drivers/staging/frontier/alphatrack.c

   1 /*
   2  * Frontier Designs Alphatrack 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 30 commands for the alphatrack. 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/kobject.h>
  41 #include <linux/mutex.h>
  42 #include <linux/version.h>
  43
  44 #include <asm/uaccess.h>
  45 #include <linux/input.h>
  46 #include <linux/usb.h>
  47 #include <linux/poll.h>
  48
  49 #include "surface_sysfs.h"
  50
  51 /* make this work on older kernel versions */
  52
  53 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 19)
  54 #include "frontier_compat.h"
  55 #endif /* older kernel versions */
  56
  57 #include "alphatrack.h"
  58
  59 #define VENDOR_ID       0x165b
  60 #define PRODUCT_ID      0xfad1
  61
  62 #ifdef CONFIG_USB_DYNAMIC_MINORS
  63 #define USB_ALPHATRACK_MINOR_BASE       0
  64 #else
  65 // FIXME 176 - is another driver's minor - apply for that
  66 // #define USB_ALPHATRACK_MINOR_BASE    177
  67 #define USB_ALPHATRACK_MINOR_BASE       176
  68 #endif
  69
  70 /* table of devices that work with this driver */
  71 static struct usb_device_id usb_alphatrack_table [] = {
  72         { USB_DEVICE(VENDOR_ID, PRODUCT_ID) },
  73         { }                                     /* Terminating entry */
  74 };
  75
  76 MODULE_DEVICE_TABLE(usb, usb_alphatrack_table);
  77 MODULE_VERSION("0.40");
  78 MODULE_AUTHOR("Mike Taht <m@taht.net>");
  79 MODULE_DESCRIPTION("Alphatrack USB Driver");
  80 MODULE_LICENSE("GPL");
  81 MODULE_SUPPORTED_DEVICE("Frontier Designs Alphatrack Control Surface");
  82
  83 /* These aren't done yet */
  84
  85 #define SUPPRESS_EXTRA_ONLINE_EVENTS 0
  86 #define BUFFERED_WRITES 0
  87 #define SUPPRESS_EXTRA_OFFLINE_EVENTS 0
  88 #define COMPRESS_FADER_EVENTS 0
  89
  90 #define BUFFERED_READS 1
  91 #define RING_BUFFER_SIZE 512
  92 #define WRITE_BUFFER_SIZE 34
  93 #define ALPHATRACK_USB_TIMEOUT 10
  94 #define OUTPUT_CMD_SIZE 8
  95 #define INPUT_CMD_SIZE 12
  96
  97
  98 static int debug = 0;
  99
 100 /* Use our own dbg macro */
 101 #define dbg_info(dev, format, arg...) do { if (debug) dev_info(dev , format , ## arg); } while (0)
 102
 103 #if 0
 104 #define alphatrack_ocmd_info(dev, cmd, format, arg...) do { if (debug) ocmd_info(dev , cmd , format, ## arg); } while (0)
 105
 106 #define alphatrack_icmd_info(dev, cmd, format, arg...) do { if (debug) icmd_info(dev , cmd, format, ## arg); } while (0)
 107 #else
 108 #define alphatrack_ocmd_info(dev, cmd, format, arg...)
 109
 110 #define alphatrack_icmd_info(dev, cmd, format, arg...)
 111
 112 #endif
 113
 114 /* Module parameters */
 115
 116 module_param(debug, int, S_IRUGO | S_IWUSR);
 117 MODULE_PARM_DESC(debug, "Debug enabled or not");
 118
 119 /* All interrupt in transfers are collected in a ring buffer to
 120  * avoid racing conditions and get better performance of the driver.
 121  */
 122
 123 static int ring_buffer_size = RING_BUFFER_SIZE;
 124
 125 module_param(ring_buffer_size, int,  S_IRUGO);
 126 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size");
 127
 128 /* The write_buffer can one day contain more than one interrupt out transfer.
 129  */
 130
 131 static int write_buffer_size = WRITE_BUFFER_SIZE;
 132 module_param(write_buffer_size, int,  S_IRUGO);
 133 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
 134
 135 /*
 136  * Increase the interval for debugging purposes.
 137  * or set to 1 to use the standard interval from the endpoint descriptors.
