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 writing 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 writing 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         u16 *dbuf;
 213         dbg("%s - port %d", __FUNCTION__, port->number);
 214         if (port->write_urb_busy)
 215                 return;
 216
 217         count = min(serial_buf_data_avail(priv->tx_buf), MAX_HCI_FRAMESIZE);
 218         if (count == 0)
 219                 return;
 220
 221         buf = kzalloc(count + HCI_HEADER_LENGTH, GFP_ATOMIC);
 222         if (!buf) {
 223                 err("%s- kzalloc(%d) failed.", __FUNCTION__,
 224                     count + HCI_HEADER_LENGTH);
 225                 return;
 226         }
 227
 228         buf[0] = TX_HEADER_0;
 229         buf[1] = TX_HEADER_1;
 230         dbuf = (u16 *)&buf[2];
 231         *dbuf = cpu_to_le16((u16)count);
 232         serial_buf_get(priv->tx_buf,buf + HCI_HEADER_LENGTH, MAX_HCI_FRAMESIZE);
 233
 234         memcpy(port->write_urb->transfer_buffer, buf,
 235                count + HCI_HEADER_LENGTH);
 236
 237         kfree(buf);
 238         port->write_urb_busy = 1;
 239         usb_serial_debug_data(debug, &port->dev, __FUNCTION__,
 240                               count + HCI_HEADER_LENGTH,
 241                               port->write_urb->transfer_buffer);
 242         port->write_urb->transfer_buffer_length = count + HCI_HEADER_LENGTH;
 243         port->write_urb->dev = port->serial->dev;
 244         result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
 245
 246         if (result) {
 247                 dev_err(&port->dev,
 248                         "%s - failed submitting write urb, error %d\n",
 249                         __FUNCTION__, result);
 250                 port->write_urb_busy = 0;
 251         }
 252
 253         schedule_work(&port->work);
 254 }
 255
 256 static void aircable_read(struct work_struct *work)
 257 {
 258         struct aircable_private *priv =
 259                 container_of(work, struct aircable_private, rx_work);
 260         struct usb_serial_port *port = priv->port;
 261         struct tty_struct *tty;
 262         unsigned char *data;
 263         int count;
 264         if (priv->rx_flags & THROTTLED){
 265                 if (priv->rx_flags & ACTUALLY_THROTTLED)
 266                         schedule_work(&priv->rx_work);
 267                 return;
 268         }
 269
 270         /* By now I will flush data to the tty in packages of no more than
 271          * 64 bytes, to ensure I do not get throttled.
 272          * Ask USB mailing list for better aproach.
 273          */
 274         tty = port->tty;
 275
 276         if (!tty) {
 277                 schedule_work(&priv->rx_work);
 278                 err("%s - No tty available", __FUNCTION__);
 279                 return ;
 280         }
 281
 282         count = min(64, serial_buf_data_avail(priv->rx_buf));
 283
 284         if (count <= 0)
 285                 return; //We have finished sending everything.
