[PATCH] of: Parse OF graph into graph structure

[Philipp Zabel]

This patch adds a function of_graph_populate() that parses the complete
device tree for port and endpoint nodes and stores them in a graph
structure.

Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
---
 drivers/of/base.c        | 243
++++++++++++++++++++++++++++++++++++++++-------
 include/linux/of_graph.h |  17 +++-
 2 files changed, 224 insertions(+), 36 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index ebb001a..a844ca2 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -28,7 +28,33 @@
 
 #include "of_private.h"
 
+struct of_graph_entity {
+	struct device_node *of_node;
+	struct list_head list;
+	struct list_head ports;
+};
+
+struct of_graph_port {
+	struct device_node *of_node;
+	struct of_graph_entity *parent;
+	struct list_head list;
+	struct list_head endpoints;
+	int id;
+};
+
+struct of_graph_endpoint {
+	struct device_node *of_node;
+	struct of_graph_port *parent;
+	struct list_head list;
+	struct list_head global_list;
+	struct device_node *remote_node;
+	struct of_graph_endpoint *remote_endpoint;
+	int id;
+};
+
 LIST_HEAD(aliases_lookup);
+LIST_HEAD(entity_list);
+LIST_HEAD(endpoint_list);
 
 struct device_node *of_allnodes;
 EXPORT_SYMBOL(of_allnodes);
@@ -1984,6 +2010,19 @@ struct device_node *of_find_next_cache_node(const
struct device_node *np)
 	return NULL;
 }
 
+static struct of_graph_endpoint *__of_graph_lookup_endpoint(
+					const struct device_node *node)
+{
+	struct of_graph_endpoint *endpoint;
+
+	list_for_each_entry(endpoint, &endpoint_list, global_list) {
+		if (endpoint->of_node == node)
+			return endpoint;
+	}
+
+	return NULL;
+}
+
 /**
  * of_graph_parse_endpoint() - parse common endpoint node properties
  * @node: pointer to endpoint device_node
@@ -1994,22 +2033,17 @@ struct device_node
*of_find_next_cache_node(const struct device_node *np)
 int of_graph_parse_endpoint(const struct device_node *node,
 			    struct of_endpoint *endpoint)
 {
-	struct device_node *port_node = of_get_parent(node);
-
-	WARN_ONCE(!port_node, "%s(): endpoint %s has no parent node\n",
-		  __func__, node->full_name);
+	struct of_graph_endpoint *ep;
 
 	memset(endpoint, 0, sizeof(*endpoint));
 
-	endpoint->local_node = node;
-	/*
-	 * It doesn't matter whether the two calls below succeed.
-	 * If they don't then the default value 0 is used.
-	 */
-	of_property_read_u32(port_node, "reg", &endpoint->port);
-	of_property_read_u32(node, "reg", &endpoint->id);
+	ep = __of_graph_lookup_endpoint(node);
+	if (!ep || !ep->parent)
+		return -EINVAL;
 
-	of_node_put(port_node);
+	endpoint->local_node = ep->of_node;
+	endpoint->port = ep->parent->id;
+	endpoint->id = ep->id;
 
 	return 0;
 }
@@ -2136,21 +2170,16 @@ EXPORT_SYMBOL(of_graph_get_next_endpoint);
 struct device_node *of_graph_get_remote_port_parent(
 			       const struct device_node *node)
 {
-	struct device_node *np;
-	unsigned int depth;
+	struct of_graph_port *port;
+	struct of_graph_endpoint *ep  = __of_graph_lookup_endpoint(node);
+	if (!ep || !ep->remote_endpoint)
+		return NULL;
 
-	/* Get remote endpoint node. */
-	np = of_parse_phandle(node, "remote-endpoint", 0);
+	port = ep->remote_endpoint->parent;
+	if (!port || !port->parent)
+		return NULL;
 
-	/* Walk 3 levels up only if there is 'ports' node */
-	for (depth = 3; depth && np; depth--) {
-		np = of_get_next_parent(np);
-		if (depth == 3 && of_node_cmp(np->name, "port"))
-			break;
-		if (depth == 2 && of_node_cmp(np->name, "ports"))
-			break;
-	}
-	return np;
+	return port->parent->of_node;
 }
 EXPORT_SYMBOL(of_graph_get_remote_port_parent);
 
@@ -2163,17 +2192,161 @@ EXPORT_SYMBOL(of_graph_get_remote_port_parent);
  */
 struct device_node *of_graph_get_remote_port(const struct device_node
*node)
 {
-	struct device_node *np;
+	struct of_graph_endpoint *ep;
 
