Requirements
============

* you need dummy_hcd.ko, i.e. a kernel compiled with CONFIG_USB_DUMMY_HCD=m
* kernel version >= 5.0 does NOT require patching
* kernel version < 5.0 needs a fixed usb_f_fs.ko, which doesn't make blind assumptions about
  everything being a HID descriptor.  See CCID.patch

On a stock Debian system, this works as follows (kernel versions will change over time,
in my case `uname -r` shows 4.19.0-4-amd64).

----
apt-get install linux-headers-4.19.0-4-amd64 linux-source-4.19
cd /usr/src
tar xf linux-source-4.19.tar.xz
cd linux-source-4.19
ln -s /boot/config-4.19.0-4-amd64 .config
ln -s /usr/src/linux-headers-4.19.0-4-amd64/Module.symvers .
patch -p1 < /my/path/to/CCID.patch
# edit .config and set CONFIG_USB_DUMMY_HCD=m
make modules_prepare
make M=drivers/usb/gadget/function
make M=drivers/usb/gadget/udc
cp drivers/usb/gadget/function/usb_f_fs.ko /lib/modules/`uname -r`/kernel/drivers/usb/gadget/function/
cp drivers/usb/gadget/udc/dummy_hcd.ko /lib/modules/`uname -r`/kernel/drivers/usb/gadget/udc/
depmod
----


Running
-------

You first have to run the `create_ccid_gadget.sh` script, which will

* load the required kernel modules with their respective options
* use usb-gadget-configfs to create a new device with configuration + interface
* mount the resulting endpoints as usb functionfs to /dev/ffs-ccid

Next, you run the actual userspace implementation of the gadget, telling it the functionfs path

	./ccid_functionfs /dev/ffs-ccid

which should make your 'dmesg' show something like

----
read descriptors
read strings
----

Finally, you can virtually connect the gadget to the virtual host controller by issuing

	echo dummy_udc.0 > /sys/kernel/config/usb_gadget/osmo-ccid/UDC

at which point your 'dmesg' should print something along the lines of

----
usb 3-1: new full-speed USB device number 8 using dummy_hcd
usb 3-1: New USB device found, idVendor=1d50, idProduct=615f, bcdDevice= 4.19
usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 3-1: Product: sysmoOCTSIM
usb 3-1: Manufacturer: sysmocom GmbH
usb 3-1: SerialNumber: 2342
configfs-gadget gadget: full-speed config #1: c
----


Using from pcsc-lite
--------------------

In order to make pcsc-lite recognize the reader, you'll need to add the VID/PID
to the /etc/libccid_Info.plist with a diff like this:

--- /tmp/libccid_Info.plist	2019-05-15 22:02:07.892925425 +0200
+++ /etc/libccid_Info.plist	2018-12-27 16:18:01.026824476 +0100
@@ -525,6 +525,7 @@
 		<string>0x08C3</string>
 		<string>0x15E1</string>
 		<string>0x062D</string>
+		<string>0x1D50</string>
 	</array>
 
 	<key>ifdProductID</key>
@@ -952,6 +953,7 @@
 		<string>0x0402</string>
 		<string>0x2007</string>
 		<string>0x0001</string>
+		<string>0x615F</string>
 	</array>
 
 	<key>ifdFriendlyName</key>
@@ -1379,6 +1381,7 @@
 		<string>Precise Biometrics Precise 200 MC</string>
 		<string>RSA RSA SecurID (R) Authenticator</string>
 		<string>THRC Smart Card Reader</string>
+		<string>sysmoOCTSIM Test Reader</string>
 	</array>
 
 	<key>Copyright</key>

