interconnect: Add a name to struct icc_path

When debugging interconnect things, it turned out that saving the path
name and including it in the traces is quite useful, especially for
devices with multiple paths.

For the path name we use the one specified in DT, or if we use platform
data, the name is based on the source and destination node names.

Suggested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>

2 files changed, 17 insertions, 3 deletions

diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
index f30a326dc7ce..4f9bdb7f9165 100644
--- a/drivers/interconnect/core.c
+++ b/drivers/interconnect/core.c
@@ -356,9 +356,17 @@ struct icc_path *of_icc_get(struct device *dev, const char *name)
 
 	mutex_lock(&icc_lock);
 	path = path_find(dev, src_node, dst_node);
-	if (IS_ERR(path))
-		dev_err(dev, "%s: invalid path=%ld\n", __func__, PTR_ERR(path));
 	mutex_unlock(&icc_lock);
+	if (IS_ERR(path)) {
+		dev_err(dev, "%s: invalid path=%ld\n", __func__, PTR_ERR(path));
+		return path;
+	}
+
+	if (name)
+		path->name = kstrdup_const(name, GFP_KERNEL);
+	else
+		path->name = kasprintf(GFP_KERNEL, "%s-%s",
+				       src_node->name, dst_node->name);
 
 	return path;
 }
@@ -481,9 +489,12 @@ struct icc_path *icc_get(struct device *dev, const int src_id, const int dst_id)
 		goto out;
 
 	path = path_find(dev, src, dst);
-	if (IS_ERR(path))
+	if (IS_ERR(path)) {
 		dev_err(dev, "%s: invalid path=%ld\n", __func__, PTR_ERR(path));
+		goto out;
+	}
 
+	path->name = kasprintf(GFP_KERNEL, "%s-%s", src->name, dst->name);
 out:
 	mutex_unlock(&icc_lock);
 	return path;
@@ -519,6 +530,7 @@ void icc_put(struct icc_path *path)
 	}
 	mutex_unlock(&icc_lock);
 
+	kfree_const(path->name);
 	kfree(path);
 }
 EXPORT_SYMBOL_GPL(icc_put);
diff --git a/drivers/interconnect/internal.h b/drivers/interconnect/internal.h
index 5853e8faf223..bf18cb7239df 100644
--- a/drivers/interconnect/internal.h
+++ b/drivers/interconnect/internal.h
@@ -29,10 +29,12 @@ struct icc_req {
 
 /**
  * struct icc_path - interconnect path structure
+ * @name: a string name of the path (useful for ftrace)
  * @num_nodes: number of hops (nodes)
  * @reqs: array of the requests applicable to this path of nodes
  */
 struct icc_path {
+	const char *name;
 	size_t num_nodes;
 	struct icc_req reqs[];
 };