2 files changed, 54 insertions, 0 deletions

diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index 2e9191a712f3..233149cb19f4 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -8,6 +8,7 @@
 #include <linux/notifier.h>
 #include <linux/miscdevice.h>
 #include <linux/device.h>
+#include <linux/workqueue.h>
 
 enum {
         PM_QOS_RESERVED = 0,
@@ -29,6 +30,7 @@ enum {
 struct pm_qos_request {
         struct plist_node node;
         int pm_qos_class;
+        struct delayed_work work; /* for pm_qos_update_request_timeout */
 };
 
 struct dev_pm_qos_request {
@@ -73,6 +75,8 @@ void pm_qos_add_request(struct pm_qos_request *req, int pm_qos_class,
                         s32 value);
 void pm_qos_update_request(struct pm_qos_request *req,
                            s32 new_value);
+void pm_qos_update_request_timeout(struct pm_qos_request *req,
+                                   s32 new_value, unsigned long timeout_us);
 void pm_qos_remove_request(struct pm_qos_request *req);
 
 int pm_qos_request(int pm_qos_class);
diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index d6d6dbd1ecc0..6a031e684026 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -230,6 +230,21 @@ int pm_qos_request_active(struct pm_qos_request *req)
 EXPORT_SYMBOL_GPL(pm_qos_request_active);
 
 /**
+ * pm_qos_work_fn - the timeout handler of pm_qos_update_request_timeout
+ * @work: work struct for the delayed work (timeout)
+ *
+ * This cancels the timeout request by falling back to the default at timeout.
+ */
+static void pm_qos_work_fn(struct work_struct *work)
+{
+        struct pm_qos_request *req = container_of(to_delayed_work(work),
+                                                  struct pm_qos_request,
+                                                  work);
+
+        pm_qos_update_request(req, PM_QOS_DEFAULT_VALUE);
+}
+
+/**
  * pm_qos_add_request - inserts new qos request into the list
  * @req: pointer to a preallocated handle
  * @pm_qos_class: identifies which list of qos request to use
@@ -253,6 +268,7 @@ void pm_qos_add_request(struct pm_qos_request *req,
                 return;
         }
         req->pm_qos_class = pm_qos_class;
+        INIT_DELAYED_WORK(&req->work, pm_qos_work_fn);
         pm_qos_update_target(pm_qos_array[pm_qos_class]->constraints,
                              &req->node, PM_QOS_ADD_REQ, value);
 }
@@ -279,6 +295,9 @@ void pm_qos_update_request(struct pm_qos_request *req,
                 return;
         }
 
+        if (delayed_work_pending(&req->work))
+                cancel_delayed_work_sync(&req->work);
+
         if (new_value != req->node.prio)
                 pm_qos_update_target(
                         pm_qos_array[req->pm_qos_class]->constraints,
@@ -287,6 +306,34 @@ void pm_qos_update_request(struct pm_qos_request *req,
 EXPORT_SYMBOL_GPL(pm_qos_update_request);
 
 /**
+ * pm_qos_update_request_timeout - modifies an existing qos request temporarily.
+ * @req : handle to list element holding a pm_qos request to use
+ * @new_value: defines the temporal qos request
+ * @timeout_us: the effective duration of this qos request in usecs.
+ *
+ * After timeout_us, this qos request is cancelled automatically.
+ */
+void pm_qos_update_request_timeout(struct pm_qos_request *req, s32 new_value,
+                                   unsigned long timeout_us)
+{
+        if (!req)
+                return;
+        if (WARN(!pm_qos_request_active(req),
+                 "%s called for unknown object.", __func__))
+                return;
+
+        if (delayed_work_pending(&req->work))
+                cancel_delayed_work_sync(&req->work);
+
+        if (new_value != req->node.prio)
+                pm_qos_update_target(
+                        pm_qos_array[req->pm_qos_class]->constraints,
+                        &req->node, PM_QOS_UPDATE_REQ, new_value);
+
+        schedule_delayed_work(&req->work, usecs_to_jiffies(timeout_us));
+}
+
+/**
  * pm_qos_remove_request - modifies an existing qos request
  * @req: handle to request list element
  *
@@ -305,6 +352,9 @@ void pm_qos_remove_request(struct pm_qos_request *req)
                 return;
         }
 
+        if (delayed_work_pending(&req->work))
+                cancel_delayed_work_sync(&req->work);
+
         pm_qos_update_target(pm_qos_array[req->pm_qos_class]->constraints,
                              &req->node, PM_QOS_REMOVE_REQ,
                              PM_QOS_DEFAULT_VALUE);