blob: 80a9845cd93fba16e50ae7797606b7b9b925c887 [file] [log] [blame]
* AIRcable USB Bluetooth Dongle Driver.
* Copyright (C) 2010 Johan Hovold <>
* Copyright (C) 2006 Manuel Francisco Naranjo (
* 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 possibilities 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 sent.
* When reading the process is almost equal except that the header starts with
* 0x00 0x20.
* The device simply need some stuff to understand data coming 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 against USB-serial, because other way, the
* driver was attaching himself to both interfaces. I have tried 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:
* And from Linux Device Driver Kit CD, which is a great work, the authors taken
* the work to recompile lots of information an knowledge in drivers development
* and made it all available inside a cd.
* URL:
#include <asm/unaligned.h>
#include <linux/tty.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/tty_flip.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
/* Vendor and Product ID */
#define AIRCABLE_VID 0x16CA
#define AIRCABLE_USB_PID 0x1502
/* Protocol Stuff */
#define TX_HEADER_0 0x20
#define TX_HEADER_1 0x29
#define RX_HEADER_0 0x00
#define RX_HEADER_1 0x20
/* rx_flags */
#define THROTTLED 0x01
#define DRIVER_AUTHOR "Naranjo, Manuel Francisco <>, Johan Hovold <>"
#define DRIVER_DESC "AIRcable USB Driver"
/* ID table that will be registered with USB core */
static const struct usb_device_id id_table[] = {
{ },
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 + HCI_HEADER_LENGTH;
static int aircable_probe(struct usb_serial *serial,
const struct usb_device_id *id)
struct usb_host_interface *iface_desc = serial->interface->
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)) {
"found bulk out on endpoint %d\n", i);
if (num_bulk_out == 0) {
dev_dbg(&serial->dev->dev, "Invalid interface, discarding\n");
return -ENODEV;
return 0;
static int aircable_process_packet(struct usb_serial_port *port,
int has_headers, char *packet, int len)
if (has_headers) {
if (len <= 0) {
dev_dbg(&port->dev, "%s - malformed packet\n", __func__);
return 0;
tty_insert_flip_string(&port->port, 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;
int has_headers;
int count;
int len;
int i;
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(port, has_headers,
&data[i], len);
if (count)
static struct usb_serial_driver aircable_device = {
.driver = {
.owner = THIS_MODULE,
.name = "aircable",
.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 struct usb_serial_driver * const serial_drivers[] = {
&aircable_device, NULL
module_usb_serial_driver(serial_drivers, id_table);