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 <linux/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         retval = mutex_lock_interruptible(&adutux_mutex);
 280         if (retval) {
 281                 dbg(2, "%s : mutex lock failed", __func__);
 282                 goto exit_no_lock;
 283         }
 284
 285         interface = usb_find_interface(&adu_driver, subminor);
 286         if (!interface) {
 287                 printk(KERN_ERR "adutux: %s - error, can't find device for "
 288                        "minor %d\n", __func__, subminor);
 289                 retval = -ENODEV;
 290                 goto exit_no_device;
 291         }
 292
 293         dev = usb_get_intfdata(interface);
 294         if (!dev || !dev->udev) {
 295                 retval = -ENODEV;
 296                 goto exit_no_device;
 297         }
 298
 299         /* check that nobody else is using the device */
 300         if (dev->open_count) {
 301                 retval = -EBUSY;
 302                 goto exit_no_device;
 303         }
 304
 305         ++dev->open_count;
 306         dbg(2, "%s : open count %d", __func__, dev->open_count);
 307
 308         /* save device in the file's private structure */
 309         file->private_data = dev;
 310
 311         /* initialize in direction */
 312         dev->read_buffer_length = 0;
 313
 314         /* fixup first read by having urb waiting for it */
 315         usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 316                          usb_rcvintpipe(dev->udev,
 317                                         dev->interrupt_in_endpoint->bEndpointAddress),
 318                          dev->interrupt_in_buffer,
 319                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 320                          adu_interrupt_in_callback, dev,
 321                          dev->interrupt_in_endpoint->bInterval);
 322         dev->read_urb_finished = 0;
 323         if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL))
 324                 dev->read_urb_finished = 1;
 325         /* we ignore failure */
 326         /* end of fixup for first read */
 327
 328         /* initialize out direction */
 329         dev->out_urb_finished = 1;
 330
 331         retval = 0;
 332
 333 exit_no_device:
 334         mutex_unlock(&adutux_mutex);
 335 exit_no_lock:
 336         dbg(2, "%s : leave, return value %d ", __func__, retval);
 337         return retval;
 338 }
 339
 340 static void adu_release_internal(struct adu_device *dev)
 341 {
 342         dbg(2, " %s : enter", __func__);
 343
 344         /* decrement our usage count for the device */
 345         --dev->open_count;
 346         dbg(2, " %s : open count %d", __func__, dev->open_count);
 347         if (dev->open_count <= 0) {
 348                 adu_abort_transfers(dev);
 349                 dev->open_count = 0;
 350         }
 351
 352         dbg(2, " %s : leave", __func__);
 353 }
 354
 355 static int adu_release(struct inode *inode, struct file *file)
 356 {
 357         struct adu_device *dev;
 358         int retval = 0;
 359
 360         dbg(2, " %s : enter", __func__);
 361
 362         if (file == NULL) {
 363                 dbg(1, " %s : file is NULL", __func__);
 364                 retval = -ENODEV;
 365                 goto exit;
 366         }
 367
 368         dev = file->private_data;
 369         if (dev == NULL) {
 370                 dbg(1, " %s : object is NULL", __func__);
 371                 retval = -ENODEV;
 372                 goto exit;
 373         }
 374
 375         mutex_lock(&adutux_mutex); /* not interruptible */
 376
 377         if (dev->open_count <= 0) {
 378                 dbg(1, " %s : device not opened", __func__);
 379                 retval = -ENODEV;
 380                 goto unlock;
 381         }
 382
 383         adu_release_internal(dev);
 384         if (dev->udev == NULL) {
 385                 /* the device was unplugged before the file was released */
 386                 if (!dev->open_count)   /* ... and we're the last user */
 387                         adu_delete(dev);
 388         }
 389 unlock:
 390         mutex_unlock(&adutux_mutex);
 391 exit:
 392         dbg(2, " %s : leave, return value %d", __func__, retval);
 393         return retval;
 394 }
 395
 396 static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
 397                         loff_t *ppos)
 398 {
 399         struct adu_device *dev;
 400         size_t bytes_read = 0;
 401         size_t bytes_to_read = count;
 402         int i;
 403         int retval = 0;
 404         int timeout = 0;
 405         int should_submit = 0;
 406         unsigned long flags;
 407         DECLARE_WAITQUEUE(wait, current);
 408
 409         dbg(2, " %s : enter, count = %Zd, file=%p", __func__, count, file);
 410
 411         dev = file->private_data;
 412         dbg(2, " %s : dev=%p", __func__, dev);
