drivers/usb/misc/adutux.c

   1 /*
   2  * adutux - driver for ADU devices from Ontrak Control Systems
   3  * This is an experimental driver. Use at your own risk.
   4  * This driver is not supported by Ontrak Control Systems.
   5  *
   6  * Copyright (c) 2003 John Homppi (SCO, leave this notice here)
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * derived from the Lego USB Tower driver 0.56:
  14  * Copyright (c) 2003 David Glance <davidgsf@sourceforge.net>
  15  *               2001 Juergen Stuber <stuber@loria.fr>
  16  * that was derived from USB Skeleton driver - 0.5
  17  * Copyright (c) 2001 Greg Kroah-Hartman (greg@kroah.com)
  18  *
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/errno.h>
  23 #include <linux/init.h>
  24 #include <linux/slab.h>
  25 #include <linux/module.h>
  26 #include <linux/usb.h>
  27 #include <linux/mutex.h>
  28 #include <asm/uaccess.h>
  29
  30 #ifdef CONFIG_USB_DEBUG
  31 static int debug = 5;
  32 #else
  33 static int debug = 1;
  34 #endif
  35
  36 /* Use our own dbg macro */
  37 #undef dbg
  38 #define dbg(lvl, format, arg...)                                        \
  39 do {                                                                    \
  40         if (debug >= lvl)                                               \
  41                 printk(KERN_DEBUG "%s: " format "\n", __FILE__, ##arg); \
  42 } while (0)
  43
  44
  45 /* Version Information */
  46 #define DRIVER_VERSION "v0.0.13"
  47 #define DRIVER_AUTHOR "John Homppi"
  48 #define DRIVER_DESC "adutux (see www.ontrak.net)"
  49
  50 /* Module parameters */
  51 module_param(debug, int, S_IRUGO | S_IWUSR);
  52 MODULE_PARM_DESC(debug, "Debug enabled or not");
  53
  54 /* Define these values to match your device */
  55 #define ADU_VENDOR_ID 0x0a07
  56 #define ADU_PRODUCT_ID 0x0064
  57
  58 /* table of devices that work with this driver */
  59 static const struct usb_device_id device_table[] = {
  60         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID) },          /* ADU100 */
  61         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+20) },       /* ADU120 */
  62         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+30) },       /* ADU130 */
  63         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+100) },      /* ADU200 */
  64         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+108) },      /* ADU208 */
  65         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+118) },      /* ADU218 */
  66         { }/* Terminating entry */
  67 };
  68
  69 MODULE_DEVICE_TABLE(usb, device_table);
  70
  71 #ifdef CONFIG_USB_DYNAMIC_MINORS
  72 #define ADU_MINOR_BASE  0
  73 #else
  74 #define ADU_MINOR_BASE  67
  75 #endif
  76
  77 /* we can have up to this number of device plugged in at once */
  78 #define MAX_DEVICES     16
  79
  80 #define COMMAND_TIMEOUT (2*HZ)  /* 60 second timeout for a command */
  81
  82 /*
  83  * The locking scheme is a vanilla 3-lock:
  84  *   adu_device.buflock: A spinlock, covers what IRQs touch.
  85  *   adutux_mutex:       A Static lock to cover open_count. It would also cover
  86  *                       any globals, but we don't have them in 2.6.
  87  *   adu_device.mtx:     A mutex to hold across sleepers like copy_from_user.
  88  *                       It covers all of adu_device, except the open_count
  89  *                       and what .buflock covers.
