drivers/usb/misc/adutux.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * adutux - driver for ADU devices from Ontrak Control Systems
   4  * This is an experimental driver. Use at your own risk.
   5  * This driver is not supported by Ontrak Control Systems.
   6  *
   7  * Copyright (c) 2003 John Homppi (SCO, leave this notice here)
   8  *
   9  * derived from the Lego USB Tower driver 0.56:
  10  * Copyright (c) 2003 David Glance <davidgsf@sourceforge.net>
  11  *               2001 Juergen Stuber <stuber@loria.fr>
  12  * that was derived from USB Skeleton driver - 0.5
  13  * Copyright (c) 2001 Greg Kroah-Hartman (greg@kroah.com)
  14  *
  15  */
  16
  17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18
  19 #include <linux/kernel.h>
  20 #include <linux/sched/signal.h>
  21 #include <linux/errno.h>
  22 #include <linux/slab.h>
  23 #include <linux/module.h>
  24 #include <linux/usb.h>
  25 #include <linux/mutex.h>
  26 #include <linux/uaccess.h>
  27
  28 #define DRIVER_AUTHOR "John Homppi"
  29 #define DRIVER_DESC "adutux (see www.ontrak.net)"
  30
  31 /* Define these values to match your device */
  32 #define ADU_VENDOR_ID 0x0a07
  33 #define ADU_PRODUCT_ID 0x0064
  34
  35 /* table of devices that work with this driver */
  36 static const struct usb_device_id device_table[] = {
  37         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID) },          /* ADU100 */
  38         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+20) },       /* ADU120 */
  39         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+30) },       /* ADU130 */
  40         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+100) },      /* ADU200 */
  41         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+108) },      /* ADU208 */
  42         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+118) },      /* ADU218 */
  43         { } /* Terminating entry */
  44 };
  45
  46 MODULE_DEVICE_TABLE(usb, device_table);
  47
  48 #ifdef CONFIG_USB_DYNAMIC_MINORS
  49 #define ADU_MINOR_BASE  0
  50 #else
  51 #define ADU_MINOR_BASE  67
  52 #endif
  53
  54 /* we can have up to this number of device plugged in at once */
  55 #define MAX_DEVICES     16
  56
  57 #define COMMAND_TIMEOUT (2*HZ)
  58
  59 /*
  60  * The locking scheme is a vanilla 3-lock:
  61  *   adu_device.buflock: A spinlock, covers what IRQs touch.
  62  *   adutux_mutex:       A Static lock to cover open_count. It would also cover
  63  *                       any globals, but we don't have them in 2.6.
  64  *   adu_device.mtx:     A mutex to hold across sleepers like copy_from_user.
  65  *                       It covers all of adu_device, except the open_count
  66  *                       and what .buflock covers.
  67  */
  68
  69 /* Structure to hold all of our device specific stuff */
  70 struct adu_device {
  71         struct mutex            mtx;
  72         struct usb_device *udev; /* save off the usb device pointer */
  73         struct usb_interface *interface;
  74         unsigned int            minor; /* the starting minor number for this device */
  75         char                    serial_number[8];
  76
  77         int                     open_count; /* number of times this port has been opened */
  78         unsigned long           disconnected:1;
  79
  80         char            *read_buffer_primary;
  81         int                     read_buffer_length;
  82         char            *read_buffer_secondary;
  83         int                     secondary_head;
  84         int                     secondary_tail;
  85         spinlock_t              buflock;
  86
  87         wait_queue_head_t       read_wait;
  88         wait_queue_head_t       write_wait;
  89
  90         char            *interrupt_in_buffer;
  91         struct usb_endpoint_descriptor *interrupt_in_endpoint;
  92         struct urb      *interrupt_in_urb;
  93         int                     read_urb_finished;
  94
  95         char            *interrupt_out_buffer;
  96         struct usb_endpoint_descriptor *interrupt_out_endpoint;
  97         struct urb      *interrupt_out_urb;
  98         int                     out_urb_finished;
  99 };
 100
 101 static DEFINE_MUTEX(adutux_mutex);
 102
 103 static struct usb_driver adu_driver;
 104
 105 static inline void adu_debug_data(struct device *dev, const char *function,
 106                                   int size, const unsigned char *data)
 107 {
 108         dev_dbg(dev, "%s - length = %d, data = %*ph\n",
 109                 function, size, size, data);
 110 }
 111
 112 /**
 113  * adu_abort_transfers
 114  *      aborts transfers and frees associated data structures
 115  */
 116 static void adu_abort_transfers(struct adu_device *dev)
 117 {
 118         unsigned long flags;
 119
 120         if (dev->disconnected)
 121                 return;
 122
 123         /* shutdown transfer */
 124
 125         /* XXX Anchor these instead */
