[PATCH v2 8/8] cmd: gpt: Add command to swap partition order

[Joshua Watt <jpewhacker@gmail.com>]

Adds a command called "gpt swap-postition" which will swap the order two
partitions are listed in the GPT partition table (but leaves them
pointing to the same locations on disk).

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
---
 cmd/gpt.c                 | 50 +++++++++++++++++++++++++++++++++++++--
 doc/usage/cmd/gpt.rst     | 23 ++++++++++++++++++
 test/py/tests/test_gpt.py | 18 ++++++++++++++
 3 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/cmd/gpt.c b/cmd/gpt.c
index 90a60fce8b..2448889573 100644
--- a/cmd/gpt.c
+++ b/cmd/gpt.c
@@ -859,7 +859,7 @@ static int do_rename_gpt_parts(struct blk_desc *dev_desc, char *subcomm,
 	int partlistlen, ret, numparts = 0, partnum, i = 1, ctr1 = 0, ctr2 = 0;
 
 	if ((subcomm == NULL) || (name1 == NULL) || (name2 == NULL) ||
-	    (strcmp(subcomm, "swap") && (strcmp(subcomm, "rename"))))
+	    (strcmp(subcomm, "swap") && strcmp(subcomm, "rename") && strcmp(subcomm, "swap-position")))
 		return -EINVAL;
 
 	ret = get_disk_guid(dev_desc, disk_guid);
@@ -920,6 +920,48 @@ static int do_rename_gpt_parts(struct blk_desc *dev_desc, char *subcomm,
 			ret = -EINVAL;
 			goto out;
 		}
+	} else if(!strcmp(subcomm, "swap-position")) {
+		int idx1, idx2;
+		struct disk_partition first, second;
+		idx1 = simple_strtoul(name1, NULL, 10);
+		if (idx1 <= 0 || idx1 > numparts) {
+			printf("Illegal partition number %s\n", name1);
+			ret = -EINVAL;
+			goto out;
+		}
+		idx2 = simple_strtoul(name2, NULL, 10);
+		if (idx2 <= 0 || idx2 > numparts) {
+			printf("Illegal partition number %s\n", name2);
+			ret = -EINVAL;
+			goto out;
+		}
+		if (idx1 == idx2) {
+			printf("Cannot swap partition with itself\n");
+			ret = -EINVAL;
+			goto out;
+		}
+
+		i = 1;
+		list_for_each(pos, &disk_partitions) {
+			curr = list_entry(pos, struct disk_part, list);
+			if (i == idx1) {
+				first = curr->gpt_part_info;
+			} else if (i == idx2) {
+				second = curr->gpt_part_info;
+			}
+			i++;
+		}
+
+		i = 1;
+		list_for_each(pos, &disk_partitions) {
+			curr = list_entry(pos, struct disk_part, list);
+			if (i == idx1) {
+				curr->gpt_part_info = second;
+			} else if (i == idx2) {
+				curr->gpt_part_info = first;
+			}
+			i++;
+		}
 	} else { /* rename */
 		if (strlen(name2) > PART_NAME_LEN) {
 			printf("Names longer than %d characters are truncated.\n", PART_NAME_LEN);
@@ -1122,7 +1164,8 @@ static int do_gpt(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 	} else if (strcmp(argv[1], "read") == 0) {
 		ret = do_get_gpt_info(blk_dev_desc, (argc == 5) ? argv[4] : NULL);
 	} else if ((strcmp(argv[1], "swap") == 0) ||
-		   (strcmp(argv[1], "rename") == 0)) {
+		   (strcmp(argv[1], "rename") == 0) ||
+		   (strcmp(argv[1], "swap-position") == 0)) {
 		ret = do_rename_gpt_parts(blk_dev_desc, argv[1], argv[4], argv[5]);
 	} else if ((strcmp(argv[1], "set-bootable") == 0)) {
 		ret = gpt_set_bootable(blk_dev_desc, argv[4]);
@@ -1175,6 +1218,8 @@ U_BOOT_CMD(gpt, CONFIG_SYS_MAXARGS, 1, do_gpt,
 	" gpt swap <interface> <dev> <name1> <name2>\n"
 	"    - change all partitions named name1 to name2\n"
 	"      and vice-versa\n"
+	" gpt swap-position <interface> <dev> <part1> <part2>\n"
+	"    - Swap the order of name1 with name2 in the partition table\n"
 	" gpt rename <interface> <dev> <part> <name>\n"
 	"    - rename the specified partition\n"
 	" gpt set-bootable <interface> <dev> <list>\n"
@@ -1183,5 +1228,6 @@ U_BOOT_CMD(gpt, CONFIG_SYS_MAXARGS, 1, do_gpt,
 	" gpt swap mmc 0 foo bar\n"
 	" gpt rename mmc 0 3 foo\n"
 	" gpt set-bootable mmc 0 boot_a,boot_b\n"
+	" gpt swap-position mmc 0 1 2\n"
 #endif
 );
diff --git a/doc/usage/cmd/gpt.rst b/doc/usage/cmd/gpt.rst
index c7a56ad825..f3f778d383 100644
--- a/doc/usage/cmd/gpt.rst
+++ b/doc/usage/cmd/gpt.rst
@@ -17,6 +17,7 @@ Synopsis
     gpt read <interface> <device no> [<varname>]
     gpt swap <interface> <dev> <name1> <name2>
     gpt rename <interface> <dev> <part> <name>
+    gpt swap-position <interface> <dev> <part1> <part2>
     gpt set-bootable <interface> <dev> <partition list>
 
