PM / devfreq: Core updates to support devices which can idle
Prepare devfreq core framework to support devices which
can idle. When device idleness is detected perhaps through
runtime-pm, need some mechanism to suspend devfreq load
monitoring and resume back when device is online. Present
code continues monitoring unless device is removed from
devfreq core.
This patch introduces following design changes,
- use per device work instead of global work to monitor device
load. This enables suspend/resume of device devfreq and
reduces monitoring code complexity.
- decouple delayed work based load monitoring logic from core
by introducing helpers functions to be used by governors. This
provides flexibility for governors either to use delayed work
based monitoring functions or to implement their own mechanism.
- devfreq core interacts with governors via events to perform
specific actions. These events include start/stop devfreq.
This sets ground for adding suspend/resume events.
The devfreq apis are not modified and are kept intact.
Signed-off-by: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/devfreq/governor_performance.c b/drivers/devfreq/governor_performance.c
index af75ddd..eea3f9b 100644
--- a/drivers/devfreq/governor_performance.c
+++ b/drivers/devfreq/governor_performance.c
@@ -26,14 +26,22 @@
return 0;
}
-static int performance_init(struct devfreq *devfreq)
+static int devfreq_performance_handler(struct devfreq *devfreq,
+ unsigned int event, void *data)
{
- return update_devfreq(devfreq);
+ int ret = 0;
+
+ if (event == DEVFREQ_GOV_START) {
+ mutex_lock(&devfreq->lock);
+ ret = update_devfreq(devfreq);
+ mutex_unlock(&devfreq->lock);
+ }
+
+ return ret;
}
const struct devfreq_governor devfreq_performance = {
.name = "performance",
- .init = performance_init,
.get_target_freq = devfreq_performance_func,
- .no_central_polling = true,
+ .event_handler = devfreq_performance_handler,
};