drivers/usb/serial/aircable.c - linux - Git at Google

 /*
  * AIRcable USB Bluetooth Dongle Driver.
  *
  * Copyright (C) 2010 Johan Hovold <jhovold@gmail.com>
  * Copyright (C) 2006 Manuel Francisco Naranjo (naranjo.manuel@gmail.com)
  *
  * This program is free software; you can redistribute it and/or modify it under
  * the terms of the GNU General Public License version 2 as published by the
  * Free Software Foundation.
  *
  * The device works as an standard CDC device, it has 2 interfaces, the first
  * one is for firmware access and the second is the serial one.
  * The protocol is very simply, there are two posibilities reading or writing.
  * When writing the first urb must have a Header that starts with 0x20 0x29 the
  * next two bytes must say how much data will be sended.
  * When reading the process is almost equal except that the header starts with
  * 0x00 0x20.
  *
  * The device simply need some stuff to understand data comming from the usb
  * buffer: The First and Second byte is used for a Header, the Third and Fourth
  * tells the  device the amount of information the package holds.
  * Packages are 60 bytes long Header Stuff.
  * When writing to the device the first two bytes of the header are 0x20 0x29
  * When reading the bytes are 0x00 0x20, or 0x00 0x10, there is an strange
  * situation, when too much data arrives to the device because it sends the data
  * but with out the header. I will use a simply hack to override this situation,
  * if there is data coming that does not contain any header, then that is data
  * that must go directly to the tty, as there is no documentation about if there
  * is any other control code, I will simply check for the first
  * one.
  *
  * The driver registers himself with the USB-serial core and the USB Core. I had
  * to implement a probe function agains USB-serial, because other way, the
  * driver was attaching himself to both interfaces. I have tryed with different
  * configurations of usb_serial_driver with out exit, only the probe function
  * could handle this correctly.
  *
  * I have taken some info from a Greg Kroah-Hartman article:
  * http://www.linuxjournal.com/article/6573
  * And from Linux Device Driver Kit CD, which is a great work, the authors taken
  * the work to recompile lots of information an knowladge in drivers development
  * and made it all avaible inside a cd.
  * URL: http://kernel.org/pub/linux/kernel/people/gregkh/ddk/
  *
  */

 #include <asm/unaligned.h>
 #include <linux/tty.h>
 #include <linux/slab.h>
 #include <linux/tty_flip.h>
 #include <linux/usb.h>
 #include <linux/usb/serial.h>

 static int debug;

 /* Vendor and Product ID */
 #define AIRCABLE_VID		0x16CA
 #define AIRCABLE_USB_PID	0x1502

 /* Protocol Stuff */
 #define HCI_HEADER_LENGTH	0x4
 #define TX_HEADER_0		0x20
 #define TX_HEADER_1		0x29
 #define RX_HEADER_0		0x00
 #define RX_HEADER_1		0x20
 #define HCI_COMPLETE_FRAME	64

 /* rx_flags */
 #define THROTTLED		0x01
 #define ACTUALLY_THROTTLED	0x02

 /*
  * Version Information
  */
 #define DRIVER_VERSION "v2.0"
 #define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>, Johan Hovold <jhovold@gmail.com>"
 #define DRIVER_DESC "AIRcable USB Driver"

 /* ID table that will be registered with USB core */
 static const struct usb_device_id id_table[] = {
 	{ USB_DEVICE(AIRCABLE_VID, AIRCABLE_USB_PID) },
 	{ },
 };
 MODULE_DEVICE_TABLE(usb, id_table);

 static int aircable_prepare_write_buffer(struct usb_serial_port *port,
 						void *dest, size_t size)
 {
 	int count;
 	unsigned char *buf = dest;

 	count = kfifo_out_locked(&port->write_fifo, buf + HCI_HEADER_LENGTH,
 					size - HCI_HEADER_LENGTH, &port->lock);
 	buf[0] = TX_HEADER_0;
 	buf[1] = TX_HEADER_1;
 	put_unaligned_le16(count, &buf[2]);

