LXR linux/drivers/usb/serial/aircable.c

   1/*
   2 * AIRcable USB Bluetooth Dongle Driver.
   3 *
   4 * Copyright (C) 2010 Johan Hovold <jhovold@gmail.com>
   5 * Copyright (C) 2006 Manuel Francisco Naranjo (naranjo.manuel@gmail.com)
   6 *
   7 * This program is free software; you can redistribute it and/or modify it under
   8 * the terms of the GNU General Public License version 2 as published by the
   9 * Free Software Foundation.
  10 *
  11 * The device works as an standard CDC device, it has 2 interfaces, the first
  12 * one is for firmware access and the second is the serial one.
  13 * The protocol is very simply, there are two posibilities reading or writing.
  14 * When writing the first urb must have a Header that starts with 0x20 0x29 the
  15 * next two bytes must say how much data will be sended.
  16 * When reading the process is almost equal except that the header starts with
  17 * 0x00 0x20.
  18 *
  19 * The device simply need some stuff to understand data coming from the usb
  20 * buffer: The First and Second byte is used for a Header, the Third and Fourth
  21 * tells the  device the amount of information the package holds.
  22 * Packages are 60 bytes long Header Stuff.
  23 * When writing to the device the first two bytes of the header are 0x20 0x29
  24 * When reading the bytes are 0x00 0x20, or 0x00 0x10, there is an strange
  25 * situation, when too much data arrives to the device because it sends the data
  26 * but with out the header. I will use a simply hack to override this situation,
  27 * if there is data coming that does not contain any header, then that is data
  28 * that must go directly to the tty, as there is no documentation about if there
  29 * is any other control code, I will simply check for the first
  30 * one.
  31 *
  32 * The driver registers himself with the USB-serial core and the USB Core. I had
  33 * to implement a probe function against USB-serial, because other way, the
  34 * driver was attaching himself to both interfaces. I have tryed with different
  35 * configurations of usb_serial_driver with out exit, only the probe function
  36 * could handle this correctly.
  37 *
  38 * I have taken some info from a Greg Kroah-Hartman article:
  39 * http://www.linuxjournal.com/article/6573
  40 * And from Linux Device Driver Kit CD, which is a great work, the authors taken
  41 * the work to recompile lots of information an knowladge in drivers development
  42 * and made it all avaible inside a cd.
  43 * URL: http://kernel.org/pub/linux/kernel/people/gregkh/ddk/
  44 *
  45 */
  46
  47#include <asm/unaligned.h>
  48#include <linux/tty.h>
  49#include <linux/slab.h>
  50#include <linux/module.h>
  51#include <linux/tty_flip.h>
  52#include <linux/usb.h>
  53#include <linux/usb/serial.h>
  54
  55/* Vendor and Product ID */
  56#define AIRCABLE_VID            0x16CA
  57#define AIRCABLE_USB_PID        0x1502
  58
  59/* Protocol Stuff */
  60#define HCI_HEADER_LENGTH       0x4
  61#define TX_HEADER_0             0x20
  62#define TX_HEADER_1             0x29
  63#define RX_HEADER_0             0x00
  64#define RX_HEADER_1             0x20
  65#define HCI_COMPLETE_FRAME      64
  66
  67/* rx_flags */
  68#define THROTTLED               0x01
  69#define ACTUALLY_THROTTLED      0x02
  70
  71/*
  72 * Version Information
  73 */
  74#define DRIVER_VERSION "v2.0"
  75#define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>, Johan Hovold <jhovold@gmail.com>"
  76#define DRIVER_DESC "AIRcable USB Driver"
  77
  78/* ID table that will be registered with USB core */
  79static const struct usb_device_id id_table[] = {
  80        { USB_DEVICE(AIRCABLE_VID, AIRCABLE_USB_PID) },
  81        { },
  82};
  83MODULE_DEVICE_TABLE(usb, id_table);
  84
  85static int aircable_prepare_write_buffer(struct usb_serial_port *port,
  86                                                void *dest, size_t size)
  87{
