USB mass storage not working on custom board

[avijitnsec]

Hi, 

I am trying to bring up a custom board based on iMX8mm. I am trying to enable mass storage on the custom board. I could mount the USB on EVK without any problem. But when I am using the same build on the custom board, I could not make it work. 

Downloaded the stock build on EVK enabling the mass storage driver. 

Mounted eMMC card partition using the driving using the following command: 

modprobe g_mass_storage file=/dev/mmcblk1p1

It worked perfectly fine. 

Log: 

# modprobe g_mass_storage file=/dev/mmcblk2p1
[ 114.147210] Mass Storage Function, version: 2009/09/11
[ 114.152682] LUN: removable file: (no medium)
[ 114.158904] LUN: file: /dev/mmcblk2p1
[ 114.162893] Number of LUNs=1
[ 114.167751] g_mass_storage gadget: Mass Storage Gadget, version: 2009/09/11
[ 114.174796] g_mass_storage gadget: userspace failed to provide iSerialNumber
[ 114.181872] g_mass_storage gadget: g_mass_storage ready
# [ 114.626916] g_mass_storage gadget: high-speed config #1: Linux File-Backed Storage

Used the same set of steps with the same build on my custom board, Didn't work. 

Log:

# modprobe g_mass_storage file=/dev/mmcblk2p1
[ 50.266199] Mass Storage Function, version: 2009/09/11
[ 50.278719] LUN: removable file: (no medium)
[ 50.287791] LUN: file: /dev/mmcblk2p1
[ 50.291987] Number of LUNs=1
[ 50.296231] g_mass_storage gadget: Mass Storage Gadget, version: 2009/09/11
[ 50.303382] g_mass_storage gadget: userspace failed to provide iSerialNumber
[ 50.310563] g_mass_storage gadget: g_mass_storage ready

I expected it to work without any change. Not sure why it is not working? I am able to download the image to eMMC using the USB interface. So I am assuming that the USB is working fine. 

Any idea how to proceed with debugging this issue?

Thanks,

Avijit

[avijitnsec · Accepted solution]

This was the problem. 

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/i-MX8MM-i-MX8MQ-USB2-0-Design-Without-US...

The suggested solution worked for me.