summaryrefslogtreecommitdiffstats
path: root/drivers/base/power
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/base/power')
-rw-r--r--drivers/base/power/qos.c89
1 files changed, 75 insertions, 14 deletions
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index cc4c541398aa..8d0b81151c14 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -17,6 +17,12 @@
*
* This QoS design is best effort based. Dependents register their QoS needs.
* Watchers register to keep track of the current QoS needs of the system.
+ * Watchers can register different types of notification callbacks:
+ * . a per-device notification callback using the dev_pm_qos_*_notifier API.
+ * The notification chain data is stored in the per-device constraint
+ * data struct.
+ * . a system-wide notification callback using the dev_pm_qos_*_global_notifier
+ * API. The notification chain data is stored in a static variable.
*
* Note about the per-device constraint data struct allocation:
* . The per-device constraints data struct ptr is tored into the device
@@ -45,6 +51,36 @@
static DEFINE_MUTEX(dev_pm_qos_mtx);
+static BLOCKING_NOTIFIER_HEAD(dev_pm_notifiers);
+
+/*
+ * apply_constraint
+ * @req: constraint request to apply
+ * @action: action to perform add/update/remove, of type enum pm_qos_req_action
+ * @value: defines the qos request
+ *
+ * Internal function to update the constraints list using the PM QoS core
+ * code and if needed call the per-device and the global notification
+ * callbacks
+ */
+static int apply_constraint(struct dev_pm_qos_request *req,
+ enum pm_qos_req_action action, int value)
+{
+ int ret, curr_value;
+
+ ret = pm_qos_update_target(req->dev->power.constraints,
+ &req->node, action, value);
+
+ if (ret) {
+ /* Call the global callbacks if needed */
+ curr_value = pm_qos_read_value(req->dev->power.constraints);
+ blocking_notifier_call_chain(&dev_pm_notifiers,
+ (unsigned long)curr_value,
+ req);
+ }
+
+ return ret;
+}
/*
* dev_pm_qos_constraints_allocate
@@ -111,12 +147,11 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
&dev->power.constraints->list,
node) {
/*
- * Update constraints list and call the per-device
+ * Update constraints list and call the notification
* callbacks if needed
*/
- pm_qos_update_target(req->dev->power.constraints,
- &req->node, PM_QOS_REMOVE_REQ,
- PM_QOS_DEFAULT_VALUE);
+ apply_constraint(req, PM_QOS_REMOVE_REQ,
+ PM_QOS_DEFAULT_VALUE);
memset(req, 0, sizeof(*req));
}
@@ -147,7 +182,7 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
* removed from the system
*/
int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
- s32 value)
+ s32 value)
{
int ret = 0;
@@ -178,8 +213,7 @@ int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
ret = dev_pm_qos_constraints_allocate(dev);
if (!ret)
- ret = pm_qos_update_target(dev->power.constraints, &req->node,
- PM_QOS_ADD_REQ, value);
+ ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
out:
mutex_unlock(&dev_pm_qos_mtx);
@@ -220,10 +254,8 @@ int dev_pm_qos_update_request(struct dev_pm_qos_request *req,
if (req->dev->power.constraints_state == DEV_PM_QOS_ALLOCATED) {
if (new_value != req->node.prio)
- ret = pm_qos_update_target(req->dev->power.constraints,
- &req->node,
- PM_QOS_UPDATE_REQ,
- new_value);
+ ret = apply_constraint(req, PM_QOS_UPDATE_REQ,
+ new_value);
} else {
/* Return if the device has been removed */
ret = -ENODEV;
@@ -262,9 +294,8 @@ int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
mutex_lock(&dev_pm_qos_mtx);
if (req->dev->power.constraints_state == DEV_PM_QOS_ALLOCATED) {
- ret = pm_qos_update_target(req->dev->power.constraints,
- &req->node, PM_QOS_REMOVE_REQ,
- PM_QOS_DEFAULT_VALUE);
+ ret = apply_constraint(req, PM_QOS_REMOVE_REQ,
+ PM_QOS_DEFAULT_VALUE);
memset(req, 0, sizeof(*req));
} else {
/* Return if the device has been removed */
@@ -336,3 +367,33 @@ out:
return retval;
}
EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier);
+
+/**
+ * dev_pm_qos_add_global_notifier - sets notification entry for changes to
+ * target value of the PM QoS constraints for any device
+ *
+ * @notifier: notifier block managed by caller.
+ *
+ * Will register the notifier into a notification chain that gets called
+ * upon changes to the target value for any device.
+ */
+int dev_pm_qos_add_global_notifier(struct notifier_block *notifier)
+{
+ return blocking_notifier_chain_register(&dev_pm_notifiers, notifier);
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_add_global_notifier);
+
+/**
+ * dev_pm_qos_remove_global_notifier - deletes notification for changes to
+ * target value of PM QoS constraints for any device
+ *
+ * @notifier: notifier block to be removed.
+ *
+ * Will remove the notifier from the notification chain that gets called
+ * upon changes to the target value for any device.
+ */
+int dev_pm_qos_remove_global_notifier(struct notifier_block *notifier)
+{
+ return blocking_notifier_chain_unregister(&dev_pm_notifiers, notifier);
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_remove_global_notifier);