git.oblomov.eu Git - linux-2.6/blob - drivers/staging/frontier/tranzport.c

   1 /*
   2  * Frontier Designs Tranzport driver
   3  *
   4  * Copyright (C) 2007 Michael Taht (m@taht.net)
   5  *
   6  * Based on the usbled driver and ldusb drivers by
   7  *
   8  * Copyright (C) 2004 Greg Kroah-Hartman (greg@kroah.com)
   9  * Copyright (C) 2005 Michael Hund <mhund@ld-didactic.de>
  10  *
  11  * The ldusb driver was, in turn, derived from Lego USB Tower driver
  12  * Copyright (C) 2003 David Glance <advidgsf@sourceforge.net>
  13  *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
  14  *
  15  *      This program is free software; you can redistribute it and/or
  16  *      modify it under the terms of the GNU General Public License as
  17  *      published by the Free Software Foundation, version 2.
  18  *
  19  */
  20
  21 /*
  22  * This driver uses a ring buffer for time critical reading of
  23  * interrupt in reports and provides read and write methods for
  24  * raw interrupt reports.
  25  */
  26
  27 /* Note: this currently uses a dumb ringbuffer for reads and writes.
  28  * A more optimal driver would cache and kill off outstanding urbs that are
  29  * now invalid, and ignore ones that already were in the queue but valid
  30  * as we only have 17 commands for the tranzport. In particular this is
  31  * key for getting lights to flash in time as otherwise many commands
  32  * can be buffered up before the light change makes it to the interface.
  33  */
  34
  35 #include <linux/kernel.h>
  36 #include <linux/errno.h>
  37 #include <linux/init.h>
  38 #include <linux/slab.h>
  39 #include <linux/module.h>
  40 #include <linux/mutex.h>
  41 #include <linux/version.h>
  42
  43 #include <linux/uaccess.h>
  44 #include <linux/input.h>
  45 #include <linux/usb.h>
  46 #include <linux/poll.h>
  47
  48 /* Define these values to match your devices */
  49 #define VENDOR_ID   0x165b
  50 #define PRODUCT_ID  0x8101
  51
  52 #ifdef CONFIG_USB_DYNAMIC_MINORS
  53 #define USB_TRANZPORT_MINOR_BASE        0
  54 #else  /* FIXME 177- is the another driver's minor - apply for a minor soon */
  55 #define USB_TRANZPORT_MINOR_BASE        177
  56 #endif
  57
  58 /* table of devices that work with this driver */
  59 static struct usb_device_id usb_tranzport_table[] = {
  60         {USB_DEVICE(VENDOR_ID, PRODUCT_ID)},
  61         {}                      /* Terminating entry */
  62 };
  63
  64 MODULE_DEVICE_TABLE(usb, usb_tranzport_table);
  65 MODULE_VERSION("0.35");
  66 MODULE_AUTHOR("Mike Taht <m@taht.net>");
  67 MODULE_DESCRIPTION("Tranzport USB Driver");
  68 MODULE_LICENSE("GPL");
  69 MODULE_SUPPORTED_DEVICE("Frontier Designs Tranzport Control Surface");
  70
  71 #define SUPPRESS_EXTRA_OFFLINE_EVENTS 1
  72 #define COMPRESS_WHEEL_EVENTS 1
  73 #define BUFFERED_READS 1
  74 #define RING_BUFFER_SIZE 1000
  75 #define WRITE_BUFFER_SIZE 34
  76 #define TRANZPORT_USB_TIMEOUT 10
  77 #define TRANZPORT_DEBUG 0
  78
  79 static int debug = TRANZPORT_DEBUG;
  80
  81 /* Use our own dbg macro */
  82 #define dbg_info(dev, format, arg...) do                        \
  83         { if (debug) dev_info(dev , format , ## arg); } while (0)
  84
  85 /* Module parameters */
  86
  87 module_param(debug, int, S_IRUGO | S_IWUSR);
  88 MODULE_PARM_DESC(debug, "Debug enabled or not");
  89
  90 /* All interrupt in transfers are collected in a ring buffer to
  91  * avoid racing conditions and get better performance of the driver.
  92  */
  93
  94 static int ring_buffer_size = RING_BUFFER_SIZE;
  95
  96 module_param(ring_buffer_size, int, S_IRUGO);
  97 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");
  98
  99 /* The write_buffer can one day contain more than one interrupt out transfer.
 100  */
 101 static int write_buffer_size = WRITE_BUFFER_SIZE;
 102 module_param(write_buffer_size, int, S_IRUGO);
 103 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
 104
 105 /*
 106  * Increase the interval for debugging purposes.
 107  * or set to 1 to use the standard interval from the endpoint descriptors.
