[PATCH v3] cmd: sf/nand: Print and return failure when 0 length is passed

[Ashok Reddy Soma]

For sf commands, when '0' length is passed for erase, update, write or
read, there might be undesired results. Ideally '0' length means nothing to
do.

So print 'ERROR: Invalid size 0' and return cmd failure when length '0' is
passed to sf commands. Same thing applies for nand commands also.

Example:

ZynqMP> sf erase 0 0
ERROR: Invalid size 0
ZynqMP> sf write 10000 0 0
ERROR: Invalid size 0
ZynqMP> sf read 10000 0 0
ERROR: Invalid size 0
ZynqMP> sf update 1000 10000 0
ERROR: Invalid size 0
ZynqMP>

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma at amd.com>
---

Changes in v3:
 - Change printf to debug as it is too verbose

Changes in v2:
 - Changed print from 'size is 0' to Invalid size 0 without quites.
 - Modified description to be imperative
 - Fixed typo in description from "samething" to "same thing"

 cmd/legacy-mtd-utils.c | 5 +++++
 cmd/sf.c               | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/cmd/legacy-mtd-utils.c b/cmd/legacy-mtd-utils.c
index ac7139f84d..5903a90fe5 100644
--- a/cmd/legacy-mtd-utils.c
+++ b/cmd/legacy-mtd-utils.c
@@ -88,6 +88,11 @@ int mtd_arg_off_size(int argc, char *const argv[], int *idx, loff_t *off,
 		return -1;
 	}
 
+	if (*size == 0) {
+		debug("ERROR: Invalid size 0\n");
+		return -1;
+	}
+
 print:
 	printf("device %d ", *idx);
 	if (*size == chipsize)
diff --git a/cmd/sf.c b/cmd/sf.c
index 11b9c25896..55bef2f769 100644
--- a/cmd/sf.c
+++ b/cmd/sf.c
@@ -353,6 +353,11 @@ static int do_spi_flash_erase(int argc, char *const argv[])
 	if (ret != 1)
 		return CMD_RET_USAGE;
 
+	if (size == 0) {
+		debug("ERROR: Invalid size 0\n");
+		return CMD_RET_FAILURE;
+	}
+
 	/* Consistency checking */
 	if (offset + size > flash->size) {
 		printf("ERROR: attempting %s past flash size (%#x)\n",
-- 
2.17.1