opp: core: implement dev_pm_opp_get_bw

Add and implement dev_pm_opp_get_bw() to retrieve the OPP's
bandwidth in the same way as the dev_pm_opp_get_voltage() helper.

Retrieving bandwidth is required in the case of the Adreno GPU
where the GPU Management Unit can handle the Bandwidth scaling.

The helper can get the peak or average bandwidth for any of
the interconnect path.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
[ Viresh: Fixed commit log and a comment in code ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/opp/core.c

@@ -106,6 +106,31 @@ static bool assert_single_clk(struct opp_table *opp_table)
 	return !WARN_ON(opp_table->clk_count > 1);
 }
 
+/**
+ * dev_pm_opp_get_bw() - Gets the bandwidth corresponding to an opp
+ * @opp:	opp for which bandwidth has to be returned for
+ * @peak:	select peak or average bandwidth
+ * @index:	bandwidth index
+ *
+ * Return: bandwidth in kBps, else return 0
+ */
+unsigned long dev_pm_opp_get_bw(struct dev_pm_opp *opp, bool peak, int index)
+{
+	if (IS_ERR_OR_NULL(opp)) {
+		pr_err("%s: Invalid parameters\n", __func__);
+		return 0;
+	}
+
+	if (index > opp->opp_table->path_count)
+		return 0;
+
+	if (!opp->bandwidth)
+		return 0;
+
+	return peak ? opp->bandwidth[index].peak : opp->bandwidth[index].avg;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_bw);
+
 /**
  * dev_pm_opp_get_voltage() - Gets the voltage corresponding to an opp
  * @opp:	opp for which voltage has to be returned for

include/linux/pm_opp.h

@@ -102,6 +102,8 @@ struct dev_pm_opp_data {
 struct opp_table *dev_pm_opp_get_opp_table(struct device *dev);
 void dev_pm_opp_put_opp_table(struct opp_table *opp_table);
 
+unsigned long dev_pm_opp_get_bw(struct dev_pm_opp *opp, bool peak, int index);
+
 unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp);
 
 int dev_pm_opp_get_supplies(struct dev_pm_opp *opp, struct dev_pm_opp_supply *supplies);
@@ -205,6 +207,11 @@ static inline struct opp_table *dev_pm_opp_get_opp_table_indexed(struct device *
 
 static inline void dev_pm_opp_put_opp_table(struct opp_table *opp_table) {}
 
+static inline unsigned long dev_pm_opp_get_bw(struct dev_pm_opp *opp, bool peak, int index)
+{
+	return 0;
+}
+
 static inline unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
 {
 	return 0;