Re: Documentation for Raw USB ConfigFS

["Sid Spry" <sid@aeam.us>]

On Mon, May 18, 2020, at 6:58 PM, Peter Chen wrote:
>  
> > > 2. Try exactly the same script I gave you, do not try change any
> > > charaters (except the position for your application)
> > >
> > > > > cd /sys/kernel/config/usb_gadget
> > > > > cd g1
> > > > > echo "0x1d6b" > idVendor
> > > > > echo "0x0105" > idProduct
> > > > > mkdir /dev/usb-ffs
> > > > > mkdir functions/ffs.usb
> > > > > mount -t functionfs usb /dev/usb-ffs ln -s functions/ffs.usb
> > > > > configs/c.1 /home/root/usb_test/ffs_test/ffs-test & /* your own
> > > > > test application */ while [ ! -e /dev/usb-ffs/ep1 ] do  echo "."
> > > > >  sleep 1;
> > > > > done
> > >
> > > >
> > > > [1]: I actually did not have CONFIG_USB_CONFIGFS_F_FS nor F_NCM/ECM
> > set however the necessary code seemed to have been pulled in some other way
> > and the modules were available. They were loaded, and as explained my shell-
> > based configfs code worked. They are set now and the problem persists.
> > >
> > 
> > Hi, sorry I was not clear. The kernel config is fine, and
> > CONFIG_USB_CONFIGFS_F_FS is set. I run your exact script (minus the ffs-test
> > line) and it fails to create the functions/ffs.usb directory as I described before. I can
> > create other functions just fine.
> 
> You may enable debug at configfs.c, f_fs.c and your udc driver to see 
> what happened.
> 

Thanks for your help Peter. Unfortunately I have hit a brick wall. The examples in libusbgx also fail to work, and I tried that library after a friend recommended it as perhaps having secret mojo. I enabled the userspace debug helpers in the kernel but they do not seem to offer me any insight, and there's no relevant dmesg output.

My device is an Allwinner H2+, and the UDC seems to be the Inventra Highspeed Dual Role Controller. I've also got the DesignWare USB3/USB2 cores enabled from my upstream but I think they are not being loaded.

If anyone can look I'd appreciate it, this is just a hobby project. It's a good chance for me to do some kernel debugging but I'm a bit lost.

Thanks for the help so far.