[RFC PATCH 2/6] of: reserved-memory: Add of_reserved_mem_lookup_by_name

[Viresh Kumar]

This adds of_reserved_mem_lookup_by_name() helper to get a
reserved-memory region based on the DT node name.

Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
 drivers/of/of_reserved_mem.c    | 27 +++++++++++++++++++++++++++
 include/linux/of_reserved_mem.h |  6 ++++++
 2 files changed, 33 insertions(+)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index e0a86c3fa656..b94c3b1d14b6 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -758,6 +758,33 @@ struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)
 }
 EXPORT_SYMBOL_GPL(of_reserved_mem_lookup);
 
+/**
+ * of_reserved_mem_lookup_by_name() - acquire reserved_mem from node name
+ * @name:	node name
+ *
+ * This function allows drivers to acquire a reference to the reserved_mem
+ * struct based on a reserved-memory node name.
+ *
+ * Returns a reserved_mem reference, or NULL on error.
+ */
+struct reserved_mem *of_reserved_mem_lookup_by_name(const char *name)
+{
+	struct device_node *np __free(device_node) =
+		of_find_node_by_path("/reserved-memory");
+	struct device_node *child __free(device_node) = NULL;
+
+	if (!np)
+		return ERR_PTR(-ENODEV);
+
+	for_each_child_of_node(np, child) {
+		if (of_node_name_eq(child, name))
+			return of_reserved_mem_lookup(child);
+	}
+
+	return ERR_PTR(-ENODEV);
+}
+EXPORT_SYMBOL_GPL(of_reserved_mem_lookup_by_name);
+
 /**
  * of_reserved_mem_region_to_resource() - Get a reserved memory region as a resource
  * @np:		node containing 'memory-region' property
diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
index 3933f1d39e9a..d6d187597b7f 100644
--- a/include/linux/of_reserved_mem.h
+++ b/include/linux/of_reserved_mem.h
@@ -41,6 +41,7 @@ int reserved_mem_device_init(struct device *dev, struct reserved_mem *rmem);
 void of_reserved_mem_device_release(struct device *dev);
 
 struct reserved_mem *of_reserved_mem_lookup(struct device_node *np);
+struct reserved_mem *of_reserved_mem_lookup_by_name(const char *name);
 int of_reserved_mem_region_to_resource(const struct device_node *np,
 				       unsigned int idx, struct resource *res);
 int of_reserved_mem_region_to_resource_byname(const struct device_node *np,
@@ -78,6 +79,11 @@ static inline struct reserved_mem *of_reserved_mem_lookup(struct device_node *np
 	return NULL;
 }
 
+static inline struct reserved_mem *of_reserved_mem_lookup_by_name(const char *name)
+{
+	return NULL;
+}
+
 static inline int of_reserved_mem_region_to_resource(const struct device_node *np,
 						     unsigned int idx,
 						     struct resource *res)
-- 
2.31.1.272.g89b43f80a514