 	return count;
 }

 static int aircable_probe(struct usb_serial *serial,
 			  const struct usb_device_id *id)
 {
 	struct usb_host_interface *iface_desc = serial->interface->
 								cur_altsetting;
 	struct usb_endpoint_descriptor *endpoint;
 	int num_bulk_out = 0;
 	int i;

 	for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
 		endpoint = &iface_desc->endpoint[i].desc;
 		if (usb_endpoint_is_bulk_out(endpoint)) {
 			dbg("found bulk out on endpoint %d", i);
 			++num_bulk_out;
 		}
 	}

 	if (num_bulk_out == 0) {
 		dbg("Invalid interface, discarding");
 		return -ENODEV;
 	}

 	return 0;
 }

 static int aircable_process_packet(struct tty_struct *tty,
 			struct usb_serial_port *port, int has_headers,
 			char *packet, int len)
 {
 	if (has_headers) {
 		len -= HCI_HEADER_LENGTH;
 		packet += HCI_HEADER_LENGTH;
 	}
 	if (len <= 0) {
 		dbg("%s - malformed packet", __func__);
 		return 0;
 	}

 	tty_insert_flip_string(tty, packet, len);

 	return len;
 }

 static void aircable_process_read_urb(struct urb *urb)
 {
 	struct usb_serial_port *port = urb->context;
 	char *data = (char *)urb->transfer_buffer;
 	struct tty_struct *tty;
 	int has_headers;
 	int count;
 	int len;
 	int i;

 	tty = tty_port_tty_get(&port->port);
 	if (!tty)
 		return;

 	has_headers = (urb->actual_length > 2 && data[0] == RX_HEADER_0);

 	count = 0;
 	for (i = 0; i < urb->actual_length; i += HCI_COMPLETE_FRAME) {
 		len = min_t(int, urb->actual_length - i, HCI_COMPLETE_FRAME);
 		count += aircable_process_packet(tty, port, has_headers,
 								&data[i], len);
 	}

 	if (count)
 		tty_flip_buffer_push(tty);
 	tty_kref_put(tty);
 }

 static struct usb_driver aircable_driver = {
 	.name =		"aircable",
 	.probe =	usb_serial_probe,
 	.disconnect =	usb_serial_disconnect,
 	.id_table =	id_table,
 	.no_dynamic_id =	1,
 };

 static struct usb_serial_driver aircable_device = {
 	.driver = {
 		.owner =	THIS_MODULE,
 		.name =		"aircable",
 	},
 	.usb_driver = 		&aircable_driver,
 	.id_table = 		id_table,
 	.num_ports =		1,
 	.bulk_out_size =	HCI_COMPLETE_FRAME,
 	.probe =		aircable_probe,
 	.process_read_urb =	aircable_process_read_urb,
 	.prepare_write_buffer =	aircable_prepare_write_buffer,
 	.throttle =		usb_serial_generic_throttle,
 	.unthrottle =		usb_serial_generic_unthrottle,
 };

 static int __init aircable_init(void)
 {
 	int retval;
 	retval = usb_serial_register(&aircable_device);
 	if (retval)
 		goto failed_serial_register;
 	retval = usb_register(&aircable_driver);
 	if (retval)
 		goto failed_usb_register;
 	return 0;

 failed_usb_register:
 	usb_serial_deregister(&aircable_device);
 failed_serial_register:
 	return retval;
 }

 static void __exit aircable_exit(void)
 {
 	usb_deregister(&aircable_driver);
 	usb_serial_deregister(&aircable_device);
 }

