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 possibilities 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 sent. 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 * I have taken some info from a Greg Kroah-Hartman article: 33 * http://www.linuxjournal.com/article/6573 34 * And from Linux Device Driver Kit CD, which is a great work, the authors taken 35 * the work to recompile lots of information an knowledge in drivers development 36 * and made it all available inside a cd. 37 * URL: http://kernel.org/pub/linux/kernel/people/gregkh/ddk/ 38 * 39 */ 40 41 #include <asm/unaligned.h> 42 #include <linux/tty.h> 43 #include <linux/slab.h> 44 #include <linux/module.h> 45 #include <linux/tty_flip.h> 46 #include <linux/usb.h> 47 #include <linux/usb/serial.h> 48 49 /* Vendor and Product ID */ 50 #define AIRCABLE_VID 0x16CA 51 #define AIRCABLE_USB_PID 0x1502 52 53 /* Protocol Stuff */ 54 #define HCI_HEADER_LENGTH 0x4 55 #define TX_HEADER_0 0x20 56 #define TX_HEADER_1 0x29 57 #define RX_HEADER_0 0x00 58 #define RX_HEADER_1 0x20 59 #define HCI_COMPLETE_FRAME 64 60 61 /* rx_flags */ 62 #define THROTTLED 0x01 63 #define ACTUALLY_THROTTLED 0x02 64 65 #define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>, Johan Hovold <jhovold@gmail.com>" 66 #define DRIVER_DESC "AIRcable USB Driver" 67 68 /* ID table that will be registered with USB core */ 69 static const struct usb_device_id id_table[] = { 70 { USB_DEVICE(AIRCABLE_VID, AIRCABLE_USB_PID) }, 71 { }, 72 }; 73 MODULE_DEVICE_TABLE(usb, id_table); 74 75 static int aircable_prepare_write_buffer(struct usb_serial_port *port, 76 void *dest, size_t size) 77 { 78 int count; 79 unsigned char *buf = dest; 80 81 count = kfifo_out_locked(&port->write_fifo, buf + HCI_HEADER_LENGTH, 82 size - HCI_HEADER_LENGTH, &port->lock); 83 buf[0] = TX_HEADER_0; 84 buf[1] = TX_HEADER_1; 85 put_unaligned_le16(count, &buf[2]); 86 87 return count + HCI_HEADER_LENGTH; 88 } 89 90 static int aircable_calc_num_ports(struct usb_serial *serial, 91 struct usb_serial_endpoints *epds) 92 { 93 /* Ignore the first interface, which has no bulk endpoints. */ 94 if (epds->num_bulk_out == 0) { 95 dev_dbg(&serial->interface->dev, 96 "ignoring interface with no bulk-out endpoints\n"); 97 return -ENODEV; 98 } 99 100 return 1; 101 } 102 103 static int aircable_process_packet(struct usb_serial_port *port, 104 int has_headers, char *packet, int len) 105 { 106 if (has_headers) { 107 len -= HCI_HEADER_LENGTH; 108 packet += HCI_HEADER_LENGTH; 109 } 110 if (len <= 0) { 111 dev_dbg(&port->dev, "%s - malformed packet\n", __func__); 112 return 0; 113 } 114 115 tty_insert_flip_string(&port->port, packet, len); 116 117 return len; 118 } 119 120 static void aircable_process_read_urb(struct urb *urb) 121 { 122 struct usb_serial_port *port = urb->context; 123 char *data = (char *)urb->transfer_buffer; 124 int has_headers; 125 int count; 126 int len; 127 int i; 128 129 has_headers = (urb->actual_length > 2 && data[0] == RX_HEADER_0); 130 131 count = 0; 132 for (i = 0; i < urb->actual_length; i += HCI_COMPLETE_FRAME) { 133 len = min_t(int, urb->actual_length - i, HCI_COMPLETE_FRAME); 134 count += aircable_process_packet(port, has_headers, 135 &data[i], len); 136 } 137 138 if (count) 139 tty_flip_buffer_push(&port->port); 140 } 141 142 static struct usb_serial_driver aircable_device = { 143 .driver = { 144 .owner = THIS_MODULE, 145 .name = "aircable", 146 }, 147 .id_table = id_table, 148 .bulk_out_size = HCI_COMPLETE_FRAME, 149 .calc_num_ports = aircable_calc_num_ports, 150 .process_read_urb = aircable_process_read_urb, 151 .prepare_write_buffer = aircable_prepare_write_buffer, 152 .throttle = usb_serial_generic_throttle, 153 .unthrottle = usb_serial_generic_unthrottle, 154 }; 155 156 static struct usb_serial_driver * const serial_drivers[] = { 157 &aircable_device, NULL 158 }; 159 160 module_usb_serial_driver(serial_drivers, id_table); 161 162 MODULE_AUTHOR(DRIVER_AUTHOR); 163 MODULE_DESCRIPTION(DRIVER_DESC); 164 MODULE_LICENSE("GPL"); 165