drivers/usb/serial/aircable.c

   1 /*
   2  * AIRcable USB Bluetooth Dongle Driver.
   3  *
   4  * Copyright (C) 2006 Manuel Francisco Naranjo (naranjo.manuel@gmail.com)
   5  * This program is free software; you can redistribute it and/or modify it under
   6  * the terms of the GNU General Public License version 2 as published by the
   7  * Free Software Foundation.
   8  *
   9  * The device works as an standard CDC device, it has 2 interfaces, the first
  10  * one is for firmware access and the second is the serial one.
  11  * The protocol is very simply, there are two posibilities reading or writing.
  12  * When writting the first urb must have a Header that starts with 0x20 0x29 the
  13  * next two bytes must say how much data will be sended.
  14  * When reading the process is almost equal except that the header starts with
  15  * 0x00 0x20.
  16  *
  17  * The device simply need some stuff to understand data comming from the usb
  18  * buffer: The First and Second byte is used for a Header, the Third and Fourth
  19  * tells the  device the amount of information the package holds.
  20  * Packages are 60 bytes long Header Stuff.
  21  * When writting to the device the first two bytes of the header are 0x20 0x29
  22  * When reading the bytes are 0x00 0x20, or 0x00 0x10, there is an strange
  23  * situation, when too much data arrives to the device because it sends the data
  24  * but with out the header. I will use a simply hack to override this situation,
  25  * if there is data coming that does not contain any header, then that is data
  26  * that must go directly to the tty, as there is no documentation about if there
  27  * is any other control code, I will simply check for the first
  28  * one.
  29  *
  30  * The driver registers himself with the USB-serial core and the USB Core. I had
  31  * to implement a probe function agains USB-serial, because other way, the
  32  * driver was attaching himself to both interfaces. I have tryed with different
  33  * configurations of usb_serial_driver with out exit, only the probe function
  34  * could handle this correctly.
  35  *
  36  * I have taken some info from a Greg Kroah-Hartman article:
  37  * http://www.linuxjournal.com/article/6573
  38  * And from Linux Device Driver Kit CD, which is a great work, the authors taken
  39  * the work to recompile lots of information an knowladge in drivers development
  40  * and made it all avaible inside a cd.
  41  * URL: http://kernel.org/pub/linux/kernel/people/gregkh/ddk/
  42  *
  43  */
  44
  45 #include <linux/tty.h>
  46 #include <linux/tty_flip.h>
  47 #include <linux/circ_buf.h>
  48 #include <linux/usb.h>
  49 #include <linux/usb/serial.h>
  50
  51 static int debug;
  52
  53 /* Vendor and Product ID */
  54 #define AIRCABLE_VID            0x16CA
  55 #define AIRCABLE_USB_PID        0x1502
  56
  57 /* write buffer size defines */
  58 #define AIRCABLE_BUF_SIZE       2048
  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 MAX_HCI_FRAMESIZE       60
  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 "v1.0b2"
  77 #define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>"
  78 #define DRIVER_DESC "AIRcable USB Driver"
  79
  80 /* ID table that will be registered with USB core */
  81 static 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
  88 /* Internal Structure */
  89 struct aircable_private {
  90         spinlock_t rx_lock;             /* spinlock for the receive lines */
  91         struct circ_buf *tx_buf;        /* write buffer */
  92         struct circ_buf *rx_buf;        /* read buffer */
  93         int rx_flags;                   /* for throttilng */
  94         struct work_struct rx_work;     /* work cue for the receiving line */
  95         struct usb_serial_port *port;   /* USB port with which associated */
  96 };
  97
  98 /* Private methods */
  99
 100 /* Circular Buffer Methods, code from ti_usb_3410_5052 used */
 101 /*
 102  * serial_buf_clear
 103  *
 104  * Clear out all data in the circular buffer.
 105  */
 106 static void serial_buf_clear(struct circ_buf *cb)
 107 {
 108         cb->head = cb->tail = 0;
 109 }
 110
 111 /*
 112  * serial_buf_alloc
 113  *
 114  * Allocate a circular buffer and all associated memory.
 115  */
 116 static struct circ_buf *serial_buf_alloc(void)
 117 {
 118         struct circ_buf *cb;
 119         cb = kmalloc(sizeof(struct circ_buf), GFP_KERNEL);
 120         if (cb == NULL)
 121                 return NULL;
 122         cb->buf = kmalloc(AIRCABLE_BUF_SIZE, GFP_KERNEL);
 123         if (cb->buf == NULL) {
 124                 kfree(cb);
 125                 return NULL;
 126         }
 127         serial_buf_clear(cb);
 128         return cb;
 129 }
 130
 131 /*
 132  * serial_buf_free
 133  *
 134  * Free the buffer and all associated memory.
