drivers/usb/misc/adutux.c

   1 /*
   2  * adutux - driver for ADU devices from Ontrak Control Systems
   3  * This is an experimental driver. Use at your own risk.
   4  * This driver is not supported by Ontrak Control Systems.
   5  *
   6  * Copyright (c) 2003 John Homppi (SCO, leave this notice here)
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * derived from the Lego USB Tower driver 0.56:
  14  * Copyright (c) 2003 David Glance <davidgsf@sourceforge.net>
  15  *               2001 Juergen Stuber <stuber@loria.fr>
  16  * that was derived from USB Skeleton driver - 0.5
  17  * Copyright (c) 2001 Greg Kroah-Hartman (greg@kroah.com)
  18  *
  19  */
  20
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/kernel.h>
  24 #include <linux/errno.h>
  25 #include <linux/slab.h>
  26 #include <linux/module.h>
  27 #include <linux/usb.h>
  28 #include <linux/mutex.h>
  29 #include <linux/uaccess.h>
  30
  31 /* Version Information */
  32 #define DRIVER_VERSION "v0.0.13"
  33 #define DRIVER_AUTHOR "John Homppi"
  34 #define DRIVER_DESC "adutux (see www.ontrak.net)"
  35
  36 /* Define these values to match your device */
  37 #define ADU_VENDOR_ID 0x0a07
  38 #define ADU_PRODUCT_ID 0x0064
  39
  40 /* table of devices that work with this driver */
  41 static const struct usb_device_id device_table[] = {
  42         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID) },          /* ADU100 */
  43         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+20) },       /* ADU120 */
  44         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+30) },       /* ADU130 */
  45         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+100) },      /* ADU200 */
  46         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+108) },      /* ADU208 */
  47         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+118) },      /* ADU218 */
  48         { } /* Terminating entry */
  49 };
  50
  51 MODULE_DEVICE_TABLE(usb, device_table);
  52
  53 #ifdef CONFIG_USB_DYNAMIC_MINORS
  54 #define ADU_MINOR_BASE  0
  55 #else
  56 #define ADU_MINOR_BASE  67
  57 #endif
  58
  59 /* we can have up to this number of device plugged in at once */
  60 #define MAX_DEVICES     16
  61
  62 #define COMMAND_TIMEOUT (2*HZ)  /* 60 second timeout for a command */
  63
  64 /*
  65  * The locking scheme is a vanilla 3-lock:
  66  *   adu_device.buflock: A spinlock, covers what IRQs touch.
  67  *   adutux_mutex:       A Static lock to cover open_count. It would also cover
  68  *                       any globals, but we don't have them in 2.6.
  69  *   adu_device.mtx:     A mutex to hold across sleepers like copy_from_user.
  70  *                       It covers all of adu_device, except the open_count
  71  *                       and what .buflock covers.
