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         __le16 *dbuf;
 213         dbg("%s - port %d", __func__, 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.", __func__,
 224                     count + HCI_HEADER_LENGTH);
 225                 return;
 226         }
 227
 228         buf[0] = TX_HEADER_0;
 229         buf[1] = TX_HEADER_1;
 230         dbuf = (__le16 *)&buf[2];
 231         *dbuf = cpu_to_le16((u16)count);
 232         serial_buf_get(priv->tx_buf, buf + HCI_HEADER_LENGTH,
 233                                                         MAX_HCI_FRAMESIZE);
 234
 235         memcpy(port->write_urb->transfer_buffer, buf,
 236                count + HCI_HEADER_LENGTH);
 237
 238         kfree(buf);
 239         port->write_urb_busy = 1;
 240         usb_serial_debug_data(debug, &port->dev, __func__,
 241                               count + HCI_HEADER_LENGTH,
 242                               port->write_urb->transfer_buffer);
 243         port->write_urb->transfer_buffer_length = count + HCI_HEADER_LENGTH;
 244         port->write_urb->dev = port->serial->dev;
 245         result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
 246
 247         if (result) {
 248                 dev_err(&port->dev,
 249                         "%s - failed submitting write urb, error %d\n",
 250                         __func__, result);
 251                 port->write_urb_busy = 0;
 252         }
 253
 254         schedule_work(&port->work);
 255 }
 256
 257 static void aircable_read(struct work_struct *work)
 258 {
 259         struct aircable_private *priv =
 260                 container_of(work, struct aircable_private, rx_work);
 261         struct usb_serial_port *port = priv->port;
 262         struct tty_struct *tty;
 263         unsigned char *data;
 264         int count;
 265         if (priv->rx_flags & THROTTLED) {
 266                 if (priv->rx_flags & ACTUALLY_THROTTLED)
 267                         schedule_work(&priv->rx_work);
 268                 return;
 269         }
 270
 271         /* By now I will flush data to the tty in packages of no more than
 272          * 64 bytes, to ensure I do not get throttled.
 273          * Ask USB mailing list for better aproach.
 274          */
 275         tty = port->port.tty;
 276
 277         if (!tty) {
 278                 schedule_work(&priv->rx_work);
 279                 err("%s - No tty available", __func__);
 280                 return ;
 281         }
 282
 283         count = min(64, serial_buf_data_avail(priv->rx_buf));
 284
 285         if (count <= 0)
 286                 return; /* We have finished sending everything. */
 287
 288         tty_prepare_flip_string(tty, &data, count);
 289         if (!data) {
 290                 err("%s- kzalloc(%d) failed.", __func__, count);
 291                 return;
 292         }
 293
 294         serial_buf_get(priv->rx_buf, data, count);
 295
 296         tty_flip_buffer_push(tty);
 297
 298         if (serial_buf_data_avail(priv->rx_buf))
 299                 schedule_work(&priv->rx_work);
 300
 301         return;
 302 }
 303 /* End of private methods */
 304
 305 static int aircable_probe(struct usb_serial *serial,
 306                           const struct usb_device_id *id)
 307 {
 308         struct usb_host_interface *iface_desc = serial->interface->
 309                                                                 cur_altsetting;
 310         struct usb_endpoint_descriptor *endpoint;
 311         int num_bulk_out = 0;
 312         int i;
 313
 314         for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
 315                 endpoint = &iface_desc->endpoint[i].desc;
 316                 if (usb_endpoint_is_bulk_out(endpoint)) {
 317                         dbg("found bulk out on endpoint %d", i);
 318                         ++num_bulk_out;
 319                 }
 320         }
 321
 322         if (num_bulk_out == 0) {
 323                 dbg("Invalid interface, discarding");
 324                 return -ENODEV;
 325         }
 326
 327         return 0;
 328 }
 329
 330 static int aircable_attach(struct usb_serial *serial)
 331 {
 332         struct usb_serial_port *port = serial->port[0];
 333         struct aircable_private *priv;
 334
 335         priv = kzalloc(sizeof(struct aircable_private), GFP_KERNEL);
 336         if (!priv) {
 337                 err("%s- kmalloc(%Zd) failed.", __func__,
 338                         sizeof(struct aircable_private));
 339                 return -ENOMEM;
 340         }
 341
 342         /* Allocation of Circular Buffers */
 343         priv->tx_buf = serial_buf_alloc();
 344         if (priv->tx_buf == NULL) {
 345                 kfree(priv);
 346                 return -ENOMEM;
 347         }
 348
 349         priv->rx_buf = serial_buf_alloc();
 350         if (priv->rx_buf == NULL) {
 351                 kfree(priv->tx_buf);
 352                 kfree(priv);
 353                 return -ENOMEM;
 354         }
 355
 356         priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
 357         priv->port = port;
 358         INIT_WORK(&priv->rx_work, aircable_read);
 359
 360         usb_set_serial_port_data(serial->port[0], priv);
 361
 362         return 0;
 363 }
 364
 365 static void aircable_shutdown(struct usb_serial *serial)
 366 {
 367
 368         struct usb_serial_port *port = serial->port[0];
 369         struct aircable_private *priv = usb_get_serial_port_data(port);
 370
 371         dbg("%s", __func__);
 372
 373         if (priv) {
