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 * 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 tried 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 knowledge in drivers development 42 * and made it all available 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 #define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>, Johan Hovold <jhovold@gmail.com>" 72 #define DRIVER_DESC "AIRcable USB Driver" 73 74 /* ID table that will be registered with USB core */ 75 static const struct usb_device_id id_table[] = { 76 { USB_DEVICE(AIRCABLE_VID, AIRCABLE_USB_PID) }, 77 { }, 78 }; 79 MODULE_DEVICE_TABLE(usb, id_table); 80 81 static int aircable_prepare_write_buffer(struct usb_serial_port *port, 82 void *dest, size_t size) 83 { 84 int count; 85 unsigned char *buf = dest; 86 87 count = kfifo_out_locked(&port->write_fifo, buf + HCI_HEADER_LENGTH, 88 size - HCI_HEADER_LENGTH, &port->lock); 89 buf[0] = TX_HEADER_0; 90 buf[1] = TX_HEADER_1; 91 put_unaligned_le16(count, &buf[2]); 92 93 return count + HCI_HEADER_LENGTH; 94 } 95 96 static int aircable_probe(struct usb_serial *serial, 97 const struct usb_device_id *id) 98 { 99 struct usb_host_interface *iface_desc = serial->interface-> 100 cur_altsetting; 101 struct usb_endpoint_descriptor *endpoint; 102 int num_bulk_out = 0; 103 int i; 104 105 for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) { 106 endpoint = &iface_desc->endpoint[i].desc; 107 if (usb_endpoint_is_bulk_out(endpoint)) { 108 dev_dbg(&serial->dev->dev, 109 "found bulk out on endpoint %d\n", i); 110 ++num_bulk_out; 111 } 112 } 113 114 if (num_bulk_out == 0) { 115 dev_dbg(&serial->dev->dev, "Invalid interface, discarding\n"); 116 return -ENODEV; 117 } 118 119 return 0; 120 } 121 122 static int aircable_process_packet(struct usb_serial_port *port, 123 int has_headers, char *packet, int len) 124 { 125 if (has_headers) { 126 len -= HCI_HEADER_LENGTH; 127 packet += HCI_HEADER_LENGTH; 128 } 129 if (len <= 0) { 130 dev_dbg(&port->dev, "%s - malformed packet\n", __func__); 131 return 0; 132 } 133 134 tty_insert_flip_string(&port->port, packet, len); 135 136 return len; 137 } 138 139 static void aircable_process_read_urb(struct urb *urb) 140 { 141 struct usb_serial_port *port = urb->context; 142 char *data = (char *)urb->transfer_buffer; 143 int has_headers; 144 int count; 145 int len; 146 int i; 147 148 has_headers = (urb->actual_length > 2 && data[0] == RX_HEADER_0); 149 150 count = 0; 151 for (i = 0; i < urb->actual_length; i += HCI_COMPLETE_FRAME) { 152 len = min_t(int, urb->actual_length - i, HCI_COMPLETE_FRAME); 153 count += aircable_process_packet(port, has_headers, 154 &data[i], len); 155 } 156 157 if (count) 158 tty_flip_buffer_push(&port->port); 159 } 160 161 static struct usb_serial_driver aircable_device = { 162 .driver = { 163 .owner = THIS_MODULE, 164 .name = "aircable", 165 }, 166 .id_table = id_table, 167 .num_ports = 1, 168 .bulk_out_size = HCI_COMPLETE_FRAME, 169 .probe = aircable_probe, 170 .process_read_urb = aircable_process_read_urb, 171 .prepare_write_buffer = aircable_prepare_write_buffer, 172 .throttle = usb_serial_generic_throttle, 173 .unthrottle = usb_serial_generic_unthrottle, 174 }; 175 176 static struct usb_serial_driver * const serial_drivers[] = { 177 &aircable_device, NULL 178 }; 179 180 module_usb_serial_driver(serial_drivers, id_table); 181 182 MODULE_AUTHOR(DRIVER_AUTHOR); 183 MODULE_DESCRIPTION(DRIVER_DESC); 184 MODULE_LICENSE("GPL"); 185