  72  */
  73
  74 /* Structure to hold all of our device specific stuff */
  75 struct adu_device {
  76         struct mutex            mtx;
  77         struct usb_device *udev; /* save off the usb device pointer */
  78         struct usb_interface *interface;
  79         unsigned int            minor; /* the starting minor number for this device */
  80         char                    serial_number[8];
  81
  82         int                     open_count; /* number of times this port has been opened */
  83         unsigned long           disconnected:1;
  84
  85         char            *read_buffer_primary;
  86         int                     read_buffer_length;
  87         char            *read_buffer_secondary;
  88         int                     secondary_head;
  89         int                     secondary_tail;
  90         spinlock_t              buflock;
  91
  92         wait_queue_head_t       read_wait;
  93         wait_queue_head_t       write_wait;
  94
  95         char            *interrupt_in_buffer;
  96         struct usb_endpoint_descriptor *interrupt_in_endpoint;
  97         struct urb      *interrupt_in_urb;
  98         int                     read_urb_finished;
  99
 100         char            *interrupt_out_buffer;
 101         struct usb_endpoint_descriptor *interrupt_out_endpoint;
 102         struct urb      *interrupt_out_urb;
 103         int                     out_urb_finished;
 104 };
 105
 106 static DEFINE_MUTEX(adutux_mutex);
 107
 108 static struct usb_driver adu_driver;
 109
 110 static inline void adu_debug_data(struct device *dev, const char *function,
 111                                   int size, const unsigned char *data)
 112 {
 113         dev_dbg(dev, "%s - length = %d, data = %*ph\n",
 114                 function, size, size, data);
 115 }
 116
 117 /**
 118  * adu_abort_transfers
 119  *      aborts transfers and frees associated data structures
 120  */
 121 static void adu_abort_transfers(struct adu_device *dev)
 122 {
 123         unsigned long flags;
 124
 125         if (dev->disconnected)
 126                 return;
 127
 128         /* shutdown transfer */
 129
 130         /* XXX Anchor these instead */
 131         spin_lock_irqsave(&dev->buflock, flags);
 132         if (!dev->read_urb_finished) {
 133                 spin_unlock_irqrestore(&dev->buflock, flags);
 134                 usb_kill_urb(dev->interrupt_in_urb);
 135         } else
 136                 spin_unlock_irqrestore(&dev->buflock, flags);
 137
 138         spin_lock_irqsave(&dev->buflock, flags);
 139         if (!dev->out_urb_finished) {
 140                 spin_unlock_irqrestore(&dev->buflock, flags);
 141                 usb_kill_urb(dev->interrupt_out_urb);
 142         } else
 143                 spin_unlock_irqrestore(&dev->buflock, flags);
 144 }
 145
 146 static void adu_delete(struct adu_device *dev)
 147 {
 148         /* free data structures */
 149         usb_free_urb(dev->interrupt_in_urb);
 150         usb_free_urb(dev->interrupt_out_urb);
 151         kfree(dev->read_buffer_primary);
 152         kfree(dev->read_buffer_secondary);
 153         kfree(dev->interrupt_in_buffer);
 154         kfree(dev->interrupt_out_buffer);
 155         usb_put_dev(dev->udev);
 156         kfree(dev);
 157 }
 158
 159 static void adu_interrupt_in_callback(struct urb *urb)
 160 {
 161         struct adu_device *dev = urb->context;
 162         int status = urb->status;
 163
 164         adu_debug_data(&dev->udev->dev, __func__,
 165                        urb->actual_length, urb->transfer_buffer);
 166
 167         spin_lock(&dev->buflock);
 168
 169         if (status != 0) {
 170                 if ((status != -ENOENT) && (status != -ECONNRESET) &&
 171                         (status != -ESHUTDOWN)) {
 172                         dev_dbg(&dev->udev->dev,
 173                                 "%s : nonzero status received: %d\n",
 174                                 __func__, status);
 175                 }
 176                 goto exit;
 177         }
 178
 179         if (urb->actual_length > 0 && dev->interrupt_in_buffer[0] != 0x00) {
 180                 if (dev->read_buffer_length <
 181                     (4 * usb_endpoint_maxp(dev->interrupt_in_endpoint)) -
 182                      (urb->actual_length)) {
 183                         memcpy (dev->read_buffer_primary +
 184                                 dev->read_buffer_length,
 185                                 dev->interrupt_in_buffer, urb->actual_length);
 186
 187                         dev->read_buffer_length += urb->actual_length;
 188                         dev_dbg(&dev->udev->dev,"%s reading  %d\n", __func__,
