PM QoS: Implement per-device PM QoS constraints

Implement the per-device PM QoS constraints by creating a device
PM QoS API, which calls the PM QoS constraints management core code.

The per-device latency constraints data strctures are stored
in the device dev_pm_info struct.

The device PM code calls the init and destroy of the per-device constraints
data struct in order to support the dynamic insertion and removal of the
devices in the system.

To minimize the data usage by the per-device constraints, the data struct
is only allocated at the first call to dev_pm_qos_add_request.
The data is later free'd when the device is removed from the system.
A global mutex protects the constraints users from the data being
allocated and free'd.

Signed-off-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

2 files changed, 51 insertions, 0 deletions

diff --git a/include/linux/pm.h b/include/linux/pm.h
index ed10f24d5259..d78187e9ca99 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -419,6 +419,13 @@ enum rpm_request {
 	RPM_REQ_RESUME,
 };
 
+/* Per-device PM QoS constraints data struct state */
+enum dev_pm_qos_state {
+	DEV_PM_QOS_NO_DEVICE,		/* No device present */
+	DEV_PM_QOS_DEVICE_PRESENT,	/* Device present, data not allocated */
+	DEV_PM_QOS_ALLOCATED,		/* Device present, data allocated */
+};
+
 struct wakeup_source;
 
 struct pm_domain_data {
@@ -480,6 +487,8 @@ struct dev_pm_info {
 	unsigned long		accounting_timestamp;
 #endif
 	struct pm_subsys_data	*subsys_data;  /* Owned by the subsystem. */
+	struct pm_qos_constraints *constraints;
+	enum dev_pm_qos_state	constraints_state;
 };
 
 extern void update_pm_runtime_accounting(struct device *dev);
diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index 84aa15089896..f75f74dd9b90 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -19,12 +19,18 @@
 #define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE	(2000 * USEC_PER_SEC)
 #define PM_QOS_NETWORK_LAT_DEFAULT_VALUE	(2000 * USEC_PER_SEC)
 #define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE	0
+#define PM_QOS_DEV_LAT_DEFAULT_VALUE		0
 
 struct pm_qos_request {
 	struct plist_node node;
 	int pm_qos_class;
 };
 
+struct dev_pm_qos_request {
+	struct plist_node node;
+	struct device *dev;
+};
+
 enum pm_qos_type {
 	PM_QOS_UNITIALIZED,
 	PM_QOS_MAX,		/* return the largest value */
@@ -51,6 +57,11 @@ enum pm_qos_req_action {
 	PM_QOS_REMOVE_REQ	/* Remove an existing request */
 };
 
+static inline int dev_pm_qos_request_active(struct dev_pm_qos_request *req)
+{
+	return req->dev != 0;
+}
+
 #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);
@@ -64,6 +75,17 @@ int pm_qos_request(int pm_qos_class);
 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);
+
+int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
+			   s32 value);
+int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value);
+int dev_pm_qos_remove_request(struct dev_pm_qos_request *req);
+int dev_pm_qos_add_notifier(struct device *dev,
+			    struct notifier_block *notifier);
+int dev_pm_qos_remove_notifier(struct device *dev,
+			       struct notifier_block *notifier);
+void dev_pm_qos_constraints_init(struct device *dev);
+void dev_pm_qos_constraints_destroy(struct device *dev);
 #else
 static inline int pm_qos_update_target(struct pm_qos_constraints *c,
 				       struct plist_node *node,
@@ -89,6 +111,26 @@ static inline int pm_qos_remove_notifier(int pm_qos_class,
 			{ return 0; }
 static inline int pm_qos_request_active(struct pm_qos_request *req)
 			{ return 0; }
+
+static inline int dev_pm_qos_add_request(struct device *dev,
+					 struct dev_pm_qos_request *req,
+					 s32 value)
+			{ return 0; }
+static inline int dev_pm_qos_update_request(struct dev_pm_qos_request *req,
+					    s32 new_value)
+			{ return 0; }
+static inline int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
+			{ return 0; }
+static inline int dev_pm_qos_add_notifier(struct device *dev,
+					  struct notifier_block *notifier)
+			{ return 0; }
+static inline int dev_pm_qos_remove_notifier(struct device *dev,
+					     struct notifier_block *notifier)
+			{ return 0; }
+static inline void dev_pm_qos_constraints_init(struct device *dev)
+			{ return; }
+static inline void dev_pm_qos_constraints_destroy(struct device *dev)
+			{ return; }
 #endif
 
 #endif