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 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                 size_t data_in_secondary = dev->secondary_tail - dev->secondary_head;
 377                 dev_dbg(&dev->udev->dev,
 378                         "%s : while, data_in_secondary=%zu, 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                         size_t amount = min(bytes_to_read, data_in_secondary);
 385                         if (copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount)) {
 386                                 retval = -EFAULT;
 387                                 goto exit;
 388                         }
 389                         dev->secondary_head += amount;
 390                         bytes_read += amount;
 391                         bytes_to_read -= amount;
 392                 } else {
 393                         /* we check the primary buffer */
 394                         spin_lock_irqsave (&dev->buflock, flags);
 395                         if (dev->read_buffer_length) {
 396                                 /* we secure access to the primary */
 397                                 char *tmp;
 398                                 dev_dbg(&dev->udev->dev,
 399                                         "%s : swap, read_buffer_length = %d\n",
 400                                         __func__, dev->read_buffer_length);
 401                                 tmp = dev->read_buffer_secondary;
 402                                 dev->read_buffer_secondary = dev->read_buffer_primary;
 403                                 dev->read_buffer_primary = tmp;
 404                                 dev->secondary_head = 0;
 405                                 dev->secondary_tail = dev->read_buffer_length;
 406                                 dev->read_buffer_length = 0;
 407                                 spin_unlock_irqrestore(&dev->buflock, flags);
 408                                 /* we have a free buffer so use it */
 409                                 should_submit = 1;
 410                         } else {
 411                                 /* even the primary was empty - we may need to do IO */
 412                                 if (!dev->read_urb_finished) {
 413                                         /* somebody is doing IO */
 414                                         spin_unlock_irqrestore(&dev->buflock, flags);
 415                                         dev_dbg(&dev->udev->dev,
 416                                                 "%s : submitted already\n",
 417                                                 __func__);
 418                                 } else {
 419                                         /* we must initiate input */
 420                                         dev_dbg(&dev->udev->dev,
 421                                                 "%s : initiate input\n",
 422                                                 __func__);
 423                                         dev->read_urb_finished = 0;
 424                                         spin_unlock_irqrestore(&dev->buflock, flags);
 425
 426                                         usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 427                                                         usb_rcvintpipe(dev->udev,
 428                                                                 dev->interrupt_in_endpoint->bEndpointAddress),
 429                                                          dev->interrupt_in_buffer,
 430                                                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 431                                                          adu_interrupt_in_callback,
 432                                                          dev,
 433                                                          dev->interrupt_in_endpoint->bInterval);
 434                                         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 435                                         if (retval) {
 436                                                 dev->read_urb_finished = 1;
 437                                                 if (retval == -ENOMEM) {
 438                                                         retval = bytes_read ? bytes_read : -ENOMEM;
 439                                                 }
 440                                                 dev_dbg(&dev->udev->dev,
 441                                                         "%s : submit failed\n",
 442                                                         __func__);
 443                                                 goto exit;
 444                                         }
 445                                 }
 446
 447                                 /* we wait for I/O to complete */
 448                                 set_current_state(TASK_INTERRUPTIBLE);
 449                                 add_wait_queue(&dev->read_wait, &wait);
 450                                 spin_lock_irqsave(&dev->buflock, flags);