 189                                 urb->actual_length);
 190                 } else {
 191                         dev_dbg(&dev->udev->dev,"%s : read_buffer overflow\n",
 192                                 __func__);
 193                 }
 194         }
 195
 196 exit:
 197         dev->read_urb_finished = 1;
 198         spin_unlock(&dev->buflock);
 199         /* always wake up so we recover from errors */
 200         wake_up_interruptible(&dev->read_wait);
 201 }
 202
 203 static void adu_interrupt_out_callback(struct urb *urb)
 204 {
 205         struct adu_device *dev = urb->context;
 206         int status = urb->status;
 207
 208         adu_debug_data(&dev->udev->dev, __func__,
 209                        urb->actual_length, urb->transfer_buffer);
 210
 211         if (status != 0) {
 212                 if ((status != -ENOENT) &&
 213                     (status != -ESHUTDOWN) &&
 214                     (status != -ECONNRESET)) {
 215                         dev_dbg(&dev->udev->dev,
 216                                 "%s :nonzero status received: %d\n", __func__,
 217                                 status);
 218                 }
 219                 return;
 220         }
 221
 222         spin_lock(&dev->buflock);
 223         dev->out_urb_finished = 1;
 224         wake_up(&dev->write_wait);
 225         spin_unlock(&dev->buflock);
 226 }
 227
 228 static int adu_open(struct inode *inode, struct file *file)
 229 {
 230         struct adu_device *dev = NULL;
 231         struct usb_interface *interface;
 232         int subminor;
 233         int retval;
 234
 235         subminor = iminor(inode);
 236
 237         retval = mutex_lock_interruptible(&adutux_mutex);
 238         if (retval)
 239                 goto exit_no_lock;
 240
 241         interface = usb_find_interface(&adu_driver, subminor);
 242         if (!interface) {
 243                 pr_err("%s - error, can't find device for minor %d\n",
 244                        __func__, subminor);
 245                 retval = -ENODEV;
 246                 goto exit_no_device;
 247         }
 248
 249         dev = usb_get_intfdata(interface);
 250         if (!dev) {
 251                 retval = -ENODEV;
 252                 goto exit_no_device;
 253         }
 254
 255         /* check that nobody else is using the device */
 256         if (dev->open_count) {
 257                 retval = -EBUSY;
 258                 goto exit_no_device;
 259         }
 260
 261         ++dev->open_count;
 262         dev_dbg(&dev->udev->dev, "%s: open count %d\n", __func__,
 263                 dev->open_count);
 264
 265         /* save device in the file's private structure */
 266         file->private_data = dev;
 267
 268         /* initialize in direction */
 269         dev->read_buffer_length = 0;
 270
 271         /* fixup first read by having urb waiting for it */
 272         usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 273                          usb_rcvintpipe(dev->udev,
 274                                         dev->interrupt_in_endpoint->bEndpointAddress),
 275                          dev->interrupt_in_buffer,
 276                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 277                          adu_interrupt_in_callback, dev,
 278                          dev->interrupt_in_endpoint->bInterval);
 279         dev->read_urb_finished = 0;
 280         if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL))
 281                 dev->read_urb_finished = 1;
 282         /* we ignore failure */
 283         /* end of fixup for first read */
 284
 285         /* initialize out direction */
 286         dev->out_urb_finished = 1;
 287
 288         retval = 0;
 289
 290 exit_no_device:
 291         mutex_unlock(&adutux_mutex);
 292 exit_no_lock:
 293         return retval;
 294 }
 295
 296 static void adu_release_internal(struct adu_device *dev)
 297 {
 298         /* decrement our usage count for the device */
 299         --dev->open_count;
 300         dev_dbg(&dev->udev->dev, "%s : open count %d\n", __func__,
 301                 dev->open_count);
 302         if (dev->open_count <= 0) {
 303                 adu_abort_transfers(dev);
 304                 dev->open_count = 0;
 305         }
 306 }
 307
 308 static int adu_release(struct inode *inode, struct file *file)
 309 {
 310         struct adu_device *dev;
 311         int retval = 0;
 312
 313         if (file == NULL) {
 314                 retval = -ENODEV;
 315                 goto exit;
 316         }
 317
 318         dev = file->private_data;
 319         if (dev == NULL) {
 320                 retval = -ENODEV;