 413
 414         if (mutex_lock_interruptible(&dev->mtx))
 415                 return -ERESTARTSYS;
 416
 417         /* verify that the device wasn't unplugged */
 418         if (dev->udev == NULL) {
 419                 retval = -ENODEV;
 420                 printk(KERN_ERR "adutux: No device or device unplugged %d\n",
 421                        retval);
 422                 goto exit;
 423         }
 424
 425         /* verify that some data was requested */
 426         if (count == 0) {
 427                 dbg(1, " %s : read request of 0 bytes", __func__);
 428                 goto exit;
 429         }
 430
 431         timeout = COMMAND_TIMEOUT;
 432         dbg(2, " %s : about to start looping", __func__);
 433         while (bytes_to_read) {
 434                 int data_in_secondary = dev->secondary_tail - dev->secondary_head;
 435                 dbg(2, " %s : while, data_in_secondary=%d, status=%d",
 436                     __func__, data_in_secondary,
 437                     dev->interrupt_in_urb->status);
 438
 439                 if (data_in_secondary) {
 440                         /* drain secondary buffer */
 441                         int amount = bytes_to_read < data_in_secondary ? bytes_to_read : data_in_secondary;
 442                         i = copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount);
 443                         if (i) {
 444                                 retval = -EFAULT;
 445                                 goto exit;
 446                         }
 447                         dev->secondary_head += (amount - i);
 448                         bytes_read += (amount - i);
 449                         bytes_to_read -= (amount - i);
 450                         if (i) {
 451                                 retval = bytes_read ? bytes_read : -EFAULT;
 452                                 goto exit;
 453                         }
 454                 } else {
 455                         /* we check the primary buffer */
 456                         spin_lock_irqsave (&dev->buflock, flags);
 457                         if (dev->read_buffer_length) {
 458                                 /* we secure access to the primary */
 459                                 char *tmp;
 460                                 dbg(2, " %s : swap, read_buffer_length = %d",
 461                                     __func__, dev->read_buffer_length);
 462                                 tmp = dev->read_buffer_secondary;
 463                                 dev->read_buffer_secondary = dev->read_buffer_primary;
 464                                 dev->read_buffer_primary = tmp;
 465                                 dev->secondary_head = 0;
 466                                 dev->secondary_tail = dev->read_buffer_length;
 467                                 dev->read_buffer_length = 0;
 468                                 spin_unlock_irqrestore(&dev->buflock, flags);
 469                                 /* we have a free buffer so use it */
 470                                 should_submit = 1;
 471                         } else {
 472                                 /* even the primary was empty - we may need to do IO */
 473                                 if (!dev->read_urb_finished) {
 474                                         /* somebody is doing IO */
 475                                         spin_unlock_irqrestore(&dev->buflock, flags);
 476                                         dbg(2, " %s : submitted already", __func__);
 477                                 } else {
 478                                         /* we must initiate input */
 479                                         dbg(2, " %s : initiate input", __func__);
 480                                         dev->read_urb_finished = 0;
 481                                         spin_unlock_irqrestore(&dev->buflock, flags);
 482
 483                                         usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 484                                                         usb_rcvintpipe(dev->udev,
 485                                                                 dev->interrupt_in_endpoint->bEndpointAddress),
 486                                                          dev->interrupt_in_buffer,
 487                                                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 488                                                          adu_interrupt_in_callback,
 489                                                          dev,
 490                                                          dev->interrupt_in_endpoint->bInterval);
 491                                         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 492                                         if (retval) {
 493                                                 dev->read_urb_finished = 1;