 MODULE_AUTHOR(DRIVER_AUTHOR);
 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_VERSION(DRIVER_VERSION);
 MODULE_LICENSE("GPL");

 module_init(aircable_init);
 module_exit(aircable_exit);

 module_param(debug, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(debug, "Debug enabled or not");
	/*
	* AIRcable USB Bluetooth Dongle Driver.
	*
	* Copyright (C) 2010 Johan Hovold <jhovold@gmail.com>
	* Copyright (C) 2006 Manuel Francisco Naranjo (naranjo.manuel@gmail.com)
	*
	* This program is free software; you can redistribute it and/or modify it under
	* the terms of the GNU General Public License version 2 as published by the
	* Free Software Foundation.
	*
	* The device works as an standard CDC device, it has 2 interfaces, the first
	* one is for firmware access and the second is the serial one.
	* The protocol is very simply, there are two posibilities reading or writing.
	* When writing the first urb must have a Header that starts with 0x20 0x29 the
	* next two bytes must say how much data will be sended.
	* When reading the process is almost equal except that the header starts with
	* 0x00 0x20.
	*
	* The device simply need some stuff to understand data comming from the usb
	* buffer: The First and Second byte is used for a Header, the Third and Fourth
	* tells the device the amount of information the package holds.
	* Packages are 60 bytes long Header Stuff.
	* When writing to the device the first two bytes of the header are 0x20 0x29
	* When reading the bytes are 0x00 0x20, or 0x00 0x10, there is an strange
	* situation, when too much data arrives to the device because it sends the data
	* but with out the header. I will use a simply hack to override this situation,
	* if there is data coming that does not contain any header, then that is data
	* that must go directly to the tty, as there is no documentation about if there
	* is any other control code, I will simply check for the first
	* one.
	*
	* The driver registers himself with the USB-serial core and the USB Core. I had
	* to implement a probe function agains USB-serial, because other way, the
	* driver was attaching himself to both interfaces. I have tryed with different
	* configurations of usb_serial_driver with out exit, only the probe function
	* could handle this correctly.
	*
	* I have taken some info from a Greg Kroah-Hartman article:
	* http://www.linuxjournal.com/article/6573
	* And from Linux Device Driver Kit CD, which is a great work, the authors taken
	* the work to recompile lots of information an knowladge in drivers development
	* and made it all avaible inside a cd.
	* URL: http://kernel.org/pub/linux/kernel/people/gregkh/ddk/
	*
	*/

	#include <asm/unaligned.h>
	#include <linux/tty.h>
	#include <linux/slab.h>
	#include <linux/tty_flip.h>
	#include <linux/usb.h>
	#include <linux/usb/serial.h>

	static int debug;

	/* Vendor and Product ID */
	#define AIRCABLE_VID 0x16CA
	#define AIRCABLE_USB_PID 0x1502

	/* Protocol Stuff */
	#define HCI_HEADER_LENGTH 0x4
	#define TX_HEADER_0 0x20
	#define TX_HEADER_1 0x29
	#define RX_HEADER_0 0x00
	#define RX_HEADER_1 0x20
	#define HCI_COMPLETE_FRAME 64

	/* rx_flags */
	#define THROTTLED 0x01
	#define ACTUALLY_THROTTLED 0x02

	/*
	* Version Information
	*/
	#define DRIVER_VERSION "v2.0"
	#define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>, Johan Hovold <jhovold@gmail.com>"
	#define DRIVER_DESC "AIRcable USB Driver"

	/* ID table that will be registered with USB core */
	static const struct usb_device_id id_table[] = {
	{ USB_DEVICE(AIRCABLE_VID, AIRCABLE_USB_PID) },
	{ },
	};
	MODULE_DEVICE_TABLE(usb, id_table);

	static int aircable_prepare_write_buffer(struct usb_serial_port *port,
	void *dest, size_t size)
	{
	int count;
	unsigned char *buf = dest;

	count = kfifo_out_locked(&port->write_fifo, buf + HCI_HEADER_LENGTH,
	size - HCI_HEADER_LENGTH, &port->lock);
	buf[0] = TX_HEADER_0;
	buf[1] = TX_HEADER_1;
	put_unaligned_le16(count, &buf[2]);

