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