN, notifier);
+		break;
+	case DEV_PM_QOS_MAX_FREQUENCY:
+		ret = freq_qos_add_notifier(&dev->power.qos->freq,
+					    FREQ_QOS_MAX, notifier);
+		break;
 	default:
 		WARN_ON(1);
 		ret = -EINVAL;
@@ -546,6 +599,14 @@ int dev_pm_qos_remove_notifier(struct device *dev,
 		ret = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers,
 							 notifier);
 		break;
+	case DEV_PM_QOS_MIN_FREQUENCY:
+		ret = freq_qos_remove_notifier(&dev->power.qos->freq,
+					       FREQ_QOS_MIN, notifier);
+		break;
+	case DEV_PM_QOS_MAX_FREQUENCY:
+		ret = freq_qos_remove_notifier(&dev->power.qos->freq,
+					       FREQ_QOS_MAX, notifier);
+		break;
 	default:
 		WARN_ON(1);
 		ret = -EINVAL;

include/linux/pm_qos.h

@@ -34,6 +34,8 @@ 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	FREQ_QOS_MAX_DEFAULT_VALUE
 #define PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT	(-1)
 
 #define PM_QOS_FLAG_NO_POWER_OFF	(1 << 0)
@@ -101,6 +103,8 @@ struct freq_qos_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,
 };
 
@@ -109,6 +113,7 @@ struct dev_pm_qos_request {
 	union {
 		struct plist_node pnode;
 		struct pm_qos_flags_request flr;
+		struct freq_qos_request freq;
 	} data;
 	struct device *dev;
 };
@@ -116,6 +121,7 @@ struct dev_pm_qos_request {
 struct dev_pm_qos {
 	struct pm_qos_constraints resume_latency;
 	struct pm_qos_constraints latency_tolerance;
+	struct freq_constraints freq;
 	struct pm_qos_flags flags;
 	struct dev_pm_qos_request *resume_latency_req;
 	struct dev_pm_qos_request *latency_tolerance_req;
@@ -214,6 +220,10 @@ 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;
@@ -293,6 +303,8 @@ int freq_qos_add_request(struct freq_constraints *qos,
 			 enum freq_qos_req_type type, s32 value);
 int freq_qos_update_request(struct freq_qos_request *req, s32 new_value);
 int freq_qos_remove_request(struct freq_qos_request *req);
+int freq_qos_apply(struct freq_qos_request *req,
+		   enum pm_qos_req_action action, s32 value);
 
 int freq_qos_add_notifier(struct freq_constraints *qos,
 			  enum freq_qos_req_type type,

kernel/power/qos.c

@@ -714,8 +714,10 @@ s32 freq_qos_read_value(struct freq_constraints *qos,
  * @req: Constraint request to apply.
  * @action: Action to perform (add/update/remove).
  * @value: Value to assign to the QoS request.
+ *
+ * This is only meant to be called from inside pm_qos, not drivers.
  */
-static int freq_qos_apply(struct freq_qos_request *req,
+int freq_qos_apply(struct freq_qos_request *req,
 			  enum pm_qos_req_action action, s32 value)
 {
 	int ret;