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 static bool debug; 56 57 /* Vendor and Product ID */ 58 #define AIRCABLE_VID 0x16CA 59 #define AIRCABLE_USB_PID 0x1502 60 61 /* Protocol Stuff */ 62 #define HCI_HEADER_LENGTH 0x4 63 #define TX_HEADER_0 0x20 64 #define TX_HEADER_1 0x29 65 #define RX_HEADER_0 0x00 66 #define RX_HEADER_1 0x20 67 #define HCI_COMPLETE_FRAME 64 68 69 /* rx_flags */ 70 #define THROTTLED 0x01 71 #define ACTUALLY_THROTTLED 0x02 72 73 /* 74 * Version Information 75 */ 76 #define DRIVER_VERSION "v2.0" 77 #define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>, Johan Hovold <jhovold@gmail.com>" 78 #define DRIVER_DESC "AIRcable USB Driver" 79 80 /* ID table that will be registered with USB core */ 81 static const struct usb_device_id id_table[] = { 82 { USB_DEVICE(AIRCABLE_VID, AIRCABLE_USB_PID) }, 83 { }, 84 }; 85 MODULE_DEVICE_TABLE(usb, id_table); 86 87 static int aircable_prepare_write_buffer(struct usb_serial_port *port, 88 void *dest, size_t size) 89 { 90 int count; 91 unsigned char *buf = dest; 92 93 count = kfifo_out_locked(&port->write_fifo, buf + HCI_HEADER_LENGTH, 94 size - HCI_HEADER_LENGTH, &port->lock); 95 buf[0] = TX_HEADER_0; 96 buf[1] = TX_HEADER_1; 97 put_unaligned_le16(count, &buf[2]); 98 99 return count + HCI_HEADER_LENGTH; 100 } 101 102 static int aircable_probe(struct usb_serial *serial, 103 const struct usb_device_id *id) 104 { 105 struct usb_host_interface *iface_desc = serial->interface-> 106 cur_altsetting; 107 struct usb_endpoint_descriptor *endpoint; 108 int num_bulk_out = 0; 109 int i; 110 111 for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) { 112 endpoint = &iface_desc->endpoint[i].desc; 113 if (usb_endpoint_is_bulk_out(endpoint)) { 114 dev_dbg(&serial->dev->dev, 115 "found bulk out on endpoint %d\n", i); 116 ++num_bulk_out; 117 } 118 } 119 120 if (num_bulk_out == 0) { 121 dev_dbg(&serial->dev->dev, "Invalid interface, discarding\n"); 122 return -ENODEV; 123 } 124 125 return 0; 126 } 127 128 static int aircable_process_packet(struct tty_struct *tty, 129 struct usb_serial_port *port, int has_headers, 130 char *packet, int len) 131 { 132 if (has_headers) { 133 len -= HCI_HEADER_LENGTH; 134 packet += HCI_HEADER_LENGTH; 135 } 136 if (len <= 0) { 137 dev_dbg(&port->dev, "%s - malformed packet\n", __func__); 138 return 0; 139 } 140 141 tty_insert_flip_string(tty, packet, len); 142 143 return len; 144 } 145 146 static void aircable_process_read_urb(struct urb *urb) 147 { 148 struct usb_serial_port *port = urb->context; 149 char *data = (char *)urb->transfer_buffer; 150 struct tty_struct *tty; 151 int has_headers; 152 int count; 153 int len; 154 int i; 155 156 tty = tty_port_tty_get(&port->port); 157 if (!tty) 158 return; 159 160 has_headers = (urb->actual_length > 2 && data[0] == RX_HEADER_0); 161 162 count = 0; 163 for (i = 0; i < urb->actual_length; i += HCI_COMPLETE_FRAME) { 164 len = min_t(int, urb->actual_length - i, HCI_COMPLETE_FRAME); 165 count += aircable_process_packet(tty, port, has_headers, 166 &data[i], len); 167 } 168 169 if (count) 170 tty_flip_buffer_push(tty); 171 tty_kref_put(tty); 172 } 173 174 static struct usb_serial_driver aircable_device = { 175 .driver = { 176 .owner = THIS_MODULE, 177 .name = "aircable", 178 }, 179 .id_table = id_table, 180 .num_ports = 1, 181 .bulk_out_size = HCI_COMPLETE_FRAME, 182 .probe = aircable_probe, 183 .process_read_urb = aircable_process_read_urb, 184 .prepare_write_buffer = aircable_prepare_write_buffer, 185 .throttle = usb_serial_generic_throttle, 186 .unthrottle = usb_serial_generic_unthrottle, 187 }; 188 189 static struct usb_serial_driver * const serial_drivers[] = { 190 &aircable_device, NULL 191 }; 192 193 module_usb_serial_driver(serial_drivers, id_table); 194 195 MODULE_AUTHOR(DRIVER_AUTHOR); 196 MODULE_DESCRIPTION(DRIVER_DESC); 197 MODULE_VERSION(DRIVER_VERSION); 198 MODULE_LICENSE("GPL"); 199 200 module_param(debug, bool, S_IRUGO | S_IWUSR); 201 MODULE_PARM_DESC(debug, "Debug enabled or not"); 202