  90  */
  91
  92 /* Structure to hold all of our device specific stuff */
  93 struct adu_device {
  94         struct mutex            mtx;
  95         struct usb_device*      udev; /* save off the usb device pointer */
  96         struct usb_interface*   interface;
  97         unsigned int            minor; /* the starting minor number for this device */
  98         char                    serial_number[8];
  99
 100         int                     open_count; /* number of times this port has been opened */
 101
 102         char*                   read_buffer_primary;
 103         int                     read_buffer_length;
 104         char*                   read_buffer_secondary;
 105         int                     secondary_head;
 106         int                     secondary_tail;
 107         spinlock_t              buflock;
 108
 109         wait_queue_head_t       read_wait;
 110         wait_queue_head_t       write_wait;
 111
 112         char*                   interrupt_in_buffer;
 113         struct usb_endpoint_descriptor* interrupt_in_endpoint;
 114         struct urb*             interrupt_in_urb;
 115         int                     read_urb_finished;
 116
 117         char*                   interrupt_out_buffer;
 118         struct usb_endpoint_descriptor* interrupt_out_endpoint;
 119         struct urb*             interrupt_out_urb;
 120         int                     out_urb_finished;
 121 };
 122
 123 static DEFINE_MUTEX(adutux_mutex);
 124
 125 static struct usb_driver adu_driver;
 126
 127 static void adu_debug_data(int level, const char *function, int size,
 128                            const unsigned char *data)
 129 {
 130         int i;
 131
 132         if (debug < level)
 133                 return;
 134
 135         printk(KERN_DEBUG "%s: %s - length = %d, data = ",
 136                __FILE__, function, size);
 137         for (i = 0; i < size; ++i)
 138                 printk("%.2x ", data[i]);
 139         printk("\n");
 140 }
 141
 142 /**
 143  * adu_abort_transfers
 144  *      aborts transfers and frees associated data structures
 145  */
 146 static void adu_abort_transfers(struct adu_device *dev)
 147 {
 148         unsigned long flags;
 149
 150         dbg(2," %s : enter", __func__);
 151
 152         if (dev->udev == NULL) {
 153                 dbg(1," %s : udev is null", __func__);
 154                 goto exit;
 155         }
 156
 157         /* shutdown transfer */
 158
 159         /* XXX Anchor these instead */
 160         spin_lock_irqsave(&dev->buflock, flags);
 161         if (!dev->read_urb_finished) {
 162                 spin_unlock_irqrestore(&dev->buflock, flags);
 163                 usb_kill_urb(dev->interrupt_in_urb);
 164         } else
 165                 spin_unlock_irqrestore(&dev->buflock, flags);
 166
 167         spin_lock_irqsave(&dev->buflock, flags);
 168         if (!dev->out_urb_finished) {
 169                 spin_unlock_irqrestore(&dev->buflock, flags);
 170                 usb_kill_urb(dev->interrupt_out_urb);
 171         } else
 172                 spin_unlock_irqrestore(&dev->buflock, flags);
 173
 174 exit:
 175         dbg(2," %s : leave", __func__);
 176 }
 177
 178 static void adu_delete(struct adu_device *dev)
 179 {
 180         dbg(2, "%s enter", __func__);
 181
 182         /* free data structures */
 183         usb_free_urb(dev->interrupt_in_urb);
 184         usb_free_urb(dev->interrupt_out_urb);
 185         kfree(dev->read_buffer_primary);
 186         kfree(dev->read_buffer_secondary);
 187         kfree(dev->interrupt_in_buffer);
 188         kfree(dev->interrupt_out_buffer);
 189         kfree(dev);
 190
 191         dbg(2, "%s : leave", __func__);
 192 }
 193
 194 static void adu_interrupt_in_callback(struct urb *urb)
 195 {
 196         struct adu_device *dev = urb->context;
 197         int status = urb->status;
 198
 199         dbg(4," %s : enter, status %d", __func__, status);
 200         adu_debug_data(5, __func__, urb->actual_length,
 201                        urb->transfer_buffer);
 202
 203         spin_lock(&dev->buflock);
 204
 205         if (status != 0) {
 206                 if ((status != -ENOENT) && (status != -ECONNRESET) &&
 207                         (status != -ESHUTDOWN)) {
 208                         dbg(1," %s : nonzero status received: %d",
 209                             __func__, status);
 210                 }
 211                 goto exit;
 212         }
 213
 214         if (urb->actual_length > 0 && dev->interrupt_in_buffer[0] != 0x00) {
 215                 if (dev->read_buffer_length <
 216                     (4 * usb_endpoint_maxp(dev->interrupt_in_endpoint)) -
 217                      (urb->actual_length)) {
 218                         memcpy (dev->read_buffer_primary +
 219                                 dev->read_buffer_length,
 220                                 dev->interrupt_in_buffer, urb->actual_length);
 221
 222                         dev->read_buffer_length += urb->actual_length;
 223                         dbg(2," %s reading  %d ", __func__,
 224                             urb->actual_length);
 225                 } else {
 226                         dbg(1," %s : read_buffer overflow", __func__);
 227                 }
