The resolution of the idle injection is limited to 1ms. If there is
a need for an injection of 1.2 ms, it is not possible.
The idle injection API is not yet used, so it is safe to convert the
existing API to the new time unit instead of adding more functions.
Convert to microsecond in order to use a finer grain time unit when
injecting idle cycles.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The play_idle resolution is 1ms. The intel_powerclamp bases the idle
duration on jiffies. The idle injection API is also using msec based
duration but has no user yet.
Unfortunately, msec based time does not fit well when we want to
inject idle cycle precisely with shallow idle state.
In order to set the scene for the incoming idle injection user, move
the precision up to usec when calling play_idle.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Initially, the cpu_cooling device for ARM was changed by adding a new
policy inserting idle cycles. The intel_powerclamp driver does a
similar action.
Instead of implementing idle injections privately in the cpu_cooling
device, move the idle injection code in a dedicated framework and give
the opportunity to other frameworks to make use of it.
The framework relies on the smpboot kthreads which handles via its
main loop the common code for hotplugging and [un]parking.
This code was previously tested with the cpu cooling device and went
through several iterations. It results now in split code and API
exported in the header file. It was tested with the cpu cooling device
with success.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Rewrite of all comments ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