 108  */
 109
 110 static int min_interrupt_in_interval = TRANZPORT_USB_TIMEOUT;
 111 module_param(min_interrupt_in_interval, int, 0);
 112 MODULE_PARM_DESC(min_interrupt_in_interval,
 113                 "Minimum interrupt in interval in ms");
 114
 115 static int min_interrupt_out_interval = TRANZPORT_USB_TIMEOUT;
 116 module_param(min_interrupt_out_interval, int, 0);
 117 MODULE_PARM_DESC(min_interrupt_out_interval,
 118                 "Minimum interrupt out interval in ms");
 119
 120 struct tranzport_cmd {
 121         unsigned char cmd[8];
 122 };
 123
 124 /* Structure to hold all of our device specific stuff */
 125
 126 struct usb_tranzport {
 127         struct semaphore sem;   /* locks this structure */
 128         struct usb_interface *intf;     /* save off the usb interface pointer */
 129         int open_count;         /* number of times this port opened */
 130         struct tranzport_cmd (*ring_buffer)[RING_BUFFER_SIZE];
 131         unsigned int ring_head;
 132         unsigned int ring_tail;
 133         wait_queue_head_t read_wait;
 134         wait_queue_head_t write_wait;
 135         unsigned char *interrupt_in_buffer;
 136         struct usb_endpoint_descriptor *interrupt_in_endpoint;
 137         struct urb *interrupt_in_urb;
 138         int interrupt_in_interval;
 139         size_t interrupt_in_endpoint_size;
 140         int interrupt_in_running;
 141         int interrupt_in_done;
 142         char *interrupt_out_buffer;
 143         struct usb_endpoint_descriptor *interrupt_out_endpoint;
 144         struct urb *interrupt_out_urb;
 145         int interrupt_out_interval;
 146         size_t interrupt_out_endpoint_size;
 147         int interrupt_out_busy;
 148
 149         /* Sysfs support */
 150
 151         unsigned char enable;   /* 0 if disabled 1 if enabled */
 152         unsigned char offline;  /* if the device is out of range or asleep */
 153         unsigned char compress_wheel;   /* flag to compress wheel events */
 154 };
 155
 156 /* prevent races between open() and disconnect() */
 157 static DEFINE_MUTEX(disconnect_mutex);
 158
 159 static struct usb_driver usb_tranzport_driver;
 160
 161 /**
 162  *      usb_tranzport_abort_transfers
 163  *      aborts transfers and frees associated data structures
 164  */
 165 static void usb_tranzport_abort_transfers(struct usb_tranzport *dev)
 166 {
 167         /* shutdown transfer */
 168         if (dev->interrupt_in_running) {
 169                 dev->interrupt_in_running = 0;
 170                 if (dev->intf)
 171                         usb_kill_urb(dev->interrupt_in_urb);
 172         }
 173         if (dev->interrupt_out_busy)
 174                 if (dev->intf)
 175                         usb_kill_urb(dev->interrupt_out_urb);
 176 }
 177
 178 #define show_int(value)                                                 \
 179   static ssize_t show_##value(struct device *dev,                       \
 180                               struct device_attribute *attr, char *buf) \
 181   {                                                                     \
 182     struct usb_interface *intf = to_usb_interface(dev);                 \
 183     struct usb_tranzport *t = usb_get_intfdata(intf);                   \
 184     return sprintf(buf, "%d\n", t->value);                              \
 185   }                                                                     \
 186   static DEVICE_ATTR(value, S_IRUGO, show_##value, NULL);
 187
 188 #define show_set_int(value)                                             \
 189   static ssize_t show_##value(struct device *dev,                       \
 190                               struct device_attribute *attr, char *buf) \
 191   {                                                                     \
 192     struct usb_interface *intf = to_usb_interface(dev);                 \
 193     struct usb_tranzport *t = usb_get_intfdata(intf);                   \
 194     return sprintf(buf, "%d\n", t->value);                              \
 195   }                                                                     \
 196   static ssize_t set_##value(struct device *dev,                        \
 197                              struct device_attribute *attr,             \
 198                              const char *buf, size_t count)             \
 199   {                                                                     \
 200     struct usb_interface *intf = to_usb_interface(dev);                 \
 201     struct usb_tranzport *t = usb_get_intfdata(intf);                   \
 202     int temp = simple_strtoul(buf, NULL, 10);                           \
 203     t->value = temp;                                                    \
 204     return count;                                                       \
 205   }                                                                     \
 206   static DEVICE_ATTR(value, S_IWUGO | S_IRUGO, show_##value, set_##value);
 207
 208 show_int(enable);
 209 show_int(offline);
 210 show_set_int(compress_wheel);
 211
 212 /**
 213  *      usb_tranzport_delete
 214  */
 215 static void usb_tranzport_delete(struct usb_tranzport *dev)
 216 {
 217         usb_tranzport_abort_transfers(dev);
 218         if (dev->intf != NULL) {
 219                 device_remove_file(&dev->intf->dev, &dev_attr_enable);
 220                 device_remove_file(&dev->intf->dev, &dev_attr_offline);
 221                 device_remove_file(&dev->intf->dev, &dev_attr_compress_wheel);
 222         }
 223
 224         /* free data structures */
 225         usb_free_urb(dev->interrupt_in_urb);
 226         usb_free_urb(dev->interrupt_out_urb);
 227         kfree(dev->ring_buffer);
 228         kfree(dev->interrupt_in_buffer);
 229         kfree(dev->interrupt_out_buffer);
 230         kfree(dev);
 231 }
 232
 233 /**
 234  *      usb_tranzport_interrupt_in_callback
 235  */
 236
 237 static void usb_tranzport_interrupt_in_callback(struct urb *urb)
 238 {
 239         struct usb_tranzport *dev = urb->context;
 240         unsigned int next_ring_head;
 241         int retval = -1;
 242
 243         if (urb->status) {
 244                 if (urb->status == -ENOENT ||
 245                         urb->status == -ECONNRESET ||
 246                         urb->status == -ESHUTDOWN) {
 247                         goto exit;
 248                 } else {
 249                         dbg_info(&dev->intf->dev,
 250                                  "%s: nonzero status received: %d\n",
 251                                  __func__, urb->status);
 252                         goto resubmit;  /* maybe we can recover */
 253                 }
 254         }
 255
 256         if (urb->actual_length != 8) {
 257                 dev_warn(&dev->intf->dev,
 258                         "Urb length was %d bytes!!"