 321                 goto exit;
 322         }
 323
 324         mutex_lock(&adutux_mutex); /* not interruptible */
 325
 326         if (dev->open_count <= 0) {
 327                 dev_dbg(&dev->udev->dev, "%s : device not opened\n", __func__);
 328                 retval = -ENODEV;
 329                 goto unlock;
 330         }
 331
 332         adu_release_internal(dev);
 333         if (dev->disconnected) {
 334                 /* the device was unplugged before the file was released */
 335                 if (!dev->open_count)   /* ... and we're the last user */
 336                         adu_delete(dev);
 337         }
 338 unlock:
 339         mutex_unlock(&adutux_mutex);
 340 exit:
 341         return retval;
 342 }
 343
 344 static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
 345                         loff_t *ppos)
 346 {
 347         struct adu_device *dev;
 348         size_t bytes_read = 0;
 349         size_t bytes_to_read = count;
 350         int i;
 351         int retval = 0;
 352         int timeout = 0;
 353         int should_submit = 0;
 354         unsigned long flags;
 355         DECLARE_WAITQUEUE(wait, current);
 356
 357         dev = file->private_data;
 358         if (mutex_lock_interruptible(&dev->mtx))
 359                 return -ERESTARTSYS;
 360
 361         /* verify that the device wasn't unplugged */
 362         if (dev->disconnected) {
 363                 retval = -ENODEV;
 364                 pr_err("No device or device unplugged %d\n", retval);
 365                 goto exit;
 366         }
 367
 368         /* verify that some data was requested */
 369         if (count == 0) {
 370                 dev_dbg(&dev->udev->dev, "%s : read request of 0 bytes\n",
 371                         __func__);
 372                 goto exit;
 373         }
 374
 375         timeout = COMMAND_TIMEOUT;
 376         dev_dbg(&dev->udev->dev, "%s : about to start looping\n", __func__);
 377         while (bytes_to_read) {
 378                 int data_in_secondary = dev->secondary_tail - dev->secondary_head;
 379                 dev_dbg(&dev->udev->dev,
 380                         "%s : while, data_in_secondary=%d, status=%d\n",
 381                         __func__, data_in_secondary,
 382                         dev->interrupt_in_urb->status);
 383
 384                 if (data_in_secondary) {
 385                         /* drain secondary buffer */
 386                         int amount = bytes_to_read < data_in_secondary ? bytes_to_read : data_in_secondary;
 387                         i = copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount);
 388                         if (i) {
 389                                 retval = -EFAULT;
 390                                 goto exit;
 391                         }
 392                         dev->secondary_head += (amount - i);
 393                         bytes_read += (amount - i);
 394                         bytes_to_read -= (amount - i);
 395                         if (i) {
 396                                 retval = bytes_read ? bytes_read : -EFAULT;
 397                                 goto exit;
 398                         }
 399                 } else {
 400                         /* we check the primary buffer */
 401                         spin_lock_irqsave (&dev->buflock, flags);
 402                         if (dev->read_buffer_length) {
 403                                 /* we secure access to the primary */
 404                                 char *tmp;
 405                                 dev_dbg(&dev->udev->dev,
 406                                         "%s : swap, read_buffer_length = %d\n",
 407                                         __func__, dev->read_buffer_length);
 408                                 tmp = dev->read_buffer_secondary;
 409                                 dev->read_buffer_secondary = dev->read_buffer_primary;
 410                                 dev->read_buffer_primary = tmp;
 411                                 dev->secondary_head = 0;
 412                                 dev->secondary_tail = dev->read_buffer_length;
 413                                 dev->read_buffer_length = 0;
 414                                 spin_unlock_irqrestore(&dev->buflock, flags);
 415                                 /* we have a free buffer so use it */
 416                                 should_submit = 1;
 417                         } else {
 418                                 /* even the primary was empty - we may need to do IO */
 419                                 if (!dev->read_urb_finished) {
 420                                         /* somebody is doing IO */
