[PATCH v3] cmd: mmc: Allow using partition name in mmc erase command

[Tomas Paukrt]

The mmc erase command currently requires blk# and cnt parameters
which can be obtained using the part start and part size commands
if the entire partition needs to be erased.

Simplify the use of the mmc erase command by allowing the partition
name to be specified directly.

Signed-off-by: Tomas Paukrt <tomaspaukrt at email.cz>
---
Changes since v1:
- Swapped init_mmc_device call and argc check
- Removed round down info.size to a multiple of erase_grp_size
- Split the syntax into two separate lines
---
 cmd/mmc.c             | 17 +++++++++++++----
 doc/usage/cmd/mmc.rst |  6 +++++-
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/cmd/mmc.c b/cmd/mmc.c
index 7244a90..2fc05f9 100644
--- a/cmd/mmc.c
+++ b/cmd/mmc.c
@@ -472,18 +472,26 @@ static int do_mmc_erase(struct cmd_tbl *cmdtp, int flag,
 			int argc, char *const argv[])
 {
 	struct mmc *mmc;
+	struct disk_partition info;
 	u32 blk, cnt, n;
 
-	if (argc != 3)
+	if (argc < 2 || argc > 3)
 		return CMD_RET_USAGE;
 
-	blk = hextoul(argv[1], NULL);
-	cnt = hextoul(argv[2], NULL);
-
 	mmc = init_mmc_device(curr_device, false);
 	if (!mmc)
 		return CMD_RET_FAILURE;
 
+	if (argc == 3) {
+		blk = hextoul(argv[1], NULL);
+		cnt = hextoul(argv[2], NULL);
+	} else if (part_get_info_by_name(mmc_get_blk_desc(mmc), argv[1], &info) >= 0) {
+		blk = info.start;
+		cnt = info.size;
+	} else {
+		return CMD_RET_FAILURE;
+	}
+
 	printf("\nMMC erase: dev # %d, block # %d, count %d ... ",
 	       curr_device, blk, cnt);
 
@@ -1271,6 +1279,7 @@ U_BOOT_CMD(
 	"mmc swrite addr blk#\n"
 #endif
 	"mmc erase blk# cnt\n"
+	"mmc erase partname\n"
 	"mmc rescan [mode]\n"
 	"mmc part - lists available partition on current mmc device\n"
 	"mmc dev [dev] [part] [mode] - show or set current mmc device [partition] and set mode\n"
diff --git a/doc/usage/cmd/mmc.rst b/doc/usage/cmd/mmc.rst
index 5a64400..55391fd 100644
--- a/doc/usage/cmd/mmc.rst
+++ b/doc/usage/cmd/mmc.rst
@@ -15,6 +15,7 @@ Synopsis
     mmc read addr blk# cnt
     mmc write addr blk# cnt
     mmc erase blk# cnt
+    mmc erase partname
     mmc rescan [mode]
     mmc part
     mmc dev [dev] [part] [mode]
@@ -44,12 +45,15 @@ The 'mmc write' command writes raw data to MMC device from memory address with b
     cnt
         block count
 
-The 'mmc erase' command erases *cnt* blocks on the MMC device starting at block *blk#*.
+The 'mmc erase' command erases *cnt* blocks on the MMC device starting at block *blk#* or
+the entire partition specified by *partname*.
 
     blk#
         start block offset
     cnt
         block count
+    partname
+        partition name
 
 The 'mmc rescan' command scans the available MMC device.
 
-- 
2.7.4