 259                         "Do something intelligent \n",
 260                          urb->actual_length);
 261         } else {
 262                 dbg_info(&dev->intf->dev,
 263                          "%s: received: %02x%02x%02x%02x%02x%02x%02x%02x\n",
 264                          __func__, dev->interrupt_in_buffer[0],
 265                          dev->interrupt_in_buffer[1],
 266                          dev->interrupt_in_buffer[2],
 267                          dev->interrupt_in_buffer[3],
 268                          dev->interrupt_in_buffer[4],
 269                          dev->interrupt_in_buffer[5],
 270                          dev->interrupt_in_buffer[6],
 271                          dev->interrupt_in_buffer[7]);
 272 #if SUPPRESS_EXTRA_OFFLINE_EVENTS
 273         if (dev->offline == 2 && dev->interrupt_in_buffer[1] == 0xff)
 274                 goto resubmit;
 275                 if (dev->offline == 1 && dev->interrupt_in_buffer[1] == 0xff) {
 276                         dev->offline = 2;
 277                         goto resubmit;
 278                 }
 279
 280                 /* Always pass one offline event up the stack */
 281                 if (dev->offline > 0 && dev->interrupt_in_buffer[1] != 0xff)
 282                         dev->offline = 0;
 283                 if (dev->offline == 0 && dev->interrupt_in_buffer[1] == 0xff)
 284                         dev->offline = 1;
 285
 286 #endif  /* SUPPRESS_EXTRA_OFFLINE_EVENTS */
 287            dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n",
 288                 __func__, dev->ring_head, dev->ring_tail);
 289
 290                 next_ring_head = (dev->ring_head + 1) % ring_buffer_size;
 291
 292                 if (next_ring_head != dev->ring_tail) {
 293                         memcpy(&((*dev->ring_buffer)[dev->ring_head]),
 294                                dev->interrupt_in_buffer, urb->actual_length);
 295                         dev->ring_head = next_ring_head;
 296                         retval = 0;
 297                         memset(dev->interrupt_in_buffer, 0, urb->actual_length);
 298                 } else {
 299                         dev_warn(&dev->intf->dev,
 300                                  "Ring buffer overflow, %d bytes dropped\n",
 301                                  urb->actual_length);
 302                         memset(dev->interrupt_in_buffer, 0, urb->actual_length);
 303                 }
 304         }
 305
 306 resubmit:
 307 /* resubmit if we're still running */
 308         if (dev->interrupt_in_running && dev->intf) {
 309                 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 310                 if (retval)
 311                         dev_err(&dev->intf->dev,
 312                                 "usb_submit_urb failed (%d)\n", retval);
 313         }
 314
 315 exit:
 316         dev->interrupt_in_done = 1;
 317         wake_up_interruptible(&dev->read_wait);
 318 }
 319
 320 /**
 321  *      usb_tranzport_interrupt_out_callback
 322  */
 323 static void usb_tranzport_interrupt_out_callback(struct urb *urb)
 324 {
 325         struct usb_tranzport *dev = urb->context;
 326         /* sync/async unlink faults aren't errors */
 327         if (urb->status && !(urb->status == -ENOENT ||
 328                                 urb->status == -ECONNRESET ||
 329                                 urb->status == -ESHUTDOWN))
 330                 dbg_info(&dev->intf->dev,
 331                         "%s - nonzero write interrupt status received: %d\n",
 332                         __func__, urb->status);
 333
 334         dev->interrupt_out_busy = 0;
 335         wake_up_interruptible(&dev->write_wait);
 336 }
 337 /**
 338  *      usb_tranzport_open
 339  */
 340 static int usb_tranzport_open(struct inode *inode, struct file *file)
 341 {
 342         struct usb_tranzport *dev;
 343         int subminor;
 344         int retval = 0;
 345         struct usb_interface *interface;
 346
 347         nonseekable_open(inode, file);
 348         subminor = iminor(inode);
 349
 350         mutex_lock(&disconnect_mutex);
 351
 352         interface = usb_find_interface(&usb_tranzport_driver, subminor);
 353
 354         if (!interface) {
 355                 err("%s - error, can't find device for minor %d\n",
 356                         __func__, subminor);
 357                 retval = -ENODEV;
 358                 goto unlock_disconnect_exit;
 359         }
 360
 361         dev = usb_get_intfdata(interface);
 362
 363         if (!dev) {
 364                 retval = -ENODEV;
 365                 goto unlock_disconnect_exit;
 366         }
 367
 368         /* lock this device */
 369         if (down_interruptible(&dev->sem)) {
 370                 retval = -ERESTARTSYS;
