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 != -ESHUTDOWN) &&
 213                     (status != -ECONNRESET)) {
 214                         dev_dbg(&dev->udev->dev,
 215                                 "%s :nonzero status received: %d\n", __func__,
 216                                 status);
 217                 }
 218                 return;
 219         }
 220
 221         spin_lock_irqsave(&dev->buflock, flags);
 222         dev->out_urb_finished = 1;
 223         wake_up(&dev->write_wait);
 224         spin_unlock_irqrestore(&dev->buflock, flags);
 225 }
 226
 227 static int adu_open(struct inode *inode, struct file *file)
 228 {
 229         struct adu_device *dev = NULL;
 230         struct usb_interface *interface;
 231         int subminor;
 232         int retval;
 233
 234         subminor = iminor(inode);
 235
 236         retval = mutex_lock_interruptible(&adutux_mutex);
 237         if (retval)
 238                 goto exit_no_lock;
 239
 240         interface = usb_find_interface(&adu_driver, subminor);
 241         if (!interface) {
 242                 pr_err("%s - error, can't find device for minor %d\n",
 243                        __func__, subminor);
 244                 retval = -ENODEV;
 245                 goto exit_no_device;
 246         }
 247
 248         dev = usb_get_intfdata(interface);
 249         if (!dev) {
 250                 retval = -ENODEV;
 251                 goto exit_no_device;
 252         }
 253
 254         /* check that nobody else is using the device */
 255         if (dev->open_count) {
 256                 retval = -EBUSY;
 257                 goto exit_no_device;
 258         }
 259
 260         ++dev->open_count;
 261         dev_dbg(&dev->udev->dev, "%s: open count %d\n", __func__,
 262                 dev->open_count);
 263
 264         /* save device in the file's private structure */
 265         file->private_data = dev;
 266
 267         /* initialize in direction */
 268         dev->read_buffer_length = 0;
 269
 270         /* fixup first read by having urb waiting for it */
 271         usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 272                          usb_rcvintpipe(dev->udev,
 273                                         dev->interrupt_in_endpoint->bEndpointAddress),
 274                          dev->interrupt_in_buffer,
 275                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 276                          adu_interrupt_in_callback, dev,
 277                          dev->interrupt_in_endpoint->bInterval);
 278         dev->read_urb_finished = 0;
 279         if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL))
 280                 dev->read_urb_finished = 1;
 281         /* we ignore failure */
 282         /* end of fixup for first read */
 283
 284         /* initialize out direction */
 285         dev->out_urb_finished = 1;
 286
 287         retval = 0;
 288
 289 exit_no_device:
 290         mutex_unlock(&adutux_mutex);
 291 exit_no_lock:
 292         return retval;
 293 }
 294
 295 static void adu_release_internal(struct adu_device *dev)
 296 {
 297         /* decrement our usage count for the device */
 298         --dev->open_count;
 299         dev_dbg(&dev->udev->dev, "%s : open count %d\n", __func__,
 300                 dev->open_count);
 301         if (dev->open_count <= 0) {
 302                 adu_abort_transfers(dev);
 303                 dev->open_count = 0;
 304         }
 305 }
 306
 307 static int adu_release(struct inode *inode, struct file *file)
 308 {
 309         struct adu_device *dev;
 310         int retval = 0;
 311
 312         if (file == NULL) {
 313                 retval = -ENODEV;
 314                 goto exit;
 315         }
 316
 317         dev = file->private_data;
 318         if (dev == NULL) {
 319                 retval = -ENODEV;
 320                 goto exit;
 321         }
 322
 323         mutex_lock(&adutux_mutex); /* not interruptible */
 324
 325         if (dev->open_count <= 0) {
 326                 dev_dbg(&dev->udev->dev, "%s : device not opened\n", __func__);
 327                 retval = -ENODEV;
 328                 goto unlock;
 329         }
 330
 331         adu_release_internal(dev);
 332         if (dev->disconnected) {
 333                 /* the device was unplugged before the file was released */
 334                 if (!dev->open_count)   /* ... and we're the last user */
 335                         adu_delete(dev);
 336         }
 337 unlock:
 338         mutex_unlock(&adutux_mutex);
 339 exit:
 340         return retval;
 341 }
 342
 343 static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
 344                         loff_t *ppos)
 345 {
 346         struct adu_device *dev;
 347         size_t bytes_read = 0;
 348         size_t bytes_to_read = count;
 349         int i;
 350         int retval = 0;
 351         int timeout = 0;
 352         int should_submit = 0;
 353         unsigned long flags;
 354         DECLARE_WAITQUEUE(wait, current);
 355
 356         dev = file->private_data;
 357         if (mutex_lock_interruptible(&dev->mtx))
 358                 return -ERESTARTSYS;
 359
 360         /* verify that the device wasn't unplugged */
