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