  88        int count;
  89        unsigned char *buf = dest;
  90
  91        count = kfifo_out_locked(&port->write_fifo, buf + HCI_HEADER_LENGTH,
  92                                        size - HCI_HEADER_LENGTH, &port->lock);
  93        buf[0] = TX_HEADER_0;
  94        buf[1] = TX_HEADER_1;
  95        put_unaligned_le16(count, &buf[2]);
  96
  97        return count + HCI_HEADER_LENGTH;
  98}
  99
 100static int aircable_probe(struct usb_serial *serial,
 101                          const struct usb_device_id *id)
 102{
 103        struct usb_host_interface *iface_desc = serial->interface->
 104                                                                cur_altsetting;
 105        struct usb_endpoint_descriptor *endpoint;
 106        int num_bulk_out = 0;
 107        int i;
 108
 109        for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
 110                endpoint = &iface_desc->endpoint[i].desc;
 111                if (usb_endpoint_is_bulk_out(endpoint)) {
 112                        dev_dbg(&serial->dev->dev,
 113                                "found bulk out on endpoint %d\n", i);
 114                        ++num_bulk_out;
 115                }
 116        }
 117
 118        if (num_bulk_out == 0) {
 119                dev_dbg(&serial->dev->dev, "Invalid interface, discarding\n");
 120                return -ENODEV;
 121        }
 122
 123        return 0;
 124}
 125
 126static int aircable_process_packet(struct tty_struct *tty,
 127                        struct usb_serial_port *port, int has_headers,
 128                        char *packet, int len)
 129{
 130        if (has_headers) {
 131                len -= HCI_HEADER_LENGTH;
 132                packet += HCI_HEADER_LENGTH;
 133        }
 134        if (len <= 0) {
 135                dev_dbg(&port->dev, "%s - malformed packet\n", __func__);
 136                return 0;
 137        }
 138
 139        tty_insert_flip_string(tty, packet, len);
 140
 141        return len;
 142}
 143
 144static void aircable_process_read_urb(struct urb *urb)
 145{
 146        struct usb_serial_port *port = urb->context;
 147        char *data = (char *)urb->transfer_buffer;
 148        struct tty_struct *tty;
 149        int has_headers;
 150        int count;
 151        int len;
 152        int i;
 153
 154        tty = tty_port_tty_get(&port->port);
 155        if (!tty)
 156                return;
 157
 158        has_headers = (urb->actual_length > 2 && data[0] == RX_HEADER_0);
 159
 160        count = 0;
 161        for (i = 0; i < urb->actual_length; i += HCI_COMPLETE_FRAME) {
 162                len = min_t(int, urb->actual_length - i, HCI_COMPLETE_FRAME);
 163                count += aircable_process_packet(tty, port, has_headers,
 164                                                                &data[i], len);
 165        }
 166
 167        if (count)
 168                tty_flip_buffer_push(tty);
 169        tty_kref_put(tty);
 170}
 171
 172static struct usb_serial_driver aircable_device = {
 173        .driver = {
 174                .owner =        THIS_MODULE,
 175                .name =         "aircable",
 176        },
 177        .id_table =             id_table,
 178        .num_ports =            1,
 179        .bulk_out_size =        HCI_COMPLETE_FRAME,
 180        .probe =                aircable_probe,
 181        .process_read_urb =     aircable_process_read_urb,
 182        .prepare_write_buffer = aircable_prepare_write_buffer,
 183        .throttle =             usb_serial_generic_throttle,
 184        .unthrottle =           usb_serial_generic_unthrottle,
 185};
 186
 187static struct usb_serial_driver * const serial_drivers[] = {
 188        &aircable_device, NULL
 189};
 190
 191module_usb_serial_driver(serial_drivers, id_table);
 192
 193MODULE_AUTHOR(DRIVER_AUTHOR);
 194MODULE_DESCRIPTION(DRIVER_DESC);
 195MODULE_VERSION(DRIVER_VERSION);
 196MODULE_LICENSE("GPL");
 197