 286
 287         tty_prepare_flip_string(tty, &data, count);
 288         if (!data){
 289                 err("%s- kzalloc(%d) failed.", __FUNCTION__, count);
 290                 return;
 291         }
 292
 293         serial_buf_get(priv->rx_buf, data, count);
 294
 295         tty_flip_buffer_push(tty);
 296
 297         if (serial_buf_data_avail(priv->rx_buf))
 298                 schedule_work(&priv->rx_work);
 299
 300         return;
 301 }
 302 /* End of private methods */
 303
 304 static int aircable_probe(struct usb_serial *serial,
 305                           const struct usb_device_id *id)
 306 {
 307         struct usb_host_interface *iface_desc = serial->interface->cur_altsetting;
 308         struct usb_endpoint_descriptor *endpoint;
 309         int num_bulk_out=0;
 310         int i;
 311
 312         for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
 313                 endpoint = &iface_desc->endpoint[i].desc;
 314                 if (usb_endpoint_is_bulk_out(endpoint)) {
 315                         dbg("found bulk out on endpoint %d", i);
 316                         ++num_bulk_out;
 317                 }
 318         }
 319
 320         if (num_bulk_out == 0) {
 321                 dbg("Invalid interface, discarding");
 322                 return -ENODEV;
 323         }
 324
 325         return 0;
 326 }
 327
 328 static int aircable_attach (struct usb_serial *serial)
 329 {
 330         struct usb_serial_port *port = serial->port[0];
 331         struct aircable_private *priv;
 332
 333         priv = kzalloc(sizeof(struct aircable_private), GFP_KERNEL);
 334         if (!priv){
 335                 err("%s- kmalloc(%Zd) failed.", __FUNCTION__,
 336                         sizeof(struct aircable_private));
 337                 return -ENOMEM;
 338         }
 339
 340         /* Allocation of Circular Buffers */
 341         priv->tx_buf = serial_buf_alloc();
 342         if (priv->tx_buf == NULL) {
 343                 kfree(priv);
 344                 return -ENOMEM;
 345         }
 346
 347         priv->rx_buf = serial_buf_alloc();
 348         if (priv->rx_buf == NULL) {
 349                 kfree(priv->tx_buf);
 350                 kfree(priv);
 351                 return -ENOMEM;
 352         }
 353
 354         priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
 355         priv->port = port;
 356         INIT_WORK(&priv->rx_work, aircable_read);
 357
 358         usb_set_serial_port_data(serial->port[0], priv);
 359
 360         return 0;
 361 }
 362
 363 static void aircable_shutdown(struct usb_serial *serial)
 364 {
 365
 366         struct usb_serial_port *port = serial->port[0];
 367         struct aircable_private *priv = usb_get_serial_port_data(port);
 368
 369         dbg("%s", __FUNCTION__);
 370
 371         if (priv) {
 372                 serial_buf_free(priv->tx_buf);
 373                 serial_buf_free(priv->rx_buf);
 374                 usb_set_serial_port_data(port, NULL);
 375                 kfree(priv);
 376         }
 377 }
 378
 379 static int aircable_write_room(struct usb_serial_port *port)
 380 {
 381         struct aircable_private *priv = usb_get_serial_port_data(port);
 382         return serial_buf_data_avail(priv->tx_buf);
 383 }
 384
 385 static int aircable_write(struct usb_serial_port *port,
 386                           const unsigned char *source, int count)
 387 {
 388         struct aircable_private *priv = usb_get_serial_port_data(port);
 389         int temp;
 390
 391         dbg("%s - port %d, %d bytes", __FUNCTION__, port->number, count);
 392
 393         usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, source);
 394
 395         if (!count){
 396                 dbg("%s - write request of 0 bytes", __FUNCTION__);
 397                 return count;
 398         }
 399
 400         temp = serial_buf_put(priv->tx_buf, source, count);
 401
 402         aircable_send(port);
 403
 404         if (count > AIRCABLE_BUF_SIZE)
 405                 count = AIRCABLE_BUF_SIZE;
 406
 407         return count;
 408
 409 }
 410
 411 static void aircable_write_bulk_callback(struct urb *urb)
 412 {
 413         struct usb_serial_port *port = urb->context;
 414         int status = urb->status;
 415         int result;
 416
 417         dbg("%s - urb status: %d", __FUNCTION__ , status);
 418
 419         /* This has been taken from cypress_m8.c cypress_write_int_callback */
 420         switch (status) {
 421                 case 0:
 422                         /* success */
 423                         break;
 424                 case -ECONNRESET:
 425                 case -ENOENT:
 426                 case -ESHUTDOWN:
