@@ -335,6 +335,10 @@ int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
if (dev->state == CLOCK_EVT_STATE_SHUTDOWN)
return 0;
+ /* We must be in ONESHOT state here */
+ WARN_ONCE(dev->state != CLOCK_EVT_STATE_ONESHOT, "Current state: %d\n",
+ dev->state);
+
/* Shortcut for clockevent devices that can deal with ktime. */
if (dev->features & CLOCK_EVT_FEAT_KTIME)
return dev->set_next_ktime(expires, dev);
@@ -543,8 +543,7 @@ hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
if (cpu_base->hang_detected)
return;
- if (cpu_base->expires_next.tv64 != KTIME_MAX)
- tick_program_event(cpu_base->expires_next, 1);
+ tick_program_event(cpu_base->expires_next, 1);
}
/*
@@ -1308,8 +1307,7 @@ void hrtimer_interrupt(struct clock_event_device *dev)
raw_spin_unlock(&cpu_base->lock);
/* Reprogramming necessary ? */
- if (expires_next.tv64 == KTIME_MAX ||
- !tick_program_event(expires_next, 0)) {
+ if (!tick_program_event(expires_next, 0)) {
cpu_base->hang_detected = 0;
return;
}
@@ -28,6 +28,22 @@ int tick_program_event(ktime_t expires, int force)
{
struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
+ if (unlikely(expires.tv64 == KTIME_MAX)) {
+ /*
+ * We don't need the clock event device any more, stop it.
+ */
+ clockevents_set_state(dev, CLOCK_EVT_STATE_ONESHOT_STOPPED);
+ return 0;
+ }
+
+ if (unlikely(dev->state == CLOCK_EVT_STATE_ONESHOT_STOPPED)) {
+ /*
+ * We need the clock event again, configure it in ONESHOT mode
+ * before using it.
+ */
+ clockevents_set_state(dev, CLOCK_EVT_STATE_ONESHOT);
+ }
+
return clockevents_program_event(dev, expires, force);
}
To avoid getting spurious interrupts on a tickless CPU, clockevent device can now be stopped by switching to ONESHOT_STOPPED state. The natural place for handling this transition is tick_program_event(). On 'expires == KTIME_MAX', we skip programming the event and so we need to fix such call sites as well, to always call tick_program_event() irrespective of the expires value. Once the clockevent device is required again, check if it was earlier put into ONESHOT_STOPPED state. If yes, switch its state to ONESHOT before programming its event. To make sure we haven't missed any corner case, add a WARN() for the case where we try to reprogram clockevent device while we aren't configured in ONESHOT_STOPPED state. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- kernel/time/clockevents.c | 4 ++++ kernel/time/hrtimer.c | 6 ++---- kernel/time/tick-oneshot.c | 16 ++++++++++++++++ 3 files changed, 22 insertions(+), 4 deletions(-)