*
* 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
* . 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.
- * . The constraints_state variable from dev_pm_info tracks the data struct
- * allocation state:
- * DEV_PM_QOS_NO_DEVICE: No device present or device removed, no data
- * allocated,
- * DEV_PM_QOS_DEVICE_PRESENT: Device present, data not allocated and will be
- * allocated at the first call to dev_pm_qos_add_request,
- * DEV_PM_QOS_ALLOCATED: Device present, data allocated. The per-device
- * PM QoS constraints framework is operational and constraints can be
- * added, updated or removed using the dev_pm_qos_* API.
* . A global mutex protects the constraints users from the data being
* allocated and free'd.
*/
static DEFINE_MUTEX(dev_pm_qos_mtx);
+static BLOCKING_NOTIFIER_HEAD(dev_pm_notifiers);
+
+/**
+ * dev_pm_qos_read_value - Get PM QoS constraint for a given device.
+ * @dev: Device to get the PM QoS constraint value for.
+ */
+s32 dev_pm_qos_read_value(struct device *dev)
+{
+ struct pm_qos_constraints *c;
+ unsigned long flags;
+ s32 ret = 0;
+
+ spin_lock_irqsave(&dev->power.lock, flags);
+
+ c = dev->power.constraints;
+ if (c)
+ ret = pm_qos_read_value(c);
+
+ spin_unlock_irqrestore(&dev->power.lock, flags);
+
+ return ret;
+}
+
+/*
+ * 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
* @dev: device to allocate data for
}
BLOCKING_INIT_NOTIFIER_HEAD(n);
+ plist_head_init(&c->list);
+ c->target_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
+ c->default_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
+ c->type = PM_QOS_MIN;
+ c->notifiers = n;
+
+ spin_lock_irq(&dev->power.lock);
dev->power.constraints = c;
- plist_head_init(&dev->power.constraints->list);
- dev->power.constraints->target_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
- dev->power.constraints->default_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
- dev->power.constraints->type = PM_QOS_MIN;
- dev->power.constraints->notifiers = n;
- dev->power.constraints_state = DEV_PM_QOS_ALLOCATED;
+ spin_unlock_irq(&dev->power.lock);
return 0;
}
/**
- * dev_pm_qos_constraints_init
+ * dev_pm_qos_constraints_init - Initalize device's PM QoS constraints pointer.
* @dev: target device
*
- * Called from the device PM subsystem at device insertion
+ * Called from the device PM subsystem during device insertion under
+ * device_pm_lock().
*/
void dev_pm_qos_constraints_init(struct device *dev)
{
mutex_lock(&dev_pm_qos_mtx);
- dev->power.constraints_state = DEV_PM_QOS_DEVICE_PRESENT;
+ dev->power.constraints = NULL;
+ dev->power.power_state = PMSG_ON;
mutex_unlock(&dev_pm_qos_mtx);
}
* dev_pm_qos_constraints_destroy
* @dev: target device
*
- * Called from the device PM subsystem at device removal
+ * Called from the device PM subsystem on device removal under device_pm_lock().
