interconnect: Add support for path tags

Consumers may have use cases with different bandwidth requirements based
on the system or driver state. The consumer driver can append a specific
tag to the path and pass this information to the interconnect platform
driver to do the aggregation based on this state.

Introduce icc_set_tag() function that will allow the consumers to append
an optional tag to each path. The aggregation of these tagged paths is
platform specific.

Reviewed-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>

drivers/interconnect/core.c

@@ -29,6 +29,7 @@ static struct dentry *icc_debugfs_dir;
  * @req_node: entry in list of requests for the particular @node
  * @node: the interconnect node to which this constraint applies
  * @dev: reference to the device that sets the constraints
+ * @tag: path tag (optional)
  * @avg_bw: an integer describing the average bandwidth in kBps
  * @peak_bw: an integer describing the peak bandwidth in kBps
  */
@@ -36,6 +37,7 @@ struct icc_req {
 	struct hlist_node req_node;
 	struct icc_node *node;
 	struct device *dev;
+	u32 tag;
 	u32 avg_bw;
 	u32 peak_bw;
 };
@@ -204,7 +206,7 @@ static int aggregate_requests(struct icc_node *node)
 	node->peak_bw = 0;
 
 	hlist_for_each_entry(r, &node->req_list, req_node)
-		p->aggregate(node, r->avg_bw, r->peak_bw,
+		p->aggregate(node, r->tag, r->avg_bw, r->peak_bw,
 			     &node->avg_bw, &node->peak_bw);
 
 	return 0;
@@ -385,6 +387,26 @@ struct icc_path *of_icc_get(struct device *dev, const char *name)
 }
 EXPORT_SYMBOL_GPL(of_icc_get);
 
+/**
+ * icc_set_tag() - set an optional tag on a path
+ * @path: the path we want to tag
+ * @tag: the tag value
+ *
+ * This function allows consumers to append a tag to the requests associated
+ * with a path, so that a different aggregation could be done based on this tag.
+ */
+void icc_set_tag(struct icc_path *path, u32 tag)
+{
+	int i;
+
+	if (!path)
+		return;
+
+	for (i = 0; i < path->num_nodes; i++)
+		path->reqs[i].tag = tag;
+}
+EXPORT_SYMBOL_GPL(icc_set_tag);
+
 /**
  * icc_set_bw() - set bandwidth constraints on an interconnect path
  * @path: reference to the path returned by icc_get()

drivers/interconnect/qcom/sdm845.c

@@ -626,7 +626,7 @@ static void bcm_aggregate(struct qcom_icc_bcm *bcm)
 	bcm->dirty = false;
 }
 
-static int qcom_icc_aggregate(struct icc_node *node, u32 avg_bw,
+static int qcom_icc_aggregate(struct icc_node *node, u32 tag, u32 avg_bw,
 			      u32 peak_bw, u32 *agg_avg, u32 *agg_peak)
 {
 	size_t i;

include/linux/interconnect-provider.h

@@ -45,8 +45,8 @@ struct icc_provider {
 	struct list_head	provider_list;
 	struct list_head	nodes;
 	int (*set)(struct icc_node *src, struct icc_node *dst);
-	int (*aggregate)(struct icc_node *node, u32 avg_bw, u32 peak_bw,
+	int (*aggregate)(struct icc_node *node, u32 tag, u32 avg_bw,
-			 u32 *agg_avg, u32 *agg_peak);
+			 u32 peak_bw, u32 *agg_avg, u32 *agg_peak);
 	struct icc_node* (*xlate)(struct of_phandle_args *spec, void *data);
 	struct device		*dev;
 	int			users;

include/linux/interconnect.h

@@ -30,6 +30,7 @@ struct icc_path *icc_get(struct device *dev, const int src_id,
 struct icc_path *of_icc_get(struct device *dev, const char *name);
 void icc_put(struct icc_path *path);
 int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw);
+void icc_set_tag(struct icc_path *path, u32 tag);
 
 #else
 
@@ -54,6 +55,10 @@ static inline int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw)
 	return 0;
 }
 
+static inline void icc_set_tag(struct icc_path *path, u32 tag)
+{
+}
+
 #endif /* CONFIG_INTERCONNECT */
 
 #endif /* __LINUX_INTERCONNECT_H */