 451                                 if (!dev->read_urb_finished) {
 452                                         spin_unlock_irqrestore(&dev->buflock, flags);
 453                                         timeout = schedule_timeout(COMMAND_TIMEOUT);
 454                                 } else {
 455                                         spin_unlock_irqrestore(&dev->buflock, flags);
 456                                         set_current_state(TASK_RUNNING);
 457                                 }
 458                                 remove_wait_queue(&dev->read_wait, &wait);
 459
 460                                 if (timeout <= 0) {
 461                                         dev_dbg(&dev->udev->dev,
 462                                                 "%s : timeout\n", __func__);
 463                                         retval = bytes_read ? bytes_read : -ETIMEDOUT;
 464                                         goto exit;
 465                                 }
 466
 467                                 if (signal_pending(current)) {
 468                                         dev_dbg(&dev->udev->dev,
 469                                                 "%s : signal pending\n",
 470                                                 __func__);
 471                                         retval = bytes_read ? bytes_read : -EINTR;
 472                                         goto exit;
 473                                 }
 474                         }
 475                 }
 476         }
 477
 478         retval = bytes_read;
 479         /* if the primary buffer is empty then use it */
 480         spin_lock_irqsave(&dev->buflock, flags);
 481         if (should_submit && dev->read_urb_finished) {
 482                 dev->read_urb_finished = 0;
 483                 spin_unlock_irqrestore(&dev->buflock, flags);
 484                 usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 485                                  usb_rcvintpipe(dev->udev,
 486                                         dev->interrupt_in_endpoint->bEndpointAddress),
 487                                 dev->interrupt_in_buffer,
 488                                 usb_endpoint_maxp(dev->interrupt_in_endpoint),
 489                                 adu_interrupt_in_callback,
 490                                 dev,
 491                                 dev->interrupt_in_endpoint->bInterval);
 492                 if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL) != 0)
 493                         dev->read_urb_finished = 1;
 494                 /* we ignore failure */
 495         } else {
 496                 spin_unlock_irqrestore(&dev->buflock, flags);
 497         }
 498
 499 exit:
 500         /* unlock the device */
 501         mutex_unlock(&dev->mtx);
 502
 503         return retval;
 504 }
 505
 506 static ssize_t adu_write(struct file *file, const __user char *buffer,
 507                          size_t count, loff_t *ppos)
 508 {
 509         DECLARE_WAITQUEUE(waita, current);
 510         struct adu_device *dev;
 511         size_t bytes_written = 0;
 512         size_t bytes_to_write;
 513         size_t buffer_size;
 514         unsigned long flags;
 515         int retval;
 516
 517         dev = file->private_data;
 518
 519         retval = mutex_lock_interruptible(&dev->mtx);
 520         if (retval)
 521                 goto exit_nolock;
 522
 523         /* verify that the device wasn't unplugged */
 524         if (dev->disconnected) {
 525                 retval = -ENODEV;
 526                 pr_err("No device or device unplugged %d\n", retval);
 527                 goto exit;
 528         }
 529
 530         /* verify that we actually have some data to write */
 531         if (count == 0) {
 532                 dev_dbg(&dev->udev->dev, "%s : write request of 0 bytes\n",
 533                         __func__);
 534                 goto exit;
 535         }
 536
 537         while (count > 0) {
 538                 add_wait_queue(&dev->write_wait, &waita);
 539                 set_current_state(TASK_INTERRUPTIBLE);
 540                 spin_lock_irqsave(&dev->buflock, flags);
 541                 if (!dev->out_urb_finished) {
 542                         spin_unlock_irqrestore(&dev->buflock, flags);
 543
 544                         mutex_unlock(&dev->mtx);
 545                         if (signal_pending(current)) {
 546                                 dev_dbg(&dev->udev->dev, "%s : interrupted\n",
 547                                         __func__);
 548                                 set_current_state(TASK_RUNNING);
 549                                 retval = -EINTR;
 550                                 goto exit_onqueue;
 551                         }
 552                         if (schedule_timeout(COMMAND_TIMEOUT) == 0) {
 553                                 dev_dbg(&dev->udev->dev,
 554                                         "%s - command timed out.\n", __func__);
 555                                 retval = -ETIMEDOUT;