 421                                         spin_unlock_irqrestore(&dev->buflock, flags);
 422                                         dev_dbg(&dev->udev->dev,
 423                                                 "%s : submitted already\n",
 424                                                 __func__);
 425                                 } else {
 426                                         /* we must initiate input */
 427                                         dev_dbg(&dev->udev->dev,
 428                                                 "%s : initiate input\n",
 429                                                 __func__);
 430                                         dev->read_urb_finished = 0;
 431                                         spin_unlock_irqrestore(&dev->buflock, flags);
 432
 433                                         usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 434                                                         usb_rcvintpipe(dev->udev,
 435                                                                 dev->interrupt_in_endpoint->bEndpointAddress),
 436                                                          dev->interrupt_in_buffer,
 437                                                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 438                                                          adu_interrupt_in_callback,
 439                                                          dev,
 440                                                          dev->interrupt_in_endpoint->bInterval);
 441                                         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 442                                         if (retval) {
 443                                                 dev->read_urb_finished = 1;
 444                                                 if (retval == -ENOMEM) {
 445                                                         retval = bytes_read ? bytes_read : -ENOMEM;
 446                                                 }
 447                                                 dev_dbg(&dev->udev->dev,
 448                                                         "%s : submit failed\n",
 449                                                         __func__);
 450                                                 goto exit;
 451                                         }
 452                                 }
 453
 454                                 /* we wait for I/O to complete */
 455                                 set_current_state(TASK_INTERRUPTIBLE);
 456                                 add_wait_queue(&dev->read_wait, &wait);
 457                                 spin_lock_irqsave(&dev->buflock, flags);
 458                                 if (!dev->read_urb_finished) {
 459                                         spin_unlock_irqrestore(&dev->buflock, flags);
 460                                         timeout = schedule_timeout(COMMAND_TIMEOUT);
 461                                 } else {
 462                                         spin_unlock_irqrestore(&dev->buflock, flags);
 463                                         set_current_state(TASK_RUNNING);
 464                                 }
 465                                 remove_wait_queue(&dev->read_wait, &wait);
 466
 467                                 if (timeout <= 0) {
 468                                         dev_dbg(&dev->udev->dev,
 469                                                 "%s : timeout\n", __func__);
 470                                         retval = bytes_read ? bytes_read : -ETIMEDOUT;
 471                                         goto exit;
 472                                 }
 473
 474                                 if (signal_pending(current)) {
 475                                         dev_dbg(&dev->udev->dev,
 476                                                 "%s : signal pending\n",
 477                                                 __func__);
 478                                         retval = bytes_read ? bytes_read : -EINTR;
 479                                         goto exit;
 480                                 }
 481                         }
 482                 }
 483         }
 484
 485         retval = bytes_read;
 486         /* if the primary buffer is empty then use it */
 487         spin_lock_irqsave(&dev->buflock, flags);
 488         if (should_submit && dev->read_urb_finished) {
 489                 dev->read_urb_finished = 0;
 490                 spin_unlock_irqrestore(&dev->buflock, flags);
 491                 usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 492                                  usb_rcvintpipe(dev->udev,