 138  */
 139
 140 static int min_interrupt_in_interval = ALPHATRACK_USB_TIMEOUT;
 141 module_param(min_interrupt_in_interval, int, 0);
 142 MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
 143
 144 static int min_interrupt_out_interval = ALPHATRACK_USB_TIMEOUT;
 145 module_param(min_interrupt_out_interval, int, 0);
 146 MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
 147
 148
 149
 150 /* Structure to hold all of our device specific stuff */
 151
 152 struct usb_alphatrack {
 153         struct semaphore        sem;            /* locks this structure */
 154         struct usb_interface*   intf;           /* save off the usb interface pointer */
 155         int                     open_count;     /* number of times this port has been opened */
 156
 157         struct alphatrack_icmd  (*ring_buffer)[RING_BUFFER_SIZE]; /* just make c happy */
 158         struct alphatrack_ocmd  (*write_buffer)[WRITE_BUFFER_SIZE]; /* just make c happy */
 159         unsigned int            ring_head;
 160         unsigned int            ring_tail;
 161
 162         wait_queue_head_t       read_wait;
 163         wait_queue_head_t       write_wait;
 164
 165         unsigned char*          interrupt_in_buffer;
 166         unsigned char*          oldi_buffer;
 167         struct usb_endpoint_descriptor* interrupt_in_endpoint;
 168         struct urb*             interrupt_in_urb;
 169         int                     interrupt_in_interval;
 170         size_t                  interrupt_in_endpoint_size;
 171         int                     interrupt_in_running;
 172         int                     interrupt_in_done;
 173
 174         char*                   interrupt_out_buffer;
 175         struct usb_endpoint_descriptor* interrupt_out_endpoint;
 176         struct urb*             interrupt_out_urb;
 177         int                     interrupt_out_interval;
 178         size_t                  interrupt_out_endpoint_size;
 179         int                     interrupt_out_busy;
 180
 181         atomic_t writes_pending;
 182         int event; /* alternate interface to events */
 183         int fader; /* 10 bits */
 184         int lights; /* 23 bits */
 185         unsigned char dump_state; /* 0 if disabled 1 if enabled */
 186         unsigned char enable; /* 0 if disabled 1 if enabled */
 187         unsigned char offline; /* if the device is out of range or asleep */
 188         unsigned char verbose; /* be verbose in error reporting */
 189         unsigned char  last_cmd[OUTPUT_CMD_SIZE];
 190         unsigned char  screen[32];
 191 };
 192
 193 /* prevent races between open() and disconnect() */
 194 static DEFINE_MUTEX(disconnect_mutex);
 195
 196 /* forward declaration */
 197
 198 static struct usb_driver usb_alphatrack_driver;
 199
 200 static void icmd_info(struct usb_alphatrack *dev, char *cmd, char *str, char *a) {
 201 /*
 202 if (dev->verbose) {
 203 } else {
 204 }
 205 */
 206 }
 207
 208 static void ocmd_info(struct usb_alphatrack *dev, char *cmd, char *str, char* a) {
 209 /*
 210 if (dev->verbose) {
 211 } else {
 212 }
 213 */
 214 }
 215
 216
 217 /**
 218  *      usb_alphatrack_abort_transfers
 219  *      aborts transfers and frees associated data structures
 220  */
 221 static void usb_alphatrack_abort_transfers(struct usb_alphatrack *dev)
 222 {
 223         /* shutdown transfer */
 224         if (dev->interrupt_in_running) {
 225                 dev->interrupt_in_running = 0;
 226                 if (dev->intf)
 227                         usb_kill_urb(dev->interrupt_in_urb);
 228         }
 229         if (dev->interrupt_out_busy)
 230                 if (dev->intf)
 231                         usb_kill_urb(dev->interrupt_out_urb);
 232 }
 233
 234 /**
 235  *      usb_alphatrack_delete
 236  */
 237 static void usb_alphatrack_delete(struct usb_alphatrack *dev)
 238 {
 239         usb_alphatrack_abort_transfers(dev);
 240         usb_free_urb(dev->interrupt_in_urb);
 241         usb_free_urb(dev->interrupt_out_urb);
 242         kfree(dev->ring_buffer);
 243         kfree(dev->interrupt_in_buffer);
 244         kfree(dev->interrupt_out_buffer);
 245         kfree(dev); // fixme oldi_buffer
 246 }
 247
 248 /**
 249  *      usb_alphatrack_interrupt_in_callback
 250  */
 251
 252 static void usb_alphatrack_interrupt_in_callback(struct urb *urb)
 253 {
 254         struct usb_alphatrack *dev = urb->context;
 255         unsigned int next_ring_head;
 256         int retval = -1;
 257         int *iptr;
 258
 259         if (urb->status) {
 260                 if (urb->status == -ENOENT ||
 261                     urb->status == -ECONNRESET ||
 262                     urb->status == -ESHUTDOWN) {
 263                         goto exit;
 264                 } else {
 265                         dbg_info(&dev->intf->dev, "%s: nonzero status received: %d\n",