 135  */
 136 static void serial_buf_free(struct circ_buf *cb)
 137 {
 138         kfree(cb->buf);
 139         kfree(cb);
 140 }
 141
 142 /*
 143  * serial_buf_data_avail
 144  *
 145  * Return the number of bytes of data available in the circular
 146  * buffer.
 147  */
 148 static int serial_buf_data_avail(struct circ_buf *cb)
 149 {
 150         return CIRC_CNT(cb->head,cb->tail,AIRCABLE_BUF_SIZE);
 151 }
 152
 153 /*
 154  * serial_buf_put
 155  *
 156  * Copy data data from a user buffer and put it into the circular buffer.
 157  * Restrict to the amount of space available.
 158  *
 159  * Return the number of bytes copied.
 160  */
 161 static int serial_buf_put(struct circ_buf *cb, const char *buf, int count)
 162 {
 163         int c, ret = 0;
 164         while (1) {
 165                 c = CIRC_SPACE_TO_END(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
 166                 if (count < c)
 167                         c = count;
 168                 if (c <= 0)
 169                         break;
 170                 memcpy(cb->buf + cb->head, buf, c);
 171                 cb->head = (cb->head + c) & (AIRCABLE_BUF_SIZE-1);
 172                 buf += c;
 173                 count -= c;
 174                 ret= c;
 175         }
 176         return ret;
 177 }
 178
 179 /*
 180  * serial_buf_get
 181  *
 182  * Get data from the circular buffer and copy to the given buffer.
 183  * Restrict to the amount of data available.
 184  *
 185  * Return the number of bytes copied.
 186  */
 187 static int serial_buf_get(struct circ_buf *cb, char *buf, int count)
 188 {
 189         int c, ret = 0;
 190         while (1) {
 191                 c = CIRC_CNT_TO_END(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
 192                 if (count < c)
 193                         c = count;
 194                 if (c <= 0)
 195                         break;
 196                 memcpy(buf, cb->buf + cb->tail, c);
 197                 cb->tail = (cb->tail + c) & (AIRCABLE_BUF_SIZE-1);
 198                 buf += c;
 199                 count -= c;
 200                 ret= c;
 201         }
 202         return ret;
 203 }
 204
 205 /* End of circula buffer methods */
 206
 207 static void aircable_send(struct usb_serial_port *port)
 208 {
 209         int count, result;
 210         struct aircable_private *priv = usb_get_serial_port_data(port);
 211         unsigned char* buf;
 212         dbg("%s - port %d", __FUNCTION__, port->number);
 213         if (port->write_urb_busy)
 214                 return;
 215
 216         count = min(serial_buf_data_avail(priv->tx_buf), MAX_HCI_FRAMESIZE);
 217         if (count == 0)
 218                 return;
 219
 220         buf = kzalloc(count + HCI_HEADER_LENGTH, GFP_ATOMIC);
 221         if (!buf) {
 222                 err("%s- kzalloc(%d) failed.", __FUNCTION__,
 223                     count + HCI_HEADER_LENGTH);
 224                 return;
 225         }
 226
 227         buf[0] = TX_HEADER_0;
 228         buf[1] = TX_HEADER_1;
 229         buf[2] = (unsigned char)count;
 230         buf[3] = (unsigned char)(count >> 8);
 231         serial_buf_get(priv->tx_buf,buf + HCI_HEADER_LENGTH, MAX_HCI_FRAMESIZE);
 232
 233         memcpy(port->write_urb->transfer_buffer, buf,
 234                count + HCI_HEADER_LENGTH);
 235
 236         kfree(buf);
 237         port->write_urb_busy = 1;
 238         usb_serial_debug_data(debug, &port->dev, __FUNCTION__,
 239                               count + HCI_HEADER_LENGTH,
 240                               port->write_urb->transfer_buffer);
 241         port->write_urb->transfer_buffer_length = count + HCI_HEADER_LENGTH;
 242         port->write_urb->dev = port->serial->dev;
 243         result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
 244
 245         if (result) {
 246                 dev_err(&port->dev,
 247                         "%s - failed submitting write urb, error %d\n",
 248                         __FUNCTION__, result);
 249                 port->write_urb_busy = 0;
 250         }
 251
 252         schedule_work(&port->work);
 253 }
 254
 255 static void aircable_read(struct work_struct *work)
 256 {
 257         struct aircable_private *priv =
 258                 container_of(work, struct aircable_private, rx_work);
 259         struct usb_serial_port *port = priv->port;
 260         struct tty_struct *tty;
 261         unsigned char *data;
 262         int count;
 263         if (priv->rx_flags & THROTTLED){
 264                 if (priv->rx_flags & ACTUALLY_THROTTLED)
 265                         schedule_work(&priv->rx_work);
 266                 return;
 267         }
 268
 269         /* By now I will flush data to the tty in packages of no more than
 270          * 64 bytes, to ensure I do not get throttled.
