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/init.h>
  26 #include <linux/slab.h>
  27 #include <linux/module.h>
  28 #include <linux/usb.h>
  29 #include <linux/mutex.h>
  30 #include <linux/uaccess.h>
  31
  32 /* Version Information */
  33 #define DRIVER_VERSION "v0.0.13"
  34 #define DRIVER_AUTHOR "John Homppi"
  35 #define DRIVER_DESC "adutux (see www.ontrak.net)"
  36
  37 /* Define these values to match your device */
  38 #define ADU_VENDOR_ID 0x0a07
  39 #define ADU_PRODUCT_ID 0x0064
  40
  41 /* table of devices that work with this driver */
  42 static const struct usb_device_id device_table[] = {
  43         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID) },          /* ADU100 */
  44         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+20) },       /* ADU120 */
  45         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+30) },       /* ADU130 */
  46         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+100) },      /* ADU200 */
  47         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+108) },      /* ADU208 */
  48         { USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+118) },      /* ADU218 */
  49         { } /* Terminating entry */
  50 };
  51
  52 MODULE_DEVICE_TABLE(usb, device_table);
  53
  54 #ifdef CONFIG_USB_DYNAMIC_MINORS
  55 #define ADU_MINOR_BASE  0
  56 #else
  57 #define ADU_MINOR_BASE  67
  58 #endif
  59
  60 /* we can have up to this number of device plugged in at once */
  61 #define MAX_DEVICES     16
  62
  63 #define COMMAND_TIMEOUT (2*HZ)  /* 60 second timeout for a command */
  64
  65 /*
  66  * The locking scheme is a vanilla 3-lock:
  67  *   adu_device.buflock: A spinlock, covers what IRQs touch.
  68  *   adutux_mutex:       A Static lock to cover open_count. It would also cover
  69  *                       any globals, but we don't have them in 2.6.
  70  *   adu_device.mtx:     A mutex to hold across sleepers like copy_from_user.
  71  *                       It covers all of adu_device, except the open_count
  72  *                       and what .buflock covers.
  73  */
  74
  75 /* Structure to hold all of our device specific stuff */
  76 struct adu_device {
  77         struct mutex            mtx;
  78         struct usb_device *udev; /* save off the usb device pointer */
  79         struct usb_interface *interface;
  80         unsigned int            minor; /* the starting minor number for this device */
  81         char                    serial_number[8];
  82
  83         int                     open_count; /* number of times this port has been opened */
  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->udev == NULL)
 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         kfree(dev);
 156 }
 157
 158 static void adu_interrupt_in_callback(struct urb *urb)
 159 {
 160         struct adu_device *dev = urb->context;
 161         int status = urb->status;
 162
 163         adu_debug_data(&dev->udev->dev, __func__,
 164                        urb->actual_length, urb->transfer_buffer);
 165
 166         spin_lock(&dev->buflock);
 167
 168         if (status != 0) {
 169                 if ((status != -ENOENT) && (status != -ECONNRESET) &&
 170                         (status != -ESHUTDOWN)) {
 171                         dev_dbg(&dev->udev->dev,
 172                                 "%s : nonzero status received: %d\n",
 173                                 __func__, status);
 174                 }
 175                 goto exit;
 176         }
 177
 178         if (urb->actual_length > 0 && dev->interrupt_in_buffer[0] != 0x00) {
 179                 if (dev->read_buffer_length <
 180                     (4 * usb_endpoint_maxp(dev->interrupt_in_endpoint)) -
 181                      (urb->actual_length)) {
 182                         memcpy (dev->read_buffer_primary +
 183                                 dev->read_buffer_length,
 184                                 dev->interrupt_in_buffer, urb->actual_length);
 185
 186                         dev->read_buffer_length += urb->actual_length;
 187                         dev_dbg(&dev->udev->dev,"%s reading  %d\n", __func__,
 188                                 urb->actual_length);
 189                 } else {
 190                         dev_dbg(&dev->udev->dev,"%s : read_buffer overflow\n",
 191                                 __func__);
 192                 }
 193         }
 194
 195 exit:
 196         dev->read_urb_finished = 1;
 197         spin_unlock(&dev->buflock);
 198         /* always wake up so we recover from errors */
 199         wake_up_interruptible(&dev->read_wait);
 200 }
 201
 202 static void adu_interrupt_out_callback(struct urb *urb)
 203 {
 204         struct adu_device *dev = urb->context;
 205         int status = urb->status;
 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(&dev->buflock);
 221         dev->out_urb_finished = 1;