 266                                  __FUNCTION__, urb->status);
 267                         goto resubmit; /* maybe we can recover */
 268                 }
 269         }
 270
 271         if (urb->actual_length != INPUT_CMD_SIZE) {
 272                 dev_warn(&dev->intf->dev,
 273                          "Urb length was %d bytes!! Do something intelligent \n", urb->actual_length);
 274         } else {
 275                  alphatrack_ocmd_info(&dev->intf->dev,&(*dev->ring_buffer)[dev->ring_tail].cmd,"%s", "bla");
 276                  if(memcmp(dev->interrupt_in_buffer,dev->oldi_buffer,INPUT_CMD_SIZE)==0) {
 277                                                 goto resubmit;
 278                 }
 279                 memcpy(dev->oldi_buffer,dev->interrupt_in_buffer,INPUT_CMD_SIZE);
 280
 281 #if SUPPRESS_EXTRA_OFFLINE_EVENTS
 282         if(dev->offline == 2 && dev->interrupt_in_buffer[1] == 0xff) { goto resubmit; }
 283                 if(dev->offline == 1 && dev->interrupt_in_buffer[1] == 0xff) { dev->offline = 2; goto resubmit; }
 284 /* Always pass one offline event up the stack */
 285                 if(dev->offline > 0 && dev->interrupt_in_buffer[1] != 0xff) { dev->offline = 0; }
 286                 if(dev->offline == 0 && dev->interrupt_in_buffer[1] == 0xff) { dev->offline = 1; }
 287 #endif
 288                 dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n", __FUNCTION__,dev->ring_head,dev->ring_tail);
 289                 next_ring_head = (dev->ring_head+1) % ring_buffer_size;
 290
 291                 if (next_ring_head != dev->ring_tail) {
 292                         memcpy(&((*dev->ring_buffer)[dev->ring_head]),
 293                                                  dev->interrupt_in_buffer, urb->actual_length);
 294                         dev->ring_head = next_ring_head;
 295                         retval = 0;
 296                         memset(dev->interrupt_in_buffer, 0, urb->actual_length);
 297                 } else {
 298                         dev_warn(&dev->intf->dev,
 299                                  "Ring buffer overflow, %d bytes dropped\n",
 300                                  urb->actual_length);
 301                         memset(dev->interrupt_in_buffer, 0, urb->actual_length);
 302                 }
 303         }
 304
 305 resubmit:
 306         /* resubmit if we're still running */
 307         if (dev->interrupt_in_running && dev->intf) {
 308                 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 309                 if (retval)
 310                         dev_err(&dev->intf->dev,
 311                                 "usb_submit_urb failed (%d)\n", retval);
 312         }
 313
 314 exit:
 315         dev->interrupt_in_done = 1;
 316         wake_up_interruptible(&dev->read_wait);
 317 }
 318
 319 /**
 320  *      usb_alphatrack_interrupt_out_callback
 321  */
 322 static void usb_alphatrack_interrupt_out_callback(struct urb *urb)
 323 {
 324         struct usb_alphatrack *dev = urb->context;
 325
 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                          __FUNCTION__, urb->status);
 333         atomic_dec(&dev->writes_pending);
 334         dev->interrupt_out_busy = 0;
 335         wake_up_interruptible(&dev->write_wait);
 336 }
 337
 338 /**
 339  *      usb_alphatrack_open
 340  */
 341 static int usb_alphatrack_open(struct inode *inode, struct file *file)
 342 {
 343         struct usb_alphatrack *dev;
 344         int subminor;
 345         int retval = 0;
 346         struct usb_interface *interface;
 347
 348         nonseekable_open(inode, file);
 349         subminor = iminor(inode);
 350
 351         mutex_lock(&disconnect_mutex);
 352
 353         interface = usb_find_interface(&usb_alphatrack_driver, subminor);
 354
 355         if (!interface) {
 356                 err("%s - error, can't find device for minor %d\n",
 357                      __FUNCTION__, subminor);
 358                 retval = -ENODEV;
 359                 goto unlock_disconnect_exit;
 360         }
 361
 362         dev = usb_get_intfdata(interface);
 363
 364         if (!dev) {
 365                 retval = -ENODEV;
 366                 goto unlock_disconnect_exit;
 367         }
 368
 369         /* lock this device */
 370         if (down_interruptible(&dev->sem)) {
 371                 retval = -ERESTARTSYS;
 372                 goto unlock_disconnect_exit;
 373         }
 374
 375         /* allow opening only once */
 376         if (dev->open_count) {
 377                 retval = -EBUSY;
 378                 goto unlock_exit;
 379         }
 380         dev->open_count = 1;
 381
 382         /* initialize in direction */
 383         dev->ring_head = 0;
 384         dev->ring_tail = 0;
 385         usb_fill_int_urb(dev->interrupt_in_urb,