 228         }
 229
 230 exit:
 231         dev->read_urb_finished = 1;
 232         spin_unlock(&dev->buflock);
 233         /* always wake up so we recover from errors */
 234         wake_up_interruptible(&dev->read_wait);
 235         adu_debug_data(5, __func__, urb->actual_length,
 236                        urb->transfer_buffer);
 237         dbg(4," %s : leave, status %d", __func__, status);
 238 }
 239
 240 static void adu_interrupt_out_callback(struct urb *urb)
 241 {
 242         struct adu_device *dev = urb->context;
 243         int status = urb->status;
 244
 245         dbg(4," %s : enter, status %d", __func__, status);
 246         adu_debug_data(5,__func__, urb->actual_length, urb->transfer_buffer);
 247
 248         if (status != 0) {
 249                 if ((status != -ENOENT) &&
 250                     (status != -ECONNRESET)) {
 251                         dbg(1, " %s :nonzero status received: %d",
 252                             __func__, status);
 253                 }
 254                 goto exit;
 255         }
 256
 257         spin_lock(&dev->buflock);
 258         dev->out_urb_finished = 1;
 259         wake_up(&dev->write_wait);
 260         spin_unlock(&dev->buflock);
 261 exit:
 262
 263         adu_debug_data(5, __func__, urb->actual_length,
 264                        urb->transfer_buffer);
 265         dbg(4," %s : leave, status %d", __func__, status);
 266 }
 267
 268 static int adu_open(struct inode *inode, struct file *file)
 269 {
 270         struct adu_device *dev = NULL;
 271         struct usb_interface *interface;
 272         int subminor;
 273         int retval;
 274
 275         dbg(2,"%s : enter", __func__);
 276
 277         subminor = iminor(inode);
 278
 279         if ((retval = mutex_lock_interruptible(&adutux_mutex))) {
 280                 dbg(2, "%s : mutex lock failed", __func__);
 281                 goto exit_no_lock;
 282         }
 283
 284         interface = usb_find_interface(&adu_driver, subminor);
 285         if (!interface) {
 286                 printk(KERN_ERR "adutux: %s - error, can't find device for "
 287                        "minor %d\n", __func__, subminor);
 288                 retval = -ENODEV;
 289                 goto exit_no_device;
 290         }
 291
 292         dev = usb_get_intfdata(interface);
 293         if (!dev || !dev->udev) {
 294                 retval = -ENODEV;
 295                 goto exit_no_device;
 296         }
 297
 298         /* check that nobody else is using the device */
 299         if (dev->open_count) {
 300                 retval = -EBUSY;
 301                 goto exit_no_device;
 302         }
 303
 304         ++dev->open_count;
 305         dbg(2,"%s : open count %d", __func__, dev->open_count);
 306
 307         /* save device in the file's private structure */
 308         file->private_data = dev;
 309
 310         /* initialize in direction */
 311         dev->read_buffer_length = 0;
 312
 313         /* fixup first read by having urb waiting for it */
 314         usb_fill_int_urb(dev->interrupt_in_urb,dev->udev,
 315                          usb_rcvintpipe(dev->udev,
 316                                         dev->interrupt_in_endpoint->bEndpointAddress),
 317                          dev->interrupt_in_buffer,
 318                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 319                          adu_interrupt_in_callback, dev,
 320                          dev->interrupt_in_endpoint->bInterval);
 321         dev->read_urb_finished = 0;
 322         if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL))
 323                 dev->read_urb_finished = 1;
 324         /* we ignore failure */
 325         /* end of fixup for first read */
 326
 327         /* initialize out direction */
 328         dev->out_urb_finished = 1;
 329
 330         retval = 0;
 331
 332 exit_no_device:
 333         mutex_unlock(&adutux_mutex);
 334 exit_no_lock:
 335         dbg(2,"%s : leave, return value %d ", __func__, retval);
 336         return retval;
 337 }
 338
 339 static void adu_release_internal(struct adu_device *dev)
 340 {
 341         dbg(2," %s : enter", __func__);
 342
 343         /* decrement our usage count for the device */
 344         --dev->open_count;
 345         dbg(2," %s : open count %d", __func__, dev->open_count);
 346         if (dev->open_count <= 0) {
 347                 adu_abort_transfers(dev);
 348                 dev->open_count = 0;
 349         }
 350
 351         dbg(2," %s : leave", __func__);
 352 }
 353
 354 static int adu_release(struct inode *inode, struct file *file)
 355 {
 356         struct adu_device *dev;
 357         int retval = 0;
 358
 359         dbg(2," %s : enter", __func__);
 360
 361         if (file == NULL) {
 362                 dbg(1," %s : file is NULL", __func__);
 363                 retval = -ENODEV;
 364                 goto exit;
 365         }
 366
 367         dev = file->private_data;
 368         if (dev == NULL) {
 369                 dbg(1," %s : object is NULL", __func__);
 370                 retval = -ENODEV;
 371                 goto exit;
 372         }
 373
 374         mutex_lock(&adutux_mutex); /* not interruptible */
 375
 376         if (dev->open_count <= 0) {