 494                                                 if (retval == -ENOMEM) {
 495                                                         retval = bytes_read ? bytes_read : -ENOMEM;
 496                                                 }
 497                                                 dbg(2, " %s : submit failed", __func__);
 498                                                 goto exit;
 499                                         }
 500                                 }
 501
 502                                 /* we wait for I/O to complete */
 503                                 set_current_state(TASK_INTERRUPTIBLE);
 504                                 add_wait_queue(&dev->read_wait, &wait);
 505                                 spin_lock_irqsave(&dev->buflock, flags);
 506                                 if (!dev->read_urb_finished) {
 507                                         spin_unlock_irqrestore(&dev->buflock, flags);
 508                                         timeout = schedule_timeout(COMMAND_TIMEOUT);
 509                                 } else {
 510                                         spin_unlock_irqrestore(&dev->buflock, flags);
 511                                         set_current_state(TASK_RUNNING);
 512                                 }
 513                                 remove_wait_queue(&dev->read_wait, &wait);
 514
 515                                 if (timeout <= 0) {
 516                                         dbg(2, " %s : timeout", __func__);
 517                                         retval = bytes_read ? bytes_read : -ETIMEDOUT;
 518                                         goto exit;
 519                                 }
 520
 521                                 if (signal_pending(current)) {
 522                                         dbg(2, " %s : signal pending", __func__);
 523                                         retval = bytes_read ? bytes_read : -EINTR;
 524                                         goto exit;
 525                                 }
 526                         }
 527                 }
 528         }
 529
 530         retval = bytes_read;
 531         /* if the primary buffer is empty then use it */
 532         spin_lock_irqsave(&dev->buflock, flags);
 533         if (should_submit && dev->read_urb_finished) {
 534                 dev->read_urb_finished = 0;
 535                 spin_unlock_irqrestore(&dev->buflock, flags);
 536                 usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 537                                  usb_rcvintpipe(dev->udev,
 538                                         dev->interrupt_in_endpoint->bEndpointAddress),
 539                                 dev->interrupt_in_buffer,
 540                                 usb_endpoint_maxp(dev->interrupt_in_endpoint),
 541                                 adu_interrupt_in_callback,
 542                                 dev,
 543                                 dev->interrupt_in_endpoint->bInterval);
 544                 if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL) != 0)
 545                         dev->read_urb_finished = 1;
 546                 /* we ignore failure */
 547         } else {
 548                 spin_unlock_irqrestore(&dev->buflock, flags);
 549         }
 550
 551 exit:
 552         /* unlock the device */
 553         mutex_unlock(&dev->mtx);
 554
 555         dbg(2, " %s : leave, return value %d", __func__, retval);
 556         return retval;
 557 }
 558
 559 static ssize_t adu_write(struct file *file, const __user char *buffer,
 560                          size_t count, loff_t *ppos)
 561 {
 562         DECLARE_WAITQUEUE(waita, current);
 563         struct adu_device *dev;
 564         size_t bytes_written = 0;
 565         size_t bytes_to_write;
 566         size_t buffer_size;
 567         unsigned long flags;
 568         int retval;
 569
 570         dbg(2, " %s : enter, count = %Zd", __func__, count);
 571
 572         dev = file->private_data;
 573
 574         retval = mutex_lock_interruptible(&dev->mtx);
 575         if (retval)
 576                 goto exit_nolock;
 577
 578         /* verify that the device wasn't unplugged */
 579         if (dev->udev == NULL) {
 580                 retval = -ENODEV;
 581                 printk(KERN_ERR "adutux: No device or device unplugged %d\n",
 582                        retval);
 583                 goto exit;
 584         }
 585
 586         /* verify that we actually have some data to write */
 587         if (count == 0) {
 588                 dbg(1, " %s : write request of 0 bytes", __func__);
 589                 goto exit;
 590         }
 591
 592         while (count > 0) {
 593                 add_wait_queue(&dev->write_wait, &waita);
 594                 set_current_state(TASK_INTERRUPTIBLE);
 595                 spin_lock_irqsave(&dev->buflock, flags);
