of: Move phandle walking to of_phandle_iterator_next()

Move the code to walk over the phandles out of the loop in
__of_parse_phandle_with_args() to a separate function that
just works with the iterator handle: of_phandle_iterator_next().
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NRob Herring <robh@kernel.org>

drivers/of/base.c

@@ -1465,74 +1465,93 @@ int of_phandle_iterator_init(struct of_phandle_iterator *it,
 	return 0;
 }
 
-static int __of_parse_phandle_with_args(const struct device_node *np,
-					const char *list_name,
-					const char *cells_name,
-					int cell_count, int index,
-					struct of_phandle_args *out_args)
+int of_phandle_iterator_next(struct of_phandle_iterator *it)
 {
-	struct of_phandle_iterator it;
-	int rc, cur_index = 0;
+	uint32_t count = 0;
 
-	rc = of_phandle_iterator_init(&it, np, list_name,
-				      cells_name, cell_count);
-	if (rc)
-		return rc;
+	if (it->node) {
+		of_node_put(it->node);
+		it->node = NULL;
+	}
 
-	/* Loop over the phandles until all the requested entry is found */
-	while (it.cur < it.list_end) {
-		rc = -EINVAL;
-		it.cur_count = 0;
+	if (!it->cur || it->phandle_end >= it->list_end)
+		return -ENOENT;
+
+	it->cur = it->phandle_end;
+
+	/* If phandle is 0, then it is an empty entry with no arguments. */
+	it->phandle = be32_to_cpup(it->cur++);
+
+	if (it->phandle) {
 
 		/*
-		 * If phandle is 0, then it is an empty entry with no
-		 * arguments.  Skip forward to the next entry.
-		 */
-		it.phandle = be32_to_cpup(it.cur++);
-		if (it.phandle) {
-			/*
-			 * Find the provider node and parse the #*-cells
-			 * property to determine the argument length.
-			 *
-			 * This is not needed if the cell count is hard-coded
-			 * (i.e. cells_name not set, but cell_count is set),
-			 * except when we're going to return the found node
-			 * below.
+		 * Find the provider node and parse the #*-cells property to
+		 * determine the argument length.
 		 */
-			if (it.cells_name || cur_index == index) {
-				it.node = of_find_node_by_phandle(it.phandle);
-				if (!it.node) {
+		it->node = of_find_node_by_phandle(it->phandle);
+
+		if (it->cells_name) {
+			if (!it->node) {
 				pr_err("%s: could not find phandle\n",
-						it.parent->full_name);
+				       it->parent->full_name);
 				goto err;
 			}
-			}
 
-			if (it.cells_name) {
-				if (of_property_read_u32(it.node, it.cells_name,
-							 &it.cur_count)) {
+			if (of_property_read_u32(it->node, it->cells_name,
+						 &count)) {
 				pr_err("%s: could not get %s for %s\n",
-						it.parent->full_name, it.cells_name,
-						it.node->full_name);
+				       it->parent->full_name,
+				       it->cells_name,
+				       it->node->full_name);
 				goto err;
 			}
 		} else {
-				it.cur_count = it.cell_count;
+			count = it->cell_count;
 		}
 
 		/*
-			 * Make sure that the arguments actually fit in the
-			 * remaining property data length
+		 * Make sure that the arguments actually fit in the remaining
+		 * property data length
 		 */
-			if (it.cur + it.cur_count > it.list_end) {
+		if (it->cur + count > it->list_end) {
 			pr_err("%s: arguments longer than property\n",
-					 it.parent->full_name);
+			       it->parent->full_name);
 			goto err;
 		}
 	}
 
+	it->phandle_end = it->cur + count;
+	it->cur_count = count;
+
+	return 0;
+
+err:
+	if (it->node) {
+		of_node_put(it->node);
+		it->node = NULL;
+	}
+
+	return -EINVAL;
+}
+
+static int __of_parse_phandle_with_args(const struct device_node *np,
+					const char *list_name,
+					const char *cells_name,
+					int cell_count, int index,
+					struct of_phandle_args *out_args)
+{
+	struct of_phandle_iterator it;
+	int rc, cur_index = 0;
+
+	rc = of_phandle_iterator_init(&it, np, list_name,
+				      cells_name, cell_count);
+	if (rc)
+		return rc;
+
+	/* Loop over the phandles until all the requested entry is found */
+	while ((rc = of_phandle_iterator_next(&it)) == 0) {
 		/*
-		 * All of the error cases above bail out of the loop, so at
+		 * All of the error cases bail out of the loop, so at
 		 * this point, the parsing is successful. If the requested
 		 * index matches, then fill the out_args structure and return,
 		 * or return -ENOENT for an empty entry.
@@ -1558,9 +1577,6 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 			return 0;
 		}
 
-		of_node_put(it.node);
-		it.node = NULL;
-		it.cur += it.cur_count;
 		cur_index++;
 	}
 
@@ -1570,7 +1586,9 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 	 * -EINVAL : parsing error on data
 	 * [1..n]  : Number of phandle (count mode; when index = -1)
 	 */
-	rc = index < 0 ? cur_index : -ENOENT;
+	if (rc == -ENOENT && index < 0)
+		rc = cur_index;
+
  err:
 	if (it.node)
 		of_node_put(it.node);

include/linux/of.h

@@ -358,6 +358,8 @@ extern int of_phandle_iterator_init(struct of_phandle_iterator *it,
 				    const char *cells_name,
 				    int cell_count);
 
+extern int of_phandle_iterator_next(struct of_phandle_iterator *it);
+
 extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align));
 extern int of_alias_get_id(struct device_node *np, const char *stem);
 extern int of_alias_get_highest_id(const char *stem);
@@ -641,6 +643,11 @@ static inline int of_phandle_iterator_init(struct of_phandle_iterator *it,
 	return -ENOSYS;
 }
 
+static inline int of_phandle_iterator_next(struct of_phandle_iterator *it)
+{
+	return -ENOSYS;
+}
+
 static inline int of_alias_get_id(struct device_node *np, const char *stem)
 {
 	return -ENOSYS;