mtd-utils: Add new syntax to get devices by name

This introduces a new feature to the MTD command line utilities that
allows MTD devices to be referenced by name instead of device node. For
example this looks like:

> # Display info for the MTD device with name "data"
> mtdinfo mtd:data
> # Copy file to MTD device with name "data"
> flashcp /my/file mtd:data

This follows the syntax supported by the kernel which allows MTD
device's to be mounted by name[1].

Add the function mtd_find_dev_node() that accepts an MTD "identifier"
and returns the MTD's device node. The function accepts a string
starting with "mtd:" which it treats as the MTD's name. It then attempts
to search for the MTD, and if found maps it back to the /dev/mtdX device
node. If the string does not start with "mtd:", then assume it's the old
style and refers directly to a MTD device node.

The function is then hooked into existing tools like flashcp, mtdinfo,
flash_unlock, etc. To load in the new MTD parsing code in a consistent
way across programs.

[1] http://www.linux-mtd.infradead.org/faq/jffs2.html#L_mtdblock

Signed-off-by: Brandon Maier <brandon.maier@collins.com>
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 9 insertions, 4 deletions

diff --git a/ubi-utils/mtdinfo.c b/ubi-utils/mtdinfo.c
index 8bd0fc8..154872d 100644
--- a/ubi-utils/mtdinfo.c
+++ b/ubi-utils/mtdinfo.c
@@ -54,7 +54,7 @@ static void display_help(void)
 	printf(
 		"%1$s version %2$s - a tool to print MTD information.\n"
 		"\n"
-		"Usage: %1$s <MTD node file path> [--map | -M] [--ubi-info | -u]\n"
+		"Usage: %1$s <mtd device> [--map | -M] [--ubi-info | -u]\n"
 		"       %1$s --all [--ubi-info | -u]\n"
 		"       %1$s [--help | --version]\n"
 		"\n"
@@ -68,6 +68,8 @@ static void display_help(void)
 		"-h, --help                      print help message\n"
 		"-V, --version                   print program version\n"
 		"\n"
+		"<mtd device>  MTD device node or 'mtd:<name>'\n"
+		"\n"
 		"Examples:\n"
 		"  %1$s /dev/mtd0             print information MTD device /dev/mtd0\n"
 		"  %1$s /dev/mtd0 -u          print information MTD device /dev/mtd0\n"
@@ -124,10 +126,13 @@ static int parse_opt(int argc, char * const argv[])
 		}
 	}
 
-	if (optind == argc - 1)
-		args.node = argv[optind];
-	else if (optind < argc)
+	if (optind == argc - 1) {
+		args.node = mtd_find_dev_node(argv[optind]);
+		if (!args.node)
+			return errmsg("Failed to find MTD device %s", argv[optind]);
+	} else if (optind < argc) {
 		return errmsg("more then one MTD device specified (use -h for help)");
+	}
 
 	if (args.all && args.node)
 		args.node = NULL;