 386                          interface_to_usbdev(interface),
 387                          usb_rcvintpipe(interface_to_usbdev(interface),
 388                                         dev->interrupt_in_endpoint->bEndpointAddress),
 389                          dev->interrupt_in_buffer,
 390                          dev->interrupt_in_endpoint_size,
 391                          usb_alphatrack_interrupt_in_callback,
 392                          dev,
 393                          dev->interrupt_in_interval);
 394
 395         dev->interrupt_in_running = 1;
 396         dev->interrupt_in_done = 0;
 397         dev->enable = 1;
 398         dev->offline = 0;
 399
 400         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 401         if (retval) {
 402                 dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
 403                 dev->interrupt_in_running = 0;
 404                 dev->open_count = 0;
 405                 goto unlock_exit;
 406         }
 407
 408         /* save device in the file's private structure */
 409         file->private_data = dev;
 410
 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_alphatrack_release
 423  */
 424 static int usb_alphatrack_release(struct inode *inode, struct file *file)
 425 {
 426         struct usb_alphatrack *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_alphatrack_delete frees dev */
 450                 usb_alphatrack_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, !dev->interrupt_out_busy, 2 * HZ);
 458         usb_alphatrack_abort_transfers(dev);
 459         dev->open_count = 0;
 460
 461 unlock_exit:
 462         up(&dev->sem);
 463
 464 exit:
 465         return retval;
 466 }
 467
 468 /**
 469  *      usb_alphatrack_poll
 470  */
 471 static unsigned int usb_alphatrack_poll(struct file *file, poll_table *wait)
 472 {
 473         struct usb_alphatrack *dev;
 474         unsigned int mask = 0;
 475
 476         dev = file->private_data;
 477
 478         poll_wait(file, &dev->read_wait, wait);
 479         poll_wait(file, &dev->write_wait, wait);
 480
 481         if (dev->ring_head != dev->ring_tail)
 482                 mask |= POLLIN | POLLRDNORM;
 483         if (!dev->interrupt_out_busy)
 484                 mask |= POLLOUT | POLLWRNORM;
 485
 486         return mask;
 487 }
 488
 489 /**
 490  *      usb_alphatrack_read
 491  */
 492 static ssize_t usb_alphatrack_read(struct file *file, char __user *buffer, size_t count,
 493                            loff_t *ppos)
 494 {
 495         struct usb_alphatrack *dev;
 496         int retval = 0;
 497
 498         int c = 0;
 499
 500         dev = file->private_data;
 501
 502         /* verify that we actually have some data to read */
 503         if (count == 0)
 504                 goto exit;
 505
 506         /* lock this object */
 507         if (down_interruptible(&dev->sem)) {
 508                 retval = -ERESTARTSYS;
 509                 goto exit;
 510         }
 511
 512         /* verify that the device wasn't unplugged */
 513         if (dev->intf == NULL) {
 514                 retval = -ENODEV;
 515                 err("No device or device unplugged %d\n", retval);
 516                 goto unlock_exit;
 517         }
 518
 519         while (dev->ring_head == dev->ring_tail) {
 520                                         if (file->f_flags & O_NONBLOCK) {
 521                                                                         retval = -EAGAIN;
 522                                                                         goto unlock_exit;
 523                                         }
 524                                         dev->interrupt_in_done = 0 ;
 525                                         retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
 526                                         if (retval < 0) {
 527                                                                         goto unlock_exit;
 528                                         }
 529         }
 530
 531         alphatrack_ocmd_info(&dev->intf->dev, &(*dev->ring_buffer)[dev->ring_tail].cmd, "%s", ": copying to userspace");
 532
 533            c = 0;
 534            while((c < count) && (dev->ring_tail != dev->ring_head)) {
 535                                                  if (copy_to_user(&buffer[c], &(*dev->ring_buffer)[dev->ring_tail], INPUT_CMD_SIZE)) {
 536                                                                                  retval = -EFAULT;
 537                                                                                  goto unlock_exit;
 538                                                  }
 539                                                  dev->ring_tail = (dev->ring_tail+1) % ring_buffer_size;
 540                                                  c+=INPUT_CMD_SIZE;
