1 files changed, 38 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/of_helpers.c b/arch/powerpc/platforms/pseries/of_helpers.c
new file mode 100644
index 000000000..2798933c0
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/of_helpers.c
@@ -0,0 +1,38 @@
+#include <linux/string.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+
+#include "of_helpers.h"
+
+/**
+ * pseries_of_derive_parent - basically like dirname(1)
+ * @path:  the full_name of a node to be added to the tree
+ *
+ * Returns the node which should be the parent of the node
+ * described by path.  E.g., for path = "/foo/bar", returns
+ * the node with full_name = "/foo".
+ */
+struct device_node *pseries_of_derive_parent(const char *path)
+{
+	struct device_node *parent;
+	char *parent_path = "/";
+	const char *tail;
+
+	/* We do not want the trailing '/' character */
+	tail = kbasename(path) - 1;
+
+	/* reject if path is "/" */
+	if (!strcmp(path, "/"))
+		return ERR_PTR(-EINVAL);
+
+	if (tail > path) {
+		parent_path = kstrndup(path, tail - path, GFP_KERNEL);
+		if (!parent_path)
+			return ERR_PTR(-ENOMEM);
+	}
+	parent = of_find_node_by_path(parent_path);
+	if (strcmp(parent_path, "/"))
+		kfree(parent_path);
+	return parent ? parent : ERR_PTR(-EINVAL);
+}