tick/broadcast: Program wakeup timer when entering idle if required

[sfrench/cifs-2.6.git] / kernel / time / tick-broadcast.c

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 0e9e06d6cc5cb97ab9bcbb383314fd0140f7969a..9b845212430bc63f3ff807e117c2565518c6b162 100644 (file)
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -96,6 +96,15 @@ static struct clock_event_device *tick_get_oneshot_wakeup_device(int cpu)
        return per_cpu(tick_oneshot_wakeup_device, cpu);
 }
 
+static void tick_oneshot_wakeup_handler(struct clock_event_device *wd)
+{
+       /*
+        * If we woke up early and the tick was reprogrammed in the
+        * meantime then this may be spurious but harmless.
+        */
+       tick_receive_broadcast();
+}
+
 static bool tick_set_oneshot_wakeup_device(struct clock_event_device *newdev,
                                           int cpu)
 {
@@ -121,6 +130,7 @@ static bool tick_set_oneshot_wakeup_device(struct clock_event_device *newdev,
        if (!try_module_get(newdev->owner))
                return false;
 
+       newdev->event_handler = tick_oneshot_wakeup_handler;
 set_device:
        clockevents_exchange_device(curdev, newdev);
        per_cpu(tick_oneshot_wakeup_device, cpu) = newdev;
@@ -909,16 +919,48 @@ out:
        return ret;
 }
 
+static int tick_oneshot_wakeup_control(enum tick_broadcast_state state,
+                                      struct tick_device *td,
+                                      int cpu)
+{
+       struct clock_event_device *dev, *wd;
+
+       dev = td->evtdev;
+       if (td->mode != TICKDEV_MODE_ONESHOT)
+               return -EINVAL;
+
+       wd = tick_get_oneshot_wakeup_device(cpu);
+       if (!wd)
+               return -ENODEV;
+
+       switch (state) {
+       case TICK_BROADCAST_ENTER:
+               clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT_STOPPED);
+               clockevents_switch_state(wd, CLOCK_EVT_STATE_ONESHOT);
+               clockevents_program_event(wd, dev->next_event, 1);
+               break;
+       case TICK_BROADCAST_EXIT:
+               /* We may have transitioned to oneshot mode while idle */
+               if (clockevent_get_state(wd) != CLOCK_EVT_STATE_ONESHOT)
+                       return -ENODEV;
+       }
+
+       return 0;
+}
+
 int __tick_broadcast_oneshot_control(enum tick_broadcast_state state)
 {
        struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
        int cpu = smp_processor_id();
 
+       if (!tick_oneshot_wakeup_control(state, td, cpu))
+               return 0;
+
        if (tick_broadcast_device.evtdev)
                return ___tick_broadcast_oneshot_control(state, td, cpu);
 
        /*
-        * If there is no broadcast device, tell the caller not
+        * If there is no broadcast or wakeup device, tell the caller not
         * to go into deep idle.
         */
        return -EBUSY;