Linux/PROCESSOR-SDK-AM437X: USB0 use for mass storage

WooSeok Nam

Tool/software: Linux

Hello!

I want to use the AM437x board as a mass storage device (our board is based on AM437x-sk-evm).
It looks like a USB memory stick.
So I found the dts file on the AM437x sdk and looked for the USB0 port.
But there is no USB0 port, only information about USB1 and USB2.

USB1 is OTG and USB2 is HOST.
But I want to use it as a mass storage device.
How do I set it up and what ports should I use?

(Our board uses SD card booting and will use SD card as mass storage device.)
SDcard (Storage) -> usb0 port -> pc

usb1{
dr_mode = "otg";
status = "okay";
...
}
usb2{
dr_mode = "host";
status = "okay";
...
}

help me plz.......

over 6 years ago

0 Biser Gatchev-XID over 6 years ago

TI__Guru**** 393215 points

The software team have been notified. They will respond here.

0 Dwarakesh Radhakrishnan over 6 years ago in reply to Biser Gatchev-XID

Guru 13620 points

Hi,
In most cases USB0 and USB1 are used interchangeably. There are only two instances of USB in AM437x. So what is USB1, should be USB0. USB2 should be USB1, if considering from 0.
Have you gone through : processors.wiki.ti.com/.../Linux_Core_DWC3_User's_Guide specifically USB MASS storage gadget

0 WooSeok Nam over 6 years ago in reply to Dwarakesh Radhakrishnan

Intellectual 460 points

Usb0 -> usb1
Usb1 -> usb2
Is that right?

How do I set dr_mode?

0 Dwarakesh Radhakrishnan over 6 years ago in reply to WooSeok Nam

Guru 13620 points

Yes. dr_mode you can set as either as peripheral in device tree, instead of OTG, if you need only Device functionality. Or set as OTG, use the appropriate cable and change as done in : processors.wiki.ti.com/.../USB_General_Guide_Linux_v3.8 to device mode . Though for older kernel, I believe it should be the same way.

0 WooSeok Nam over 6 years ago in reply to Dwarakesh Radhakrishnan

Intellectual 460 points

Thank you for your help.
I will test it.

0 Bin Liu over 6 years ago in reply to WooSeok Nam

TI__Guru*** 125136 points

Wooseok,

If you use the AM437x SK board as the reference in your board, you don't have to change anything in kernel or dts, you just need to load the g_mass_storage gadget driver as 'modprobe g_mass_storage file=...' using your preferred backend storage.

Please ensure you use the latest Processor Linux SDK kernel.

0 WooSeok Nam over 6 years ago in reply to Bin Liu

Intellectual 460 points

Thank you bro!!

I succeeded with "modprobe g_mass_storage file = / dev / mmcblk0p1 stall = 0".
But I do not know the definition of the [stall] option.
And even if you create a file in the mmcblk0p1 area of the board, it will not sync with the PC.
When reconnect the USB cable, the files are synchronized.

Why?? Do I have to update or refresh manually?

0 Bin Liu over 6 years ago in reply to WooSeok Nam

TI__Guru*** 125136 points

WooSeok Nam said:
But I do not know the definition of the [stall] option.

Sorry, I don't know it either, never needed to figure what it is for. Some articles on internet mentioned stall=0 is required for Windows host.

WooSeok Nam said:
And even if you create a file in the mmcblk0p1 area of the board, it will not sync with the PC.
When reconnect the USB cable, the files are synchronized.

Why?? Do I have to update or refresh manually?

g_mass_storage gadget is not intended for simultaneously accessing the backend storage from both USB host and the gadget Linux OS, you would have data corruption if you did so.

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Linux/PROCESSOR-SDK-AM437X: USB0 use for mass storage