1.. SPDX-License-Identifier: GPL-2.0+
2
3ums command
4===========
5
6Synopsis
7--------
8
9::
10
11    ums <dev> [<interface>] <devnum[:partnum]>
12
13Description
14-----------
15
16Use the USB Mass Storage class (also known as UMS) to make accessible an U-Boot
17block device (fully or with :ref:`U-Boot's partition syntax <partitions>`)
18to a USB host and to enable file transfers. U-Boot, the USB device, acts as a
19simple external hard drive plugged on the host USB port.
20
21This command "ums" stays in the USB's treatment loop until user enters Ctrl-C.
22
23dev
24    USB gadget device number
25
26interface
27    interface for accessing the block device (mmc, sata, scsi, usb, ....)
28    defaults is "mmc"
29
30devnum
31    device number for selected interface
32
33partnum
34    partition number or 0 to expose all partitions, defaults to 0
35
36Example
37-------
38
39::
40
41    => ums 0 mmc 0
42    => ums 0 usb 1:2
43
44Configuration
45-------------
46
47The ums command is only available if CONFIG_CMD_USB_MASS_STORAGE=y
48and depends on CONFIG_USB_USB_GADGET and CONFIG_BLK.
49
50Return value
51------------
52
53The return value $? is set to 0 (true) when the USB stack was successfully
54started and interrupted, with Ctrl-C or after USB cable issue (detection
55timeout or cable removal).
56
57If an error occurs, the return value $? is set to 1 (false).
58