 427                         /* this urb is terminated, clean up */
 428                         dbg("%s - urb shutting down with status: %d",
 429                             __FUNCTION__, status);
 430                         port->write_urb_busy = 0;
 431                         return;
 432                 default:
 433                         /* error in the urb, so we have to resubmit it */
 434                         dbg("%s - Overflow in write", __FUNCTION__);
 435                         dbg("%s - nonzero write bulk status received: %d",
 436                             __FUNCTION__, status);
 437                         port->write_urb->transfer_buffer_length = 1;
 438                         port->write_urb->dev = port->serial->dev;
 439                         result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
 440                         if (result)
 441                                 dev_err(&urb->dev->dev,
 442                                         "%s - failed resubmitting write urb, error %d\n",
 443                                         __FUNCTION__, result);
 444                         else
 445                                 return;
 446         }
 447
 448         port->write_urb_busy = 0;
 449
 450         aircable_send(port);
 451 }
 452
 453 static void aircable_read_bulk_callback(struct urb *urb)
 454 {
 455         struct usb_serial_port *port = urb->context;
 456         struct aircable_private *priv = usb_get_serial_port_data(port);
 457         struct tty_struct *tty;
 458         unsigned long no_packages, remaining, package_length, i;
 459         int result, shift = 0;
 460         unsigned char *temp;
 461         int status = urb->status;
 462
 463         dbg("%s - port %d", __FUNCTION__, port->number);
 464
 465         if (status) {
 466                 dbg("%s - urb status = %d", __FUNCTION__, status);
 467                 if (!port->open_count) {
 468                         dbg("%s - port is closed, exiting.", __FUNCTION__);
 469                         return;
 470                 }
 471                 if (status == -EPROTO) {
 472                         dbg("%s - caught -EPROTO, resubmitting the urb",
 473                             __FUNCTION__);
 474                         usb_fill_bulk_urb(port->read_urb, port->serial->dev,
 475                                           usb_rcvbulkpipe(port->serial->dev,
 476                                                           port->bulk_in_endpointAddress),
 477                                           port->read_urb->transfer_buffer,
 478                                           port->read_urb->transfer_buffer_length,
 479                                           aircable_read_bulk_callback, port);
 480
 481                         result = usb_submit_urb(urb, GFP_ATOMIC);
 482                         if (result)
 483                                 dev_err(&urb->dev->dev,
 484                                         "%s - failed resubmitting read urb, error %d\n",
 485                                         __FUNCTION__, result);
 486                         return;
 487                 }
 488                 dbg("%s - unable to handle the error, exiting.", __FUNCTION__);
 489                 return;
 490         }
 491
 492         usb_serial_debug_data(debug, &port->dev, __FUNCTION__,
 493                                 urb->actual_length,urb->transfer_buffer);
 494
 495         tty = port->tty;
 496         if (tty && urb->actual_length) {
 497                 if (urb->actual_length <= 2) {
 498                         /* This is an incomplete package */
 499                         serial_buf_put(priv->rx_buf, urb->transfer_buffer,
 500                                        urb->actual_length);
 501                 } else {
 502                         temp = urb->transfer_buffer;
 503                         if (temp[0] == RX_HEADER_0)
 504                                 shift = HCI_HEADER_LENGTH;
 505
 506                         remaining = urb->actual_length;
 507                         no_packages = urb->actual_length / (HCI_COMPLETE_FRAME);
 508
 509                         if (urb->actual_length % HCI_COMPLETE_FRAME != 0)
 510                                 no_packages+=1;
 511
 512                         for (i = 0; i < no_packages ;i++) {
 513                                 if (remaining > (HCI_COMPLETE_FRAME))
 514                                         package_length = HCI_COMPLETE_FRAME;
 515                                 else
 516                                         package_length = remaining;
 517                                 remaining -= package_length;