 596                 if (!dev->out_urb_finished) {
 597                         spin_unlock_irqrestore(&dev->buflock, flags);
 598
 599                         mutex_unlock(&dev->mtx);
 600                         if (signal_pending(current)) {
 601                                 dbg(1, " %s : interrupted", __func__);
 602                                 set_current_state(TASK_RUNNING);
 603                                 retval = -EINTR;
 604                                 goto exit_onqueue;
 605                         }
 606                         if (schedule_timeout(COMMAND_TIMEOUT) == 0) {
 607                                 dbg(1, "%s - command timed out.", __func__);
 608                                 retval = -ETIMEDOUT;
 609                                 goto exit_onqueue;
 610                         }
 611                         remove_wait_queue(&dev->write_wait, &waita);
 612                         retval = mutex_lock_interruptible(&dev->mtx);
 613                         if (retval) {
 614                                 retval = bytes_written ? bytes_written : retval;
 615                                 goto exit_nolock;
 616                         }
 617
 618                         dbg(4, " %s : in progress, count = %Zd", __func__, count);
 619                 } else {
 620                         spin_unlock_irqrestore(&dev->buflock, flags);
 621                         set_current_state(TASK_RUNNING);
 622                         remove_wait_queue(&dev->write_wait, &waita);
 623                         dbg(4, " %s : sending, count = %Zd", __func__, count);
 624
 625                         /* write the data into interrupt_out_buffer from userspace */
 626                         buffer_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 627                         bytes_to_write = count > buffer_size ? buffer_size : count;
 628                         dbg(4, " %s : buffer_size = %Zd, count = %Zd, bytes_to_write = %Zd",
 629                             __func__, buffer_size, count, bytes_to_write);
 630
 631                         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
 632                                 retval = -EFAULT;
 633                                 goto exit;
 634                         }
 635
 636                         /* send off the urb */
 637                         usb_fill_int_urb(
 638                                 dev->interrupt_out_urb,
 639                                 dev->udev,
 640                                 usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 641                                 dev->interrupt_out_buffer,
 642                                 bytes_to_write,
 643                                 adu_interrupt_out_callback,
 644                                 dev,
 645                                 dev->interrupt_out_endpoint->bInterval);
 646                         dev->interrupt_out_urb->actual_length = bytes_to_write;
 647                         dev->out_urb_finished = 0;
 648                         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 649                         if (retval < 0) {
 650                                 dev->out_urb_finished = 1;
 651                                 dev_err(&dev->udev->dev, "Couldn't submit "
 652                                         "interrupt_out_urb %d\n", retval);
 653                                 goto exit;
 654                         }
 655
 656                         buffer += bytes_to_write;
 657                         count -= bytes_to_write;
 658
 659                         bytes_written += bytes_to_write;
 660                 }
 661         }
 662         mutex_unlock(&dev->mtx);
 663         return bytes_written;
 664
 665 exit:
 666         mutex_unlock(&dev->mtx);
 667 exit_nolock:
 668         dbg(2, " %s : leave, return value %d", __func__, retval);
 669         return retval;
 670
 671 exit_onqueue:
 672         remove_wait_queue(&dev->write_wait, &waita);
 673         return retval;
 674 }
 675
 676 /* file operations needed when we register this driver */
 677 static const struct file_operations adu_fops = {
 678         .owner = THIS_MODULE,
 679         .read  = adu_read,
 680         .write = adu_write,
 681         .open = adu_open,
 682         .release = adu_release,
 683         .llseek = noop_llseek,
 684 };
 685
 686 /*
 687  * usb class driver info in order to get a minor number from the usb core,
 688  * and to have the device registered with devfs and the driver core
 689  */
 690 static struct usb_class_driver adu_class = {
 691         .name = "usb/adutux%d",
 692         .fops = &adu_fops,
 693         .minor_base = ADU_MINOR_BASE,
 694 };
 695
 696 /**
 697  * adu_probe
 698  *
 699  * Called by the usb core when a new device is connected that it thinks
 700  * this driver might be interested in.