 126         spin_lock_irqsave(&dev->buflock, flags);
 127         if (!dev->read_urb_finished) {
 128                 spin_unlock_irqrestore(&dev->buflock, flags);
 129                 usb_kill_urb(dev->interrupt_in_urb);
 130         } else
 131                 spin_unlock_irqrestore(&dev->buflock, flags);
 132
 133         spin_lock_irqsave(&dev->buflock, flags);
 134         if (!dev->out_urb_finished) {
 135                 spin_unlock_irqrestore(&dev->buflock, flags);
 136                 wait_event_timeout(dev->write_wait, dev->out_urb_finished,
 137                         COMMAND_TIMEOUT);
 138                 usb_kill_urb(dev->interrupt_out_urb);
 139         } else
 140                 spin_unlock_irqrestore(&dev->buflock, flags);
 141 }
 142
 143 static void adu_delete(struct adu_device *dev)
 144 {
 145         /* free data structures */
 146         usb_free_urb(dev->interrupt_in_urb);
 147         usb_free_urb(dev->interrupt_out_urb);
 148         kfree(dev->read_buffer_primary);
 149         kfree(dev->read_buffer_secondary);
 150         kfree(dev->interrupt_in_buffer);
 151         kfree(dev->interrupt_out_buffer);
 152         usb_put_dev(dev->udev);
 153         kfree(dev);
 154 }
 155
 156 static void adu_interrupt_in_callback(struct urb *urb)
 157 {
 158         struct adu_device *dev = urb->context;
 159         int status = urb->status;
 160         unsigned long flags;
 161
 162         adu_debug_data(&dev->udev->dev, __func__,
 163                        urb->actual_length, urb->transfer_buffer);
 164
 165         spin_lock_irqsave(&dev->buflock, flags);
 166
 167         if (status != 0) {
 168                 if ((status != -ENOENT) && (status != -ECONNRESET) &&
 169                         (status != -ESHUTDOWN)) {
 170                         dev_dbg(&dev->udev->dev,
 171                                 "%s : nonzero status received: %d\n",
 172                                 __func__, status);
 173                 }
 174                 goto exit;
 175         }
 176
 177         if (urb->actual_length > 0 && dev->interrupt_in_buffer[0] != 0x00) {
 178                 if (dev->read_buffer_length <
 179                     (4 * usb_endpoint_maxp(dev->interrupt_in_endpoint)) -
 180                      (urb->actual_length)) {
 181                         memcpy (dev->read_buffer_primary +
 182                                 dev->read_buffer_length,
 183                                 dev->interrupt_in_buffer, urb->actual_length);
 184
 185                         dev->read_buffer_length += urb->actual_length;
 186                         dev_dbg(&dev->udev->dev,"%s reading  %d\n", __func__,
 187                                 urb->actual_length);
 188                 } else {
 189                         dev_dbg(&dev->udev->dev,"%s : read_buffer overflow\n",
 190                                 __func__);
 191                 }
 192         }
 193
 194 exit:
 195         dev->read_urb_finished = 1;
 196         spin_unlock_irqrestore(&dev->buflock, flags);
 197         /* always wake up so we recover from errors */
 198         wake_up_interruptible(&dev->read_wait);
 199 }
 200
 201 static void adu_interrupt_out_callback(struct urb *urb)
 202 {
 203         struct adu_device *dev = urb->context;
 204         int status = urb->status;
 205         unsigned long flags;
 206
 207         adu_debug_data(&dev->udev->dev, __func__,
 208                        urb->actual_length, urb->transfer_buffer);
 209
 210         if (status != 0) {
 211                 if ((status != -ENOENT) &&
 212                     (status != -ECONNRESET)) {
 213                         dev_dbg(&dev->udev->dev,
 214                                 "%s :nonzero status received: %d\n", __func__,
 215                                 status);
 216                 }
 217                 return;
 218         }
 219
 220         spin_lock_irqsave(&dev->buflock, flags);
 221         dev->out_urb_finished = 1;
 222         wake_up(&dev->write_wait);
 223         spin_unlock_irqrestore(&dev->buflock, flags);
 224 }
 225
 226 static int adu_open(struct inode *inode, struct file *file)
 227 {
 228         struct adu_device *dev = NULL;
 229         struct usb_interface *interface;
 230         int subminor;
 231         int retval;
 232
 233         subminor = iminor(inode);
 234
 235         retval = mutex_lock_interruptible(&adutux_mutex);
 236         if (retval)
 237                 goto exit_no_lock;
 238
 239         interface = usb_find_interface(&adu_driver, subminor);
 240         if (!interface) {
 241                 pr_err("%s - error, can't find device for minor %d\n",
 242                        __func__, subminor);
 243                 retval = -ENODEV;
 244                 goto exit_no_device;
 245         }
 246
 247         dev = usb_get_intfdata(interface);
 248         if (!dev) {
 249                 retval = -ENODEV;
 250                 goto exit_no_device;