 361         if (dev->disconnected) {
 362                 retval = -ENODEV;
 363                 pr_err("No device or device unplugged %d\n", retval);
 364                 goto exit;
 365         }
 366
 367         /* verify that some data was requested */
 368         if (count == 0) {
 369                 dev_dbg(&dev->udev->dev, "%s : read request of 0 bytes\n",
 370                         __func__);
 371                 goto exit;
 372         }
 373
 374         timeout = COMMAND_TIMEOUT;
 375         dev_dbg(&dev->udev->dev, "%s : about to start looping\n", __func__);
 376         while (bytes_to_read) {
 377                 int data_in_secondary = dev->secondary_tail - dev->secondary_head;
 378                 dev_dbg(&dev->udev->dev,
 379                         "%s : while, data_in_secondary=%d, status=%d\n",
 380                         __func__, data_in_secondary,
 381                         dev->interrupt_in_urb->status);
 382
 383                 if (data_in_secondary) {
 384                         /* drain secondary buffer */
 385                         int amount = bytes_to_read < data_in_secondary ? bytes_to_read : data_in_secondary;
 386                         i = copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount);
 387                         if (i) {
 388                                 retval = -EFAULT;
 389                                 goto exit;
 390                         }
 391                         dev->secondary_head += (amount - i);
 392                         bytes_read += (amount - i);
 393                         bytes_to_read -= (amount - i);
 394                 } else {
 395                         /* we check the primary buffer */
 396                         spin_lock_irqsave (&dev->buflock, flags);
 397                         if (dev->read_buffer_length) {
 398                                 /* we secure access to the primary */
 399                                 char *tmp;
 400                                 dev_dbg(&dev->udev->dev,
 401                                         "%s : swap, read_buffer_length = %d\n",
 402                                         __func__, dev->read_buffer_length);
 403                                 tmp = dev->read_buffer_secondary;
 404                                 dev->read_buffer_secondary = dev->read_buffer_primary;
 405                                 dev->read_buffer_primary = tmp;
 406                                 dev->secondary_head = 0;
 407                                 dev->secondary_tail = dev->read_buffer_length;
 408                                 dev->read_buffer_length = 0;
 409                                 spin_unlock_irqrestore(&dev->buflock, flags);
 410                                 /* we have a free buffer so use it */
 411                                 should_submit = 1;
 412                         } else {
 413                                 /* even the primary was empty - we may need to do IO */
 414                                 if (!dev->read_urb_finished) {
 415                                         /* somebody is doing IO */
 416                                         spin_unlock_irqrestore(&dev->buflock, flags);
 417                                         dev_dbg(&dev->udev->dev,
 418                                                 "%s : submitted already\n",
 419                                                 __func__);
 420                                 } else {
 421                                         /* we must initiate input */
 422                                         dev_dbg(&dev->udev->dev,
 423                                                 "%s : initiate input\n",
 424                                                 __func__);
 425                                         dev->read_urb_finished = 0;
 426                                         spin_unlock_irqrestore(&dev->buflock, flags);
 427
 428                                         usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 429                                                         usb_rcvintpipe(dev->udev,
 430                                                                 dev->interrupt_in_endpoint->bEndpointAddress),
 431                                                          dev->interrupt_in_buffer,
 432                                                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 433                                                          adu_interrupt_in_callback,
 434                                                          dev,
 435                                                          dev->interrupt_in_endpoint->bInterval);
 436                                         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 437                                         if (retval) {
 438                                                 dev->read_urb_finished = 1;
 439                                                 if (retval == -ENOMEM) {
 440                                                         retval = bytes_read ? bytes_read : -ENOMEM;
 441                                                 }
 442                                                 dev_dbg(&dev->udev->dev,
