[U-Boot] [PATCH 1/4] dfu:cmd: get the default command arguments from environment

[Przemyslaw Marczak]

This change adds support to store the default DFU cmd line
arguments in the environment.

This is useful for users who usually use the same arguments
for dfu command and do the upgrade frequently.

DFU command use cases:
- dfu <usb ctrl> <if> <dev> [<list>] - use command line args
- dfu [<list>] - take the default command line args from env
And for both - optional list the initialized DFU entities.

To use the default dfu device configuration user should define:
- $dfu_usb_con - e.g. "0"
- $dfu_interface - e.g. "mmc"
- $dfu_device - e.g. "0"

Signed-off-by: Przemyslaw Marczak <p.marczak at samsung.com>
Cc: Lukasz Majewski <l.majewski at samsung.com>
Cc: Marek Vasut <marex at denx.de>
---
 common/cmd_dfu.c | 35 ++++++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/common/cmd_dfu.c b/common/cmd_dfu.c
index a03538d..7c6bb6b 100644
--- a/common/cmd_dfu.c
+++ b/common/cmd_dfu.c
@@ -15,21 +15,42 @@
 
 static int do_dfu(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
-	if (argc < 4)
-		return CMD_RET_USAGE;
+	char *usb_controller;
+	char *interface;
+	char *devstring;
+	int argv_list = 0;
+	int ret, i = 0;
 
-	char *usb_controller = argv[1];
-	char *interface = argv[2];
-	char *devstring = argv[3];
+	switch (argc) {
+	case 2:
+		argv_list = 1;
+	case 1:
+		usb_controller = strdup(getenv("dfu_usb_con"));
+		interface = strdup(getenv("dfu_interface"));
+		devstring = strdup(getenv("dfu_device"));
 
-	int ret, i = 0;
+		if (!usb_controller || !interface || !devstring) {
+			puts("DFU: default device environment is not set.\n");
+			return CMD_RET_USAGE;
+		}
+		break;
+	case 5:
+		argv_list = 4;
+	case 4:
+		usb_controller = argv[1];
+		interface = argv[2];
+		devstring = argv[3];
+		break;
+	default:
+		return CMD_RET_USAGE;
+	}
 
 	ret = dfu_init_env_entities(interface, simple_strtoul(devstring,
 							      NULL, 10));
 	if (ret)
 		return ret;
 
-	if (argc > 4 && strcmp(argv[4], "list") == 0) {
+	if (argv_list && !strcmp(argv[argv_list], "list")) {
 		dfu_show_entities();
 		goto done;
 	}
-- 
1.9.1