 377                 dbg(1," %s : device not opened", __func__);
 378                 retval = -ENODEV;
 379                 goto unlock;
 380         }
 381
 382         adu_release_internal(dev);
 383         if (dev->udev == NULL) {
 384                 /* the device was unplugged before the file was released */
 385                 if (!dev->open_count)   /* ... and we're the last user */
 386                         adu_delete(dev);
 387         }
 388 unlock:
 389         mutex_unlock(&adutux_mutex);
 390 exit:
 391         dbg(2," %s : leave, return value %d", __func__, retval);
 392         return retval;
 393 }
 394
 395 static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
 396                         loff_t *ppos)
 397 {
 398         struct adu_device *dev;
 399         size_t bytes_read = 0;
 400         size_t bytes_to_read = count;
 401         int i;
 402         int retval = 0;
 403         int timeout = 0;
 404         int should_submit = 0;
 405         unsigned long flags;
 406         DECLARE_WAITQUEUE(wait, current);
 407
 408         dbg(2," %s : enter, count = %Zd, file=%p", __func__, count, file);
 409
 410         dev = file->private_data;
 411         dbg(2," %s : dev=%p", __func__, dev);
 412
 413         if (mutex_lock_interruptible(&dev->mtx))
 414                 return -ERESTARTSYS;
 415
 416         /* verify that the device wasn't unplugged */
 417         if (dev->udev == NULL) {
 418                 retval = -ENODEV;
 419                 printk(KERN_ERR "adutux: No device or device unplugged %d\n",
 420                        retval);
 421                 goto exit;
 422         }
 423
 424         /* verify that some data was requested */
 425         if (count == 0) {
 426                 dbg(1," %s : read request of 0 bytes", __func__);
 427                 goto exit;
 428         }
 429
 430         timeout = COMMAND_TIMEOUT;
 431         dbg(2," %s : about to start looping", __func__);
 432         while (bytes_to_read) {
 433                 int data_in_secondary = dev->secondary_tail - dev->secondary_head;
 434                 dbg(2," %s : while, data_in_secondary=%d, status=%d",
 435                     __func__, data_in_secondary,
 436                     dev->interrupt_in_urb->status);
 437
 438                 if (data_in_secondary) {
 439                         /* drain secondary buffer */
 440                         int amount = bytes_to_read < data_in_secondary ? bytes_to_read : data_in_secondary;
 441                         i = copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount);
 442                         if (i) {
 443                                 retval = -EFAULT;
 444                                 goto exit;
 445                         }
 446                         dev->secondary_head += (amount - i);
 447                         bytes_read += (amount - i);
 448                         bytes_to_read -= (amount - i);
 449                         if (i) {
 450                                 retval = bytes_read ? bytes_read : -EFAULT;
 451                                 goto exit;
 452                         }
 453                 } else {
 454                         /* we check the primary buffer */
 455                         spin_lock_irqsave (&dev->buflock, flags);
 456                         if (dev->read_buffer_length) {
 457                                 /* we secure access to the primary */
 458                                 char *tmp;
 459                                 dbg(2," %s : swap, read_buffer_length = %d",
 460                                     __func__, dev->read_buffer_length);
 461                                 tmp = dev->read_buffer_secondary;
 462                                 dev->read_buffer_secondary = dev->read_buffer_primary;
 463                                 dev->read_buffer_primary = tmp;
 464                                 dev->secondary_head = 0;
 465                                 dev->secondary_tail = dev->read_buffer_length;
 466                                 dev->read_buffer_length = 0;
 467                                 spin_unlock_irqrestore(&dev->buflock, flags);
 468                                 /* we have a free buffer so use it */
 469                                 should_submit = 1;
 470                         } else {
 471                                 /* even the primary was empty - we may need to do IO */
 472                                 if (!dev->read_urb_finished) {
 473                                         /* somebody is doing IO */
 474                                         spin_unlock_irqrestore(&dev->buflock, flags);
 475                                         dbg(2," %s : submitted already", __func__);
 476                                 } else {
 477                                         /* we must initiate input */
 478                                         dbg(2," %s : initiate input", __func__);
 479                                         dev->read_urb_finished = 0;
 480                                         spin_unlock_irqrestore(&dev->buflock, flags);
 481
 482                                         usb_fill_int_urb(dev->interrupt_in_urb,dev->udev,
 483                                                          usb_rcvintpipe(dev->udev,
