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