 374                 serial_buf_free(priv->tx_buf);
 375                 serial_buf_free(priv->rx_buf);
 376                 usb_set_serial_port_data(port, NULL);
 377                 kfree(priv);
 378         }
 379 }
 380
 381 static int aircable_write_room(struct tty_struct *tty)
 382 {
 383         struct usb_serial_port *port = tty->driver_data;
 384         struct aircable_private *priv = usb_get_serial_port_data(port);
 385         return serial_buf_data_avail(priv->tx_buf);
 386 }
 387
 388 static int aircable_write(struct tty_struct *tty, struct usb_serial_port *port,
 389                           const unsigned char *source, int count)
 390 {
 391         struct aircable_private *priv = usb_get_serial_port_data(port);
 392         int temp;
 393
 394         dbg("%s - port %d, %d bytes", __func__, port->number, count);
 395
 396         usb_serial_debug_data(debug, &port->dev, __func__, count, source);
 397
 398         if (!count) {
 399                 dbg("%s - write request of 0 bytes", __func__);
 400                 return count;
 401         }
 402
 403         temp = serial_buf_put(priv->tx_buf, source, count);
 404
 405         aircable_send(port);
 406
 407         if (count > AIRCABLE_BUF_SIZE)
 408                 count = AIRCABLE_BUF_SIZE;
 409
 410         return count;
 411
 412 }
 413
 414 static void aircable_write_bulk_callback(struct urb *urb)
 415 {
 416         struct usb_serial_port *port = urb->context;
 417         int status = urb->status;
 418         int result;
 419
 420         dbg("%s - urb status: %d", __func__ , status);
 421
 422         /* This has been taken from cypress_m8.c cypress_write_int_callback */
 423         switch (status) {
 424         case 0:
 425                 /* success */
 426                 break;
 427         case -ECONNRESET:
 428         case -ENOENT:
 429         case -ESHUTDOWN:
 430                 /* this urb is terminated, clean up */
 431                 dbg("%s - urb shutting down with status: %d",
 432                     __func__, status);
 433                 port->write_urb_busy = 0;
 434                 return;
 435         default:
 436                 /* error in the urb, so we have to resubmit it */
 437                 dbg("%s - Overflow in write", __func__);
 438                 dbg("%s - nonzero write bulk status received: %d",
 439                     __func__, status);
 440                 port->write_urb->transfer_buffer_length = 1;
 441                 port->write_urb->dev = port->serial->dev;
 442                 result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
 443                 if (result)
 444                         dev_err(&urb->dev->dev,
 445                             "%s - failed resubmitting write urb, error %d\n",
 446                                                         __func__, result);
 447                 else
 448                         return;
 449         }
 450
 451         port->write_urb_busy = 0;
 452
 453         aircable_send(port);
 454 }
 455
 456 static void aircable_read_bulk_callback(struct urb *urb)
 457 {
 458         struct usb_serial_port *port = urb->context;
 459         struct aircable_private *priv = usb_get_serial_port_data(port);
 460         struct tty_struct *tty;
 461         unsigned long no_packages, remaining, package_length, i;
 462         int result, shift = 0;
 463         unsigned char *temp;
 464         int status = urb->status;
 465
 466         dbg("%s - port %d", __func__, port->number);
 467
 468         if (status) {
 469                 dbg("%s - urb status = %d", __func__, status);
 470                 if (!port->port.count) {
 471                         dbg("%s - port is closed, exiting.", __func__);
 472                         return;
 473                 }
 474                 if (status == -EPROTO) {
 475                         dbg("%s - caught -EPROTO, resubmitting the urb",
 476                             __func__);
 477                         usb_fill_bulk_urb(port->read_urb, port->serial->dev,
 478                                 usb_rcvbulkpipe(port->serial->dev,
 479                                         port->bulk_in_endpointAddress),
 480                                 port->read_urb->transfer_buffer,
 481                                 port->read_urb->transfer_buffer_length,
 482                                 aircable_read_bulk_callback, port);
 483
 484                         result = usb_submit_urb(urb, GFP_ATOMIC);
 485                         if (result)
 486                                 dev_err(&urb->dev->dev,
 487                                         "%s - failed resubmitting read urb, error %d\n",
 488                                         __func__, result);
 489                         return;
 490                 }
 491                 dbg("%s - unable to handle the error, exiting.", __func__);
 492                 return;
 493         }
 494
 495         usb_serial_debug_data(debug, &port->dev, __func__,
 496                                 urb->actual_length, urb->transfer_buffer);
 497
 498         tty = port->port.tty;
 499         if (tty && urb->actual_length) {
 500                 if (urb->actual_length <= 2) {
 501                         /* This is an incomplete package */
 502                         serial_buf_put(priv->rx_buf, urb->transfer_buffer,
 503                                        urb->actual_length);
 504                 } else {
 505                         temp = urb->transfer_buffer;
