doc: usage: man-page for ums command

Provide a man-page for the ums command for USB Mass Storage.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
---

 doc/usage/index.rst |  1 +
 doc/usage/ums.rst   | 54 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 doc/usage/ums.rst

On 6/2/21 3:52 PM, Patrick Delaunay wrote:
> Provide a man-page for the ums command for USB Mass Storage.
>
> Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
> ---
>
>   doc/usage/index.rst |  1 +
>   doc/usage/ums.rst   | 54 +++++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 55 insertions(+)
>   create mode 100644 doc/usage/ums.rst
>
> diff --git a/doc/usage/index.rst b/doc/usage/index.rst
> index 41b247bc62..1bab6ae3e9 100644
> --- a/doc/usage/index.rst
> +++ b/doc/usage/index.rst
> @@ -43,3 +43,4 @@ Shell commands
>      scp03
>      size
>      true
> +   ums
> diff --git a/doc/usage/ums.rst b/doc/usage/ums.rst
> new file mode 100644
> index 0000000000..cf0e3a9479
> --- /dev/null
> +++ b/doc/usage/ums.rst
> @@ -0,0 +1,54 @@
> +.. SPDX-License-Identifier: GPL-2.0+
> +
> +ums command
> +===========
> +
> +Synopsis
> +--------
> +
> +::
> +
> +    <USB_controller> [<devtype>] <dev[:part]>
> +
> +Description
> +-----------
> +
> +Use the USB Mass Storage class (also known as USB MSC or UMS) to make
> +accessible a block device (based on UCLASS_BLK) to a host computing device and
> +to enable file transfers between the host and the U-Boot device.

Thank you for writing this man-page.

Unfortunately it is still unclear to me how to use it. Is this related
to USB OTG? What requirements have to be met to use the command?

> +
> +This command "ums" stays in the USB's treatment loop until user enters Ctrl-C.
> +
> +USB_controller
> +    USB device number
> +
> +devtype
> +    block device interface, defaults to "mmc"
> +
> +dev
> +    device number for devtype
> +
> +part
> +    partition number, defaults to 0 (first partition)
> +
> +Example
> +-------
> +
> +::
> +
> +    => ums 0 mmc 0
> +    => ums 0 usb 1:2
> +
> +Configuration
> +-------------
> +
> +The ums command is only available if CONFIG_CMD_USB_MASS_STORAGE=y.

The symbol does not even depend on USB and mass storage being enabled. I
would have expected CONFIG_USB_GADGET and CONFIG_BLK as requirements.
Either this description or cmd/Kconfig is wrong. I suggest both to be
updated.

Best regards

Heinrich

> +
> +Return value
> +------------
> +
> +The return value $? is set to 0 (true) when the USB stack was successfully
> +started and interrupted Ctrl-C or after USB cable detection issue
> +(timeout or cable removal).
> +
> +If an error occurs, the return value $? is set to 1 (false).
>

Hi

On 6/2/21 8:06 PM, Heinrich Schuchardt wrote:
> On 6/2/21 3:52 PM, Patrick Delaunay wrote:
>> Provide a man-page for the ums command for USB Mass Storage.
>>
>> Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
>> ---
>>
>>   doc/usage/index.rst |  1 +
>>   doc/usage/ums.rst   | 54 +++++++++++++++++++++++++++++++++++++++++++++
>>   2 files changed, 55 insertions(+)
>>   create mode 100644 doc/usage/ums.rst
>>
>> diff --git a/doc/usage/index.rst b/doc/usage/index.rst
>> index 41b247bc62..1bab6ae3e9 100644
>> --- a/doc/usage/index.rst
>> +++ b/doc/usage/index.rst
>> @@ -43,3 +43,4 @@ Shell commands
>>      scp03
>>      size
>>      true
>> +   ums
>> diff --git a/doc/usage/ums.rst b/doc/usage/ums.rst
>> new file mode 100644
>> index 0000000000..cf0e3a9479
>> --- /dev/null
>> +++ b/doc/usage/ums.rst
>> @@ -0,0 +1,54 @@
>> +.. SPDX-License-Identifier: GPL-2.0+
>> +
>> +ums command
>> +===========
>> +
>> +Synopsis
>> +--------
>> +
>> +::
>> +
>> +    <USB_controller> [<devtype>] <dev[:part]>
>> +
>> +Description
>> +-----------
>> +
>> +Use the USB Mass Storage class (also known as USB MSC or UMS) to make
>> +accessible a block device (based on UCLASS_BLK) to a host computing 
>> device and
>> +to enable file transfers between the host and the U-Boot device.
>
> Thank you for writing this man-page.
>
> Unfortunately it is still unclear to me how to use it. Is this related
> to USB OTG? What requirements have to be met to use the command?
>

it is linked to USB gadget (USB device), I will clarified in V2


>> +
>> +This command "ums" stays in the USB's treatment loop until user 
>> enters Ctrl-C.
>> +
>> +USB_controller
>> +    USB device number
>> +
>> +devtype
>> +    block device interface, defaults to "mmc"
>> +
>> +dev
>> +    device number for devtype
>> +
>> +part
>> +    partition number, defaults to 0 (first partition)
>> +
>> +Example
>> +-------
>> +
>> +::
>> +
>> +    => ums 0 mmc 0
>> +    => ums 0 usb 1:2
>> +
>> +Configuration
>> +-------------
>> +
>> +The ums command is only available if CONFIG_CMD_USB_MASS_STORAGE=y.
>
> The symbol does not even depend on USB and mass storage being enabled. I
> would have expected CONFIG_USB_GADGET and CONFIG_BLK as requirements.
> Either this description or cmd/Kconfig is wrong. I suggest both to be
> updated.
>
yes it is a indirect dependency

=> if the CONFIG_USB_GADGET or CONFIG_BLK is not activated the ums 
command don't compile (or work I don't sure)

CMD_USB_MASS_STORAGE => select USB_FUNCTION_MASS_STORAGE (witch depends 
on USB_GADGET / USB)

CONFIG_BLK => required in usb_mass_storage.c (blk_dread/blk_dwrite)

I will add the 2 dependencies in V2

configCMD_USB_MASS_STORAGE
bool"UMS usb mass storage"
selectUSB_FUNCTION_MASS_STORAGE
+ depends onBLK&& USB_GADGET
help
USB mass storage support


> Best regards
>
> Heinrich
>
>
(...)

Regards

Patrick