 493                                         dev->interrupt_in_endpoint->bEndpointAddress),
 494                                 dev->interrupt_in_buffer,
 495                                 usb_endpoint_maxp(dev->interrupt_in_endpoint),
 496                                 adu_interrupt_in_callback,
 497                                 dev,
 498                                 dev->interrupt_in_endpoint->bInterval);
 499                 if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL) != 0)
 500                         dev->read_urb_finished = 1;
 501                 /* we ignore failure */
 502         } else {
 503                 spin_unlock_irqrestore(&dev->buflock, flags);
 504         }
 505
 506 exit:
 507         /* unlock the device */
 508         mutex_unlock(&dev->mtx);
 509
 510         return retval;
 511 }
 512
 513 static ssize_t adu_write(struct file *file, const __user char *buffer,
 514                          size_t count, loff_t *ppos)
 515 {
 516         DECLARE_WAITQUEUE(waita, current);
 517         struct adu_device *dev;
 518         size_t bytes_written = 0;
 519         size_t bytes_to_write;
 520         size_t buffer_size;
 521         unsigned long flags;
 522         int retval;
 523
 524         dev = file->private_data;
 525
 526         retval = mutex_lock_interruptible(&dev->mtx);
 527         if (retval)
 528                 goto exit_nolock;
 529
 530         /* verify that the device wasn't unplugged */
 531         if (dev->disconnected) {
 532                 retval = -ENODEV;
 533                 pr_err("No device or device unplugged %d\n", retval);
 534                 goto exit;
 535         }
 536
 537         /* verify that we actually have some data to write */
 538         if (count == 0) {
 539                 dev_dbg(&dev->udev->dev, "%s : write request of 0 bytes\n",
 540                         __func__);
 541                 goto exit;
 542         }
 543
 544         while (count > 0) {
 545                 add_wait_queue(&dev->write_wait, &waita);
 546                 set_current_state(TASK_INTERRUPTIBLE);
 547                 spin_lock_irqsave(&dev->buflock, flags);
 548                 if (!dev->out_urb_finished) {
 549                         spin_unlock_irqrestore(&dev->buflock, flags);
 550
 551                         mutex_unlock(&dev->mtx);
 552                         if (signal_pending(current)) {
 553                                 dev_dbg(&dev->udev->dev, "%s : interrupted\n",
 554                                         __func__);
 555                                 set_current_state(TASK_RUNNING);
 556                                 retval = -EINTR;
 557                                 goto exit_onqueue;
 558                         }
 559                         if (schedule_timeout(COMMAND_TIMEOUT) == 0) {
 560                                 dev_dbg(&dev->udev->dev,
 561                                         "%s - command timed out.\n", __func__);
 562                                 retval = -ETIMEDOUT;
 563                                 goto exit_onqueue;
 564                         }
 565                         remove_wait_queue(&dev->write_wait, &waita);
 566                         retval = mutex_lock_interruptible(&dev->mtx);
 567                         if (retval) {
 568                                 retval = bytes_written ? bytes_written : retval;
 569                                 goto exit_nolock;
 570                         }
 571
 572                         dev_dbg(&dev->udev->dev,
 573                                 "%s : in progress, count = %Zd\n",
 574                                 __func__, count);
 575                 } else {
 576                         spin_unlock_irqrestore(&dev->buflock, flags);
 577                         set_current_state(TASK_RUNNING);
 578                         remove_wait_queue(&dev->write_wait, &waita);
 579                         dev_dbg(&dev->udev->dev, "%s : sending, count = %Zd\n",
 580                                 __func__, count);
 581
 582                         /* write the data into interrupt_out_buffer from userspace */
 583                         buffer_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 584                         bytes_to_write = count > buffer_size ? buffer_size : count;
 585                         dev_dbg(&dev->udev->dev,
 586                                 "%s : buffer_size = %Zd, count = %Zd, bytes_to_write = %Zd\n",
 587                                 __func__, buffer_size, count, bytes_to_write);
 588
 589                         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
