opp: Keep track of currently programmed OPP

The dev_pm_opp_set_rate() helper needs to know the currently programmed
OPP to make few decisions and currently we try to find it on every
invocation of this routine.

Lets start keeping track of the current_opp programmed for the devices
of the opp table, that will be quite useful going forward.

If we fail to find the current OPP, we pick the first one available in
the list, as the list is in ascending order of frequencies, level, or
bandwidth and that's the best guess we can make anyway.

Note that we used to do the frequency comparison a bit early in
dev_pm_opp_set_rate() previously, and now instead we check the target
opp, which shall be more accurate anyway.

We need to make sure that current_opp's memory doesn't get freed while
it is being used and so we keep a reference of it until the time it is
used.

Now that current_opp will always be set, we can drop some unnecessary
checks as well.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Dmitry Osipenko <digetx@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index 64b9cb782a93..372df68e185b 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -135,6 +135,7 @@ enum opp_table_access {
  * @clock_latency_ns_max: Max clock latency in nanoseconds.
  * @parsed_static_opps: Count of devices for which OPPs are initialized from DT.
  * @shared_opp: OPP is shared between multiple devices.
+ * @current_opp: Currently configured OPP for the table.
  * @suspend_opp: Pointer to OPP to be used during device suspend.
  * @genpd_virt_dev_lock: Mutex protecting the genpd virtual device pointers.
  * @genpd_virt_devs: List of virtual devices for multiple genpd support.
@@ -183,6 +184,7 @@ struct opp_table {
 
 	unsigned int parsed_static_opps;
 	enum opp_table_access shared_opp;
+	struct dev_pm_opp *current_opp;
 	struct dev_pm_opp *suspend_opp;
 
 	struct mutex genpd_virt_dev_lock;