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>

1 files changed, 9 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);