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 = tty_port_tty_get(&port->port);
 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                 goto out; /* We have finished sending everything. */
 287
 288         tty_prepare_flip_string(tty, &data, count);
 289         if (!data) {
 290                 dev_err(&port->dev, "%s- kzalloc(%d) failed.",
 291                                                         __func__, count);
 292                 goto out;
 293         }
 294
 295         serial_buf_get(priv->rx_buf, data, count);
 296
 297         tty_flip_buffer_push(tty);
 298
 299         if (serial_buf_data_avail(priv->rx_buf))
 300                 schedule_work(&priv->rx_work);
 301 out:
 302         tty_kref_put(tty);
 303         return;
 304 }
 305 /* End of private methods */
 306
 307 static int aircable_probe(struct usb_serial *serial,
 308                           const struct usb_device_id *id)
 309 {
 310         struct usb_host_interface *iface_desc = serial->interface->
 311                                                                 cur_altsetting;
 312         struct usb_endpoint_descriptor *endpoint;
 313         int num_bulk_out = 0;
 314         int i;
 315
 316         for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
 317                 endpoint = &iface_desc->endpoint[i].desc;
 318                 if (usb_endpoint_is_bulk_out(endpoint)) {
 319                         dbg("found bulk out on endpoint %d", i);
 320                         ++num_bulk_out;
 321                 }
 322         }
 323
 324         if (num_bulk_out == 0) {
 325                 dbg("Invalid interface, discarding");
 326                 return -ENODEV;
 327         }
 328
 329         return 0;
 330 }
 331
 332 static int aircable_attach(struct usb_serial *serial)
 333 {
 334         struct usb_serial_port *port = serial->port[0];
 335         struct aircable_private *priv;
 336
 337         priv = kzalloc(sizeof(struct aircable_private), GFP_KERNEL);
 338         if (!priv) {
 339                 err("%s- kmalloc(%Zd) failed.", __func__,
 340                         sizeof(struct aircable_private));
 341                 return -ENOMEM;
 342         }
 343
 344         /* Allocation of Circular Buffers */
 345         priv->tx_buf = serial_buf_alloc();
 346         if (priv->tx_buf == NULL) {
 347                 kfree(priv);
 348                 return -ENOMEM;
 349         }
 350
 351         priv->rx_buf = serial_buf_alloc();
 352         if (priv->rx_buf == NULL) {
 353                 kfree(priv->tx_buf);
 354                 kfree(priv);
 355                 return -ENOMEM;
 356         }
 357
 358         priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
 359         priv->port = port;
 360         INIT_WORK(&priv->rx_work, aircable_read);
 361
 362         usb_set_serial_port_data(serial->port[0], priv);
 363
 364         return 0;
 365 }
 366
 367 static void aircable_shutdown(struct usb_serial *serial)
 368 {
 369
 370         struct usb_serial_port *port = serial->port[0];
 371         struct aircable_private *priv = usb_get_serial_port_data(port);
 372
 373         dbg("%s", __func__);
 374
 375         if (priv) {
 376                 serial_buf_free(priv->tx_buf);
 377                 serial_buf_free(priv->rx_buf);
 378                 usb_set_serial_port_data(port, NULL);
 379                 kfree(priv);
 380         }
 381 }
 382
 383 static int aircable_write_room(struct tty_struct *tty)
 384 {
 385         struct usb_serial_port *port = tty->driver_data;
 386         struct aircable_private *priv = usb_get_serial_port_data(port);
 387         return serial_buf_data_avail(priv->tx_buf);
 388 }
 389
 390 static int aircable_write(struct tty_struct *tty, struct usb_serial_port *port,
 391                           const unsigned char *source, int count)
 392 {
 393         struct aircable_private *priv = usb_get_serial_port_data(port);
 394         int temp;
 395
 396         dbg("%s - port %d, %d bytes", __func__, port->number, count);
 397
 398         usb_serial_debug_data(debug, &port->dev, __func__, count, source);
 399
 400         if (!count) {
 401                 dbg("%s - write request of 0 bytes", __func__);
 402                 return count;
 403         }
 404
 405         temp = serial_buf_put(priv->tx_buf, source, count);
 406
 407         aircable_send(port);
 408
 409         if (count > AIRCABLE_BUF_SIZE)
 410                 count = AIRCABLE_BUF_SIZE;
 411
 412         return count;
 413
 414 }
 415
 416 static void aircable_write_bulk_callback(struct urb *urb)
 417 {
 418         struct usb_serial_port *port = urb->context;
 419         int status = urb->status;
 420         int result;
 421
 422         dbg("%s - urb status: %d", __func__ , status);