 271          * Ask USB mailing list for better aproach.
 272          */
 273         tty = port->tty;
 274
 275         if (!tty)
 276                 schedule_work(&priv->rx_work);
 277
 278         count = min(64, serial_buf_data_avail(priv->rx_buf));
 279
 280         if (count <= 0)
 281                 return; //We have finished sending everything.
 282
 283         tty_prepare_flip_string(tty, &data, count);
 284         if (!data){
 285                 err("%s- kzalloc(%d) failed.", __FUNCTION__, count);
 286                 return;
 287         }
 288
 289         serial_buf_get(priv->rx_buf, data, count);
 290
 291         tty_flip_buffer_push(tty);
 292
 293         if (serial_buf_data_avail(priv->rx_buf))
 294                 schedule_work(&priv->rx_work);
 295
 296         return;
 297 }
 298 /* End of private methods */
 299
 300 static int aircable_probe(struct usb_serial *serial,
 301                           const struct usb_device_id *id)
 302 {
 303         struct usb_host_interface *iface_desc = serial->interface->cur_altsetting;
 304         struct usb_endpoint_descriptor *endpoint;
 305         int num_bulk_out=0;
 306         int i;
 307
 308         for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
 309                 endpoint = &iface_desc->endpoint[i].desc;
 310                 if (((endpoint->bEndpointAddress & 0x80) == 0x00) &&
 311                         ((endpoint->bmAttributes & 3) == 0x02)) {
 312                         /* we found our bulk out endpoint */
 313                         dbg("found bulk out on endpoint %d", i);
 314                         ++num_bulk_out;
 315                 }
 316         }
 317
 318         if (num_bulk_out == 0) {
 319                 dbg("Invalid interface, discarding");
 320                 return -ENODEV;
 321         }
 322
 323         return 0;
 324 }
 325
 326 static int aircable_attach (struct usb_serial *serial)
 327 {
 328         struct usb_serial_port *port = serial->port[0];
 329         struct aircable_private *priv;
 330
 331         priv = kzalloc(sizeof(struct aircable_private), GFP_KERNEL);
 332         if (!priv){
 333                 err("%s- kmalloc(%Zd) failed.", __FUNCTION__,
 334                         sizeof(struct aircable_private));
 335                 return -ENOMEM;
 336         }
 337
 338         /* Allocation of Circular Buffers */
 339         priv->tx_buf = serial_buf_alloc();
 340         if (priv->tx_buf == NULL) {
 341                 kfree(priv);
 342                 return -ENOMEM;
 343         }
 344
 345         priv->rx_buf = serial_buf_alloc();
 346         if (priv->rx_buf == NULL) {
 347                 kfree(priv->tx_buf);
 348                 kfree(priv);
 349                 return -ENOMEM;
 350         }
 351
 352         priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
 353         priv->port = port;
 354         INIT_WORK(&priv->rx_work, aircable_read);
 355
 356         usb_set_serial_port_data(serial->port[0], priv);
 357
 358         return 0;
 359 }
 360
 361 static void aircable_shutdown(struct usb_serial *serial)
 362 {
 363
 364         struct usb_serial_port *port = serial->port[0];
 365         struct aircable_private *priv = usb_get_serial_port_data(port);
 366
 367         dbg("%s", __FUNCTION__);
 368
 369         if (priv) {
 370                 serial_buf_free(priv->tx_buf);
 371                 serial_buf_free(priv->rx_buf);
 372                 usb_set_serial_port_data(port, NULL);
 373                 kfree(priv);
 374         }
 375 }
 376
 377 static int aircable_write_room(struct usb_serial_port *port)
 378 {
 379         struct aircable_private *priv = usb_get_serial_port_data(port);
 380         return serial_buf_data_avail(priv->tx_buf);
 381 }
 382
 383 static int aircable_write(struct usb_serial_port *port,
 384                           const unsigned char *source, int count)
 385 {
 386         struct aircable_private *priv = usb_get_serial_port_data(port);
 387         int temp;
 388
 389         dbg("%s - port %d, %d bytes", __FUNCTION__, port->number, count);
 390
 391         usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, source);
 392
 393         if (!count){
 394                 dbg("%s - write request of 0 bytes", __FUNCTION__);
 395                 return count;
 396         }
 397
 398         temp = serial_buf_put(priv->tx_buf, source, count);
 399
 400         aircable_send(port);
 401
 402         if (count > AIRCABLE_BUF_SIZE)
 403                 count = AIRCABLE_BUF_SIZE;
 404
 405         return count;
 406
 407 }
 408
 409 static void aircable_write_bulk_callback(struct urb *urb)
 410 {
 411         struct usb_serial_port *port = urb->context;
 412         int result;
 413