 506                         if (temp[0] == RX_HEADER_0)
 507                                 shift = HCI_HEADER_LENGTH;
 508
 509                         remaining = urb->actual_length;
 510                         no_packages = urb->actual_length / (HCI_COMPLETE_FRAME);
 511
 512                         if (urb->actual_length % HCI_COMPLETE_FRAME != 0)
 513                                 no_packages++;
 514
 515                         for (i = 0; i < no_packages; i++) {
 516                                 if (remaining > (HCI_COMPLETE_FRAME))
 517                                         package_length = HCI_COMPLETE_FRAME;
 518                                 else
 519                                         package_length = remaining;
 520                                 remaining -= package_length;
 521
 522                                 serial_buf_put(priv->rx_buf,
 523                                         urb->transfer_buffer + shift +
 524                                         (HCI_COMPLETE_FRAME) * (i),
 525                                         package_length - shift);
 526                         }
 527                 }
 528                 aircable_read(&priv->rx_work);
 529         }
 530
 531         /* Schedule the next read _if_ we are still open */
 532         if (port->port.count) {
 533                 usb_fill_bulk_urb(port->read_urb, port->serial->dev,
 534                                   usb_rcvbulkpipe(port->serial->dev,
 535                                           port->bulk_in_endpointAddress),
 536                                   port->read_urb->transfer_buffer,
 537                                   port->read_urb->transfer_buffer_length,
 538                                   aircable_read_bulk_callback, port);
 539
 540                 result = usb_submit_urb(urb, GFP_ATOMIC);
 541                 if (result)
 542                         dev_err(&urb->dev->dev,
 543                                 "%s - failed resubmitting read urb, error %d\n",
 544                                 __func__, result);
 545         }
 546
 547         return;
 548 }
 549
 550 /* Based on ftdi_sio.c throttle */
 551 static void aircable_throttle(struct tty_struct *tty)
 552 {
 553         struct usb_serial_port *port = tty->driver_data;
 554         struct aircable_private *priv = usb_get_serial_port_data(port);
 555         unsigned long flags;
 556
 557         dbg("%s - port %d", __func__, port->number);
 558
 559         spin_lock_irqsave(&priv->rx_lock, flags);
 560         priv->rx_flags |= THROTTLED;
 561         spin_unlock_irqrestore(&priv->rx_lock, flags);
 562 }
 563
 564 /* Based on ftdi_sio.c unthrottle */
 565 static void aircable_unthrottle(struct tty_struct *tty)
 566 {
 567         struct usb_serial_port *port = tty->driver_data;
 568         struct aircable_private *priv = usb_get_serial_port_data(port);
 569         int actually_throttled;
 570         unsigned long flags;
 571
 572         dbg("%s - port %d", __func__, port->number);
 573
 574         spin_lock_irqsave(&priv->rx_lock, flags);
 575         actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
 576         priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
 577         spin_unlock_irqrestore(&priv->rx_lock, flags);
 578
 579         if (actually_throttled)
 580                 schedule_work(&priv->rx_work);
 581 }
 582
 583 static struct usb_driver aircable_driver = {
 584         .name =         "aircable",
 585         .probe =        usb_serial_probe,
 586         .disconnect =   usb_serial_disconnect,
 587         .id_table =     id_table,
 588         .no_dynamic_id =        1,
 589 };
 590
 591 static struct usb_serial_driver aircable_device = {
 592         .driver = {
 593                 .owner =        THIS_MODULE,
 594                 .name =         "aircable",
 595         },
 596         .usb_driver =           &aircable_driver,
 597         .id_table =             id_table,
 598         .num_ports =            1,
 599         .attach =               aircable_attach,
 600         .probe =                aircable_probe,
 601         .shutdown =             aircable_shutdown,
 602         .write =                aircable_write,
 603         .write_room =           aircable_write_room,
 604         .write_bulk_callback =  aircable_write_bulk_callback,
 605         .read_bulk_callback =   aircable_read_bulk_callback,
 606         .throttle =             aircable_throttle,
 607         .unthrottle =           aircable_unthrottle,
 608 };
 609
 610 static int __init aircable_init(void)
 611 {
 612         int retval;
 613         retval = usb_serial_register(&aircable_device);
 614         if (retval)
 615                 goto failed_serial_register;
 616         retval = usb_register(&aircable_driver);
 617         if (retval)
 618                 goto failed_usb_register;
 619         return 0;
 620
 621 failed_serial_register:
 622         usb_serial_deregister(&aircable_device);
 623 failed_usb_register:
 624         return retval;
 625 }
 626
 627 static void __exit aircable_exit(void)
 628 {
 629         usb_deregister(&aircable_driver);
 630         usb_serial_deregister(&aircable_device);
 631 }
 632
 633 MODULE_AUTHOR(DRIVER_AUTHOR);
 634 MODULE_DESCRIPTION(DRIVER_DESC);
 635 MODULE_VERSION(DRIVER_VERSION);
 636 MODULE_LICENSE("GPL");
 637
 638 module_init(aircable_init);
 639 module_exit(aircable_exit);
 640
 641 module_param(debug, bool, S_IRUGO | S_IWUSR);
 642 MODULE_PARM_DESC(debug, "Debug enabled or not");