-	/* Get remote endpoint node. */
-	np = of_parse_phandle(node, "remote-endpoint", 0);
-	if (!np)
+	ep = __of_graph_lookup_endpoint(node);
+	if (!ep || !ep->remote_endpoint || !ep->remote_endpoint->parent)
 		return NULL;
-	np = of_get_next_parent(np);
-	if (of_node_cmp(np->name, "port")) {
-		of_node_put(np);
-		return NULL;
-	}
-	return np;
+
+	return ep->remote_endpoint->parent->of_node;
 }
 EXPORT_SYMBOL(of_graph_get_remote_port);
+
+static int of_graph_add_endpoint(struct of_graph_port *port,
+				struct device_node *node)
+{
+	struct of_graph_endpoint *ep = kzalloc(sizeof(*ep), GFP_KERNEL);
+	if (!ep)
+		return -ENOMEM;
+
+	ep->of_node = node;
+	ep->parent = port;
+	of_property_read_u32(node, "reg", &ep->id);
+	ep->remote_node = of_parse_phandle(node, "remote-endpoint", 0);
+
+	list_add_tail(&ep->global_list, &endpoint_list);
+	list_add_tail(&ep->list, &port->endpoints);
+	return 0;
+}
+
+static int of_graph_add_port(struct of_graph_entity *entity,
+				struct device_node *node)
+{
+	struct device_node *child;
+	struct of_graph_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
+	if (!port)
+		return -ENOMEM;
+
+	port->of_node = node;
+	port->parent = entity;
+	of_property_read_u32(node, "reg", &port->id);
+	INIT_LIST_HEAD(&port->endpoints);
+
+	for_each_child_of_node(node, child) {
+		int rc;
+		if (of_node_cmp(child->name, "endpoint") != 0) {
+			pr_warn("%s(): non-endpoint node inside port %s\n",
+				__func__, node->full_name);
+			continue;
+		}
+
+		rc = of_graph_add_endpoint(port, child);
+		if (rc)
+			return rc;
+	}
+
+	list_add_tail(&port->list, &entity->ports);
+	return 0;
+}
+
+static int of_graph_add_entity(struct device_node *node,
+				struct device_node *child, bool ports_node)
+{
+	struct device_node *parent = node;
+	struct of_graph_entity *entity;
+	int rc = 0;
+
+	entity = kzalloc(sizeof(*entity), GFP_KERNEL);
+	if (!entity)
+		return -ENOMEM;
+
+	entity->of_node = node;
+	INIT_LIST_HEAD(&entity->ports);
+
+	if (ports_node) {
+		parent = child;
+		child = of_get_next_child(parent, NULL);
+	}
+	while (child) {
+		rc = of_graph_add_port(entity, child);
+		if (rc)
+			return rc;
+
+		do {
+			child = of_get_next_child(parent, child);
+			if (!child)
+				break;
+		} while (of_node_cmp(child->name, "port"));
+	}
+
+	list_add_tail(&entity->list, &entity_list);
+	return 0;
+}
+
+static int of_graph_recurse(struct device_node *node)
+{
+	struct device_node *child;
+	int rc = 0;
+
+	for_each_child_of_node(node, child) {
+		if (of_node_cmp(child->name, "ports") == 0) {
+			rc = of_graph_add_entity(node, child, true);
+			break;
+		} else if ((of_node_cmp(child->name, "port") == 0) &&
+			   (!of_find_property(child, "compatible", NULL))) {
+			rc = of_graph_add_entity(node, child, false);
+			break;
+		} else {
+			rc = of_graph_recurse(child);
+		}
+	}
+
+	return rc;
+}
+
+int of_graph_populate(struct device_node *root)
+{
+	struct of_graph_endpoint *ep1, *ep2;
+	struct of_graph_entity *entity;
+	struct of_graph_port *port;
+	int rc = 0;
+
+	/* Skip if the graph is already populated */
+	if (!list_empty(&endpoint_list))
+		return 0;
+
+	root = root ? of_node_get(root) : of_find_node_by_path("/");
+
+	/* Parse device tree */
+	rc = of_graph_recurse(root);
+	if (rc)
+		return rc;
+
+	/* Connect endpoints */
+	list_for_each_entry(ep1, &endpoint_list, global_list) {
+		ep2 = ep1;
+		list_for_each_entry_continue(ep2, &endpoint_list, global_list) {
+			struct of_graph_endpoint *from, *to;
+
+			if (ep1->remote_node) {
+				from = ep1;
+				to = ep2;
+			} else {
+				from = ep2;
+				to = ep1;
+			}
+			if (from->remote_node &&
+			    from->remote_node == to->of_node) {
+				WARN_ON(to->remote_node &&
+					to->remote_node != from->of_node);
+				to->remote_node = from->of_node;
+				to->remote_endpoint = from;
+				from->remote_endpoint = to;
+			}
+		}
+	}
+
+	of_node_put(root);
+	return rc;
+}
+EXPORT_SYMBOL(of_graph_populate);
diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
index 3a3c5a9..70f5809 100644
--- a/include/linux/of_graph.h
+++ b/include/linux/of_graph.h
@@ -23,7 +23,14 @@
 struct of_endpoint {
 	unsigned int port;
 	unsigned int id;
-	const struct device_node *local_node;
+	struct device_node *local_node;
+	struct device_node *remote_node;
+	struct of_endpoint *remote_ep;
+
+	/* Internal use only */
+	struct list_head list;
+	void (*callback)(struct of_endpoint *ep, void *data);
+	void *data;
 };
 
 #ifdef CONFIG_OF
@@ -35,6 +42,9 @@ struct device_node *of_graph_get_next_endpoint(const
struct device_node *parent,
 struct device_node *of_graph_get_remote_port_parent(
 					const struct device_node *node);
 struct device_node *of_graph_get_remote_port(const struct device_node
*node);
+
+int of_graph_populate(struct device_node *root);
+
 #else
 
 static inline int of_graph_parse_endpoint(const struct device_node
*node,
@@ -68,6 +78,11 @@ static inline struct device_node
*of_graph_get_remote_port(
 	return NULL;
 }
 
+static inline int of_graph_populate(struct device_node *root)
+{
+	return -ENOSYS;
+}
+
 #endif /* CONFIG_OF */
 
 #endif /* __LINUX_OF_GRAPH_H */
-- 
1.9.0

regards
Philipp

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