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