 Description
@@ -136,6 +137,28 @@ CONFIG_CMD_GPT_RENAME=y is required.
 The 'gpt rename' command renames all partitions named 'part' to be 'name1'.
 CONFIG_CMD_GPT_RENAME=y is required.
 
+The 'gpt swap-position' command swaps the order of two partition index in the
+partition table, but otherwise leaves the actual partition data untouched. For
+example, to swap the order of the 'boot' and 'rootfs' partitions in the disk
+described above, you would do:
+
+::
+    => gpt setenv mmc 0 rootfs
+    => echo ${gpt_partition_entry}
+    2
+    => gpt setenv mmc 0 boot
+    => echo ${gpt_partition_entry}
+    1
+
+    => gpt swap-position mmc 0 1 2
+
+    => gpt setenv mmc 0 rootfs
+    => echo ${gpt_partition_entry}
+    1
+    => gpt setenv mmc 0 boot
+    => echo ${gpt_partition_entry}
+    2
+
 The 'gpt set-bootable' command sets the bootable flag for all partitions in the
 table. If the partition name is in 'partition list' (separated by ','), the
 bootable flag is set, otherwise it is cleared. CONFIG_CMD_GPT_RENAME=y is
diff --git a/test/py/tests/test_gpt.py b/test/py/tests/test_gpt.py
index 6d79d07b09..af25bcd998 100644
--- a/test/py/tests/test_gpt.py
+++ b/test/py/tests/test_gpt.py
@@ -321,3 +321,21 @@ def test_gpt_write(state_disk_image, u_boot_console):
     output = u_boot_console.run_command('gpt guid host 0')
     assert '375a56f7-d6c9-4e81-b5f0-09d41ca89efe' in output
 
+@pytest.mark.buildconfigspec('cmd_gpt')
+@pytest.mark.buildconfigspec('cmd_gpt_rename')
+@pytest.mark.buildconfigspec('cmd_part')
+@pytest.mark.requiredtool('sgdisk')
+def test_gpt_swap_position(state_disk_image, u_boot_console):
+    """Test the gpt swap-position command."""
+
+    u_boot_console.run_command('host bind 0 ' + state_disk_image.path)
+    output = u_boot_console.run_command('part list host 0')
+    assert '1\t0x00000800\t0x00000fff\t"part1"' in output
+    assert '2\t0x00001000\t0x00001bff\t"part2"' in output
+
+    output = u_boot_console.run_command('gpt swap-position host 0 1 2')
+    assert 'success!' in output
+
+    output = u_boot_console.run_command('part list host 0')
+    assert '2\t0x00000800\t0x00000fff\t"part1"' in output
+    assert '1\t0x00001000\t0x00001bff\t"part2"' in output
-- 
2.33.0