 518
 519                                 serial_buf_put(priv->rx_buf,
 520                                         urb->transfer_buffer + shift +
 521                                         (HCI_COMPLETE_FRAME) * (i),
 522                                         package_length - shift);
 523                         }
 524                 }
 525                 aircable_read(&priv->rx_work);
 526         }
 527
 528         /* Schedule the next read _if_ we are still open */
 529         if (port->open_count) {
 530                 usb_fill_bulk_urb(port->read_urb, port->serial->dev,
 531                                   usb_rcvbulkpipe(port->serial->dev,
 532                                                   port->bulk_in_endpointAddress),
 533                                   port->read_urb->transfer_buffer,
 534                                   port->read_urb->transfer_buffer_length,
 535                                   aircable_read_bulk_callback, port);
 536
 537                 result = usb_submit_urb(urb, GFP_ATOMIC);
 538                 if (result)
 539                         dev_err(&urb->dev->dev,
 540                                 "%s - failed resubmitting read urb, error %d\n",
 541                                 __FUNCTION__, result);
 542         }
 543
 544         return;
 545 }
 546
 547 /* Based on ftdi_sio.c throttle */
 548 static void aircable_throttle(struct usb_serial_port *port)
 549 {
 550         struct aircable_private *priv = usb_get_serial_port_data(port);
 551         unsigned long flags;
 552
 553         dbg("%s - port %d", __FUNCTION__, port->number);
 554
 555         spin_lock_irqsave(&priv->rx_lock, flags);
 556         priv->rx_flags |= THROTTLED;
 557         spin_unlock_irqrestore(&priv->rx_lock, flags);
 558 }
 559
 560 /* Based on ftdi_sio.c unthrottle */
 561 static void aircable_unthrottle(struct usb_serial_port *port)
 562 {
 563         struct aircable_private *priv = usb_get_serial_port_data(port);
 564         int actually_throttled;
 565         unsigned long flags;
 566
 567         dbg("%s - port %d", __FUNCTION__, port->number);
 568
 569         spin_lock_irqsave(&priv->rx_lock, flags);
 570         actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
 571         priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
 572         spin_unlock_irqrestore(&priv->rx_lock, flags);
 573
 574         if (actually_throttled)
 575                 schedule_work(&priv->rx_work);
 576 }
 577
 578 static struct usb_driver aircable_driver = {
 579         .name =         "aircable",
 580         .probe =        usb_serial_probe,
 581         .disconnect =   usb_serial_disconnect,
 582         .id_table =     id_table,
 583         .no_dynamic_id =        1,
 584 };
 585
 586 static struct usb_serial_driver aircable_device = {
 587         .driver = {
 588                 .owner =        THIS_MODULE,
 589                 .name =         "aircable",
 590         },
 591         .usb_driver =           &aircable_driver,
 592         .id_table =             id_table,
 593         .num_ports =            1,
 594         .attach =               aircable_attach,
 595         .probe =                aircable_probe,
 596         .shutdown =             aircable_shutdown,
 597         .write =                aircable_write,
 598         .write_room =           aircable_write_room,
 599         .write_bulk_callback =  aircable_write_bulk_callback,
 600         .read_bulk_callback =   aircable_read_bulk_callback,
 601         .throttle =             aircable_throttle,
 602         .unthrottle =           aircable_unthrottle,
 603 };
 604
 605 static int __init aircable_init (void)
 606 {
 607         int retval;
 608         retval = usb_serial_register(&aircable_device);
 609         if (retval)
 610                 goto failed_serial_register;
 611         retval = usb_register(&aircable_driver);
 612         if (retval)
 613                 goto failed_usb_register;
 614         return 0;
 615
 616 failed_serial_register:
 617         usb_serial_deregister(&aircable_device);
 618 failed_usb_register:
 619         return retval;
 620 }
 621
 622 static void __exit aircable_exit (void)
 623 {
 624         usb_deregister(&aircable_driver);
 625         usb_serial_deregister(&aircable_device);
 626 }
 627
 628 MODULE_AUTHOR(DRIVER_AUTHOR);
 629 MODULE_DESCRIPTION(DRIVER_DESC);
 630 MODULE_VERSION(DRIVER_VERSION);
 631 MODULE_LICENSE("GPL");
 632
 633 module_init(aircable_init);
 634 module_exit(aircable_exit);
 635
 636 module_param(debug, bool, S_IRUGO | S_IWUSR);
 637 MODULE_PARM_DESC(debug, "Debug enabled or not");