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