 251         }
 252
 253         /* check that nobody else is using the device */
 254         if (dev->open_count) {
 255                 retval = -EBUSY;
 256                 goto exit_no_device;
 257         }
 258
 259         ++dev->open_count;
 260         dev_dbg(&dev->udev->dev, "%s: open count %d\n", __func__,
 261                 dev->open_count);
 262
 263         /* save device in the file's private structure */
 264         file->private_data = dev;
 265
 266         /* initialize in direction */
 267         dev->read_buffer_length = 0;
 268
 269         /* fixup first read by having urb waiting for it */
 270         usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 271                          usb_rcvintpipe(dev->udev,
 272                                         dev->interrupt_in_endpoint->bEndpointAddress),
 273                          dev->interrupt_in_buffer,
 274                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 275                          adu_interrupt_in_callback, dev,
 276                          dev->interrupt_in_endpoint->bInterval);
 277         dev->read_urb_finished = 0;
 278         if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL))
 279                 dev->read_urb_finished = 1;
 280         /* we ignore failure */
 281         /* end of fixup for first read */
 282
 283         /* initialize out direction */
 284         dev->out_urb_finished = 1;
 285
 286         retval = 0;
 287
 288 exit_no_device:
 289         mutex_unlock(&adutux_mutex);
 290 exit_no_lock:
 291         return retval;
 292 }
 293
 294 static void adu_release_internal(struct adu_device *dev)
 295 {
 296         /* decrement our usage count for the device */
 297         --dev->open_count;
 298         dev_dbg(&dev->udev->dev, "%s : open count %d\n", __func__,
 299                 dev->open_count);
 300         if (dev->open_count <= 0) {
 301                 adu_abort_transfers(dev);
 302                 dev->open_count = 0;
 303         }
 304 }
 305
 306 static int adu_release(struct inode *inode, struct file *file)
 307 {
 308         struct adu_device *dev;
 309         int retval = 0;
 310
 311         if (file == NULL) {
 312                 retval = -ENODEV;
 313                 goto exit;
 314         }
 315
 316         dev = file->private_data;
 317         if (dev == NULL) {
 318                 retval = -ENODEV;
 319                 goto exit;
 320         }
 321
 322         mutex_lock(&adutux_mutex); /* not interruptible */
 323
 324         if (dev->open_count <= 0) {
 325                 dev_dbg(&dev->udev->dev, "%s : device not opened\n", __func__);
 326                 retval = -ENODEV;
 327                 goto unlock;
 328         }
 329
 330         adu_release_internal(dev);
 331         if (dev->disconnected) {
 332                 /* the device was unplugged before the file was released */
 333                 if (!dev->open_count)   /* ... and we're the last user */
 334                         adu_delete(dev);
 335         }
 336 unlock:
 337         mutex_unlock(&adutux_mutex);
 338 exit:
 339         return retval;
 340 }
 341
 342 static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
 343                         loff_t *ppos)
 344 {
 345         struct adu_device *dev;
 346         size_t bytes_read = 0;
 347         size_t bytes_to_read = count;
 348         int i;
 349         int retval = 0;
 350         int timeout = 0;
 351         int should_submit = 0;
 352         unsigned long flags;
 353         DECLARE_WAITQUEUE(wait, current);
 354
 355         dev = file->private_data;
 356         if (mutex_lock_interruptible(&dev->mtx))
 357                 return -ERESTARTSYS;
 358
 359         /* verify that the device wasn't unplugged */
 360         if (dev->disconnected) {
 361                 retval = -ENODEV;
 362                 pr_err("No device or device unplugged %d\n", retval);
 363                 goto exit;
 364         }
 365
 366         /* verify that some data was requested */
 367         if (count == 0) {
 368                 dev_dbg(&dev->udev->dev, "%s : read request of 0 bytes\n",
 369                         __func__);
 370                 goto exit;
 371         }
 372
 373         timeout = COMMAND_TIMEOUT;
 374         dev_dbg(&dev->udev->dev, "%s : about to start looping\n", __func__);
 375         while (bytes_to_read) {
 376                 int data_in_secondary = dev->secondary_tail - dev->secondary_head;
 377                 dev_dbg(&dev->udev->dev,
 378                         "%s : while, data_in_secondary=%d, status=%d\n",
 379                         __func__, data_in_secondary,
 380                         dev->interrupt_in_urb->status);
 381
 382                 if (data_in_secondary) {
 383                         /* drain secondary buffer */
 384                         int amount = bytes_to_read < data_in_secondary ? bytes_to_read : data_in_secondary;
