PM / OPP Introduce APIs to remove OPPs

OPPs are created statically (from DT) or dynamically. Currently we don't free
OPPs that are created statically, when the module unloads. And so if the module
is inserted back again, we get warning for duplicate OPPs as the same were
already present.

Also, there might be a need to remove dynamic OPPs in future and so API for that
is also added.

This patch adds helper APIs to remove/free existing static and dynamic OPPs.

Because the OPPs are used both under RCU and SRCU, we have to wait for grace
period of both. And so are using kfree_rcu() from within call_srcu().

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 0330217abfad..cec2d4540914 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -21,7 +21,7 @@ struct dev_pm_opp;
 struct device;
 
 enum dev_pm_opp_event {
-        OPP_EVENT_ADD, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE,
+        OPP_EVENT_ADD, OPP_EVENT_REMOVE, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE,
 };
 
 #if defined(CONFIG_PM_OPP)
@@ -44,6 +44,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
 
 int dev_pm_opp_add(struct device *dev, unsigned long freq,
                    unsigned long u_volt);
+void dev_pm_opp_remove(struct device *dev, unsigned long freq);
 
 int dev_pm_opp_enable(struct device *dev, unsigned long freq);
 
@@ -90,6 +91,10 @@ static inline int dev_pm_opp_add(struct device *dev, unsigned long freq,
         return -EINVAL;
 }
 
+static inline void dev_pm_opp_remove(struct device *dev, unsigned long freq)
+{
+}
+
 static inline int dev_pm_opp_enable(struct device *dev, unsigned long freq)
 {
         return 0;
@@ -109,11 +114,16 @@ static inline struct srcu_notifier_head *dev_pm_opp_get_notifier(
 
 #if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
 int of_init_opp_table(struct device *dev);
+void of_free_opp_table(struct device *dev);
 #else
 static inline int of_init_opp_table(struct device *dev)
 {
         return -EINVAL;
 }
+
+static inline void of_free_opp_table(struct device *dev)
+{
+}
 #endif
 
 #endif          /* __LINUX_OPP_H__ */