cmd: part: Add partition-related type command

This implements the following command:

    part type mmc 0:1
      -> print partition type UUID
    part type mmc 0:1 uuid
      -> set environment variable to partition type UUID

"part type" can be useful when writing a bootcmd which searches for a
specific partition type to enable automatic discovery of partitions and
their intended usage or mount point.

Signed-off-by: Enric Balletbo i Serra <eballetbo@redhat.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
[trini: Fix when CONFIG_PARTITION_TYPE_GUID is disabled and have the
command check for "types" before "type"]
Signed-off-by: Tom Rini <trini@konsulko.com>

cmd/part.c

@@ -182,6 +182,31 @@ static int do_part_number(int argc, char *const argv[])
 	return do_part_info(argc, argv, CMD_PART_INFO_NUMBER);
 }
 
+#ifdef CONFIG_PARTITION_TYPE_GUID
+static int do_part_type(int argc, char *const argv[])
+{
+	int part;
+	struct blk_desc *dev_desc;
+	struct disk_partition info;
+
+	if (argc < 2)
+		return CMD_RET_USAGE;
+	if (argc > 3)
+		return CMD_RET_USAGE;
+
+	part = blk_get_device_part_str(argv[0], argv[1], &dev_desc, &info, 0);
+	if (part < 0)
+		return 1;
+
+	if (argc > 2)
+		env_set(argv[2], info.type_guid);
+	else
+		printf("%s\n", info.type_guid);
+
+	return 0;
+}
+#endif
+
 static int do_part_types(int argc, char * const argv[])
 {
 	struct part_driver *drv = ll_entry_start(struct part_driver,
@@ -220,6 +245,10 @@ static int do_part(struct cmd_tbl *cmdtp, int flag, int argc,
 		return do_part_number(argc - 2, argv + 2);
 	else if (!strcmp(argv[1], "types"))
 		return do_part_types(argc - 2, argv + 2);
+#ifdef CONFIG_PARTITION_TYPE_GUID
+	else if (!strcmp(argv[1], "type"))
+		return do_part_type(argc - 2, argv + 2);
+#endif
 	return CMD_RET_USAGE;
 }
 
@@ -244,6 +273,12 @@ U_BOOT_CMD(
 	"part number <interface> <dev> <part> <varname>\n"
 	"    - set environment variable to the partition number using the partition name\n"
 	"      part must be specified as partition name\n"
+#ifdef CONFIG_PARTITION_TYPE_GUID
+	"part type <interface> <dev>:<part>\n"
+	"    - print partition type\n"
+#endif
+	"part type <interface> <dev>:<part> <varname>\n"
+	"    - set environment variable to partition type\n"
 	"part types\n"
 	"    - list supported partition table types"
 );

doc/usage/cmd/part.rst

@@ -13,6 +13,7 @@ Synopis
     part start <interface> <dev> <part> <varname>
     part size <interface> <dev> <part> <varname>
     part number <interface> <dev> <part> <varname>
+    part type <interface> <dev>:<part> [varname]
     part types
 
 Description
@@ -81,6 +82,17 @@ part must be specified as partition name.
     varname
         a variable to store the current partition number value into
 
+The 'part type' command prints or sets an environment variable to the partition type UUID.
+
+    interface
+        interface for accessing the block device (mmc, sata, scsi, usb, ....)
+    dev
+        device number
+    part
+        partition number
+    varname
+        a variable to store the current partition type UUID value into
+
 The 'part types' command list supported partition table types.
 
 Examples
@@ -126,6 +138,12 @@ Examples
     => env print varname
     varname=0x2
     =>
+    => part type host 0:1
+    ebd0a0a2-b9e5-4433-87c0-68b6b72699c7
+    => part type host 0:1 varname
+    => env print varname
+    varname=ebd0a0a2-b9e5-4433-87c0-68b6b72699c7
+    =>
     => part types
     Supported partition tables: EFI, AMIGA, DOS, ISO, MAC