 443                                                         "%s : submit failed\n",
 444                                                         __func__);
 445                                                 goto exit;
 446                                         }
 447                                 }
 448
 449                                 /* we wait for I/O to complete */
 450                                 set_current_state(TASK_INTERRUPTIBLE);
 451                                 add_wait_queue(&dev->read_wait, &wait);
 452                                 spin_lock_irqsave(&dev->buflock, flags);
 453                                 if (!dev->read_urb_finished) {
 454                                         spin_unlock_irqrestore(&dev->buflock, flags);
 455                                         timeout = schedule_timeout(COMMAND_TIMEOUT);
 456                                 } else {
 457                                         spin_unlock_irqrestore(&dev->buflock, flags);
 458                                         set_current_state(TASK_RUNNING);
 459                                 }
 460                                 remove_wait_queue(&dev->read_wait, &wait);
 461
 462                                 if (timeout <= 0) {
 463                                         dev_dbg(&dev->udev->dev,
 464                                                 "%s : timeout\n", __func__);
 465                                         retval = bytes_read ? bytes_read : -ETIMEDOUT;
 466                                         goto exit;
 467                                 }
 468
 469                                 if (signal_pending(current)) {
 470                                         dev_dbg(&dev->udev->dev,
 471                                                 "%s : signal pending\n",
 472                                                 __func__);
 473                                         retval = bytes_read ? bytes_read : -EINTR;
 474                                         goto exit;
 475                                 }
 476                         }
 477                 }
 478         }
 479
 480         retval = bytes_read;
 481         /* if the primary buffer is empty then use it */
 482         spin_lock_irqsave(&dev->buflock, flags);
 483         if (should_submit && dev->read_urb_finished) {
 484                 dev->read_urb_finished = 0;
 485                 spin_unlock_irqrestore(&dev->buflock, flags);
 486                 usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 487                                  usb_rcvintpipe(dev->udev,
 488                                         dev->interrupt_in_endpoint->bEndpointAddress),
 489                                 dev->interrupt_in_buffer,
 490                                 usb_endpoint_maxp(dev->interrupt_in_endpoint),
 491                                 adu_interrupt_in_callback,
 492                                 dev,
 493                                 dev->interrupt_in_endpoint->bInterval);
 494                 if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL) != 0)
 495                         dev->read_urb_finished = 1;
 496                 /* we ignore failure */
 497         } else {
 498                 spin_unlock_irqrestore(&dev->buflock, flags);
 499         }
 500
 501 exit:
 502         /* unlock the device */
 503         mutex_unlock(&dev->mtx);
 504
 505         return retval;
 506 }
 507
 508 static ssize_t adu_write(struct file *file, const __user char *buffer,
 509                          size_t count, loff_t *ppos)
 510 {
 511         DECLARE_WAITQUEUE(waita, current);
 512         struct adu_device *dev;
 513         size_t bytes_written = 0;
 514         size_t bytes_to_write;
 515         size_t buffer_size;
 516         unsigned long flags;
 517         int retval;
 518
 519         dev = file->private_data;
 520
 521         retval = mutex_lock_interruptible(&dev->mtx);
 522         if (retval)
 523                 goto exit_nolock;
 524
 525         /* verify that the device wasn't unplugged */
 526         if (dev->disconnected) {
 527                 retval = -ENODEV;
 528                 pr_err("No device or device unplugged %d\n", retval);
 529                 goto exit;
 530         }
 531
 532         /* verify that we actually have some data to write */
 533         if (count == 0) {
 534                 dev_dbg(&dev->udev->dev, "%s : write request of 0 bytes\n",
 535                         __func__);
 536                 goto exit;
 537         }
 538
 539         while (count > 0) {
 540                 add_wait_queue(&dev->write_wait, &waita);
 541                 set_current_state(TASK_INTERRUPTIBLE);
 542                 spin_lock_irqsave(&dev->buflock, flags);
 543                 if (!dev->out_urb_finished) {
 544                         spin_unlock_irqrestore(&dev->buflock, flags);
 545
 546                         mutex_unlock(&dev->mtx);
 547                         if (signal_pending(current)) {
 548                                 dev_dbg(&dev->udev->dev, "%s : interrupted\n",
 549                                         __func__);
 550                                 set_current_state(TASK_RUNNING);
 551                                 retval = -EINTR;