 590                                 retval = -EFAULT;
 591                                 goto exit;
 592                         }
 593
 594                         /* send off the urb */
 595                         usb_fill_int_urb(
 596                                 dev->interrupt_out_urb,
 597                                 dev->udev,
 598                                 usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 599                                 dev->interrupt_out_buffer,
 600                                 bytes_to_write,
 601                                 adu_interrupt_out_callback,
 602                                 dev,
 603                                 dev->interrupt_out_endpoint->bInterval);
 604                         dev->interrupt_out_urb->actual_length = bytes_to_write;
 605                         dev->out_urb_finished = 0;
 606                         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 607                         if (retval < 0) {
 608                                 dev->out_urb_finished = 1;
 609                                 dev_err(&dev->udev->dev, "Couldn't submit "
 610                                         "interrupt_out_urb %d\n", retval);
 611                                 goto exit;
 612                         }
 613
 614                         buffer += bytes_to_write;
 615                         count -= bytes_to_write;
 616
 617                         bytes_written += bytes_to_write;
 618                 }
 619         }
 620         mutex_unlock(&dev->mtx);
 621         return bytes_written;
 622
 623 exit:
 624         mutex_unlock(&dev->mtx);
 625 exit_nolock:
 626         return retval;
 627
 628 exit_onqueue:
 629         remove_wait_queue(&dev->write_wait, &waita);
 630         return retval;
 631 }
 632
 633 /* file operations needed when we register this driver */
 634 static const struct file_operations adu_fops = {
 635         .owner = THIS_MODULE,
 636         .read  = adu_read,
 637         .write = adu_write,
 638         .open = adu_open,
 639         .release = adu_release,
 640         .llseek = noop_llseek,
 641 };
 642
 643 /*
 644  * usb class driver info in order to get a minor number from the usb core,
 645  * and to have the device registered with devfs and the driver core
 646  */
 647 static struct usb_class_driver adu_class = {
 648         .name = "usb/adutux%d",
 649         .fops = &adu_fops,
 650         .minor_base = ADU_MINOR_BASE,
 651 };
 652
 653 /**
 654  * adu_probe
 655  *
 656  * Called by the usb core when a new device is connected that it thinks
 657  * this driver might be interested in.
 658  */
 659 static int adu_probe(struct usb_interface *interface,
 660                      const struct usb_device_id *id)
 661 {
 662         struct usb_device *udev = interface_to_usbdev(interface);
 663         struct adu_device *dev = NULL;
 664         struct usb_host_interface *iface_desc;
 665         struct usb_endpoint_descriptor *endpoint;
 666         int retval = -ENODEV;
 667         int in_end_size;
 668         int out_end_size;
 669         int i;
 670
 671         if (udev == NULL) {
 672                 dev_err(&interface->dev, "udev is NULL.\n");
 673                 goto exit;
 674         }
 675
 676         /* allocate memory for our device state and initialize it */
 677         dev = kzalloc(sizeof(struct adu_device), GFP_KERNEL);
 678         if (!dev) {
 679                 retval = -ENOMEM;
 680                 goto exit;
 681         }
 682
 683         mutex_init(&dev->mtx);
 684         spin_lock_init(&dev->buflock);
 685         dev->udev = usb_get_dev(udev);
 686         init_waitqueue_head(&dev->read_wait);
 687         init_waitqueue_head(&dev->write_wait);
 688
 689         iface_desc = &interface->cur_altsetting[0];
 690
 691         /* set up the endpoint information */
 692         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 693                 endpoint = &iface_desc->endpoint[i].desc;
 694
 695                 if (usb_endpoint_is_int_in(endpoint))
 696                         dev->interrupt_in_endpoint = endpoint;
 697
 698                 if (usb_endpoint_is_int_out(endpoint))
 699                         dev->interrupt_out_endpoint = endpoint;
 700         }
 701         if (dev->interrupt_in_endpoint == NULL) {
 702                 dev_err(&interface->dev, "interrupt in endpoint not found\n");
 703                 goto error;
 704         }
 705         if (dev->interrupt_out_endpoint == NULL) {
 706                 dev_err(&interface->dev, "interrupt out endpoint not found\n");
 707                 goto error;
 708         }
 709
