[PATCH v3 6/6] interconnect: Add OPP table support for interconnects

[Saravana Kannan <saravanak@google.com>]

Interconnect paths can have different performance points. Now that OPP
framework supports bandwidth OPP tables, add OPP table support for
interconnects.

Devices can use the interconnect-opp-table DT property to specify OPP
tables for interconnect paths. And the driver can obtain the OPP table for
an interconnect path by calling icc_get_opp_table().

Signed-off-by: Saravana Kannan <saravanak@google.com>
---
 drivers/interconnect/core.c  | 27 ++++++++++++++++++++++++++-
 include/linux/interconnect.h |  7 +++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
index 871eb4bc4efc..881bac80bc1e 100644
--- a/drivers/interconnect/core.c
+++ b/drivers/interconnect/core.c
@@ -47,6 +47,7 @@ struct icc_req {
  */
 struct icc_path {
 	size_t num_nodes;
+	struct opp_table *opp_table;
 	struct icc_req reqs[];
 };
 
@@ -313,7 +314,7 @@ struct icc_path *of_icc_get(struct device *dev, const char *name)
 {
 	struct icc_path *path = ERR_PTR(-EPROBE_DEFER);
 	struct icc_node *src_node, *dst_node;
-	struct device_node *np = NULL;
+	struct device_node *np = NULL, *opp_node;
 	struct of_phandle_args src_args, dst_args;
 	int idx = 0;
 	int ret;
@@ -381,10 +382,34 @@ struct icc_path *of_icc_get(struct device *dev, const char *name)
 		dev_err(dev, "%s: invalid path=%ld\n", __func__, PTR_ERR(path));
 	mutex_unlock(&icc_lock);
 
+	opp_node = of_parse_phandle(np, "interconnect-opp-table", idx);
+	if (opp_node) {
+		path->opp_table = dev_pm_opp_of_find_table_from_node(opp_node);
+		of_node_put(opp_node);
+	}
+
+
 	return path;
 }
 EXPORT_SYMBOL_GPL(of_icc_get);
 
+/**
+ * icc_get_opp_table() - Get the OPP table that corresponds to a path
+ * @path: reference to the path returned by icc_get()
+ *
+ * This function will return the OPP table that corresponds to a path handle.
+ * If the interconnect API is disabled, NULL is returned and the consumer
+ * drivers will still build. Drivers are free to handle this specifically, but
+ * they don't have to.
+ *
+ * Return: opp_table pointer on success. NULL is returned when the API is
+ * disabled or the OPP table is missing.
+ */
+struct opp_table *icc_get_opp_table(struct icc_path *path)
+{
+	return path->opp_table;
+}
+
 /**
  * icc_set_bw() - set bandwidth constraints on an interconnect path
  * @path: reference to the path returned by icc_get()
diff --git a/include/linux/interconnect.h b/include/linux/interconnect.h
index dc25864755ba..0c0bc55f0e89 100644
--- a/include/linux/interconnect.h
+++ b/include/linux/interconnect.h
@@ -9,6 +9,7 @@
 
 #include <linux/mutex.h>
 #include <linux/types.h>
+#include <linux/pm_opp.h>
 
 /* macros for converting to icc units */
 #define Bps_to_icc(x)	((x) / 1000)
@@ -28,6 +29,7 @@ struct device;
 struct icc_path *icc_get(struct device *dev, const int src_id,
 			 const int dst_id);
 struct icc_path *of_icc_get(struct device *dev, const char *name);
+struct opp_table *icc_get_opp_table(struct icc_path *path);
 void icc_put(struct icc_path *path);
 int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw);
 
@@ -49,6 +51,11 @@ static inline void icc_put(struct icc_path *path)
 {
 }
 
+static inline struct opp_table *icc_get_opp_table(struct icc_path *path)
+{
+	return NULL;
+}
+
 static inline int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw)
 {
 	return 0;
-- 
2.22.0.410.gd8fdbe21b5-goog