*/
void dev_pm_qos_constraints_destroy(struct device *dev)
{
struct dev_pm_qos_request *req, *tmp;
+ struct pm_qos_constraints *c;
mutex_lock(&dev_pm_qos_mtx);
- if (dev->power.constraints_state == DEV_PM_QOS_ALLOCATED) {
- /* Flush the constraints list for the device */
- plist_for_each_entry_safe(req, tmp,
- &dev->power.constraints->list,
- node) {
- /*
- * Update constraints list and call the per-device
- * callbacks if needed
- */
- pm_qos_update_target(req->dev->power.constraints,
- &req->node, PM_QOS_REMOVE_REQ,
- PM_QOS_DEFAULT_VALUE);
- memset(req, 0, sizeof(*req));
- }
+ dev->power.power_state = PMSG_INVALID;
+ c = dev->power.constraints;
+ if (!c)
+ goto out;
- kfree(dev->power.constraints->notifiers);
- kfree(dev->power.constraints);
- dev->power.constraints = NULL;
+ /* Flush the constraints list for the device */
+ plist_for_each_entry_safe(req, tmp, &c->list, node) {
+ /*
+ * Update constraints list and call the notification
+ * callbacks if needed
+ */
+ apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
+ memset(req, 0, sizeof(*req));
}
- dev->power.constraints_state = DEV_PM_QOS_NO_DEVICE;
+ spin_lock_irq(&dev->power.lock);
+ dev->power.constraints = NULL;
+ spin_unlock_irq(&dev->power.lock);
+
+ kfree(c->notifiers);
+ kfree(c);
+
+ out:
mutex_unlock(&dev_pm_qos_mtx);
}
*
* Returns 1 if the aggregated constraint value has changed,
* 0 if the aggregated constraint value has not changed,
- * -EINVAL in case of wrong parameters, -ENODEV if the device has been
- * removed from the system
+ * -EINVAL in case of wrong parameters, -ENOMEM if there's not enough memory
+ * to allocate for data structures, -ENODEV if the device has just been 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;
return -EINVAL;
}
- mutex_lock(&dev_pm_qos_mtx);
req->dev = dev;
- /* Return if the device has been removed */
- if (req->dev->power.constraints_state == DEV_PM_QOS_NO_DEVICE) {
- ret = -ENODEV;
- goto out;
- }
+ mutex_lock(&dev_pm_qos_mtx);
- /*
- * Allocate the constraints data on the first call to add_request,
- * i.e. only if the data is not already allocated and if the device has
- * not been removed
- */
- if (dev->power.constraints_state == DEV_PM_QOS_DEVICE_PRESENT)
- ret = dev_pm_qos_constraints_allocate(dev);
+ if (!dev->power.constraints) {
+ if (dev->power.power_state.event == PM_EVENT_INVALID) {
+ /* The device has been removed from the system. */
+ req->dev = NULL;
+ ret = -ENODEV;
+ goto out;
+ } else {
+ /*
+ * Allocate the constraints data on the first call to
+ * add_request, i.e. only if the data is not already
+ * allocated and if the device has not been removed.
+ */
+ 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:
+ out:
mutex_unlock(&dev_pm_qos_mtx);
+
return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_qos_add_request);
mutex_lock(&dev_pm_qos_mtx);
- if (req->dev->power.constraints_state == DEV_PM_QOS_ALLOCATED) {
+ if (req->dev->power.constraints) {
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;
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);
+ if (req->dev->power.constraints) {
+ 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 */
mutex_lock(&dev_pm_qos_mtx);
- /* Silently return if the device has been removed */
- if (dev->power.constraints_state != DEV_PM_QOS_ALLOCATED)
- goto out;
-
- retval = blocking_notifier_chain_register(
- dev->power.constraints->notifiers,
- notifier);
+ /* Silently return if the constraints object is not present. */
+ if (dev->power.constraints)
+ retval = blocking_notifier_chain_register(
+ dev->power.constraints->notifiers,
+ notifier);
-out:
mutex_unlock(&dev_pm_qos_mtx);
return retval;
}
mutex_lock(&dev_pm_qos_mtx);
- /* Silently return if the device has been removed */
- if (dev->power.constraints_state != DEV_PM_QOS_ALLOCATED)
- goto out;
-
- retval = blocking_notifier_chain_unregister(
- dev->power.constraints->notifiers,
- notifier);
+ /* Silently return if the constraints object is not present. */
+ if (dev->power.constraints)
+ retval = blocking_notifier_chain_unregister(
+ dev->power.constraints->notifiers,
+ notifier);
-out:
mutex_unlock(&dev_pm_qos_mtx);
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);
git.openpandora.org / pandora-kernel.git / blobdiff