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.
The proposed patch introduces a new flag CPUIDLE_FLAG_TIMER_STOP to let the cpuidle framework to call clockevents_notify instead of duplicating again and again these lines in all the cpuidle drivers.
Signed-off-by: Daniel Lezcano daniel.lezcano@linaro.org --- drivers/cpuidle/cpuidle.c | 9 +++++++++ include/linux/cpuidle.h | 1 + 2 files changed, 10 insertions(+)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index eba6929..c500370 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 */ diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 480c14d..a837b33 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -57,6 +57,7 @@ struct cpuidle_state { /* Idle State Flags */ #define CPUIDLE_FLAG_TIME_VALID (0x01) /* is residency time measurable? */ #define CPUIDLE_FLAG_COUPLED (0x02) /* state applies to multiple cpus */ +#define CPUIDLE_FLAG_TIMER_STOP (0x04) /* timer is stopped on this state */
#define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)