cmd: nfsdown: update usage description

The nfsdown has optional argument part for server ip address  and
precondition to use nfs command but it is not described from command
usage. Update nfsdown usage description with required steps and
optional argument part.

Change-Id: I16e941ef386e1301f4e1581956e1b0b06dc33246
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>

diff --git a/cmd/nfsdown.c b/cmd/nfsdown.c
index bd31a7a23015e5f4392eec36c236c307d33e533c..36ea97469b21c2ba6113d01810fda9caadab39d9 100644 (file)
--- a/cmd/nfsdown.c
+++ b/cmd/nfsdown.c
@@ -438,9 +438,11 @@ error_end:
 
 U_BOOT_CMD(nfsdown, CONFIG_SYS_MAXARGS, 1, do_nfs_down,
           "TIZEN \"nfs\" downloader",
-          "<IP_ADDR>:<IMG_PATH>\n"
+          "[<IP_ADDR>:]<IMG_PATH>\n"
           "  - device firmware upgrade via nfs for Tizen\n"
           "    fusing images from <IP_ADDR>:<IMG_PATH> to MMC.\n"
+          "  - required to set env for ipaddr, serverip, gatewayip,\n"
+          "    and netmask.\n"
           "\n"
           "(e.g) nfsdown 192.168.0.1:/nfs\n"
 );