 484                                                                         dev->interrupt_in_endpoint->bEndpointAddress),
 485                                                          dev->interrupt_in_buffer,
 486                                                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 487                                                          adu_interrupt_in_callback,
 488                                                          dev,
 489                                                          dev->interrupt_in_endpoint->bInterval);
 490                                         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 491                                         if (retval) {
 492                                                 dev->read_urb_finished = 1;
 493                                                 if (retval == -ENOMEM) {
 494                                                         retval = bytes_read ? bytes_read : -ENOMEM;
 495                                                 }
 496                                                 dbg(2," %s : submit failed", __func__);
 497                                                 goto exit;
 498                                         }
 499                                 }
 500
 501                                 /* we wait for I/O to complete */
 502                                 set_current_state(TASK_INTERRUPTIBLE);
 503                                 add_wait_queue(&dev->read_wait, &wait);
 504                                 spin_lock_irqsave(&dev->buflock, flags);
 505                                 if (!dev->read_urb_finished) {
 506                                         spin_unlock_irqrestore(&dev->buflock, flags);
 507                                         timeout = schedule_timeout(COMMAND_TIMEOUT);
 508                                 } else {
 509                                         spin_unlock_irqrestore(&dev->buflock, flags);
 510                                         set_current_state(TASK_RUNNING);
 511                                 }
 512                                 remove_wait_queue(&dev->read_wait, &wait);
 513
 514                                 if (timeout <= 0) {
 515                                         dbg(2," %s : timeout", __func__);
 516                                         retval = bytes_read ? bytes_read : -ETIMEDOUT;
 517                                         goto exit;
 518                                 }
 519
 520                                 if (signal_pending(current)) {
 521                                         dbg(2," %s : signal pending", __func__);
 522                                         retval = bytes_read ? bytes_read : -EINTR;
 523                                         goto exit;
 524                                 }
 525                         }
 526                 }
 527         }
 528
 529         retval = bytes_read;
 530         /* if the primary buffer is empty then use it */
 531         spin_lock_irqsave(&dev->buflock, flags);
 532         if (should_submit && dev->read_urb_finished) {
 533                 dev->read_urb_finished = 0;
 534                 spin_unlock_irqrestore(&dev->buflock, flags);
 535                 usb_fill_int_urb(dev->interrupt_in_urb,dev->udev,
 536                                  usb_rcvintpipe(dev->udev,
 537                                                 dev->interrupt_in_endpoint->bEndpointAddress),
 538                                 dev->interrupt_in_buffer,
 539                                 usb_endpoint_maxp(dev->interrupt_in_endpoint),
 540                                 adu_interrupt_in_callback,
 541                                 dev,
 542                                 dev->interrupt_in_endpoint->bInterval);
 543                 if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL) != 0)
 544                         dev->read_urb_finished = 1;
 545                 /* we ignore failure */
 546         } else {
 547                 spin_unlock_irqrestore(&dev->buflock, flags);
 548         }
 549
 550 exit:
 551         /* unlock the device */
 552         mutex_unlock(&dev->mtx);
 553
 554         dbg(2," %s : leave, return value %d", __func__, retval);
 555         return retval;
 556 }
 557
 558 static ssize_t adu_write(struct file *file, const __user char *buffer,
 559                          size_t count, loff_t *ppos)
 560 {
 561         DECLARE_WAITQUEUE(waita, current);
 562         struct adu_device *dev;
 563         size_t bytes_written = 0;
 564         size_t bytes_to_write;
 565         size_t buffer_size;
 566         unsigned long flags;
 567         int retval;
 568
 569         dbg(2," %s : enter, count = %Zd", __func__, count);
 570
 571         dev = file->private_data;
 572
 573         retval = mutex_lock_interruptible(&dev->mtx);
 574         if (retval)
 575                 goto exit_nolock;
 576
 577         /* verify that the device wasn't unplugged */
 578         if (dev->udev == NULL) {
 579                 retval = -ENODEV;
 580                 printk(KERN_ERR "adutux: No device or device unplugged %d\n",
 581                        retval);
 582                 goto exit;
 583         }
 584
