mtd: ofpart: move ofpart partitions to a dedicated dt node

Parsing direct subnodes of a mtd device as partitions is unreliable
since the mtd device is also part of its bus subsystem and can contain
bus data in subnodes.

Move ofpart data to a subnode of its own so it is clear which data is
part of the partition layout.
Signed-off-by: Michal Suchanek <hramrach@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/ofpart.c

@@ -29,23 +29,33 @@ static int parse_ofpart_partitions(struct mtd_info *master,
 				   struct mtd_partition **pparts,
 				   struct mtd_part_parser_data *data)
 {
-	struct device_node *node;
+	struct device_node *mtd_node;
+	struct device_node *ofpart_node;
 	const char *partname;
 	struct device_node *pp;
-	int nr_parts, i;
+	int nr_parts, i, ret = 0;
+	bool dedicated = true;
 
 
 	if (!data)
 		return 0;
 
-	node = data->of_node;
-	if (!node)
+	mtd_node = data->of_node;
+	if (!mtd_node)
 		return 0;
 
+	ofpart_node = of_get_child_by_name(mtd_node, "partitions");
+	if (!ofpart_node) {
+		pr_warn("%s: 'partitions' subnode not found on %s. Trying to parse direct subnodes as partitions.\n",
+			master->name, mtd_node->full_name);
+		ofpart_node = mtd_node;
+		dedicated = false;
+	}
+
 	/* First count the subnodes */
 	nr_parts = 0;
-	for_each_child_of_node(node,  pp) {
-		if (node_has_compatible(pp))
+	for_each_child_of_node(ofpart_node,  pp) {
+		if (!dedicated && node_has_compatible(pp))
 			continue;
 
 		nr_parts++;
@@ -59,22 +69,36 @@ static int parse_ofpart_partitions(struct mtd_info *master,
 		return -ENOMEM;
 
 	i = 0;
-	for_each_child_of_node(node,  pp) {
+	for_each_child_of_node(ofpart_node,  pp) {
 		const __be32 *reg;
 		int len;
 		int a_cells, s_cells;
 
-		if (node_has_compatible(pp))
+		if (!dedicated && node_has_compatible(pp))
 			continue;
 
 		reg = of_get_property(pp, "reg", &len);
 		if (!reg) {
-			nr_parts--;
-			continue;
+			if (dedicated) {
+				pr_debug("%s: ofpart partition %s (%s) missing reg property.\n",
+					 master->name, pp->full_name,
+					 mtd_node->full_name);
+				goto ofpart_fail;
+			} else {
+				nr_parts--;
+				continue;
+			}
 		}
 
 		a_cells = of_n_addr_cells(pp);
 		s_cells = of_n_size_cells(pp);
+		if (len / 4 != a_cells + s_cells) {
+			pr_debug("%s: ofpart partition %s (%s) error parsing reg property.\n",
+				 master->name, pp->full_name,
+				 mtd_node->full_name);
+			goto ofpart_fail;
+		}
+
 		(*pparts)[i].offset = of_read_number(reg, a_cells);
 		(*pparts)[i].size = of_read_number(reg + a_cells, s_cells);
 
@@ -92,15 +116,20 @@ static int parse_ofpart_partitions(struct mtd_info *master,
 		i++;
 	}
 
-	if (!i) {
-		of_node_put(pp);
-		pr_err("No valid partition found on %s\n", node->full_name);
-		kfree(*pparts);
-		*pparts = NULL;
-		return -EINVAL;
-	}
+	if (!nr_parts)
+		goto ofpart_none;
 
 	return nr_parts;
+
+ofpart_fail:
+	pr_err("%s: error parsing ofpart partition %s (%s)\n",
+	       master->name, pp->full_name, mtd_node->full_name);
+	ret = -EINVAL;
+ofpart_none:
+	of_node_put(pp);
+	kfree(*pparts);
+	*pparts = NULL;
+	return ret;
 }
 
 static struct mtd_part_parser ofpart_parser = {