@@ -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)
{
@@ -116,6 +125,7 @@ static bool tick_set_oneshot_wakeup_device(struct clock_event_device *newdev,
if (curdev && newdev->rating <= curdev->rating)
return false;
+ newdev->event_handler = tick_oneshot_wakeup_handler;
set_device:
per_cpu(tick_oneshot_wakeup_device, cpu) = newdev;
return true;
@@ -903,16 +913,42 @@ static int ___tick_broadcast_oneshot_control(enum tick_broadcast_state state,
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;
+
+ if (state == 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);
+ }
+
+ 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;
When configuring the broadcast timer on entry to and exit from deep idle states, prefer a per-CPU wakeup timer if one exists. On entry to idle, stop the tick device and transfer the next event into the oneshot wakeup device, which will serve as the wakeup from idle. To avoid the overhead of additional hardware accesses on exit from idle, leave the timer armed and treat the inevitable interrupt as a (possibly spurious) tick event. Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Marc Zyngier <maz@kernel.org> Cc: Lorenzo Colitti <lorenzo@google.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Stephen Boyd <sboyd@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> --- kernel/time/tick-broadcast.c | 38 +++++++++++++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-)