of: merge of_find_all_nodes() implementations

Merge common code between Microblaze and PowerPC, and make it available
to Sparc

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Michal Simek <monstr@monstr.eu>
Acked-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
diff --git a/drivers/of/base.c b/drivers/of/base.c
index ddf224d..e6627b2 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -9,7 +9,8 @@
  *
  *  Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
  *
- *  Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell.
+ *  Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
+ *  Grant Likely.
  *
  *      This program is free software; you can redistribute it and/or
  *      modify it under the terms of the GNU General Public License
@@ -82,6 +83,29 @@
 }
 EXPORT_SYMBOL(of_find_property);
 
+/**
+ * of_find_all_nodes - Get next node in global list
+ * @prev:	Previous node or NULL to start iteration
+ *		of_node_put() will be called on it
+ *
+ * Returns a node pointer with refcount incremented, use
+ * of_node_put() on it when done.
+ */
+struct device_node *of_find_all_nodes(struct device_node *prev)
+{
+	struct device_node *np;
+
+	read_lock(&devtree_lock);
+	np = prev ? prev->allnext : allnodes;
+	for (; np != NULL; np = np->allnext)
+		if (of_node_get(np))
+			break;
+	of_node_put(prev);
+	read_unlock(&devtree_lock);
+	return np;
+}
+EXPORT_SYMBOL(of_find_all_nodes);
+
 /*
  * Find a property with a given name for a given node
  * and return the value.