opp: Add apis to retrieve opps with interconnect bandwidth

Add dev_pm_opp_find_bw_ceil and dev_pm_opp_find_bw_floor to retrieve opps
based on interconnect associated with the opp and bandwidth. The index
variable is the index of the interconnect as specified in the opp table
in Devicetree.
Co-developed-by: Thara Gopinath <thara.gopinath@linaro.org>
Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/opp/core.c

@@ -729,6 +729,126 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil_by_volt(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil_by_volt);
 
+/**
+ * dev_pm_opp_find_bw_ceil() - Search for a rounded ceil bandwidth
+ * @dev:	device for which we do this operation
+ * @freq:	start bandwidth
+ * @index:	which bandwidth to compare, in case of OPPs with several values
+ *
+ * Search for the matching floor *available* OPP from a starting bandwidth
+ * for a device.
+ *
+ * Return: matching *opp and refreshes *bw accordingly, else returns
+ * ERR_PTR in case of error and should be handled using IS_ERR. Error return
+ * values can be:
+ * EINVAL:	for bad pointer
+ * ERANGE:	no match found for search
+ * ENODEV:	if device not found in list of registered devices
+ *
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
+ */
+struct dev_pm_opp *dev_pm_opp_find_bw_ceil(struct device *dev,
+					   unsigned int *bw, int index)
+{
+	struct opp_table *opp_table;
+	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
+
+	if (!dev || !bw) {
+		dev_err(dev, "%s: Invalid argument bw=%p\n", __func__, bw);
+		return ERR_PTR(-EINVAL);
+	}
+
+	opp_table = _find_opp_table(dev);
+	if (IS_ERR(opp_table))
+		return ERR_CAST(opp_table);
+
+	if (index >= opp_table->path_count)
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&opp_table->lock);
+
+	list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
+		if (temp_opp->available && temp_opp->bandwidth) {
+			if (temp_opp->bandwidth[index].peak >= *bw) {
+				opp = temp_opp;
+				*bw = opp->bandwidth[index].peak;
+
+				/* Increment the reference count of OPP */
+				dev_pm_opp_get(opp);
+				break;
+			}
+		}
+	}
+
+	mutex_unlock(&opp_table->lock);
+	dev_pm_opp_put_opp_table(opp_table);
+
+	return opp;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_find_bw_ceil);
+
+/**
+ * dev_pm_opp_find_bw_floor() - Search for a rounded floor bandwidth
+ * @dev:	device for which we do this operation
+ * @freq:	start bandwidth
+ * @index:	which bandwidth to compare, in case of OPPs with several values
+ *
+ * Search for the matching floor *available* OPP from a starting bandwidth
+ * for a device.
+ *
+ * Return: matching *opp and refreshes *bw accordingly, else returns
+ * ERR_PTR in case of error and should be handled using IS_ERR. Error return
+ * values can be:
+ * EINVAL:	for bad pointer
+ * ERANGE:	no match found for search
+ * ENODEV:	if device not found in list of registered devices
+ *
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
+ */
+struct dev_pm_opp *dev_pm_opp_find_bw_floor(struct device *dev,
+					    unsigned int *bw, int index)
+{
+	struct opp_table *opp_table;
+	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
+
+	if (!dev || !bw) {
+		dev_err(dev, "%s: Invalid argument bw=%p\n", __func__, bw);
+		return ERR_PTR(-EINVAL);
+	}
+
+	opp_table = _find_opp_table(dev);
+	if (IS_ERR(opp_table))
+		return ERR_CAST(opp_table);
+
+	if (index >= opp_table->path_count)
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&opp_table->lock);
+
+	list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
+		if (temp_opp->available && temp_opp->bandwidth) {
+			/* go to the next node, before choosing prev */
+			if (temp_opp->bandwidth[index].peak > *bw)
+				break;
+			opp = temp_opp;
+		}
+	}
+
+	/* Increment the reference count of OPP */
+	if (!IS_ERR(opp))
+		dev_pm_opp_get(opp);
+	mutex_unlock(&opp_table->lock);
+	dev_pm_opp_put_opp_table(opp_table);
+
+	if (!IS_ERR(opp))
+		*bw = opp->bandwidth[index].peak;
+
+	return opp;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_find_bw_floor);
+
 static int _set_opp_voltage(struct device *dev, struct regulator *reg,
 			    struct dev_pm_opp_supply *supply)
 {

include/linux/pm_opp.h

@@ -129,6 +129,13 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil_by_volt(struct device *dev,
 
 struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
 					     unsigned long *freq);
+
+struct dev_pm_opp *dev_pm_opp_find_bw_ceil(struct device *dev,
+					   unsigned int *bw, int index);
+
+struct dev_pm_opp *dev_pm_opp_find_bw_floor(struct device *dev,
+					   unsigned int *bw, int index);
+
 void dev_pm_opp_put(struct dev_pm_opp *opp);
 
 int dev_pm_opp_add(struct device *dev, unsigned long freq,
@@ -279,6 +286,18 @@ static inline struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
 	return ERR_PTR(-EOPNOTSUPP);
 }
 
+static inline struct dev_pm_opp *dev_pm_opp_find_bw_ceil(struct device *dev,
+					unsigned int *bw, int index)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline struct dev_pm_opp *dev_pm_opp_find_bw_floor(struct device *dev,
+					unsigned int *bw, int index)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
 static inline void dev_pm_opp_put(struct dev_pm_opp *opp) {}
 
 static inline int dev_pm_opp_add(struct device *dev, unsigned long freq,