 385                         i = copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount);
 386                         if (i) {
 387                                 retval = -EFAULT;
 388                                 goto exit;
 389                         }
 390                         dev->secondary_head += (amount - i);
 391                         bytes_read += (amount - i);
 392                         bytes_to_read -= (amount - i);
 393                 } else {
 394                         /* we check the primary buffer */
 395                         spin_lock_irqsave (&dev->buflock, flags);
 396                         if (dev->read_buffer_length) {
 397                                 /* we secure access to the primary */
 398                                 char *tmp;
 399                                 dev_dbg(&dev->udev->dev,
 400                                         "%s : swap, read_buffer_length = %d\n",
 401                                         __func__, dev->read_buffer_length);
 402                                 tmp = dev->read_buffer_secondary;
 403                                 dev->read_buffer_secondary = dev->read_buffer_primary;
 404                                 dev->read_buffer_primary = tmp;
 405                                 dev->secondary_head = 0;
 406                                 dev->secondary_tail = dev->read_buffer_length;
 407                                 dev->read_buffer_length = 0;
 408                                 spin_unlock_irqrestore(&dev->buflock, flags);
 409                                 /* we have a free buffer so use it */
 410                                 should_submit = 1;
 411                         } else {
 412                                 /* even the primary was empty - we may need to do IO */
 413                                 if (!dev->read_urb_finished) {
 414                                         /* somebody is doing IO */
 415                                         spin_unlock_irqrestore(&dev->buflock, flags);
 416                                         dev_dbg(&dev->udev->dev,
 417                                                 "%s : submitted already\n",
 418                                                 __func__);
 419                                 } else {
 420                                         /* we must initiate input */
 421                                         dev_dbg(&dev->udev->dev,
 422                                                 "%s : initiate input\n",
 423                                                 __func__);
 424                                         dev->read_urb_finished = 0;
 425                                         spin_unlock_irqrestore(&dev->buflock, flags);
 426
 427                                         usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 428                                                         usb_rcvintpipe(dev->udev,
 429                                                                 dev->interrupt_in_endpoint->bEndpointAddress),
 430                                                          dev->interrupt_in_buffer,
 431                                                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 432                                                          adu_interrupt_in_callback,
 433                                                          dev,
 434                                                          dev->interrupt_in_endpoint->bInterval);
 435                                         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 436                                         if (retval) {
 437                                                 dev->read_urb_finished = 1;
 438                                                 if (retval == -ENOMEM) {
 439                                                         retval = bytes_read ? bytes_read : -ENOMEM;
 440                                                 }
 441                                                 dev_dbg(&dev->udev->dev,
 442                                                         "%s : submit failed\n",
 443                                                         __func__);
 444                                                 goto exit;
 445                                         }
 446                                 }
 447
 448                                 /* we wait for I/O to complete */
 449                                 set_current_state(TASK_INTERRUPTIBLE);
 450                                 add_wait_queue(&dev->read_wait, &wait);
 451                                 spin_lock_irqsave(&dev->buflock, flags);
 452                                 if (!dev->read_urb_finished) {
 453                                         spin_unlock_irqrestore(&dev->buflock, flags);
 454                                         timeout = schedule_timeout(COMMAND_TIMEOUT);
 455                                 } else {