 423
 424         /* This has been taken from cypress_m8.c cypress_write_int_callback */
 425         switch (status) {
 426         case 0:
 427                 /* success */
 428                 break;
 429         case -ECONNRESET:
 430         case -ENOENT:
 431         case -ESHUTDOWN:
 432                 /* this urb is terminated, clean up */
 433                 dbg("%s - urb shutting down with status: %d",
 434                     __func__, status);
 435                 port->write_urb_busy = 0;
 436                 return;
 437         default:
 438                 /* error in the urb, so we have to resubmit it */
 439                 dbg("%s - Overflow in write", __func__);
 440                 dbg("%s - nonzero write bulk status received: %d",
 441                     __func__, status);
 442                 port->write_urb->transfer_buffer_length = 1;
 443                 port->write_urb->dev = port->serial->dev;
 444                 result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
 445                 if (result)
 446                         dev_err(&urb->dev->dev,
 447                             "%s - failed resubmitting write urb, error %d\n",
 448                                                         __func__, result);
 449                 else
 450                         return;
 451         }
 452
 453         port->write_urb_busy = 0;
 454
 455         aircable_send(port);
 456 }
 457
 458 static void aircable_read_bulk_callback(struct urb *urb)
 459 {
 460         struct usb_serial_port *port = urb->context;
 461         struct aircable_private *priv = usb_get_serial_port_data(port);
 462         struct tty_struct *tty;
 463         unsigned long no_packages, remaining, package_length, i;
 464         int result, shift = 0;
 465         unsigned char *temp;
 466         int status = urb->status;
 467
 468         dbg("%s - port %d", __func__, port->number);
 469
 470         if (status) {
 471                 dbg("%s - urb status = %d", __func__, status);
 472                 if (!port->port.count) {
 473                         dbg("%s - port is closed, exiting.", __func__);
 474                         return;
 475                 }
 476                 if (status == -EPROTO) {
 477                         dbg("%s - caught -EPROTO, resubmitting the urb",
 478                             __func__);
 479                         usb_fill_bulk_urb(port->read_urb, port->serial->dev,
 480                                 usb_rcvbulkpipe(port->serial->dev,
 481                                         port->bulk_in_endpointAddress),
 482                                 port->read_urb->transfer_buffer,
 483                                 port->read_urb->transfer_buffer_length,
 484                                 aircable_read_bulk_callback, port);
 485
 486                         result = usb_submit_urb(urb, GFP_ATOMIC);
 487                         if (result)
 488                                 dev_err(&urb->dev->dev,
 489                                         "%s - failed resubmitting read urb, error %d\n",
 490                                         __func__, result);
 491                         return;
 492                 }
 493                 dbg("%s - unable to handle the error, exiting.", __func__);
 494                 return;
 495         }
 496
 497         usb_serial_debug_data(debug, &port->dev, __func__,
 498                                 urb->actual_length, urb->transfer_buffer);
 499
 500         tty = tty_port_tty_get(&port->port);
 501         if (tty && urb->actual_length) {
 502                 if (urb->actual_length <= 2) {
 503                         /* This is an incomplete package */
 504                         serial_buf_put(priv->rx_buf, urb->transfer_buffer,
 505                                        urb->actual_length);
 506                 } else {
 507                         temp = urb->transfer_buffer;
 508                         if (temp[0] == RX_HEADER_0)
 509                                 shift = HCI_HEADER_LENGTH;
 510
 511                         remaining = urb->actual_length;
 512                         no_packages = urb->actual_length / (HCI_COMPLETE_FRAME);
 513
 514                         if (urb->actual_length % HCI_COMPLETE_FRAME != 0)
 515                                 no_packages++;
 516
 517                         for (i = 0; i < no_packages; i++) {
 518                                 if (remaining > (HCI_COMPLETE_FRAME))
 519                                         package_length = HCI_COMPLETE_FRAME;
 520                                 else
 521                                         package_length = remaining;
 522                                 remaining -= package_length;