 556                                 goto exit_onqueue;
 557                         }
 558                         remove_wait_queue(&dev->write_wait, &waita);
 559                         retval = mutex_lock_interruptible(&dev->mtx);
 560                         if (retval) {
 561                                 retval = bytes_written ? bytes_written : retval;
 562                                 goto exit_nolock;
 563                         }
 564
 565                         dev_dbg(&dev->udev->dev,
 566                                 "%s : in progress, count = %zd\n",
 567                                 __func__, count);
 568                 } else {
 569                         spin_unlock_irqrestore(&dev->buflock, flags);
 570                         set_current_state(TASK_RUNNING);
 571                         remove_wait_queue(&dev->write_wait, &waita);
 572                         dev_dbg(&dev->udev->dev, "%s : sending, count = %zd\n",
 573                                 __func__, count);
 574
 575                         /* write the data into interrupt_out_buffer from userspace */
 576                         buffer_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 577                         bytes_to_write = count > buffer_size ? buffer_size : count;
 578                         dev_dbg(&dev->udev->dev,
 579                                 "%s : buffer_size = %zd, count = %zd, bytes_to_write = %zd\n",
 580                                 __func__, buffer_size, count, bytes_to_write);
 581
 582                         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
 583                                 retval = -EFAULT;
 584                                 goto exit;
 585                         }
 586
 587                         /* send off the urb */
 588                         usb_fill_int_urb(
 589                                 dev->interrupt_out_urb,
 590                                 dev->udev,
 591                                 usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 592                                 dev->interrupt_out_buffer,
 593                                 bytes_to_write,
 594                                 adu_interrupt_out_callback,
 595                                 dev,
 596                                 dev->interrupt_out_endpoint->bInterval);
 597                         dev->interrupt_out_urb->actual_length = bytes_to_write;
 598                         dev->out_urb_finished = 0;
 599                         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 600                         if (retval < 0) {
 601                                 dev->out_urb_finished = 1;
 602                                 dev_err(&dev->udev->dev, "Couldn't submit "
 603                                         "interrupt_out_urb %d\n", retval);
 604                                 goto exit;
 605                         }
 606
 607                         buffer += bytes_to_write;
 608                         count -= bytes_to_write;
 609
 610                         bytes_written += bytes_to_write;
 611                 }
 612         }
 613         mutex_unlock(&dev->mtx);
 614         return bytes_written;
 615
 616 exit:
 617         mutex_unlock(&dev->mtx);
 618 exit_nolock:
 619         return retval;
 620
 621 exit_onqueue:
 622         remove_wait_queue(&dev->write_wait, &waita);
 623         return retval;
 624 }
 625
 626 /* file operations needed when we register this driver */
 627 static const struct file_operations adu_fops = {
 628         .owner = THIS_MODULE,
 629         .read  = adu_read,
 630         .write = adu_write,
 631         .open = adu_open,
 632         .release = adu_release,
 633         .llseek = noop_llseek,
 634 };
 635
 636 /*
 637  * usb class driver info in order to get a minor number from the usb core,
 638  * and to have the device registered with devfs and the driver core
 639  */
 640 static struct usb_class_driver adu_class = {
 641         .name = "usb/adutux%d",
 642         .fops = &adu_fops,
 643         .minor_base = ADU_MINOR_BASE,
 644 };
 645
 646 /*
 647  * adu_probe
 648  *
 649  * Called by the usb core when a new device is connected that it thinks
 650  * this driver might be interested in.
 651  */
 652 static int adu_probe(struct usb_interface *interface,
 653                      const struct usb_device_id *id)
 654 {
 655         struct usb_device *udev = interface_to_usbdev(interface);
 656         struct adu_device *dev = NULL;
 657         int retval = -ENOMEM;
 658         int in_end_size;
 659         int out_end_size;
 660         int res;
 661
 662         /* allocate memory for our device state and initialize it */
 663         dev = kzalloc(sizeof(struct adu_device), GFP_KERNEL);
 664         if (!dev)
 665                 return -ENOMEM;
 666
 667         mutex_init(&dev->mtx);
 668         spin_lock_init(&dev->buflock);
 669         dev->udev = usb_get_dev(udev);
 670         init_waitqueue_head(&dev->read_wait);
 671         init_waitqueue_head(&dev->write_wait);
