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UVC ConfigFS Gadget configuration tool
#!/bin/sh
set -e
#set -x
CONFIGFS="/sys/kernel/config"
GADGET="$CONFIGFS/usb_gadget"
VID="0x0525"
PID="0xa4a2"
SERIAL="0123456789"
MANUF=$(hostname)
PRODUCT="UVC Gadget"
USBFILE=/root/usbstorage.img
BOARD=$(strings /proc/device-tree/model)
case $BOARD in
"Renesas Salvator-X board based on r8a7795 ES1.x")
UDC_USB2=e6590000.usb
UDC_USB3=ee020000.usb
UDC_ROLE2=/sys/devices/platform/soc/ee080200.usb-phy/role
UDC_ROLE2=/dev/null #Not needed - always peripheral
UDC_ROLE3=/sys/devices/platform/soc/ee020000.usb/role
UDC=$UDC_USB2
UDC_ROLE=$UDC_ROLE2
;;
"TI OMAP4 PandaBoard-ES")
UDC=`ls /sys/class/udc` # Should be musb-hdrc.0.auto
UDC_ROLE=/dev/null # Not needed - peripheral enabled
;;
*)
UDC=`ls /sys/class/udc` # will identify the 'first' UDC
UDC_ROLE=/dev/null # Not generic
;;
esac
echo "Detecting platform:"
echo " board : $BOARD"
echo " udc : $UDC"
create_msd() {
# Example usage:
# create_msd <target config> <function name> <image file>
# create_msd configs/c.1 mass_storage.0 /root/backing.img
CONFIG=$1
FUNCTION=$2
BACKING_STORE=$3
if [ ! -f $BACKING_STORE ]
then
echo "\tCreating backing file"
dd if=/dev/zero of=$BACKING_STORE bs=1M count=32 > /dev/null 2>&1
mkfs.ext4 $USBFILE > /dev/null 2>&1
echo "\tOK"
fi
echo "\tCreating MSD gadget functionality"
mkdir functions/$FUNCTION
echo 1 > functions/$FUNCTION/stall
echo $BACKING_STORE > functions/$FUNCTION/lun.0/file
echo 1 > functions/$FUNCTION/lun.0/removable
echo 0 > functions/$FUNCTION/lun.0/cdrom
ln -s functions/$FUNCTION configs/c.1
echo "\tOK"
}
delete_msd() {
# Example usage:
# delete_msd <target config> <function name>
# delete_msd config/c.1 uvc.0
CONFIG=$1
FUNCTION=$2
echo "Removing Mass Storage interface : $FUNCTION"
rm -f $CONFIG/$FUNCTION
rmdir functions/$FUNCTION
echo "OK"
}
create_uvc() {
# Example usage:
# create_uvc <target config> <function name>
# create_uvc config/c.1 uvc.0
CONFIG=$1
FUNCTION=$2
echo " Creating UVC gadget functionality : $FUNCTION"
mkdir functions/$FUNCTION
mkdir -p functions/$FUNCTION/streaming/uncompressed/u/360p
cat <<EOF > functions/$FUNCTION/streaming/uncompressed/u/360p/dwFrameInterval
666666
1000000
5000000
EOF
mkdir functions/$FUNCTION/streaming/header/h
cd functions/$FUNCTION/streaming/header/h
ln -s ../../uncompressed/u
cd ../../class/fs
ln -s ../../header/h
cd ../../class/hs
ln -s ../../header/h
cd ../../../control
mkdir header/h
ln -s header/h class/fs
ln -s header/h class/ss
cd ../../../
echo 2048 > functions/$FUNCTION/streaming_maxpacket
ln -s functions/$FUNCTION configs/c.1
}
delete_uvc() {
# Example usage:
# delete_uvc <target config> <function name>
# delete_uvc config/c.1 uvc.0
CONFIG=$1
FUNCTION=$2
echo " Deleting UVC gadget functionality : $FUNCTION"
rm $CONFIG/$FUNCTION
rm functions/$FUNCTION/control/class/*/h
rm functions/$FUNCTION/streaming/class/*/h
rm functions/$FUNCTION/streaming/header/h/u
rmdir functions/$FUNCTION/streaming/uncompressed/u/360p
rmdir functions/$FUNCTION/streaming/uncompressed/u
rmdir functions/$FUNCTION/streaming/header/h
rmdir functions/$FUNCTION/control/header/h
rmdir functions/$FUNCTION
}
case "$1" in
start)
echo "Creating the USB gadget"
#echo "Loading composite module"
#modprobe libcomposite
echo "Creating gadget directory g1"
mkdir -p $GADGET/g1
cd $GADGET/g1
if [ $? -ne 0 ]; then
echo "Error creating usb gadget in configfs"
exit 1;
else
echo "OK"
fi
echo "Setting Vendor and Product ID's"
echo $VID > idVendor
echo $PID > idProduct
echo "OK"
echo "Setting English strings"
mkdir -p strings/0x409
echo $SERIAL > strings/0x409/serialnumber
echo $MANUF > strings/0x409/manufacturer
echo $PRODUCT > strings/0x409/product
echo "OK"
echo "Creating Config"
mkdir configs/c.1
mkdir configs/c.1/strings/0x409
echo "Creating functions..."
#create_msd configs/c.1 mass_storage.0 $USBFILE
create_uvc configs/c.1 uvc.0
echo "OK"
echo "Binding USB Device Controller"
echo $UDC > UDC
echo peripheral > $UDC_ROLE
cat $UDC_ROLE
echo "OK"
;;
stop)
echo "Stopping the USB gadget"
set +e # Ignore all errors here on a best effort
cd $GADGET/g1
if [ $? -ne 0 ]; then
echo "Error: no configfs gadget found"
exit 1;
fi
echo "Unbinding USB Device Controller"
grep $UDC UDC && echo "" > UDC
echo "OK"
delete_uvc configs/c.1 uvc.0
#delete_msd configs/c.1 mass_storage.0
echo "Clearing English strings"
rmdir strings/0x409
echo "OK"
echo "Cleaning up configuration"
rmdir configs/c.1/strings/0x409
rmdir configs/c.1
echo "OK"
echo "Removing gadget directory"
cd $GADGET
rmdir g1
cd /
echo "OK"
#echo "Disable composite USB gadgets"
#modprobe -r libcomposite
#echo "OK"
;;
*)
echo "Usage : $0 {start|stop}"
esac
@ikester

