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, 5 insertions, 1 deletions

diff --git a/misc-utils/flash_erase.c b/misc-utils/flash_erase.c
index 49a880f..000f94a 100644
--- a/misc-utils/flash_erase.c
+++ b/misc-utils/flash_erase.c
@@ -71,6 +71,8 @@ static void display_help (void)
 			"      --silent      same as --quiet\n"
 			"      --help        display this help and exit\n"
 			"      --version     output version information and exit\n",
+			"\n"
+			"  MTD_DEVICE  MTD device node or 'mtd:<name>'\n"
 			PROGRAM_NAME);
 }
 
@@ -169,7 +171,9 @@ int main(int argc, char *argv[])
 	}
 	switch (argc - optind) {
 	case 3:
-		mtd_device = argv[optind];
+		mtd_device = mtd_find_dev_node(argv[optind]);
+		if (!mtd_device)
+			return errmsg("Can't find MTD device %s", argv[optind]);
 		start = simple_strtoull(argv[optind + 1], &error);
 		eb_cnt = simple_strtoul(argv[optind + 2], &error);
 		break;