 371                 goto unlock_disconnect_exit;
 372         }
 373
 374         /* allow opening only once */
 375         if (dev->open_count) {
 376                 retval = -EBUSY;
 377                 goto unlock_exit;
 378         }
 379         dev->open_count = 1;
 380
 381         /* initialize in direction */
 382         dev->ring_head = 0;
 383         dev->ring_tail = 0;
 384         usb_fill_int_urb(dev->interrupt_in_urb,
 385                         interface_to_usbdev(interface),
 386                         usb_rcvintpipe(interface_to_usbdev(interface),
 387                                 dev->interrupt_in_endpoint->
 388                                 bEndpointAddress),
 389                         dev->interrupt_in_buffer,
 390                         dev->interrupt_in_endpoint_size,
 391                         usb_tranzport_interrupt_in_callback, dev,
 392                         dev->interrupt_in_interval);
 393
 394         dev->interrupt_in_running = 1;
 395         dev->interrupt_in_done = 0;
 396         dev->enable = 1;
 397         dev->offline = 0;
 398         dev->compress_wheel = 1;
 399
 400         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 401         if (retval) {
 402                 dev_err(&interface->dev,
 403                         "Couldn't submit interrupt_in_urb %d\n", retval);
 404                 dev->interrupt_in_running = 0;
 405                 dev->open_count = 0;
 406                 goto unlock_exit;
 407         }
 408
 409         /* save device in the file's private structure */
 410         file->private_data = dev;
 411
 412 unlock_exit:
 413         up(&dev->sem);
 414
 415 unlock_disconnect_exit:
 416         mutex_unlock(&disconnect_mutex);
 417
 418         return retval;
 419 }
 420
 421 /**
 422  *      usb_tranzport_release
 423  */
 424 static int usb_tranzport_release(struct inode *inode, struct file *file)
 425 {
 426         struct usb_tranzport *dev;
 427         int retval = 0;
 428
 429         dev = file->private_data;
 430
 431         if (dev == NULL) {
 432                 retval = -ENODEV;
 433                 goto exit;
 434         }
 435
 436         if (down_interruptible(&dev->sem)) {
 437                 retval = -ERESTARTSYS;
 438                 goto exit;
 439         }
 440
 441         if (dev->open_count != 1) {
 442                 retval = -ENODEV;
 443                 goto unlock_exit;
 444         }
 445
 446         if (dev->intf == NULL) {
 447                 /* the device was unplugged before the file was released */
 448                 up(&dev->sem);
 449                 /* unlock here as usb_tranzport_delete frees dev */
 450                 usb_tranzport_delete(dev);
 451                 retval = -ENODEV;
 452                 goto exit;
 453         }
 454
 455         /* wait until write transfer is finished */
 456         if (dev->interrupt_out_busy)
 457                 wait_event_interruptible_timeout(dev->write_wait,
 458                                                 !dev->interrupt_out_busy,
 459                                                 2 * HZ);
 460         usb_tranzport_abort_transfers(dev);
 461         dev->open_count = 0;
 462
 463 unlock_exit:
 464         up(&dev->sem);
 465
 466 exit:
 467         return retval;
 468 }
 469
 470 /**
 471  *      usb_tranzport_poll
 472  */
 473 static unsigned int usb_tranzport_poll(struct file *file, poll_table * wait)
 474 {
 475         struct usb_tranzport *dev;
 476         unsigned int mask = 0;
 477         dev = file->private_data;
 478         poll_wait(file, &dev->read_wait, wait);
 479         poll_wait(file, &dev->write_wait, wait);
 480         if (dev->ring_head != dev->ring_tail)
 481                 mask |= POLLIN | POLLRDNORM;
 482         if (!dev->interrupt_out_busy)
 483                 mask |= POLLOUT | POLLWRNORM;
 484         return mask;
 485 }
 486 /**
 487  *      usb_tranzport_read
 488  */
 489
 490 static ssize_t usb_tranzport_read(struct file *file, char __user *buffer,
 491                                 size_t count, loff_t *ppos)
 492 {
 493         struct usb_tranzport *dev;
 494         int retval = 0;
 495 #if BUFFERED_READS
 496         int c = 0;
 497 #endif
 498 #if COMPRESS_WHEEL_EVENTS
 499         signed char oldwheel;
 500         signed char newwheel;
 501         int cancompress = 1;
 502         int next_tail;
 503 #endif
 504
 505         /* do I have such a thing as a null event? */
 506
 507         dev = file->private_data;
 508
 509         /* verify that we actually have some data to read */
 510         if (count == 0)
 511                 goto exit;
 512
 513         /* lock this object */
 514         if (down_interruptible(&dev->sem)) {