 523
 524                                 serial_buf_put(priv->rx_buf,
 525                                         urb->transfer_buffer + shift +
 526                                         (HCI_COMPLETE_FRAME) * (i),
 527                                         package_length - shift);
 528                         }
 529                 }
 530                 aircable_read(&priv->rx_work);
 531         }
 532         tty_kref_put(tty);
 533
 534         /* Schedule the next read _if_ we are still open */
 535         if (port->port.count) {
 536                 usb_fill_bulk_urb(port->read_urb, port->serial->dev,
 537                                   usb_rcvbulkpipe(port->serial->dev,
 538                                           port->bulk_in_endpointAddress),
 539                                   port->read_urb->transfer_buffer,
 540                                   port->read_urb->transfer_buffer_length,
 541                                   aircable_read_bulk_callback, port);
 542
 543                 result = usb_submit_urb(urb, GFP_ATOMIC);
 544                 if (result)
 545                         dev_err(&urb->dev->dev,
 546                                 "%s - failed resubmitting read urb, error %d\n",
 547                                 __func__, result);
 548         }
 549
 550         return;
 551 }
 552
 553 /* Based on ftdi_sio.c throttle */
 554 static void aircable_throttle(struct tty_struct *tty)
 555 {
 556         struct usb_serial_port *port = tty->driver_data;
 557         struct aircable_private *priv = usb_get_serial_port_data(port);
 558         unsigned long flags;
 559
 560         dbg("%s - port %d", __func__, port->number);
 561
 562         spin_lock_irqsave(&priv->rx_lock, flags);
 563         priv->rx_flags |= THROTTLED;
 564         spin_unlock_irqrestore(&priv->rx_lock, flags);
 565 }
 566
 567 /* Based on ftdi_sio.c unthrottle */
 568 static void aircable_unthrottle(struct tty_struct *tty)
 569 {
 570         struct usb_serial_port *port = tty->driver_data;
 571         struct aircable_private *priv = usb_get_serial_port_data(port);
 572         int actually_throttled;
 573         unsigned long flags;
 574
 575         dbg("%s - port %d", __func__, port->number);
 576
 577         spin_lock_irqsave(&priv->rx_lock, flags);
 578         actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
 579         priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
 580         spin_unlock_irqrestore(&priv->rx_lock, flags);
 581
 582         if (actually_throttled)
 583                 schedule_work(&priv->rx_work);
 584 }
 585
 586 static struct usb_driver aircable_driver = {
 587         .name =         "aircable",
 588         .probe =        usb_serial_probe,
 589         .disconnect =   usb_serial_disconnect,
 590         .id_table =     id_table,
 591         .no_dynamic_id =        1,
 592 };
 593
 594 static struct usb_serial_driver aircable_device = {
 595         .driver = {
 596                 .owner =        THIS_MODULE,
 597                 .name =         "aircable",
 598         },
 599         .usb_driver =           &aircable_driver,
 600         .id_table =             id_table,
 601         .num_ports =            1,
 602         .attach =               aircable_attach,
 603         .probe =                aircable_probe,
 604         .shutdown =             aircable_shutdown,
 605         .write =                aircable_write,
 606         .write_room =           aircable_write_room,
 607         .write_bulk_callback =  aircable_write_bulk_callback,
 608         .read_bulk_callback =   aircable_read_bulk_callback,
 609         .throttle =             aircable_throttle,
 610         .unthrottle =           aircable_unthrottle,
 611 };
 612
 613 static int __init aircable_init(void)
 614 {
 615         int retval;
 616         retval = usb_serial_register(&aircable_device);
 617         if (retval)
 618                 goto failed_serial_register;
 619         retval = usb_register(&aircable_driver);
 620         if (retval)
 621                 goto failed_usb_register;
 622         return 0;
 623
 624 failed_serial_register:
 625         usb_serial_deregister(&aircable_device);
 626 failed_usb_register:
 627         return retval;
 628 }
 629
 630 static void __exit aircable_exit(void)
 631 {
 632         usb_deregister(&aircable_driver);
 633         usb_serial_deregister(&aircable_device);
 634 }
 635
 636 MODULE_AUTHOR(DRIVER_AUTHOR);
 637 MODULE_DESCRIPTION(DRIVER_DESC);
 638 MODULE_VERSION(DRIVER_VERSION);
 639 MODULE_LICENSE("GPL");
 640
 641 module_init(aircable_init);
 642 module_exit(aircable_exit);
 643
 644 module_param(debug, bool, S_IRUGO | S_IWUSR);
 645 MODULE_PARM_DESC(debug, "Debug enabled or not");