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