 456                                         spin_unlock_irqrestore(&dev->buflock, flags);
 457                                         set_current_state(TASK_RUNNING);
 458                                 }
 459                                 remove_wait_queue(&dev->read_wait, &wait);
 460
 461                                 if (timeout <= 0) {
 462                                         dev_dbg(&dev->udev->dev,
 463                                                 "%s : timeout\n", __func__);
 464                                         retval = bytes_read ? bytes_read : -ETIMEDOUT;
 465                                         goto exit;
 466                                 }
 467
 468                                 if (signal_pending(current)) {
 469                                         dev_dbg(&dev->udev->dev,
 470                                                 "%s : signal pending\n",
 471                                                 __func__);
 472                                         retval = bytes_read ? bytes_read : -EINTR;
 473                                         goto exit;
 474                                 }
 475                         }
 476                 }
 477         }
 478
 479         retval = bytes_read;
 480         /* if the primary buffer is empty then use it */
 481         spin_lock_irqsave(&dev->buflock, flags);
 482         if (should_submit && dev->read_urb_finished) {
 483                 dev->read_urb_finished = 0;
 484                 spin_unlock_irqrestore(&dev->buflock, flags);
 485                 usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 486                                  usb_rcvintpipe(dev->udev,
 487                                         dev->interrupt_in_endpoint->bEndpointAddress),
 488                                 dev->interrupt_in_buffer,
 489                                 usb_endpoint_maxp(dev->interrupt_in_endpoint),
 490                                 adu_interrupt_in_callback,
 491                                 dev,
 492                                 dev->interrupt_in_endpoint->bInterval);
 493                 if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL) != 0)
 494                         dev->read_urb_finished = 1;
 495                 /* we ignore failure */
 496         } else {
 497                 spin_unlock_irqrestore(&dev->buflock, flags);
 498         }
 499
 500 exit:
 501         /* unlock the device */
 502         mutex_unlock(&dev->mtx);
 503
 504         return retval;
 505 }
 506
 507 static ssize_t adu_write(struct file *file, const __user char *buffer,
 508                          size_t count, loff_t *ppos)
 509 {
 510         DECLARE_WAITQUEUE(waita, current);
 511         struct adu_device *dev;
 512         size_t bytes_written = 0;
 513         size_t bytes_to_write;
 514         size_t buffer_size;
 515         unsigned long flags;
 516         int retval;
 517
 518         dev = file->private_data;
 519
 520         retval = mutex_lock_interruptible(&dev->mtx);
 521         if (retval)
 522                 goto exit_nolock;
 523
 524         /* verify that the device wasn't unplugged */
 525         if (dev->disconnected) {
 526                 retval = -ENODEV;
 527                 pr_err("No device or device unplugged %d\n", retval);
 528                 goto exit;
 529         }
 530
 531         /* verify that we actually have some data to write */
 532         if (count == 0) {
 533                 dev_dbg(&dev->udev->dev, "%s : write request of 0 bytes\n",
 534                         __func__);
 535                 goto exit;
 536         }
 537
 538         while (count > 0) {
 539                 add_wait_queue(&dev->write_wait, &waita);
 540                 set_current_state(TASK_INTERRUPTIBLE);
 541                 spin_lock_irqsave(&dev->buflock, flags);
 542                 if (!dev->out_urb_finished) {
 543                         spin_unlock_irqrestore(&dev->buflock, flags);
 544
 545                         mutex_unlock(&dev->mtx);
 546                         if (signal_pending(current)) {
 547                                 dev_dbg(&dev->udev->dev, "%s : interrupted\n",
 548                                         __func__);
 549                                 set_current_state(TASK_RUNNING);
 550                                 retval = -EINTR;
 551                                 goto exit_onqueue;
 552                         }
 553                         if (schedule_timeout(COMMAND_TIMEOUT) == 0) {
 554                                 dev_dbg(&dev->udev->dev,
 555                                         "%s - command timed out.\n", __func__);
 556                                 retval = -ETIMEDOUT;
 557                                 goto exit_onqueue;
 558                         }
 559                         remove_wait_queue(&dev->write_wait, &waita);
 560                         retval = mutex_lock_interruptible(&dev->mtx);
