freifunkist-firmware/target/linux/lantiq/patches-4.14/0101-find_active_root.patch

--- a/drivers/mtd/ofpart.c
+++ b/drivers/mtd/ofpart.c
@@ -25,6 +25,38 @@ static bool node_has_compatible(struct d
 	return of_get_property(pp, "compatible", NULL);
 }
 
+static uint8_t * brnboot_get_selected_root_part(struct mtd_info *master,
+						loff_t offset)
+{
+	static uint8_t root_id;
+	int err, len;
+
+	err = mtd_read(master, offset, 0x01, &len, &root_id);
+
+	if (mtd_is_bitflip(err) || !err)
+		return &root_id;
+
+	return NULL;
+}
+
+static void brnboot_set_active_root_part(struct mtd_partition *pparts,
+					 struct device_node **part_nodes,
+					 int nr_parts,
+					 uint8_t *root_id)
+{
+	int i;
+
+	for (i = 0; i < nr_parts; i++) {
+		int part_root_id;
+
+		if (!of_property_read_u32(part_nodes[i], "brnboot,root-id", &part_root_id)
+		    && part_root_id == *root_id) {
+			pparts[i].name = "firmware";
+			break;
+		}
+	}
+}
+
 static int parse_fixed_partitions(struct mtd_info *master,
 				  const struct mtd_partition **pparts,
 				  struct mtd_part_parser_data *data)
@@ -36,7 +68,8 @@ static int parse_fixed_partitions(struct
 	struct device_node *pp;
 	int nr_parts, i, ret = 0;
 	bool dedicated = true;
-
+	uint8_t *proot_id = NULL;
+	struct device_node **part_nodes;
 
 	/* Pull of_node from the master device node */
 	mtd_node = mtd_get_of_node(master);
@@ -72,7 +105,9 @@ static int parse_fixed_partitions(struct
 		return 0;
 
 	parts = kzalloc(nr_parts * sizeof(*parts), GFP_KERNEL);
-	if (!parts)
+	part_nodes = kzalloc(nr_parts * sizeof(*part_nodes), GFP_KERNEL);
+
+	if (!parts || !part_nodes)
 		return -ENOMEM;
 
 	i = 0;
@@ -121,12 +156,22 @@ static int parse_fixed_partitions(struct
 		if (of_get_property(pp, "lock", &len))
 			parts[i].mask_flags |= MTD_POWERUP_LOCK;
 
+		if (!proot_id && of_device_is_compatible(pp, "brnboot,root-selector"))
+			proot_id = brnboot_get_selected_root_part(master, parts[i].offset);
+
+		part_nodes[i] = pp;
+
 		i++;
 	}
 
 	if (!nr_parts)
 		goto ofpart_none;
 
+	if (proot_id)
+		brnboot_set_active_root_part(parts, part_nodes, nr_parts, proot_id);
+
+	kfree(part_nodes);
+
 	*pparts = parts;
 	return nr_parts;
 
@@ -137,6 +182,7 @@ ofpart_fail:
 ofpart_none:
 	of_node_put(pp);
 	kfree(parts);
+	kfree(part_nodes);
 	return ret;
 }