 710         in_end_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 711         out_end_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 712
 713         dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
 714         if (!dev->read_buffer_primary) {
 715                 retval = -ENOMEM;
 716                 goto error;
 717         }
 718
 719         /* debug code prime the buffer */
 720         memset(dev->read_buffer_primary, 'a', in_end_size);
 721         memset(dev->read_buffer_primary + in_end_size, 'b', in_end_size);
 722         memset(dev->read_buffer_primary + (2 * in_end_size), 'c', in_end_size);
 723         memset(dev->read_buffer_primary + (3 * in_end_size), 'd', in_end_size);
 724
 725         dev->read_buffer_secondary = kmalloc((4 * in_end_size), GFP_KERNEL);
 726         if (!dev->read_buffer_secondary) {
 727                 retval = -ENOMEM;
 728                 goto error;
 729         }
 730
 731         /* debug code prime the buffer */
 732         memset(dev->read_buffer_secondary, 'e', in_end_size);
 733         memset(dev->read_buffer_secondary + in_end_size, 'f', in_end_size);
 734         memset(dev->read_buffer_secondary + (2 * in_end_size), 'g', in_end_size);
 735         memset(dev->read_buffer_secondary + (3 * in_end_size), 'h', in_end_size);
 736
 737         dev->interrupt_in_buffer = kmalloc(in_end_size, GFP_KERNEL);
 738         if (!dev->interrupt_in_buffer)
 739                 goto error;
 740
 741         /* debug code prime the buffer */
 742         memset(dev->interrupt_in_buffer, 'i', in_end_size);
 743
 744         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 745         if (!dev->interrupt_in_urb)
 746                 goto error;
 747         dev->interrupt_out_buffer = kmalloc(out_end_size, GFP_KERNEL);
 748         if (!dev->interrupt_out_buffer)
 749                 goto error;
 750         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 751         if (!dev->interrupt_out_urb)
 752                 goto error;
 753
 754         if (!usb_string(udev, udev->descriptor.iSerialNumber, dev->serial_number,
 755                         sizeof(dev->serial_number))) {
 756                 dev_err(&interface->dev, "Could not retrieve serial number\n");
 757                 goto error;
 758         }
 759         dev_dbg(&interface->dev,"serial_number=%s", dev->serial_number);
 760
 761         /* we can register the device now, as it is ready */
 762         usb_set_intfdata(interface, dev);
 763
 764         retval = usb_register_dev(interface, &adu_class);
 765
 766         if (retval) {
 767                 /* something prevented us from registering this driver */
 768                 dev_err(&interface->dev, "Not able to get a minor for this device.\n");
 769                 usb_set_intfdata(interface, NULL);
 770                 goto error;
 771         }
 772
 773         dev->minor = interface->minor;
 774
 775         /* let the user know what node this device is now attached to */
 776         dev_info(&interface->dev, "ADU%d %s now attached to /dev/usb/adutux%d\n",
 777                  le16_to_cpu(udev->descriptor.idProduct), dev->serial_number,
 778                  (dev->minor - ADU_MINOR_BASE));
 779 exit:
 780         return retval;
 781
 782 error:
 783         adu_delete(dev);
 784         return retval;
 785 }
 786
 787 /**
 788  * adu_disconnect
 789  *
 790  * Called by the usb core when the device is removed from the system.
 791  */
 792 static void adu_disconnect(struct usb_interface *interface)
 793 {
 794         struct adu_device *dev;
 795
 796         dev = usb_get_intfdata(interface);
 797
 798         usb_deregister_dev(interface, &adu_class);
 799
 800         usb_poison_urb(dev->interrupt_in_urb);
 801         usb_poison_urb(dev->interrupt_out_urb);
 802
 803         mutex_lock(&adutux_mutex);
 804         usb_set_intfdata(interface, NULL);
 805
 806         mutex_lock(&dev->mtx);  /* not interruptible */
 807         dev->disconnected = 1;
 808         mutex_unlock(&dev->mtx);
 809
 810         /* if the device is not opened, then we clean up right now */
 811         if (!dev->open_count)
 812                 adu_delete(dev);
 813
 814         mutex_unlock(&adutux_mutex);
 815 }
 816
 817 /* usb specific object needed to register this driver with the usb subsystem */
 818 static struct usb_driver adu_driver = {
 819         .name = "adutux",
 820         .probe = adu_probe,
 821         .disconnect = adu_disconnect,
 822         .id_table = device_table,
 823 };
 824
 825 module_usb_driver(adu_driver);
 826
 827 MODULE_AUTHOR(DRIVER_AUTHOR);
 828 MODULE_DESCRIPTION(DRIVER_DESC);
 829 MODULE_LICENSE("GPL");