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/tty_flip.h> 51 #include <linux/usb.h> 52 #include <linux/usb/serial.h> 53 54 static int debug; 55 56 /* Vendor and Product ID */ 57 #define AIRCABLE_VID 0x16CA 58 #define AIRCABLE_USB_PID 0x1502 59 60 /* Protocol Stuff */ 61 #define HCI_HEADER_LENGTH 0x4 62 #define TX_HEADER_0 0x20 63 #define TX_HEADER_1 0x29 64 #define RX_HEADER_0 0x00 65 #define RX_HEADER_1 0x20 66 #define HCI_COMPLETE_FRAME 64 67 68 /* rx_flags */ 69 #define THROTTLED 0x01 70 #define ACTUALLY_THROTTLED 0x02 71 72 /* 73 * Version Information 74 */ 75 #define DRIVER_VERSION "v2.0" 76 #define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>, Johan Hovold <jhovold@gmail.com>" 77 #define DRIVER_DESC "AIRcable USB Driver" 78 79 /* ID table that will be registered with USB core */ 80 static const struct usb_device_id id_table[] = { 81 { USB_DEVICE(AIRCABLE_VID, AIRCABLE_USB_PID) }, 82 { }, 83 }; 84 MODULE_DEVICE_TABLE(usb, id_table); 85 86 static int aircable_prepare_write_buffer(struct usb_serial_port *port, 87 void *dest, size_t size) 88 { 89 int count; 90 unsigned char *buf = dest; 91 92 count = kfifo_out_locked(&port->write_fifo, buf + HCI_HEADER_LENGTH, 93 size - HCI_HEADER_LENGTH, &port->lock); 94 buf[0] = TX_HEADER_0; 95 buf[1] = TX_HEADER_1; 96 put_unaligned_le16(count, &buf[2]); 97 98 return count + HCI_HEADER_LENGTH; 99 } 100 101 static int aircable_probe(struct usb_serial *serial, 102 const struct usb_device_id *id) 103 { 104 struct usb_host_interface *iface_desc = serial->interface-> 105 cur_altsetting; 106 struct usb_endpoint_descriptor *endpoint; 107 int num_bulk_out = 0; 108 int i; 109 110 for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) { 111 endpoint = &iface_desc->endpoint[i].desc; 112 if (usb_endpoint_is_bulk_out(endpoint)) { 113 dbg("found bulk out on endpoint %d", i); 114 ++num_bulk_out; 115 } 116 } 117 118 if (num_bulk_out == 0) { 119 dbg("Invalid interface, discarding"); 120 return -ENODEV; 121 } 122 123 return 0; 124 } 125 126 static 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 dbg("%s - malformed packet", __func__); 136 return 0; 137 } 138 139 tty_insert_flip_string(tty, packet, len); 140 141 return len; 142 } 143 144 static 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 } 171 172 static struct usb_driver aircable_driver = { 173 .name = "aircable", 174 .probe = usb_serial_probe, 175 .disconnect = usb_serial_disconnect, 176 .id_table = id_table, 177 .no_dynamic_id = 1, 178 }; 179 180 static struct usb_serial_driver aircable_device = { 181 .driver = { 182 .owner = THIS_MODULE, 183 .name = "aircable", 184 }, 185 .usb_driver = &aircable_driver, 186 .id_table = id_table, 187 .num_ports = 1, 188 .bulk_out_size = HCI_COMPLETE_FRAME, 189 .probe = aircable_probe, 190 .process_read_urb = aircable_process_read_urb, 191 .prepare_write_buffer = aircable_prepare_write_buffer, 192 .throttle = usb_serial_generic_throttle, 193 .unthrottle = usb_serial_generic_unthrottle, 194 }; 195 196 static int __init aircable_init(void) 197 { 198 int retval; 199 retval = usb_serial_register(&aircable_device); 200 if (retval) 201 goto failed_serial_register; 202 retval = usb_register(&aircable_driver); 203 if (retval) 204 goto failed_usb_register; 205 return 0; 206 207 failed_usb_register: 208 usb_serial_deregister(&aircable_device); 209 failed_serial_register: 210 return retval; 211 } 212 213 static void __exit aircable_exit(void) 214 { 215 usb_deregister(&aircable_driver); 216 usb_serial_deregister(&aircable_device); 217 } 218 219 MODULE_AUTHOR(DRIVER_AUTHOR); 220 MODULE_DESCRIPTION(DRIVER_DESC); 221 MODULE_VERSION(DRIVER_VERSION); 222 MODULE_LICENSE("GPL"); 223 224 module_init(aircable_init); 225 module_exit(aircable_exit); 226 227 module_param(debug, bool, S_IRUGO | S_IWUSR); 228 MODULE_PARM_DESC(debug, "Debug enabled or not"); 229