enable usb read-only file-store

[networkimprov]

o.020 enable usb read-only file-store For PC drivers, helper apps, docs. Tony suggested this pseudocode:

# dd if=/dev/zero of=/tmp/storage1 bs=1M count=32
# mkfs.vfat /tmp/storage1
# mount -oloop /tmp/storage1 /mnt
# cp /media/data/doc/* /mnt
# echo /tmp/storage1 > /sys/configfs/whatever/storage/file

And then /tmp/storage1 appears as a disk on the PC.

[thomasdziedzic]

Can't this just be accomplished with the samba task, where we store documents under a docs folder? Is there a reason why we need it to show up as a file store?

[networkimprov]

This file-store would provide setup files to a PC that's not yet configured to find the anvl via wifi p2p or usb-ethernet.

[thomasdziedzic]

I tried to configure the following:

I used the following as a reference: https://www.kernel.org/doc/Documentation/ABI/testing/configfs-usb-gadget-mass-storage

I created a vfat partition on /tmp/storage1

mkdir /sys/kernel/config/usb_gadget/g1/functions/mass_storage.0
echo /tmp/storage1 > /sys/kernel/config/usb_gadget/g1/functions/mass_storage.0/lun.0/file
ln -s  /sys/kernel/config/usb_gadget/g1/functions/mass_storage.0 /sys/kernel/config/usb_gadget/g1/configs/Anvl.1

NOTE: I'm reusing the same folder as your other configs, namely "Anvl.1", not sure if that matters.

I got the following in dmesg on the anvl:

[ 2403.496917] Number of LUNs=8
[ 2403.500244] Mass Storage Function, version: 2009/09/11
[ 2403.505645] LUN: removable file: (no medium)
[ 2428.265655] mass_storage.0/lun.0: open backing file: /tmp/storage1

The anvl is connected to my computer (linux box) but it didn't create any news nodes under /dev/sd* I'm probably missing something obvious, ideas?

[networkimprov]

@tmlind?

[tmlind]

Well the storage is working as the installer is working :) Probably you have to first disable the gadget by doing echo "" > /sys/kernel/config/UDC, then do the configuration, then echo musb-hdrc.0.auto > UDC to enable it again.

[thomasdziedzic]

So I tried the following:

#!/usr/bin/bash

set -x

echo '' > /sys/kernel/config/usb_gadget/g1/UDC 

dd if=/dev/zero of=/tmp/storage1 bs=1M count=32
mkfs.vfat /tmp/storage1
mount -oloop /tmp/storage1 /mnt
echo test > /mnt/tom
umount /mnt

mkdir /sys/kernel/config/usb_gadget/g1/functions/mass_storage.0
echo /tmp/storage1 > /sys/kernel/config/usb_gadget/g1/functions/mass_storage.0/lun.0/file

mkdir /sys/kernel/config/usb_gadget/g1/configs/Anvl.1
ln -s  /sys/kernel/config/usb_gadget/g1/functions/mass_storage.0 /sys/kernel/config/usb_gadget/g2/configs/Anvl.1

echo 'musb-hdrc.0.auto' > /sys/kernel/config/usb_gadget/g1/UDC 

And the script gets stuck with a constant white light on:

+ echo ''

cu: Got hangup signal

Disconnected.

I was wondering, could we have multiple gadgets that use the same UDC driver? I don't think so but it might be worth asking to see if we can separate out the usb-manager related functions from the filestore function. I tried to run the same script but with g2, and when I did the final echo to /sys/kernel/config/usb_gadget/g1/UDC it said the device or resource was busy.

[thomasdziedzic]

Just as a remark, another option is to use the usb-manager to bring up the mass_storage gadget if it turns out that you can't add functions to gadgets that have already been started.

[tmlind]

Yeah we should use usb-manager to configure the mass storage except not configure any backend file for it. Then all the script has to do is echo the backend file name to /sys/kernel/config and it should show up on the PC.

[thomasdziedzic]

Looks like libusbg does not support mass storage after looking through the code. We will have to add this functionality.

@tmlind I think you might be the better person for implementing this since you've already written usb-manager and should be much more familiar with libusbg than I am.

Also, will echoing the file after bringing up the driver work?

[tmlind]

Sure I'll take a look at it a bit later if no huge rush on this. It's removable media, so yes it at least used to work.

[thomasdziedzic]

@tmlind any status on this?

[tmlind]

Sorry have not had a chance to look into this yet.