 414         dbg("%s - urb->status: %d", __FUNCTION__ , urb->status);
 415
 416         /* This has been taken from cypress_m8.c cypress_write_int_callback */
 417         switch (urb->status) {
 418                 case 0:
 419                         /* success */
 420                         break;
 421                 case -ECONNRESET:
 422                 case -ENOENT:
 423                 case -ESHUTDOWN:
 424                         /* this urb is terminated, clean up */
 425                         dbg("%s - urb shutting down with status: %d",
 426                             __FUNCTION__, urb->status);
 427                         port->write_urb_busy = 0;
 428                         return;
 429                 default:
 430                         /* error in the urb, so we have to resubmit it */
 431                         dbg("%s - Overflow in write", __FUNCTION__);
 432                         dbg("%s - nonzero write bulk status received: %d",
 433                             __FUNCTION__, urb->status);
 434                         port->write_urb->transfer_buffer_length = 1;
 435                         port->write_urb->dev = port->serial->dev;
 436                         result = usb_submit_urb(port->write_urb, GFP_KERNEL);
 437                         if (result)
 438                                 dev_err(&urb->dev->dev,
 439                                         "%s - failed resubmitting write urb, error %d\n",
 440                                         __FUNCTION__, result);
 441                         else
 442                                 return;
 443         }
 444
 445         port->write_urb_busy = 0;
 446
 447         aircable_send(port);
 448 }
 449
 450 static void aircable_read_bulk_callback(struct urb *urb)
 451 {
 452         struct usb_serial_port *port = urb->context;
 453         struct aircable_private *priv = usb_get_serial_port_data(port);
 454         struct tty_struct *tty;
 455         unsigned long no_packages, remaining, package_length, i;
 456         int result, shift = 0;
 457         unsigned char *temp;
 458
 459         dbg("%s - port %d", __FUNCTION__, port->number);
 460
 461         if (urb->status) {
 462                 dbg("%s - urb->status = %d", __FUNCTION__, urb->status);
 463                 if (!port->open_count) {
 464                         dbg("%s - port is closed, exiting.", __FUNCTION__);
 465                         return;
 466                 }
 467                 if (urb->status == -EPROTO) {
 468                         dbg("%s - caught -EPROTO, resubmitting the urb",
 469                             __FUNCTION__);
 470                         usb_fill_bulk_urb(port->read_urb, port->serial->dev,
 471                                           usb_rcvbulkpipe(port->serial->dev,
 472                                                           port->bulk_in_endpointAddress),
 473                                           port->read_urb->transfer_buffer,
 474                                           port->read_urb->transfer_buffer_length,
 475                                           aircable_read_bulk_callback, port);
 476
 477                         result = usb_submit_urb(urb, GFP_ATOMIC);
 478                         if (result)
 479                                 dev_err(&urb->dev->dev,
 480                                         "%s - failed resubmitting read urb, error %d\n",
 481                                         __FUNCTION__, result);
 482                         return;
 483                 }
 484                 dbg("%s - unable to handle the error, exiting.", __FUNCTION__);
 485                 return;
 486         }
 487
 488         usb_serial_debug_data(debug, &port->dev, __FUNCTION__,
 489                                 urb->actual_length,urb->transfer_buffer);
 490
 491         tty = port->tty;
 492         if (tty && urb->actual_length) {
 493                 if (urb->actual_length <= 2) {
 494                         /* This is an incomplete package */
 495                         serial_buf_put(priv->rx_buf, urb->transfer_buffer,
 496                                        urb->actual_length);
 497                 } else {
 498                         temp = urb->transfer_buffer;
 499                         if (temp[0] == RX_HEADER_0)
 500                                 shift = HCI_HEADER_LENGTH;
 501
 502                         remaining = urb->actual_length;
 503                         no_packages = urb->actual_length / (HCI_COMPLETE_FRAME);
 504
 505                         if (urb->actual_length % HCI_COMPLETE_FRAME != 0)
 506                                 no_packages+=1;
 507
 508                         for (i = 0; i < no_packages ;i++) {