 515                 retval = -ERESTARTSYS;
 516                 goto exit;
 517         }
 518
 519         /* verify that the device wasn't unplugged */ if (dev->intf == NULL) {
 520                 retval = -ENODEV;
 521                 err("No device or device unplugged %d\n", retval);
 522                 goto unlock_exit;
 523         }
 524
 525         while (dev->ring_head == dev->ring_tail) {
 526
 527                 if (file->f_flags & O_NONBLOCK) {
 528                         retval = -EAGAIN;
 529                         goto unlock_exit;
 530                 }
 531                 /* tiny race - FIXME: make atomic? */
 532                 /* atomic_cmp_exchange(&dev->interrupt_in_done,0,0); */
 533                 dev->interrupt_in_done = 0;
 534                 retval = wait_event_interruptible(dev->read_wait,
 535                                                   dev->interrupt_in_done);
 536                 if (retval < 0)
 537                         goto unlock_exit;
 538         }
 539
 540         dbg_info(&dev->intf->dev,
 541                 "%s: copying to userspace: "
 542                 "%02x%02x%02x%02x%02x%02x%02x%02x\n",
 543                  __func__,
 544                  (*dev->ring_buffer)[dev->ring_tail].cmd[0],
 545                  (*dev->ring_buffer)[dev->ring_tail].cmd[1],
 546                  (*dev->ring_buffer)[dev->ring_tail].cmd[2],
 547                  (*dev->ring_buffer)[dev->ring_tail].cmd[3],
 548                  (*dev->ring_buffer)[dev->ring_tail].cmd[4],
 549                  (*dev->ring_buffer)[dev->ring_tail].cmd[5],
 550                  (*dev->ring_buffer)[dev->ring_tail].cmd[6],
 551                  (*dev->ring_buffer)[dev->ring_tail].cmd[7]);
 552
 553 #if BUFFERED_READS
 554         c = 0;
 555         while ((c < count) && (dev->ring_tail != dev->ring_head)) {
 556
 557 #if COMPRESS_WHEEL_EVENTS
 558                 next_tail = (dev->ring_tail+1) % ring_buffer_size;
 559                 if (dev->compress_wheel)
 560                         cancompress = 1;
 561                 while (dev->ring_head != next_tail && cancompress == 1) {
 562                         newwheel = (*dev->ring_buffer)[next_tail].cmd[6];
 563                         oldwheel = (*dev->ring_buffer)[dev->ring_tail].cmd[6];
 564                         /* if both are wheel events, and
 565                            no buttons have changes (FIXME, do I have to check?),
 566                            and we are the same sign, we can compress +- 7F
 567                         */
 568                         dbg_info(&dev->intf->dev,
 569                                 "%s: trying to compress: "
 570                                 "%02x%02x%02x%02x%02x%02x%02x%02x\n",
 571                                 __func__,
 572                                 (*dev->ring_buffer)[dev->ring_tail].cmd[0],
 573                                 (*dev->ring_buffer)[dev->ring_tail].cmd[1],
 574                                 (*dev->ring_buffer)[dev->ring_tail].cmd[2],
 575                                 (*dev->ring_buffer)[dev->ring_tail].cmd[3],
 576                                 (*dev->ring_buffer)[dev->ring_tail].cmd[4],
 577                                 (*dev->ring_buffer)[dev->ring_tail].cmd[5],
 578                                 (*dev->ring_buffer)[dev->ring_tail].cmd[6],
 579                                 (*dev->ring_buffer)[dev->ring_tail].cmd[7]);
 580
 581                         if (((*dev->ring_buffer)[dev->ring_tail].cmd[6] != 0 &&
 582                                 (*dev->ring_buffer)[next_tail].cmd[6] != 0) &&
 583                                 ((newwheel > 0 && oldwheel > 0) ||
 584                                         (newwheel < 0 && oldwheel < 0)) &&
 585                                 ((*dev->ring_buffer)[dev->ring_tail].cmd[2] ==
 586                                 (*dev->ring_buffer)[next_tail].cmd[2]) &&
 587                                 ((*dev->ring_buffer)[dev->ring_tail].cmd[3] ==
 588                                 (*dev->ring_buffer)[next_tail].cmd[3]) &&
 589                                 ((*dev->ring_buffer)[dev->ring_tail].cmd[4] ==
 590                                 (*dev->ring_buffer)[next_tail].cmd[4]) &&
 591                                 ((*dev->ring_buffer)[dev->ring_tail].cmd[5] ==
 592                                 (*dev->ring_buffer)[next_tail].cmd[5])) {
 593                                 dbg_info(&dev->intf->dev,
 594                                         "%s: should compress: "
 595                                         "%02x%02x%02x%02x%02x%02x%02x%02x\n",
 596                                         __func__,
 597                                         (*dev->ring_buffer)[dev->ring_tail].