 701  */
 702 static int adu_probe(struct usb_interface *interface,
 703                      const struct usb_device_id *id)
 704 {
 705         struct usb_device *udev = interface_to_usbdev(interface);
 706         struct adu_device *dev = NULL;
 707         struct usb_host_interface *iface_desc;
 708         struct usb_endpoint_descriptor *endpoint;
 709         int retval = -ENODEV;
 710         int in_end_size;
 711         int out_end_size;
 712         int i;
 713
 714         dbg(2, " %s : enter", __func__);
 715
 716         if (udev == NULL) {
 717                 dev_err(&interface->dev, "udev is NULL.\n");
 718                 goto exit;
 719         }
 720
 721         /* allocate memory for our device state and initialize it */
 722         dev = kzalloc(sizeof(struct adu_device), GFP_KERNEL);
 723         if (dev == NULL) {
 724                 dev_err(&interface->dev, "Out of memory\n");
 725                 retval = -ENOMEM;
 726                 goto exit;
 727         }
 728
 729         mutex_init(&dev->mtx);
 730         spin_lock_init(&dev->buflock);
 731         dev->udev = udev;
 732         init_waitqueue_head(&dev->read_wait);
 733         init_waitqueue_head(&dev->write_wait);
 734
 735         iface_desc = &interface->altsetting[0];
 736
 737         /* set up the endpoint information */
 738         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 739                 endpoint = &iface_desc->endpoint[i].desc;
 740
 741                 if (usb_endpoint_is_int_in(endpoint))
 742                         dev->interrupt_in_endpoint = endpoint;
 743
 744                 if (usb_endpoint_is_int_out(endpoint))
 745                         dev->interrupt_out_endpoint = endpoint;
 746         }
 747         if (dev->interrupt_in_endpoint == NULL) {
 748                 dev_err(&interface->dev, "interrupt in endpoint not found\n");
 749                 goto error;
 750         }
 751         if (dev->interrupt_out_endpoint == NULL) {
 752                 dev_err(&interface->dev, "interrupt out endpoint not found\n");
 753                 goto error;
 754         }
 755
 756         in_end_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 757         out_end_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 758
 759         dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
 760         if (!dev->read_buffer_primary) {
 761                 dev_err(&interface->dev, "Couldn't allocate read_buffer_primary\n");
 762                 retval = -ENOMEM;
 763                 goto error;
 764         }
 765
 766         /* debug code prime the buffer */
 767         memset(dev->read_buffer_primary, 'a', in_end_size);
 768         memset(dev->read_buffer_primary + in_end_size, 'b', in_end_size);
 769         memset(dev->read_buffer_primary + (2 * in_end_size), 'c', in_end_size);
 770         memset(dev->read_buffer_primary + (3 * in_end_size), 'd', in_end_size);
 771
 772         dev->read_buffer_secondary = kmalloc((4 * in_end_size), GFP_KERNEL);
 773         if (!dev->read_buffer_secondary) {
 774                 dev_err(&interface->dev, "Couldn't allocate read_buffer_secondary\n");
 775                 retval = -ENOMEM;
 776                 goto error;
 777         }
 778
 779         /* debug code prime the buffer */
 780         memset(dev->read_buffer_secondary, 'e', in_end_size);
 781         memset(dev->read_buffer_secondary + in_end_size, 'f', in_end_size);
 782         memset(dev->read_buffer_secondary + (2 * in_end_size), 'g', in_end_size);
 783         memset(dev->read_buffer_secondary + (3 * in_end_size), 'h', in_end_size);
 784
 785         dev->interrupt_in_buffer = kmalloc(in_end_size, GFP_KERNEL);
 786         if (!dev->interrupt_in_buffer) {
 787                 dev_err(&interface->dev, "Couldn't allocate interrupt_in_buffer\n");
 788                 goto error;
