[U-Boot] [PATCH 3/4] cmd: dtimg: Make <varname> an optional argument

[Eugeniu Rosca]

Unlike dtimg, U-Boot commands like part [1], fstype [2] and uuid [3]
accept an _optional_ <varname> parameter, which means that they will
output the result to console whenever <varname> is skipped. This is
extremely useful during development.

Allow "dtimg" to behave in a similar fashion [4]. In addition:
 - replace env_set() by env_set_hex()
 - track and report the failures of env_set_hex()
 - amend command's help/usage text

[1] => part start mmc 0 1
    800
    => part start mmc 0 1 myvar; print myvar
    myvar=800
[2] => fstype mmc 0:1
    ext4
    => fstype mmc 0:1 myvar; print myvar
    myvar=ext4
[3] => uuid
    b3909b50-55df-4173-b83c-b05343d2d5d2
    => uuid myvar; print myvar
    myvar=4c04b15f-d0c1-4f98-9aca-ab62a66be864
[4] => dtimg start 0x48000000 0
    0x480000e0
    => dtimg start 0x48000000 0 myvar; print myvar
    myvar=480000e0

Signed-off-by: Eugeniu Rosca <erosca at de.adit-jv.com>
---
 cmd/dtimg.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/cmd/dtimg.c b/cmd/dtimg.c
index 5989081b0c14..5348a4ad46e8 100644
--- a/cmd/dtimg.c
+++ b/cmd/dtimg.c
@@ -55,9 +55,10 @@ static int dtimg_get_fdt(int argc, char * const argv[], enum cmd_dtimg_info cmd)
 	char *endp;
 	ulong fdt_addr;
 	u32 fdt_size;
-	char buf[65];
+	ulong envval;
+	int ret;
 
-	if (argc != 4)
+	if (argc < 3)
 		return CMD_RET_USAGE;
 
 	if (dtimg_get_argv_addr(argv[1], &hdr_addr) != CMD_RET_SUCCESS)
@@ -74,17 +75,24 @@ static int dtimg_get_fdt(int argc, char * const argv[], enum cmd_dtimg_info cmd)
 
 	switch (cmd) {
 	case CMD_DTIMG_START:
-		snprintf(buf, sizeof(buf), "%lx", fdt_addr);
+		envval = fdt_addr;
 		break;
 	case CMD_DTIMG_SIZE:
-		snprintf(buf, sizeof(buf), "%x", fdt_size);
+		envval = fdt_size;
 		break;
 	default:
 		printf("Error: Unknown cmd_dtimg_info value: %d\n", cmd);
 		return CMD_RET_FAILURE;
 	}
 
-	env_set(argv[3], buf);
+	if (argv[3]) {
+		ret = env_set_hex(argv[3], envval);
+		if (ret)
+			printf("Error(%d) env-setting '%s=0x%lx'\n",
+			       ret, argv[3], envval);
+	} else {
+		printf("0x%lx\n", envval);
+	}
 
 	return CMD_RET_SUCCESS;
 }
@@ -131,12 +139,12 @@ U_BOOT_CMD(
 	"dump <addr>\n"
 	"    - parse specified image and print its structure info\n"
 	"      <addr>: image address in RAM, in hex\n"
-	"dtimg start <addr> <index> <varname>\n"
+	"dtimg start <addr> <index> [<varname>]\n"
 	"    - get address (hex) of FDT in the image, by index\n"
 	"      <addr>: image address in RAM, in hex\n"
 	"      <index>: index of desired FDT in the image\n"
 	"      <varname>: name of variable where to store address of FDT\n"
-	"dtimg size <addr> <index> <varname>\n"
+	"dtimg size <addr> <index> [<varname>]\n"
 	"    - get size (hex, bytes) of FDT in the image, by index\n"
 	"      <addr>: image address in RAM, in hex\n"
 	"      <index>: index of desired FDT in the image\n"
-- 
2.24.0