 598                                         cmd[0],
 599                                         (*dev->ring_buffer)[dev->ring_tail].
 600                                         cmd[1],
 601                                         (*dev->ring_buffer)[dev->ring_tail].
 602                                         cmd[2],
 603                                         (*dev->ring_buffer)[dev->ring_tail].
 604                                         cmd[3],
 605                                         (*dev->ring_buffer)[dev->ring_tail].
 606                                         cmd[4],
 607                                         (*dev->ring_buffer)[dev->ring_tail].
 608                                         cmd[5],
 609                                         (*dev->ring_buffer)[dev->ring_tail].
 610                                         cmd[6],
 611                                         (*dev->ring_buffer)[dev->ring_tail].
 612                                         cmd[7]);
 613                                 newwheel += oldwheel;
 614                                 if (oldwheel > 0 && !(newwheel > 0)) {
 615                                         newwheel = 0x7f;
 616                                         cancompress = 0;
 617                                 }
 618                                 if (oldwheel < 0 && !(newwheel < 0)) {
 619                                         newwheel = 0x80;
 620                                         cancompress = 0;
 621                                 }
 622
 623                                 (*dev->ring_buffer)[next_tail].cmd[6] =
 624                                         newwheel;
 625                                 dev->ring_tail = next_tail;
 626                                 next_tail =
 627                                         (dev->ring_tail + 1) % ring_buffer_size;
 628                         } else {
 629                                 cancompress = 0;
 630                         }
 631                 }
 632 #endif /* COMPRESS_WHEEL_EVENTS */
 633                 if (copy_to_user(
 634                                 &buffer[c],
 635                                 &(*dev->ring_buffer)[dev->ring_tail], 8)) {
 636                         retval = -EFAULT;
 637                         goto unlock_exit;
 638                 }
 639                 dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size;
 640                 c += 8;
 641                 dbg_info(&dev->intf->dev,
 642                          "%s: head, tail are %x, %x\n",
 643                          __func__, dev->ring_head, dev->ring_tail);
 644         }
 645         retval = c;
 646
 647 #else
 648 /*  if (copy_to_user(buffer, &(*dev->ring_buffer)[dev->ring_tail], 8)) { */
 649         retval = -EFAULT;
 650         goto unlock_exit;
 651 }
 652
 653 dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size;
 654 dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n",
 655          __func__, dev->ring_head, dev->ring_tail);
 656
 657 retval = 8;
 658 #endif /* BUFFERED_READS */
 659
 660 unlock_exit:
 661 /* unlock the device */
 662 up(&dev->sem);
 663
 664 exit:
 665 return retval;
 666 }
 667
 668 /**
 669  *      usb_tranzport_write
 670  */
 671 static ssize_t usb_tranzport_write(struct file *file,
 672                                 const char __user *buffer, size_t count,
 673                                 loff_t *ppos)
 674 {
 675         struct usb_tranzport *dev;
 676         size_t bytes_to_write;
 677         int retval = 0;
 678
 679         dev = file->private_data;
 680
 681         /* verify that we actually have some data to write */
 682         if (count == 0)
 683                 goto exit;
 684
 685         /* lock this object */
 686         if (down_interruptible(&dev->sem)) {
 687                 retval = -ERESTARTSYS;
 688                 goto exit;
 689         }
 690         /* verify that the device wasn't unplugged */
 691         if (dev->intf == NULL) {
 692                 retval = -ENODEV;
 693                 err("No device or device unplugged %d\n", retval);
 694                 goto unlock_exit;
 695         }
 696
 697         /* wait until previous transfer is finished */
 698         if (dev->interrupt_out_busy) {
 699                 if (file->f_flags & O_NONBLOCK) {
 700                         retval = -EAGAIN;
 701                         goto unlock_exit;
 702                 }
 703                 retval = wait_event_interruptible(dev->write_wait,
 704                                                 !dev->interrupt_out_busy);
 705                 if (retval < 0)
 706                         goto unlock_exit;
 707         }
 708
 709         /* write the data into interrupt_out_buffer from userspace */
 710         bytes_to_write = min(count,
 711                         write_buffer_size *
 712                         dev->interrupt_out_endpoint_size);
 713         if (bytes_to_write < count)
 714                 dev_warn(&dev->intf->dev,
 715                         "Write buffer overflow, %zd bytes dropped\n",
 716                         count - bytes_to_write);
 717
 718         dbg_info(&dev->intf->dev,
 719                 "%s: count = %zd, bytes_to_write = %zd\n", __func__,
 720                 count, bytes_to_write);
 721
 722         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 723                 retval = -EFAULT;
 724                 goto unlock_exit;
 725         }
 726