 541                                                  dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n", __FUNCTION__,dev->ring_head,dev->ring_tail);
 542            }
 543            retval = c;
 544
 545 unlock_exit:
 546         /* unlock the device */
 547         up(&dev->sem);
 548
 549 exit:
 550         return retval;
 551 }
 552
 553 /**
 554  *      usb_alphatrack_write
 555  */
 556 static ssize_t usb_alphatrack_write(struct file *file, const char __user *buffer,
 557                             size_t count, loff_t *ppos)
 558 {
 559         struct usb_alphatrack *dev;
 560         size_t bytes_to_write;
 561         int retval = 0;
 562
 563         dev = file->private_data;
 564
 565         /* verify that we actually have some data to write */
 566         if (count == 0)
 567                 goto exit;
 568
 569         /* lock this object */
 570         if (down_interruptible(&dev->sem)) {
 571                 retval = -ERESTARTSYS;
 572                 goto exit;
 573         }
 574
 575         /* verify that the device wasn't unplugged */
 576         if (dev->intf == NULL) {
 577                 retval = -ENODEV;
 578                 err("No device or device unplugged %d\n", retval);
 579                 goto unlock_exit;
 580         }
 581
 582         /* wait until previous transfer is finished */
 583         if (dev->interrupt_out_busy) {
 584                 if (file->f_flags & O_NONBLOCK) {
 585                         retval = -EAGAIN;
 586                         goto unlock_exit;
 587                 }
 588                 retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
 589                 if (retval < 0) {
 590                         goto unlock_exit;
 591                 }
 592         }
 593
 594         /* write the data into interrupt_out_buffer from userspace */
 595   /* FIXME - if you write more than 12 bytes this breaks */
 596         bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
 597         if (bytes_to_write < count)
 598                 dev_warn(&dev->intf->dev, "Write buffer overflow, %zd bytes dropped\n",count-bytes_to_write);
 599
 600         dbg_info(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n", __FUNCTION__, count, bytes_to_write);
 601
 602         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 603                 retval = -EFAULT;
 604                 goto unlock_exit;
 605         }
 606
 607         if (dev->interrupt_out_endpoint == NULL) {
 608                 err("Endpoint should not be be null! \n");
 609                 goto unlock_exit;
 610         }
 611
 612         /* send off the urb */
 613         usb_fill_int_urb(dev->interrupt_out_urb,
 614                          interface_to_usbdev(dev->intf),
 615                          usb_sndintpipe(interface_to_usbdev(dev->intf),
 616                                         dev->interrupt_out_endpoint->bEndpointAddress),
 617                          dev->interrupt_out_buffer,
 618                          bytes_to_write,
 619                          usb_alphatrack_interrupt_out_callback,
 620                          dev,
 621                          dev->interrupt_out_interval);
 622         dev->interrupt_out_busy = 1;
 623         atomic_inc(&dev->writes_pending);
 624         wmb();
 625
 626         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 627         if (retval) {
 628                 dev->interrupt_out_busy = 0;
 629                 err("Couldn't submit interrupt_out_urb %d\n", retval);
 630                 atomic_dec(&dev->writes_pending);
 631                 goto unlock_exit;
 632         }
 633         retval = bytes_to_write;
 634
 635 unlock_exit:
 636         /* unlock the device */
 637         up(&dev->sem);
 638
 639 exit:
 640         return retval;
 641 }
 642
 643 /* file operations needed when we register this driver */
 644 static const struct file_operations usb_alphatrack_fops = {
 645         .owner =        THIS_MODULE,
 646         .read  =        usb_alphatrack_read,
 647         .write =        usb_alphatrack_write,
 648         .open =         usb_alphatrack_open,
 649         .release =      usb_alphatrack_release,
 650         .poll =         usb_alphatrack_poll,
 651 };
 652
 653 /*
 654  * usb class driver info in order to get a minor number from the usb core,
 655  * and to have the device registered with the driver core
 656  */
 657
 658 static struct usb_class_driver usb_alphatrack_class = {
 659         .name =         "alphatrack%d",
 660         .fops =         &usb_alphatrack_fops,
 661         .minor_base =   USB_ALPHATRACK_MINOR_BASE,
 662 };
 663
 664
 665 /**
 666  *      usb_alphatrack_probe
 667  *
 668  *      Called by the usb core when a new device is connected that it thinks
 669  *      this driver might be interested in.