 585         /* verify that we actually have some data to write */
 586         if (count == 0) {
 587                 dbg(1," %s : write request of 0 bytes", __func__);
 588                 goto exit;
 589         }
 590
 591         while (count > 0) {
 592                 add_wait_queue(&dev->write_wait, &waita);
 593                 set_current_state(TASK_INTERRUPTIBLE);
 594                 spin_lock_irqsave(&dev->buflock, flags);
 595                 if (!dev->out_urb_finished) {
 596                         spin_unlock_irqrestore(&dev->buflock, flags);
 597
 598                         mutex_unlock(&dev->mtx);
 599                         if (signal_pending(current)) {
 600                                 dbg(1," %s : interrupted", __func__);
 601                                 set_current_state(TASK_RUNNING);
 602                                 retval = -EINTR;
 603                                 goto exit_onqueue;
 604                         }
 605                         if (schedule_timeout(COMMAND_TIMEOUT) == 0) {
 606                                 dbg(1, "%s - command timed out.", __func__);
 607                                 retval = -ETIMEDOUT;
 608                                 goto exit_onqueue;
 609                         }
 610                         remove_wait_queue(&dev->write_wait, &waita);
 611                         retval = mutex_lock_interruptible(&dev->mtx);
 612                         if (retval) {
 613                                 retval = bytes_written ? bytes_written : retval;
 614                                 goto exit_nolock;
 615                         }
 616
 617                         dbg(4," %s : in progress, count = %Zd", __func__, count);
 618                 } else {
 619                         spin_unlock_irqrestore(&dev->buflock, flags);
 620                         set_current_state(TASK_RUNNING);
 621                         remove_wait_queue(&dev->write_wait, &waita);
 622                         dbg(4," %s : sending, count = %Zd", __func__, count);
 623
 624                         /* write the data into interrupt_out_buffer from userspace */
 625                         buffer_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 626                         bytes_to_write = count > buffer_size ? buffer_size : count;
 627                         dbg(4," %s : buffer_size = %Zd, count = %Zd, bytes_to_write = %Zd",
 628                             __func__, buffer_size, count, bytes_to_write);
 629
 630                         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
 631                                 retval = -EFAULT;
 632                                 goto exit;
 633                         }
 634
 635                         /* send off the urb */
 636                         usb_fill_int_urb(
 637                                 dev->interrupt_out_urb,
 638                                 dev->udev,
 639                                 usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 640                                 dev->interrupt_out_buffer,
 641                                 bytes_to_write,
 642                                 adu_interrupt_out_callback,
 643                                 dev,
 644                                 dev->interrupt_out_endpoint->bInterval);
 645                         dev->interrupt_out_urb->actual_length = bytes_to_write;
 646                         dev->out_urb_finished = 0;
 647                         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 648                         if (retval < 0) {
 649                                 dev->out_urb_finished = 1;
 650                                 dev_err(&dev->udev->dev, "Couldn't submit "
 651                                         "interrupt_out_urb %d\n", retval);
 652                                 goto exit;
 653                         }
 654
 655                         buffer += bytes_to_write;
 656                         count -= bytes_to_write;
 657
 658                         bytes_written += bytes_to_write;
 659                 }
 660         }
 661         mutex_unlock(&dev->mtx);
 662         return bytes_written;
 663
 664 exit:
 665         mutex_unlock(&dev->mtx);
 666 exit_nolock:
 667         dbg(2," %s : leave, return value %d", __func__, retval);
 668         return retval;
 669
 670 exit_onqueue:
 671         remove_wait_queue(&dev->write_wait, &waita);
 672         return retval;
 673 }
 674
 675 /* file operations needed when we register this driver */
 676 static const struct file_operations adu_fops = {
 677         .owner = THIS_MODULE,
 678         .read  = adu_read,
 679         .write = adu_write,
 680         .open = adu_open,
 681         .release = adu_release,
 682         .llseek = noop_llseek,
 683 };
 684
 685 /*
 686  * usb class driver info in order to get a minor number from the usb core,
 687  * and to have the device registered with devfs and the driver core
 688  */
 689 static struct usb_class_driver adu_class = {
 690         .name = "usb/adutux%d",
 691         .fops = &adu_fops,
 692         .minor_base = ADU_MINOR_BASE,
 693 };
 694
 695 /**
 696  * adu_probe
 697  *
 698  * Called by the usb core when a new device is connected that it thinks
 699  * this driver might be interested in.