 727         if (dev->interrupt_out_endpoint == NULL) {
 728                 err("Endpoint should not be be null! \n");
 729                 goto unlock_exit;
 730         }
 731
 732         /* send off the urb */
 733         usb_fill_int_urb(dev->interrupt_out_urb,
 734                         interface_to_usbdev(dev->intf),
 735                         usb_sndintpipe(interface_to_usbdev(dev->intf),
 736                                 dev->interrupt_out_endpoint->
 737                                 bEndpointAddress),
 738                         dev->interrupt_out_buffer, bytes_to_write,
 739                         usb_tranzport_interrupt_out_callback, dev,
 740                         dev->interrupt_out_interval);
 741
 742         dev->interrupt_out_busy = 1;
 743         wmb();
 744
 745         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 746         if (retval) {
 747                 dev->interrupt_out_busy = 0;
 748                 err("Couldn't submit interrupt_out_urb %d\n", retval);
 749                 goto unlock_exit;
 750         }
 751         retval = bytes_to_write;
 752
 753 unlock_exit:
 754         /* unlock the device */
 755         up(&dev->sem);
 756
 757 exit:
 758         return retval;
 759 }
 760
 761 /* file operations needed when we register this driver */
 762 static const struct file_operations usb_tranzport_fops = {
 763         .owner = THIS_MODULE,
 764         .read = usb_tranzport_read,
 765         .write = usb_tranzport_write,
 766         .open = usb_tranzport_open,
 767         .release = usb_tranzport_release,
 768         .poll = usb_tranzport_poll,
 769 };
 770
 771 /*
 772  * usb class driver info in order to get a minor number from the usb core,
 773  * and to have the device registered with the driver core
 774  */
 775 static struct usb_class_driver usb_tranzport_class = {
 776         .name = "tranzport%d",
 777         .fops = &usb_tranzport_fops,
 778         .minor_base = USB_TRANZPORT_MINOR_BASE,
 779 };
 780
 781 /**
 782  *      usb_tranzport_probe
 783  *
 784  *      Called by the usb core when a new device is connected that it thinks
 785  *      this driver might be interested in.
 786  */
 787 static int usb_tranzport_probe(struct usb_interface *intf,
 788                                const struct usb_device_id *id) {
 789         struct usb_device *udev = interface_to_usbdev(intf);
 790         struct usb_tranzport *dev = NULL;
 791         struct usb_host_interface *iface_desc;
 792         struct usb_endpoint_descriptor *endpoint;
 793         int i;
 794         int true_size;
 795         int retval = -ENOMEM;
 796
 797         /* allocate memory for our device state and intialize it */
 798
 799          dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 800         if (dev == NULL) {
 801                 dev_err(&intf->dev, "Out of memory\n");
 802                 goto exit;
 803         }
 804         init_MUTEX(&dev->sem);
 805         dev->intf = intf;
 806         init_waitqueue_head(&dev->read_wait);
 807         init_waitqueue_head(&dev->write_wait);
 808
 809         iface_desc = intf->cur_altsetting;
 810
 811         /* set up the endpoint information */
 812         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 813                 endpoint = &iface_desc->endpoint[i].desc;
 814
 815                 if (usb_endpoint_is_int_in(endpoint))
 816                         dev->interrupt_in_endpoint = endpoint;
 817
 818                 if (usb_endpoint_is_int_out(endpoint))
 819                         dev->interrupt_out_endpoint = endpoint;
 820         }
 821         if (dev->interrupt_in_endpoint == NULL) {
 822                 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 823                 goto error;
 824         }
 825         if (dev->interrupt_out_endpoint == NULL)
 826                 dev_warn(&intf->dev,
 827                         "Interrupt out endpoint not found"
 828                         "(using control endpoint instead)\n");
 829
 830         dev->interrupt_in_endpoint_size =
 831             le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
 832
 833         if (dev->interrupt_in_endpoint_size != 8)
 834                 dev_warn(&intf->dev, "Interrupt in endpoint size is not 8!\n");
 835
 836         if (ring_buffer_size == 0)
 837                 ring_buffer_size = RING_BUFFER_SIZE;
 838         true_size = min(ring_buffer_size, RING_BUFFER_SIZE);
 839
 840         /* FIXME - there are more usb_alloc routines for dma correctness.
 841            Needed? */
 842
 843         dev->ring_buffer =
 844             kmalloc((true_size * sizeof(struct tranzport_cmd)) + 8, GFP_KERNEL);
 845
 846         if (!dev->ring_buffer) {
 847                 dev_err(&intf->dev,
 848                         "Couldn't allocate ring_buffer size %d\n", true_size);
 849                 goto error;
 850         }
 851         dev->interrupt_in_buffer =
 852             kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 853         if (!dev->interrupt_in_buffer) {
 854                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_buffer\n");
 855                 goto error;
 856         }
 857         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 858         if (!dev->interrupt_in_urb) {
 859                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_urb\n");
 860                 goto error;
 861         }
 862         dev->interrupt_out_endpoint_size =
 863             dev->interrupt_out_endpoint ?
