cpuidle : handle clockevent notify from the cpuidle framework

When a cpu enters a deep idle state, the local timers are stopped and
the time framework falls back to the timer device used as a broadcast
timer.

The different cpuidle drivers are calling clockevents_notify ENTER/EXIT
when the idle state stops the local timer.

Add a new flag CPUIDLE_FLAG_TIMER_STOP which can be set by the cpuidle
drivers. If the flag is set, the cpuidle core code takes care of the
notification on behalf of the driver to avoid pointless code duplication.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index eba69290e074..c50037029184 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -8,6 +8,7 @@
  * This code is licenced under the GPL.
  */
 
+#include <linux/clockchips.h>
 #include <linux/kernel.h>
 #include <linux/mutex.h>
 #include <linux/sched.h>
@@ -146,12 +147,20 @@ int cpuidle_idle_call(void)
 
         trace_cpu_idle_rcuidle(next_state, dev->cpu);
 
+        if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP)
+                clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
+                                   &dev->cpu);
+
         if (cpuidle_state_is_coupled(dev, drv, next_state))
                 entered_state = cpuidle_enter_state_coupled(dev, drv,
                                                             next_state);
         else
                 entered_state = cpuidle_enter_state(dev, drv, next_state);
 
+        if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP)
+                clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
+                                   &dev->cpu);
+
         trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
 
         /* give the governor an opportunity to reflect on the outcome */