 789         }
 790
 791         /* debug code prime the buffer */
 792         memset(dev->interrupt_in_buffer, 'i', in_end_size);
 793
 794         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 795         if (!dev->interrupt_in_urb) {
 796                 dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
 797                 goto error;
 798         }
 799         dev->interrupt_out_buffer = kmalloc(out_end_size, GFP_KERNEL);
 800         if (!dev->interrupt_out_buffer) {
 801                 dev_err(&interface->dev, "Couldn't allocate interrupt_out_buffer\n");
 802                 goto error;
 803         }
 804         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 805         if (!dev->interrupt_out_urb) {
 806                 dev_err(&interface->dev, "Couldn't allocate interrupt_out_urb\n");
 807                 goto error;
 808         }
 809
 810         if (!usb_string(udev, udev->descriptor.iSerialNumber, dev->serial_number,
 811                         sizeof(dev->serial_number))) {
 812                 dev_err(&interface->dev, "Could not retrieve serial number\n");
 813                 goto error;
 814         }
 815         dbg(2, " %s : serial_number=%s", __func__, dev->serial_number);
 816
 817         /* we can register the device now, as it is ready */
 818         usb_set_intfdata(interface, dev);
 819
 820         retval = usb_register_dev(interface, &adu_class);
 821
 822         if (retval) {
 823                 /* something prevented us from registering this driver */
 824                 dev_err(&interface->dev, "Not able to get a minor for this device.\n");
 825                 usb_set_intfdata(interface, NULL);
 826                 goto error;
 827         }
 828
 829         dev->minor = interface->minor;
 830
 831         /* let the user know what node this device is now attached to */
 832         dev_info(&interface->dev, "ADU%d %s now attached to /dev/usb/adutux%d\n",
 833                  udev->descriptor.idProduct, dev->serial_number,
 834                  (dev->minor - ADU_MINOR_BASE));
 835 exit:
 836         dbg(2, " %s : leave, return value %p (dev)", __func__, dev);
 837
 838         return retval;
 839
 840 error:
 841         adu_delete(dev);
 842         return retval;
 843 }
 844
 845 /**
 846  * adu_disconnect
 847  *
 848  * Called by the usb core when the device is removed from the system.
 849  */
 850 static void adu_disconnect(struct usb_interface *interface)
 851 {
 852         struct adu_device *dev;
 853         int minor;
 854
 855         dbg(2, " %s : enter", __func__);
 856
 857         dev = usb_get_intfdata(interface);
 858
 859         mutex_lock(&dev->mtx);  /* not interruptible */
 860         dev->udev = NULL;       /* poison */
 861         minor = dev->minor;
 862         usb_deregister_dev(interface, &adu_class);
 863         mutex_unlock(&dev->mtx);
 864
 865         mutex_lock(&adutux_mutex);
 866         usb_set_intfdata(interface, NULL);
 867
 868         /* if the device is not opened, then we clean up right now */
 869         dbg(2, " %s : open count %d", __func__, dev->open_count);
 870         if (!dev->open_count)
 871                 adu_delete(dev);
 872
 873         mutex_unlock(&adutux_mutex);
 874
 875         dev_info(&interface->dev, "ADU device adutux%d now disconnected\n",
 876                  (minor - ADU_MINOR_BASE));
 877
 878         dbg(2, " %s : leave", __func__);
 879 }
 880
 881 /* usb specific object needed to register this driver with the usb subsystem */
 882 static struct usb_driver adu_driver = {
 883         .name = "adutux",
 884         .probe = adu_probe,
 885         .disconnect = adu_disconnect,
 886         .id_table = device_table,
 887 };
 888
 889 module_usb_driver(adu_driver);
 890
 891 MODULE_AUTHOR(DRIVER_AUTHOR);
 892 MODULE_DESCRIPTION(DRIVER_DESC);
 893 MODULE_LICENSE("GPL");