 509                                 if (remaining > (HCI_COMPLETE_FRAME))
 510                                         package_length = HCI_COMPLETE_FRAME;
 511                                 else
 512                                         package_length = remaining;
 513                                 remaining -= package_length;
 514
 515                                 serial_buf_put(priv->rx_buf,
 516                                         urb->transfer_buffer + shift +
 517                                         (HCI_COMPLETE_FRAME) * (i),
 518                                         package_length - shift);
 519                         }
 520                 }
 521                 aircable_read(&priv->rx_work);
 522         }
 523
 524         /* Schedule the next read _if_ we are still open */
 525         if (port->open_count) {
 526                 usb_fill_bulk_urb(port->read_urb, port->serial->dev,
 527                                   usb_rcvbulkpipe(port->serial->dev,
 528                                                   port->bulk_in_endpointAddress),
 529                                   port->read_urb->transfer_buffer,
 530                                   port->read_urb->transfer_buffer_length,
 531                                   aircable_read_bulk_callback, port);
 532
 533                 result = usb_submit_urb(urb, GFP_ATOMIC);
 534                 if (result)
 535                         dev_err(&urb->dev->dev,
 536                                 "%s - failed resubmitting read urb, error %d\n",
 537                                 __FUNCTION__, result);
 538         }
 539
 540         return;
 541 }
 542
 543 /* Based on ftdi_sio.c throttle */
 544 static void aircable_throttle(struct usb_serial_port *port)
 545 {
 546         struct aircable_private *priv = usb_get_serial_port_data(port);
 547         unsigned long flags;
 548
 549         dbg("%s - port %d", __FUNCTION__, port->number);
 550
 551         spin_lock_irqsave(&priv->rx_lock, flags);
 552         priv->rx_flags |= THROTTLED;
 553         spin_unlock_irqrestore(&priv->rx_lock, flags);
 554 }
 555
 556 /* Based on ftdi_sio.c unthrottle */
 557 static void aircable_unthrottle(struct usb_serial_port *port)
 558 {
 559         struct aircable_private *priv = usb_get_serial_port_data(port);
 560         int actually_throttled;
 561         unsigned long flags;
 562
 563         dbg("%s - port %d", __FUNCTION__, port->number);
 564
 565         spin_lock_irqsave(&priv->rx_lock, flags);
 566         actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
 567         priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
 568         spin_unlock_irqrestore(&priv->rx_lock, flags);
 569
 570         if (actually_throttled)
 571                 schedule_work(&priv->rx_work);
 572 }
 573
 574 static struct usb_serial_driver aircable_device = {
 575         .description =          "aircable",
 576         .id_table =             id_table,
 577         .num_ports =            1,
 578         .attach =               aircable_attach,
 579         .probe =                aircable_probe,
 580         .shutdown =             aircable_shutdown,
 581         .write =                aircable_write,
 582         .write_room =           aircable_write_room,
 583         .write_bulk_callback =  aircable_write_bulk_callback,
 584         .read_bulk_callback =   aircable_read_bulk_callback,
 585         .throttle =             aircable_throttle,
 586         .unthrottle =           aircable_unthrottle,
 587 };
 588
 589 static struct usb_driver aircable_driver = {
 590         .name =         "aircable",
 591         .probe =        usb_serial_probe,
 592         .disconnect =   usb_serial_disconnect,
 593         .id_table =     id_table,
 594 };
 595
 596 static int __init aircable_init (void)
 597 {
 598         int retval;
 599         retval = usb_serial_register(&aircable_device);
 600         if (retval)
 601                 goto failed_serial_register;
 602         retval = usb_register(&aircable_driver);
 603         if (retval)
 604                 goto failed_usb_register;
 605         return 0;
 606
 607 failed_serial_register:
 608         usb_serial_deregister(&aircable_device);
 609 failed_usb_register:
 610         return retval;
 611 }
 612
 613 static void __exit aircable_exit (void)
 614 {
 615         usb_deregister(&aircable_driver);
 616         usb_serial_deregister(&aircable_device);
 617 }
 618
 619 MODULE_AUTHOR(DRIVER_AUTHOR);
 620 MODULE_DESCRIPTION(DRIVER_DESC);
 621 MODULE_VERSION(DRIVER_VERSION);
 622 MODULE_LICENSE("GPL");
 623
 624 module_init(aircable_init);
 625 module_exit(aircable_exit);
 626
 627 module_param(debug, bool, S_IRUGO | S_IWUSR);
 628 MODULE_PARM_DESC(debug, "Debug enabled or not");