 552                                 goto exit_onqueue;
 553                         }
 554                         if (schedule_timeout(COMMAND_TIMEOUT) == 0) {
 555                                 dev_dbg(&dev->udev->dev,
 556                                         "%s - command timed out.\n", __func__);
 557                                 retval = -ETIMEDOUT;
 558                                 goto exit_onqueue;
 559                         }
 560                         remove_wait_queue(&dev->write_wait, &waita);
 561                         retval = mutex_lock_interruptible(&dev->mtx);
 562                         if (retval) {
 563                                 retval = bytes_written ? bytes_written : retval;
 564                                 goto exit_nolock;
 565                         }
 566
 567                         dev_dbg(&dev->udev->dev,
 568                                 "%s : in progress, count = %zd\n",
 569                                 __func__, count);
 570                 } else {
 571                         spin_unlock_irqrestore(&dev->buflock, flags);
 572                         set_current_state(TASK_RUNNING);
 573                         remove_wait_queue(&dev->write_wait, &waita);
 574                         dev_dbg(&dev->udev->dev, "%s : sending, count = %zd\n",
 575                                 __func__, count);
 576
 577                         /* write the data into interrupt_out_buffer from userspace */
 578                         buffer_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 579                         bytes_to_write = count > buffer_size ? buffer_size : count;
 580                         dev_dbg(&dev->udev->dev,
 581                                 "%s : buffer_size = %zd, count = %zd, bytes_to_write = %zd\n",
 582                                 __func__, buffer_size, count, bytes_to_write);
 583
 584                         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
 585                                 retval = -EFAULT;
 586                                 goto exit;
 587                         }
 588
 589                         /* send off the urb */
 590                         usb_fill_int_urb(
 591                                 dev->interrupt_out_urb,
 592                                 dev->udev,
 593                                 usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 594                                 dev->interrupt_out_buffer,
 595                                 bytes_to_write,
 596                                 adu_interrupt_out_callback,
 597                                 dev,
 598                                 dev->interrupt_out_endpoint->bInterval);
 599                         dev->interrupt_out_urb->actual_length = bytes_to_write;
 600                         dev->out_urb_finished = 0;
 601                         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 602                         if (retval < 0) {
 603                                 dev->out_urb_finished = 1;
 604                                 dev_err(&dev->udev->dev, "Couldn't submit "
 605                                         "interrupt_out_urb %d\n", retval);
 606                                 goto exit;
 607                         }
 608
 609                         buffer += bytes_to_write;
 610                         count -= bytes_to_write;
 611
 612                         bytes_written += bytes_to_write;
 613                 }
 614         }
 615         mutex_unlock(&dev->mtx);
 616         return bytes_written;
 617
 618 exit:
 619         mutex_unlock(&dev->mtx);
 620 exit_nolock:
 621         return retval;
 622
 623 exit_onqueue:
 624         remove_wait_queue(&dev->write_wait, &waita);
 625         return retval;
 626 }
 627
 628 /* file operations needed when we register this driver */
 629 static const struct file_operations adu_fops = {
 630         .owner = THIS_MODULE,
 631         .read  = adu_read,
 632         .write = adu_write,
 633         .open = adu_open,
 634         .release = adu_release,
 635         .llseek = noop_llseek,
 636 };
 637
 638 /*
 639  * usb class driver info in order to get a minor number from the usb core,
 640  * and to have the device registered with devfs and the driver core
 641  */
 642 static struct usb_class_driver adu_class = {
 643         .name = "usb/adutux%d",
 644         .fops = &adu_fops,
 645         .minor_base = ADU_MINOR_BASE,
 646 };
 647
 648 /**
 649  * adu_probe
 650  *
 651  * Called by the usb core when a new device is connected that it thinks
 652  * this driver might be interested in.
 653  */
 654 static int adu_probe(struct usb_interface *interface,
 655                      const struct usb_device_id *id)
 656 {
 657         struct usb_device *udev = interface_to_usbdev(interface);
 658         struct adu_device *dev = NULL;
 659         int retval = -ENOMEM;
 660         int in_end_size;
 661         int out_end_size;
 662         int res;
 663
 664         /* allocate memory for our device state and initialize it */
 665         dev = kzalloc(sizeof(struct adu_device), GFP_KERNEL);
 666         if (!dev)
 667                 return -ENOMEM;
 668
 669         mutex_init(&dev->mtx);