 864             le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize) :
 865             udev->descriptor.bMaxPacketSize0;
 866
 867         if (dev->interrupt_out_endpoint_size != 8)
 868                 dev_warn(&intf->dev,
 869                          "Interrupt out endpoint size is not 8!)\n");
 870
 871         dev->interrupt_out_buffer =
 872             kmalloc(write_buffer_size * dev->interrupt_out_endpoint_size,
 873                     GFP_KERNEL);
 874         if (!dev->interrupt_out_buffer) {
 875                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_buffer\n");
 876                 goto error;
 877         }
 878         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 879         if (!dev->interrupt_out_urb) {
 880                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_urb\n");
 881                 goto error;
 882         }
 883         dev->interrupt_in_interval =
 884             min_interrupt_in_interval >
 885             dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval
 886             : dev->interrupt_in_endpoint->bInterval;
 887
 888         if (dev->interrupt_out_endpoint) {
 889                 dev->interrupt_out_interval =
 890                     min_interrupt_out_interval >
 891                     dev->interrupt_out_endpoint->bInterval ?
 892                     min_interrupt_out_interval :
 893                     dev->interrupt_out_endpoint->bInterval;
 894         }
 895
 896         /* we can register the device now, as it is ready */
 897         usb_set_intfdata(intf, dev);
 898
 899         retval = usb_register_dev(intf, &usb_tranzport_class);
 900         if (retval) {
 901                 /* something prevented us from registering this driver */
 902                 dev_err(&intf->dev,
 903                         "Not able to get a minor for this device.\n");
 904                 usb_set_intfdata(intf, NULL);
 905                 goto error;
 906         }
 907
 908         retval = device_create_file(&intf->dev, &dev_attr_compress_wheel);
 909         if (retval)
 910                 goto error;
 911         retval = device_create_file(&intf->dev, &dev_attr_enable);
 912         if (retval)
 913                 goto error;
 914         retval = device_create_file(&intf->dev, &dev_attr_offline);
 915         if (retval)
 916                 goto error;
 917
 918         /* let the user know what node this device is now attached to */
 919         dev_info(&intf->dev,
 920                 "Tranzport Device #%d now attached to major %d minor %d\n",
 921                 (intf->minor - USB_TRANZPORT_MINOR_BASE), USB_MAJOR,
 922                 intf->minor);
 923
 924 exit:
 925         return retval;
 926
 927 error:
 928         usb_tranzport_delete(dev);
 929         return retval;
 930 }
 931
 932 /**
 933  *      usb_tranzport_disconnect
 934  *
 935  *      Called by the usb core when the device is removed from the system.
 936  */
 937 static void usb_tranzport_disconnect(struct usb_interface *intf)
 938 {
 939         struct usb_tranzport *dev;
 940         int minor;
 941         mutex_lock(&disconnect_mutex);
 942         dev = usb_get_intfdata(intf);
 943         usb_set_intfdata(intf, NULL);
 944         down(&dev->sem);
 945         minor = intf->minor;
 946         /* give back our minor */
 947         usb_deregister_dev(intf, &usb_tranzport_class);
 948
 949         /* if the device is not opened, then we clean up right now */
 950         if (!dev->open_count) {
 951                 up(&dev->sem);
 952                 usb_tranzport_delete(dev);
 953         } else {
 954                 dev->intf = NULL;
 955                 up(&dev->sem);
 956         }
 957
 958         mutex_unlock(&disconnect_mutex);
 959
 960         dev_info(&intf->dev, "Tranzport Surface #%d now disconnected\n",
 961                 (minor - USB_TRANZPORT_MINOR_BASE));
 962 }
 963
 964 /* usb specific object needed to register this driver with the usb subsystem */
 965 static struct usb_driver usb_tranzport_driver = {
 966         .name = "tranzport",
 967         .probe = usb_tranzport_probe,
 968         .disconnect = usb_tranzport_disconnect,
 969         .id_table = usb_tranzport_table,
 970 };
 971
 972 /**
 973  *      usb_tranzport_init
 974  */
 975 static int __init usb_tranzport_init(void)
 976 {
 977         int retval;
 978
 979         /* register this driver with the USB subsystem */
 980         retval = usb_register(&usb_tranzport_driver);
 981         if (retval)
 982                 err("usb_register failed for the " __FILE__
 983                         " driver. Error number %d\n", retval);
 984         return retval;
 985 }
 986 /**
 987  *      usb_tranzport_exit
 988  */
 989
 990 static void __exit usb_tranzport_exit(void)
 991 {
 992         /* deregister this driver with the USB subsystem */
 993         usb_deregister(&usb_tranzport_driver);
 994 }
 995
 996 module_init(usb_tranzport_init);
 997 module_exit(usb_tranzport_exit);