 672
 673         res = usb_find_common_endpoints_reverse(interface->cur_altsetting,
 674                         NULL, NULL,
 675                         &dev->interrupt_in_endpoint,
 676                         &dev->interrupt_out_endpoint);
 677         if (res) {
 678                 dev_err(&interface->dev, "interrupt endpoints not found\n");
 679                 retval = res;
 680                 goto error;
 681         }
 682
 683         in_end_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 684         out_end_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 685
 686         dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
 687         if (!dev->read_buffer_primary)
 688                 goto error;
 689
 690         /* debug code prime the buffer */
 691         memset(dev->read_buffer_primary, 'a', in_end_size);
 692         memset(dev->read_buffer_primary + in_end_size, 'b', in_end_size);
 693         memset(dev->read_buffer_primary + (2 * in_end_size), 'c', in_end_size);
 694         memset(dev->read_buffer_primary + (3 * in_end_size), 'd', in_end_size);
 695
 696         dev->read_buffer_secondary = kmalloc((4 * in_end_size), GFP_KERNEL);
 697         if (!dev->read_buffer_secondary)
 698                 goto error;
 699
 700         /* debug code prime the buffer */
 701         memset(dev->read_buffer_secondary, 'e', in_end_size);
 702         memset(dev->read_buffer_secondary + in_end_size, 'f', in_end_size);
 703         memset(dev->read_buffer_secondary + (2 * in_end_size), 'g', in_end_size);
 704         memset(dev->read_buffer_secondary + (3 * in_end_size), 'h', in_end_size);
 705
 706         dev->interrupt_in_buffer = kmalloc(in_end_size, GFP_KERNEL);
 707         if (!dev->interrupt_in_buffer)
 708                 goto error;
 709
 710         /* debug code prime the buffer */
 711         memset(dev->interrupt_in_buffer, 'i', in_end_size);
 712
 713         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 714         if (!dev->interrupt_in_urb)
 715                 goto error;
 716         dev->interrupt_out_buffer = kmalloc(out_end_size, GFP_KERNEL);
 717         if (!dev->interrupt_out_buffer)
 718                 goto error;
 719         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 720         if (!dev->interrupt_out_urb)
 721                 goto error;
 722
 723         if (!usb_string(udev, udev->descriptor.iSerialNumber, dev->serial_number,
 724                         sizeof(dev->serial_number))) {
 725                 dev_err(&interface->dev, "Could not retrieve serial number\n");
 726                 retval = -EIO;
 727                 goto error;
 728         }
 729         dev_dbg(&interface->dev, "serial_number=%s", dev->serial_number);
 730
 731         /* we can register the device now, as it is ready */
 732         usb_set_intfdata(interface, dev);
 733
 734         retval = usb_register_dev(interface, &adu_class);
 735
 736         if (retval) {
 737                 /* something prevented us from registering this driver */
 738                 dev_err(&interface->dev, "Not able to get a minor for this device.\n");
 739                 usb_set_intfdata(interface, NULL);
 740                 goto error;
 741         }
 742
 743         dev->minor = interface->minor;
 744
 745         /* let the user know what node this device is now attached to */
 746         dev_info(&interface->dev, "ADU%d %s now attached to /dev/usb/adutux%d\n",
 747                  le16_to_cpu(udev->descriptor.idProduct), dev->serial_number,
 748                  (dev->minor - ADU_MINOR_BASE));
 749
 750         return 0;
 751
 752 error:
 753         adu_delete(dev);
 754         return retval;
 755 }
 756
 757 /*
 758  * adu_disconnect
 759  *
 760  * Called by the usb core when the device is removed from the system.
 761  */
 762 static void adu_disconnect(struct usb_interface *interface)
 763 {
 764         struct adu_device *dev;
 765
 766         dev = usb_get_intfdata(interface);
 767
 768         usb_deregister_dev(interface, &adu_class);
 769
 770         usb_poison_urb(dev->interrupt_in_urb);
 771         usb_poison_urb(dev->interrupt_out_urb);
 772
 773         mutex_lock(&adutux_mutex);
 774         usb_set_intfdata(interface, NULL);
 775
 776         mutex_lock(&dev->mtx);  /* not interruptible */
 777         dev->disconnected = 1;
 778         mutex_unlock(&dev->mtx);
 779
 780         /* if the device is not opened, then we clean up right now */
 781         if (!dev->open_count)
 782                 adu_delete(dev);
 783
 784         mutex_unlock(&adutux_mutex);
 785 }
 786
 787 /* usb specific object needed to register this driver with the usb subsystem */
 788 static struct usb_driver adu_driver = {
 789         .name = "adutux",
 790         .probe = adu_probe,
 791         .disconnect = adu_disconnect,
 792         .id_table = device_table,
 793 };
 794
 795 module_usb_driver(adu_driver);
 796
 797 MODULE_AUTHOR(DRIVER_AUTHOR);
 798 MODULE_DESCRIPTION(DRIVER_DESC);
 799 MODULE_LICENSE("GPL");