 670  */
 671 static int usb_alphatrack_probe(struct usb_interface *intf, const struct usb_device_id *id)
 672 {
 673         struct usb_device *udev = interface_to_usbdev(intf);
 674         struct usb_alphatrack *dev = NULL;
 675         struct usb_host_interface *iface_desc;
 676         struct usb_endpoint_descriptor *endpoint;
 677         int i;
 678         int true_size;
 679         int retval = -ENOMEM;
 680
 681         /* allocate memory for our device state and intialize it */
 682
 683         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 684         if (dev == NULL) {
 685                 dev_err(&intf->dev, "Out of memory\n");
 686                 goto exit;
 687         }
 688         init_MUTEX(&dev->sem);
 689         dev->intf = intf;
 690         init_waitqueue_head(&dev->read_wait);
 691         init_waitqueue_head(&dev->write_wait);
 692
 693         iface_desc = intf->cur_altsetting;
 694
 695         /* set up the endpoint information */
 696         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 697                 endpoint = &iface_desc->endpoint[i].desc;
 698
 699                 if (usb_endpoint_is_int_in(endpoint))
 700                         dev->interrupt_in_endpoint = endpoint;
 701
 702                 if (usb_endpoint_is_int_out(endpoint))
 703                         dev->interrupt_out_endpoint = endpoint;
 704         }
 705         if (dev->interrupt_in_endpoint == NULL) {
 706                 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 707                 goto error;
 708         }
 709         if (dev->interrupt_out_endpoint == NULL)
 710                 dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
 711
 712         dev->interrupt_in_endpoint_size = le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
 713
 714         if (dev->interrupt_in_endpoint_size != 64)
 715             dev_warn(&intf->dev, "Interrupt in endpoint size is not 64!\n");
 716
 717         if(ring_buffer_size == 0) { ring_buffer_size = RING_BUFFER_SIZE; }
 718
 719         true_size = min(ring_buffer_size,RING_BUFFER_SIZE);
 720
 721         /* FIXME - there are more usb_alloc routines for dma correctness. Needed? */
 722
 723 //      dev->ring_buffer = kmalloc((true_size*sizeof(struct alphatrack_icmd))+12, GFP_KERNEL);
 724         dev->ring_buffer = kmalloc((true_size*sizeof(struct alphatrack_icmd)), GFP_KERNEL);
 725
 726         if (!dev->ring_buffer) {
 727                 dev_err(&intf->dev, "Couldn't allocate input ring_buffer of size %d\n",true_size);
 728                 goto error;
 729         }
 730
 731         dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 732
 733         if (!dev->interrupt_in_buffer) {
 734                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_buffer\n");
 735                 goto error;
 736         }
 737         dev->oldi_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 738         if (!dev->oldi_buffer) {
 739                 dev_err(&intf->dev, "Couldn't allocate old buffer\n");
 740                 goto error;
 741         }
 742         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 743         if (!dev->interrupt_in_urb) {
 744                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_urb\n");
 745                 goto error;
 746         }
 747
 748         dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize) :
 749                                                                          udev->descriptor.bMaxPacketSize0;
 750
 751         if (dev->interrupt_out_endpoint_size !=64)
 752                 dev_warn(&intf->dev, "Interrupt out endpoint size is not 64!)\n");
 753
 754         if(write_buffer_size == 0) { write_buffer_size = WRITE_BUFFER_SIZE; }
 755         true_size = min(write_buffer_size,WRITE_BUFFER_SIZE);
 756
 757         dev->interrupt_out_buffer = kmalloc(true_size*dev->interrupt_out_endpoint_size, GFP_KERNEL);
 758
 759         if (!dev->interrupt_out_buffer) {