 561                         if (retval) {
 562                                 retval = bytes_written ? bytes_written : retval;
 563                                 goto exit_nolock;
 564                         }
 565
 566                         dev_dbg(&dev->udev->dev,
 567                                 "%s : in progress, count = %zd\n",
 568                                 __func__, count);
 569                 } else {
 570                         spin_unlock_irqrestore(&dev->buflock, flags);
 571                         set_current_state(TASK_RUNNING);
 572                         remove_wait_queue(&dev->write_wait, &waita);
 573                         dev_dbg(&dev->udev->dev, "%s : sending, count = %zd\n",
 574                                 __func__, count);
 575
 576                         /* write the data into interrupt_out_buffer from userspace */
 577                         buffer_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 578                         bytes_to_write = count > buffer_size ? buffer_size : count;
 579                         dev_dbg(&dev->udev->dev,
 580                                 "%s : buffer_size = %zd, count = %zd, bytes_to_write = %zd\n",
 581                                 __func__, buffer_size, count, bytes_to_write);
 582
 583                         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
 584                                 retval = -EFAULT;
 585                                 goto exit;
 586                         }
 587
 588                         /* send off the urb */
 589                         usb_fill_int_urb(
 590                                 dev->interrupt_out_urb,
 591                                 dev->udev,
 592                                 usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 593                                 dev->interrupt_out_buffer,
 594                                 bytes_to_write,
 595                                 adu_interrupt_out_callback,
 596                                 dev,
 597                                 dev->interrupt_out_endpoint->bInterval);
 598                         dev->interrupt_out_urb->actual_length = bytes_to_write;
 599                         dev->out_urb_finished = 0;
 600                         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 601                         if (retval < 0) {
 602                                 dev->out_urb_finished = 1;
 603                                 dev_err(&dev->udev->dev, "Couldn't submit "
 604                                         "interrupt_out_urb %d\n", retval);
 605                                 goto exit;
 606                         }
 607
 608                         buffer += bytes_to_write;
 609                         count -= bytes_to_write;
 610
 611                         bytes_written += bytes_to_write;
 612                 }
 613         }
 614         mutex_unlock(&dev->mtx);
 615         return bytes_written;
 616
 617 exit:
 618         mutex_unlock(&dev->mtx);
 619 exit_nolock:
 620         return retval;
 621
 622 exit_onqueue:
 623         remove_wait_queue(&dev->write_wait, &waita);
 624         return retval;
 625 }
 626
 627 /* file operations needed when we register this driver */
 628 static const struct file_operations adu_fops = {
 629         .owner = THIS_MODULE,
 630         .read  = adu_read,
 631         .write = adu_write,
 632         .open = adu_open,
 633         .release = adu_release,
 634         .llseek = noop_llseek,
 635 };
 636
 637 /*
 638  * usb class driver info in order to get a minor number from the usb core,
 639  * and to have the device registered with devfs and the driver core
 640  */
 641 static struct usb_class_driver adu_class = {
 642         .name = "usb/adutux%d",
 643         .fops = &adu_fops,
 644         .minor_base = ADU_MINOR_BASE,
 645 };
 646
 647 /**
 648  * adu_probe
 649  *
 650  * Called by the usb core when a new device is connected that it thinks
 651  * this driver might be interested in.
 652  */
 653 static int adu_probe(struct usb_interface *interface,
 654                      const struct usb_device_id *id)
 655 {
 656         struct usb_device *udev = interface_to_usbdev(interface);
 657         struct adu_device *dev = NULL;
 658         int retval = -ENOMEM;
 659         int in_end_size;
 660         int out_end_size;
 661         int res;
 662
 663         /* allocate memory for our device state and initialize it */
 664         dev = kzalloc(sizeof(struct adu_device), GFP_KERNEL);
 665         if (!dev)
 666                 return -ENOMEM;
 667
 668         mutex_init(&dev->mtx);
 669         spin_lock_init(&dev->buflock);
 670         dev->udev = usb_get_dev(udev);
 671         init_waitqueue_head(&dev->read_wait);
 672         init_waitqueue_head(&dev->write_wait);
 673
 674         res = usb_find_common_endpoints_reverse(&interface->altsetting[0],