 670         spin_lock_init(&dev->buflock);
 671         dev->udev = usb_get_dev(udev);
 672         init_waitqueue_head(&dev->read_wait);
 673         init_waitqueue_head(&dev->write_wait);
 674
 675         res = usb_find_common_endpoints_reverse(interface->cur_altsetting,
 676                         NULL, NULL,
 677                         &dev->interrupt_in_endpoint,
 678                         &dev->interrupt_out_endpoint);
 679         if (res) {
 680                 dev_err(&interface->dev, "interrupt endpoints not found\n");
 681                 retval = res;
 682                 goto error;
 683         }
 684
 685         in_end_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 686         out_end_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 687
 688         dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
 689         if (!dev->read_buffer_primary)
 690                 goto error;
 691
 692         /* debug code prime the buffer */
 693         memset(dev->read_buffer_primary, 'a', in_end_size);
 694         memset(dev->read_buffer_primary + in_end_size, 'b', in_end_size);
 695         memset(dev->read_buffer_primary + (2 * in_end_size), 'c', in_end_size);
 696         memset(dev->read_buffer_primary + (3 * in_end_size), 'd', in_end_size);
 697
 698         dev->read_buffer_secondary = kmalloc((4 * in_end_size), GFP_KERNEL);
 699         if (!dev->read_buffer_secondary)
 700                 goto error;
 701
 702         /* debug code prime the buffer */
 703         memset(dev->read_buffer_secondary, 'e', in_end_size);
 704         memset(dev->read_buffer_secondary + in_end_size, 'f', in_end_size);
 705         memset(dev->read_buffer_secondary + (2 * in_end_size), 'g', in_end_size);
 706         memset(dev->read_buffer_secondary + (3 * in_end_size), 'h', in_end_size);
 707
 708         dev->interrupt_in_buffer = kmalloc(in_end_size, GFP_KERNEL);
 709         if (!dev->interrupt_in_buffer)
 710                 goto error;
 711
 712         /* debug code prime the buffer */
 713         memset(dev->interrupt_in_buffer, 'i', in_end_size);
 714
 715         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 716         if (!dev->interrupt_in_urb)
 717                 goto error;
 718         dev->interrupt_out_buffer = kmalloc(out_end_size, GFP_KERNEL);
 719         if (!dev->interrupt_out_buffer)
 720                 goto error;
 721         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 722         if (!dev->interrupt_out_urb)
 723                 goto error;
 724
 725         if (!usb_string(udev, udev->descriptor.iSerialNumber, dev->serial_number,
 726                         sizeof(dev->serial_number))) {
 727                 dev_err(&interface->dev, "Could not retrieve serial number\n");
 728                 retval = -EIO;
 729                 goto error;
 730         }
 731         dev_dbg(&interface->dev,"serial_number=%s", dev->serial_number);
 732
 733         /* we can register the device now, as it is ready */
 734         usb_set_intfdata(interface, dev);
 735
 736         retval = usb_register_dev(interface, &adu_class);
 737
 738         if (retval) {
 739                 /* something prevented us from registering this driver */
 740                 dev_err(&interface->dev, "Not able to get a minor for this device.\n");
 741                 usb_set_intfdata(interface, NULL);
 742                 goto error;
 743         }
 744
 745         dev->minor = interface->minor;
 746
 747         /* let the user know what node this device is now attached to */
 748         dev_info(&interface->dev, "ADU%d %s now attached to /dev/usb/adutux%d\n",
 749                  le16_to_cpu(udev->descriptor.idProduct), dev->serial_number,
 750                  (dev->minor - ADU_MINOR_BASE));
 751
 752         return 0;
 753
 754 error:
 755         adu_delete(dev);
 756         return retval;
 757 }
 758
 759 /**
 760  * adu_disconnect
 761  *
 762  * Called by the usb core when the device is removed from the system.
 763  */
 764 static void adu_disconnect(struct usb_interface *interface)
 765 {
 766         struct adu_device *dev;
 767
 768         dev = usb_get_intfdata(interface);
 769
 770         usb_deregister_dev(interface, &adu_class);
 771
 772         usb_poison_urb(dev->interrupt_in_urb);
 773         usb_poison_urb(dev->interrupt_out_urb);
 774
 775         mutex_lock(&adutux_mutex);
 776         usb_set_intfdata(interface, NULL);
 777
 778         mutex_lock(&dev->mtx);  /* not interruptible */
 779         dev->disconnected = 1;
 780         mutex_unlock(&dev->mtx);
 781
 782         /* if the device is not opened, then we clean up right now */
 783         if (!dev->open_count)
 784                 adu_delete(dev);
 785
 786         mutex_unlock(&adutux_mutex);
 787 }
 788
 789 /* usb specific object needed to register this driver with the usb subsystem */
 790 static struct usb_driver adu_driver = {
 791         .name = "adutux",
 792         .probe = adu_probe,
 793         .disconnect = adu_disconnect,
 794         .id_table = device_table,
 795 };
 796
 797 module_usb_driver(adu_driver);
 798
 799 MODULE_AUTHOR(DRIVER_AUTHOR);
 800 MODULE_DESCRIPTION(DRIVER_DESC);
 801 MODULE_LICENSE("GPL");