 700  */
 701 static int adu_probe(struct usb_interface *interface,
 702                      const struct usb_device_id *id)
 703 {
 704         struct usb_device *udev = interface_to_usbdev(interface);
 705         struct adu_device *dev = NULL;
 706         struct usb_host_interface *iface_desc;
 707         struct usb_endpoint_descriptor *endpoint;
 708         int retval = -ENODEV;
 709         int in_end_size;
 710         int out_end_size;
 711         int i;
 712
 713         dbg(2," %s : enter", __func__);
 714
 715         if (udev == NULL) {
 716                 dev_err(&interface->dev, "udev is NULL.\n");
 717                 goto exit;
 718         }
 719
 720         /* allocate memory for our device state and initialize it */
 721         dev = kzalloc(sizeof(struct adu_device), GFP_KERNEL);
 722         if (dev == NULL) {
 723                 dev_err(&interface->dev, "Out of memory\n");
 724                 retval = -ENOMEM;
 725                 goto exit;
 726         }
 727
 728         mutex_init(&dev->mtx);
 729         spin_lock_init(&dev->buflock);
 730         dev->udev = udev;
 731         init_waitqueue_head(&dev->read_wait);
 732         init_waitqueue_head(&dev->write_wait);
 733
 734         iface_desc = &interface->altsetting[0];
 735
 736         /* set up the endpoint information */
 737         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 738                 endpoint = &iface_desc->endpoint[i].desc;
 739
 740                 if (usb_endpoint_is_int_in(endpoint))
 741                         dev->interrupt_in_endpoint = endpoint;
 742
 743                 if (usb_endpoint_is_int_out(endpoint))
 744                         dev->interrupt_out_endpoint = endpoint;
 745         }
 746         if (dev->interrupt_in_endpoint == NULL) {
 747                 dev_err(&interface->dev, "interrupt in endpoint not found\n");
 748                 goto error;
 749         }
 750         if (dev->interrupt_out_endpoint == NULL) {
 751                 dev_err(&interface->dev, "interrupt out endpoint not found\n");
 752                 goto error;
 753         }
 754
 755         in_end_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 756         out_end_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 757
 758         dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
 759         if (!dev->read_buffer_primary) {
 760                 dev_err(&interface->dev, "Couldn't allocate read_buffer_primary\n");
 761                 retval = -ENOMEM;
 762                 goto error;
 763         }
 764
 765         /* debug code prime the buffer */
 766         memset(dev->read_buffer_primary, 'a', in_end_size);
 767         memset(dev->read_buffer_primary + in_end_size, 'b', in_end_size);
 768         memset(dev->read_buffer_primary + (2 * in_end_size), 'c', in_end_size);
 769         memset(dev->read_buffer_primary + (3 * in_end_size), 'd', in_end_size);
 770
 771         dev->read_buffer_secondary = kmalloc((4 * in_end_size), GFP_KERNEL);
 772         if (!dev->read_buffer_secondary) {
 773                 dev_err(&interface->dev, "Couldn't allocate read_buffer_secondary\n");
 774                 retval = -ENOMEM;
 775                 goto error;
 776         }
 777
 778         /* debug code prime the buffer */
 779         memset(dev->read_buffer_secondary, 'e', in_end_size);
 780         memset(dev->read_buffer_secondary + in_end_size, 'f', in_end_size);
 781         memset(dev->read_buffer_secondary + (2 * in_end_size), 'g', in_end_size);
 782         memset(dev->read_buffer_secondary + (3 * in_end_size), 'h', in_end_size);
 783
 784         dev->interrupt_in_buffer = kmalloc(in_end_size, GFP_KERNEL);
 785         if (!dev->interrupt_in_buffer) {
 786                 dev_err(&interface->dev, "Couldn't allocate interrupt_in_buffer\n");
 787                 goto error;
 788         }
 789
 790         /* debug code prime the buffer */
 791         memset(dev->interrupt_in_buffer, 'i', in_end_size);
 792
 793         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 794         if (!dev->interrupt_in_urb) {
 795                 dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
 796                 goto error;
 797         }
 798         dev->interrupt_out_buffer = kmalloc(out_end_size, GFP_KERNEL);
 799         if (!dev->interrupt_out_buffer) {