 675                         NULL, NULL,
 676                         &dev->interrupt_in_endpoint,
 677                         &dev->interrupt_out_endpoint);
 678         if (res) {
 679                 dev_err(&interface->dev, "interrupt endpoints not found\n");
 680                 retval = res;
 681                 goto error;
 682         }
 683
 684         in_end_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 685         out_end_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 686
 687         dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
 688         if (!dev->read_buffer_primary)
 689                 goto error;
 690
 691         /* debug code prime the buffer */
 692         memset(dev->read_buffer_primary, 'a', in_end_size);
 693         memset(dev->read_buffer_primary + in_end_size, 'b', in_end_size);
 694         memset(dev->read_buffer_primary + (2 * in_end_size), 'c', in_end_size);
 695         memset(dev->read_buffer_primary + (3 * in_end_size), 'd', in_end_size);
 696
 697         dev->read_buffer_secondary = kmalloc((4 * in_end_size), GFP_KERNEL);
 698         if (!dev->read_buffer_secondary)
 699                 goto error;
 700
 701         /* debug code prime the buffer */
 702         memset(dev->read_buffer_secondary, 'e', in_end_size);
 703         memset(dev->read_buffer_secondary + in_end_size, 'f', in_end_size);
 704         memset(dev->read_buffer_secondary + (2 * in_end_size), 'g', in_end_size);
 705         memset(dev->read_buffer_secondary + (3 * in_end_size), 'h', in_end_size);
 706
 707         dev->interrupt_in_buffer = kmalloc(in_end_size, GFP_KERNEL);
 708         if (!dev->interrupt_in_buffer)
 709                 goto error;
 710
 711         /* debug code prime the buffer */
 712         memset(dev->interrupt_in_buffer, 'i', in_end_size);
 713
 714         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 715         if (!dev->interrupt_in_urb)
 716                 goto error;
 717         dev->interrupt_out_buffer = kmalloc(out_end_size, GFP_KERNEL);
 718         if (!dev->interrupt_out_buffer)
 719                 goto error;
 720         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 721         if (!dev->interrupt_out_urb)
 722                 goto error;
 723
 724         if (!usb_string(udev, udev->descriptor.iSerialNumber, dev->serial_number,
 725                         sizeof(dev->serial_number))) {
 726                 dev_err(&interface->dev, "Could not retrieve serial number\n");
 727                 retval = -EIO;
 728                 goto error;
 729         }
 730         dev_dbg(&interface->dev,"serial_number=%s", dev->serial_number);
 731
 732         /* we can register the device now, as it is ready */
 733         usb_set_intfdata(interface, dev);
 734
 735         retval = usb_register_dev(interface, &adu_class);
 736
 737         if (retval) {
 738                 /* something prevented us from registering this driver */
 739                 dev_err(&interface->dev, "Not able to get a minor for this device.\n");
 740                 usb_set_intfdata(interface, NULL);
 741                 goto error;
 742         }
 743
 744         dev->minor = interface->minor;
 745
 746         /* let the user know what node this device is now attached to */
 747         dev_info(&interface->dev, "ADU%d %s now attached to /dev/usb/adutux%d\n",
 748                  le16_to_cpu(udev->descriptor.idProduct), dev->serial_number,
 749                  (dev->minor - ADU_MINOR_BASE));
 750
 751         return 0;
 752
 753 error:
 754         adu_delete(dev);
 755         return retval;
 756 }
 757
 758 /**
 759  * adu_disconnect
 760  *
 761  * Called by the usb core when the device is removed from the system.
 762  */
 763 static void adu_disconnect(struct usb_interface *interface)
 764 {
 765         struct adu_device *dev;
 766
 767         dev = usb_get_intfdata(interface);
 768
 769         usb_deregister_dev(interface, &adu_class);
 770
 771         usb_poison_urb(dev->interrupt_in_urb);
 772         usb_poison_urb(dev->interrupt_out_urb);
 773
 774         mutex_lock(&adutux_mutex);
 775         usb_set_intfdata(interface, NULL);
 776
 777         mutex_lock(&dev->mtx);  /* not interruptible */
 778         dev->disconnected = 1;
 779         mutex_unlock(&dev->mtx);
 780
 781         /* if the device is not opened, then we clean up right now */
 782         if (!dev->open_count)
 783                 adu_delete(dev);
 784
 785         mutex_unlock(&adutux_mutex);
 786 }
 787
 788 /* usb specific object needed to register this driver with the usb subsystem */
 789 static struct usb_driver adu_driver = {
 790         .name = "adutux",
 791         .probe = adu_probe,
 792         .disconnect = adu_disconnect,
 793         .id_table = device_table,
 794 };
 795
 796 module_usb_driver(adu_driver);
 797
 798 MODULE_AUTHOR(DRIVER_AUTHOR);
 799 MODULE_DESCRIPTION(DRIVER_DESC);
 800 MODULE_LICENSE("GPL");