disk: part: scan the disk if the part_type is unknown

If a DUT do not have partition table, and we write one with 'gpt write'
cmd, we should able to list the partition with 'part list' cmd.
It's reasonable to scan the disk again if the initial part_type is
unknown in case we just write a new one into disk.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>

disk/part.c

@@ -27,16 +27,28 @@
 DECLARE_GLOBAL_DATA_PTR;
 
 #ifdef CONFIG_HAVE_BLOCK_DEVICE
-static struct part_driver *part_driver_lookup_type(int part_type)
+static struct part_driver *part_driver_lookup_type(struct blk_desc *dev_desc)
 {
 	struct part_driver *drv =
 		ll_entry_start(struct part_driver, part_driver);
 	const int n_ents = ll_entry_count(struct part_driver, part_driver);
 	struct part_driver *entry;
 
-	for (entry = drv; entry != drv + n_ents; entry++) {
-		if (part_type == entry->part_type)
-			return entry;
+	if (dev_desc->part_type == PART_TYPE_UNKNOWN) {
+		for (entry = drv; entry != drv + n_ents; entry++) {
+			int ret;
+
+			ret = entry->test(dev_desc);
+			if (!ret) {
+				dev_desc->part_type = entry->part_type;
+				return entry;
+			}
+		}
+	} else {
+		for (entry = drv; entry != drv + n_ents; entry++) {
+			if (dev_desc->part_type == entry->part_type)
+				return entry;
+		}
 	}
 
 	/* Not found */
@@ -285,7 +297,7 @@ void part_print(struct blk_desc *dev_desc)
 {
 	struct part_driver *drv;
 
-	drv = part_driver_lookup_type(dev_desc->part_type);
+	drv = part_driver_lookup_type(dev_desc);
 	if (!drv) {
 		printf("## Unknown partition table type %x\n",
 		       dev_desc->part_type);
@@ -314,7 +326,7 @@ int part_get_info(struct blk_desc *dev_desc, int part,
 	info->type_guid[0] = 0;
 #endif
 
-	drv = part_driver_lookup_type(dev_desc->part_type);
+	drv = part_driver_lookup_type(dev_desc);
 	if (!drv) {
 		debug("## Unknown partition table type %x\n",
 		      dev_desc->part_type);