 800                 dev_err(&interface->dev, "Couldn't allocate interrupt_out_buffer\n");
 801                 goto error;
 802         }
 803         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 804         if (!dev->interrupt_out_urb) {
 805                 dev_err(&interface->dev, "Couldn't allocate interrupt_out_urb\n");
 806                 goto error;
 807         }
 808
 809         if (!usb_string(udev, udev->descriptor.iSerialNumber, dev->serial_number,
 810                         sizeof(dev->serial_number))) {
 811                 dev_err(&interface->dev, "Could not retrieve serial number\n");
 812                 goto error;
 813         }
 814         dbg(2," %s : serial_number=%s", __func__, dev->serial_number);
 815
 816         /* we can register the device now, as it is ready */
 817         usb_set_intfdata(interface, dev);
 818
 819         retval = usb_register_dev(interface, &adu_class);
 820
 821         if (retval) {
 822                 /* something prevented us from registering this driver */
 823                 dev_err(&interface->dev, "Not able to get a minor for this device.\n");
 824                 usb_set_intfdata(interface, NULL);
 825                 goto error;
 826         }
 827
 828         dev->minor = interface->minor;
 829
 830         /* let the user know what node this device is now attached to */
 831         dev_info(&interface->dev, "ADU%d %s now attached to /dev/usb/adutux%d\n",
 832                  udev->descriptor.idProduct, dev->serial_number,
 833                  (dev->minor - ADU_MINOR_BASE));
 834 exit:
 835         dbg(2," %s : leave, return value %p (dev)", __func__, dev);
 836
 837         return retval;
 838
 839 error:
 840         adu_delete(dev);
 841         return retval;
 842 }
 843
 844 /**
 845  * adu_disconnect
 846  *
 847  * Called by the usb core when the device is removed from the system.
 848  */
 849 static void adu_disconnect(struct usb_interface *interface)
 850 {
 851         struct adu_device *dev;
 852         int minor;
 853
 854         dbg(2," %s : enter", __func__);
 855
 856         dev = usb_get_intfdata(interface);
 857
 858         mutex_lock(&dev->mtx);  /* not interruptible */
 859         dev->udev = NULL;       /* poison */
 860         minor = dev->minor;
 861         usb_deregister_dev(interface, &adu_class);
 862         mutex_unlock(&dev->mtx);
 863
 864         mutex_lock(&adutux_mutex);
 865         usb_set_intfdata(interface, NULL);
 866
 867         /* if the device is not opened, then we clean up right now */
 868         dbg(2," %s : open count %d", __func__, dev->open_count);
 869         if (!dev->open_count)
 870                 adu_delete(dev);
 871
 872         mutex_unlock(&adutux_mutex);
 873
 874         dev_info(&interface->dev, "ADU device adutux%d now disconnected\n",
 875                  (minor - ADU_MINOR_BASE));
 876
 877         dbg(2," %s : leave", __func__);
 878 }
 879
 880 /* usb specific object needed to register this driver with the usb subsystem */
 881 static struct usb_driver adu_driver = {
 882         .name = "adutux",
 883         .probe = adu_probe,
 884         .disconnect = adu_disconnect,
 885         .id_table = device_table,
 886 };
 887
 888 static int __init adu_init(void)
 889 {
 890         int result;
 891
 892         dbg(2," %s : enter", __func__);
 893
 894         /* register this driver with the USB subsystem */
 895         result = usb_register(&adu_driver);
 896         if (result < 0) {
 897                 printk(KERN_ERR "usb_register failed for the "__FILE__
 898                        " driver. Error number %d\n", result);
 899                 goto exit;
 900         }
 901
 902         printk(KERN_INFO "adutux " DRIVER_DESC " " DRIVER_VERSION "\n");
 903         printk(KERN_INFO "adutux is an experimental driver. "
 904                "Use at your own risk\n");
 905
 906 exit:
 907         dbg(2," %s : leave, return value %d", __func__, result);
 908
 909         return result;
 910 }
 911
 912 static void __exit adu_exit(void)
 913 {
 914         dbg(2," %s : enter", __func__);
 915         /* deregister this driver with the USB subsystem */
 916         usb_deregister(&adu_driver);
 917         dbg(2," %s : leave", __func__);
 918 }
 919
 920 module_init(adu_init);
 921 module_exit(adu_exit);
 922
 923 MODULE_AUTHOR(DRIVER_AUTHOR);
 924 MODULE_DESCRIPTION(DRIVER_DESC);
 925 MODULE_LICENSE("GPL");