	return count;
	}

	static int aircable_probe(struct usb_serial *serial,
	const struct usb_device_id *id)
	{
	struct usb_host_interface *iface_desc = serial->interface->
	cur_altsetting;
	struct usb_endpoint_descriptor *endpoint;
	int num_bulk_out = 0;
	int i;

	for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
	endpoint = &iface_desc->endpoint[i].desc;
	if (usb_endpoint_is_bulk_out(endpoint)) {
	dbg("found bulk out on endpoint %d", i);
	++num_bulk_out;
	}
	}

	if (num_bulk_out == 0) {
	dbg("Invalid interface, discarding");
	return -ENODEV;
	}

	return 0;
	}

	static int aircable_process_packet(struct tty_struct *tty,
	struct usb_serial_port *port, int has_headers,
	char *packet, int len)
	{
	if (has_headers) {
	len -= HCI_HEADER_LENGTH;
	packet += HCI_HEADER_LENGTH;
	}
	if (len <= 0) {
	dbg("%s - malformed packet", __func__);
	return 0;
	}

	tty_insert_flip_string(tty, packet, len);

	return len;
	}

	static void aircable_process_read_urb(struct urb *urb)
	{
	struct usb_serial_port *port = urb->context;
	char data = (char )urb->transfer_buffer;
	struct tty_struct *tty;
	int has_headers;
	int count;
	int len;
	int i;

	tty = tty_port_tty_get(&port->port);
	if (!tty)
	return;

	has_headers = (urb->actual_length > 2 && data[0] == RX_HEADER_0);

	count = 0;
	for (i = 0; i < urb->actual_length; i += HCI_COMPLETE_FRAME) {
	len = min_t(int, urb->actual_length - i, HCI_COMPLETE_FRAME);
	count += aircable_process_packet(tty, port, has_headers,
	&data[i], len);
	}

	if (count)
	tty_flip_buffer_push(tty);
	tty_kref_put(tty);
	}

	static struct usb_driver aircable_driver = {
	.name = "aircable",
	.probe = usb_serial_probe,
	.disconnect = usb_serial_disconnect,
	.id_table = id_table,
	.no_dynamic_id = 1,
	};

	static struct usb_serial_driver aircable_device = {
	.driver = {
	.owner = THIS_MODULE,
	.name = "aircable",
	},
	.usb_driver = &aircable_driver,
	.id_table = id_table,
	.num_ports = 1,
	.bulk_out_size = HCI_COMPLETE_FRAME,
	.probe = aircable_probe,
	.process_read_urb = aircable_process_read_urb,
	.prepare_write_buffer = aircable_prepare_write_buffer,
	.throttle = usb_serial_generic_throttle,
	.unthrottle = usb_serial_generic_unthrottle,
	};

	static int __init aircable_init(void)
	{
	int retval;
	retval = usb_serial_register(&aircable_device);
	if (retval)
	goto failed_serial_register;
	retval = usb_register(&aircable_driver);
	if (retval)
	goto failed_usb_register;
	return 0;

	failed_usb_register:
	usb_serial_deregister(&aircable_device);
	failed_serial_register:
	return retval;
	}

	static void __exit aircable_exit(void)
	{
	usb_deregister(&aircable_driver);
	usb_serial_deregister(&aircable_device);
	}

	MODULE_AUTHOR(DRIVER_AUTHOR);
	MODULE_DESCRIPTION(DRIVER_DESC);
	MODULE_VERSION(DRIVER_VERSION);
	MODULE_LICENSE("GPL");

	module_init(aircable_init);
	module_exit(aircable_exit);

	module_param(debug, bool, S_IRUGO \| S_IWUSR);
	MODULE_PARM_DESC(debug, "Debug enabled or not");