 760                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_buffer\n");
 761                 goto error;
 762         }
 763
 764         dev->write_buffer = kmalloc(sizeof(struct alphatrack_ocmd)*true_size, GFP_KERNEL);
 765
 766         if (!dev->write_buffer) {
 767                 dev_err(&intf->dev, "Couldn't allocate write_buffer \n");
 768                 goto error;
 769         }
 770
 771         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 772         if (!dev->interrupt_out_urb) {
 773                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_urb\n");
 774                 goto error;
 775         }
 776         dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 777         if (dev->interrupt_out_endpoint)
 778                 dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 779
 780         /* we can register the device now, as it is ready */
 781         usb_set_intfdata(intf, dev);
 782
 783         atomic_set(&dev->writes_pending,0);
 784         retval = usb_register_dev(intf, &usb_alphatrack_class);
 785         if (retval) {
 786                 /* something prevented us from registering this driver */
 787                 dev_err(&intf->dev, "Not able to get a minor for this device.\n");
 788                 usb_set_intfdata(intf, NULL);
 789                 goto error;
 790         }
 791
 792         /* let the user know what node this device is now attached to */
 793         dev_info(&intf->dev, "Alphatrack Device #%d now attached to major %d minor %d\n",
 794                 (intf->minor - USB_ALPHATRACK_MINOR_BASE), USB_MAJOR, intf->minor);
 795
 796 exit:
 797         return retval;
 798
 799 error:
 800         usb_alphatrack_delete(dev);
 801
 802         return retval;
 803 }
 804
 805 /**
 806  *      usb_alphatrack_disconnect
 807  *
 808  *      Called by the usb core when the device is removed from the system.
 809  */
 810 static void usb_alphatrack_disconnect(struct usb_interface *intf)
 811 {
 812         struct usb_alphatrack *dev;
 813         int minor;
 814
 815         mutex_lock(&disconnect_mutex);
 816
 817         dev = usb_get_intfdata(intf);
 818         usb_set_intfdata(intf, NULL);
 819
 820         down(&dev->sem);
 821
 822         minor = intf->minor;
 823
 824         /* give back our minor */
 825         usb_deregister_dev(intf, &usb_alphatrack_class);
 826
 827         /* if the device is not opened, then we clean up right now */
 828         if (!dev->open_count) {
 829                 up(&dev->sem);
 830                 usb_alphatrack_delete(dev);
 831         } else {
 832                 dev->intf = NULL;
 833                 up(&dev->sem);
 834         }
 835
 836         atomic_set(&dev->writes_pending,0);
 837         mutex_unlock(&disconnect_mutex);
 838
 839         dev_info(&intf->dev, "Alphatrack Surface #%d now disconnected\n",
 840                  (minor - USB_ALPHATRACK_MINOR_BASE));
 841 }
 842
 843 /* usb specific object needed to register this driver with the usb subsystem */
 844 static struct usb_driver usb_alphatrack_driver = {
 845         .name =         "alphatrack",
 846         .probe =        usb_alphatrack_probe,
 847         .disconnect =   usb_alphatrack_disconnect,
 848         .id_table =     usb_alphatrack_table,
 849 };
 850
 851 /**
 852  *      usb_alphatrack_init
 853  */
 854 static int __init usb_alphatrack_init(void)
 855 {
 856         int retval;
 857
 858         /* register this driver with the USB subsystem */
 859         retval = usb_register(&usb_alphatrack_driver);
 860         if (retval)
 861                 err("usb_register failed for the "__FILE__" driver. Error number %d\n", retval);
 862
 863         return retval;
 864 }
 865
 866 /**
 867  *      usb_alphatrack_exit
 868  */
 869 static void __exit usb_alphatrack_exit(void)
 870 {
 871         /* deregister this driver with the USB subsystem */
 872         usb_deregister(&usb_alphatrack_driver);
 873 }
 874
 875 module_init(usb_alphatrack_init);
 876 module_exit(usb_alphatrack_exit);
 877