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@ikester ikester commented Apr 26, 2020

Hi! I'm not sure if you've used this script recently.

I'm trying it now on a Pi Zero W with the latest version of Buster (Linux raspberrypi 4.19.97+ #1294 Thu Jan 30 13:10:54 GMT 2020 armv6l GNU/Linux) but I'm getting this error on the line that is doing echo $UDC > UDC, right after "Binding USB Device Controller":

echo: echo: I/O error

If I try writing to /sys/kernel/config/usb_gadget/g1/UDC manually (after creating the parent dir g1) as root I still get a permissions error.

I don't think the UVC device is getting configured completely. Any idea why this line may be failing with a recent version or Raspbian? Is that line absolutely necessary for the device to work?

@kbingham

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@kbingham kbingham commented Apr 26, 2020

Hi, I'm afraid I haven't used it at all lately, and I haven't used it on a raspberry pi - so it might have some differences.

I would like to see uvc-gadget working on the RPi0 though so I'd be keen to help you get this going, and I can try to bring up the UDC on my RPi0 too.

I believe binding is important, so I suspect if it's not allowing it to be bound, perhaps it's already bound to another gadget function?

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@ikester ikester commented Apr 26, 2020

Thanks for the reply. I figured out that it wasn't binding because I was loading g_ether first. Once I removed that and connected to the Pi through WiFi I was able to get the script to create the ConfigFS and bind properly. However, I cannot get the uvc-gadget binaries to work. They start and bind to the device, but the buffers are not allocated and it doesn't register on the host.

If I use the old g_webcam driver (it's as simple as running sudo modprobe g_webcam, instead of the configfs approach) I'm able to get this binary to stream a synthetic pattern to a Mac:
https://github.com/wlhe/uvc-gadget

Using uvc-gadget -d

But that same application does not work with the configfs method. I suspect I might need to find some additional configuration/function values to create a proper tree for the RPi Zero.

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@kbingham kbingham commented Apr 26, 2020

Ah ok - so some progress. Indeed there are two methods to configure. The g_webcam is quite simple and doesn't allow much configuration, but shows that the device is functional. I'm sure I remember coding the uvc-gadget to detect and support the old g_webcam and still work - but we really did focus on the configfs route, so I wouldn't be surprised if the current uvc-gadget master only really works with configfs methods.

Have you got any logs that show the errors you experience? Perhaps worth moving to e-mail to help debug: - feel free to send details to kieran.bingham@ideasonboard.com, and I'll try to take a look during the week, or next.

@ikester

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@ikester ikester commented Apr 26, 2020

Thanks for offering to follow-up. That's very generous. I'll write you an email with some more detail. The upstream uvc-gadget only supports streaming from another video device to the virtual one (i.e. from /dev/video10 to /dev/video0). Since I'm trying to make a video loopback device, I'm trying to use some of the forks (like the one mentioned above) that include some patches and enhancements, like sending a test pattern.

Thanks again!

@johnelliott

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@johnelliott johnelliott commented May 4, 2020

@ikester I am also hoping to do the same thing with my pi zero w

@teafella

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@teafella teafella commented May 6, 2020

EDIT: Found this thread on the raspi forums. It appears discussion about this has moved there.

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