 222         wake_up(&dev->write_wait);
 223         spin_unlock(&dev->buflock);
 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 || !dev->udev) {
 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->udev == NULL) {
 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 i;
 349         int retval = 0;
 350         int timeout = 0;
 351         int should_submit = 0;
 352         unsigned long flags;
 353         DECLARE_WAITQUEUE(wait, current);
 354
 355         dev = file->private_data;
 356         if (mutex_lock_interruptible(&dev->mtx))
 357                 return -ERESTARTSYS;
 358
 359         /* verify that the device wasn't unplugged */
 360         if (dev->udev == NULL) {
 361                 retval = -ENODEV;
 362                 pr_err("No device or device unplugged %d\n", retval);
 363                 goto exit;
 364         }
 365
 366         /* verify that some data was requested */
 367         if (count == 0) {
 368                 dev_dbg(&dev->udev->dev, "%s : read request of 0 bytes\n",
 369                         __func__);
 370                 goto exit;
 371         }
 372
 373         timeout = COMMAND_TIMEOUT;
 374         dev_dbg(&dev->udev->dev, "%s : about to start looping\n", __func__);
 375         while (bytes_to_read) {
 376                 int data_in_secondary = dev->secondary_tail - dev->secondary_head;
 377                 dev_dbg(&dev->udev->dev,
 378                         "%s : while, data_in_secondary=%d, status=%d\n",
 379                         __func__, data_in_secondary,
 380                         dev->interrupt_in_urb->status);
 381
 382                 if (data_in_secondary) {
 383                         /* drain secondary buffer */
 384                         int amount = bytes_to_read < data_in_secondary ? bytes_to_read : data_in_secondary;
 385                         i = copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount);
 386                         if (i) {
 387                                 retval = -EFAULT;
 388                                 goto exit;
 389                         }
 390                         dev->secondary_head += (amount - i);
 391                         bytes_read += (amount - i);
 392                         bytes_to_read -= (amount - i);
 393                         if (i) {
 394                                 retval = bytes_read ? bytes_read : -EFAULT;
 395                                 goto exit;
 396                         }
 397                 } else {
 398                         /* we check the primary buffer */
 399                         spin_lock_irqsave (&dev->buflock, flags);
 400                         if (dev->read_buffer_length) {
 401                                 /* we secure access to the primary */
 402                                 char *tmp;
 403                                 dev_dbg(&dev->udev->dev,
 404                                         "%s : swap, read_buffer_length = %d\n",
 405                                         __func__, dev->read_buffer_length);
 406                                 tmp = dev->read_buffer_secondary;
 407                                 dev->read_buffer_secondary = dev->read_buffer_primary;
 408                                 dev->read_buffer_primary = tmp;
 409                                 dev->secondary_head = 0;
 410                                 dev->secondary_tail = dev->read_buffer_length;
 411                                 dev->read_buffer_length = 0;
 412                                 spin_unlock_irqrestore(&dev->buflock, flags);
 413                                 /* we have a free buffer so use it */
 414                                 should_submit = 1;
 415                         } else {
 416                                 /* even the primary was empty - we may need to do IO */
 417                                 if (!dev->read_urb_finished) {
 418                                         /* somebody is doing IO */
 419                                         spin_unlock_irqrestore(&dev->buflock, flags);
 420                                         dev_dbg(&dev->udev->dev,
 421                                                 "%s : submitted already\n",
 422                                                 __func__);
 423                                 } else {
 424                                         /* we must initiate input */
 425                                         dev_dbg(&dev->udev->dev,
 426                                                 "%s : initiate input\n",
 427                                                 __func__);
 428                                         dev->read_urb_finished = 0;
 429                                         spin_unlock_irqrestore(&dev->buflock, flags);
 430
 431                                         usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 432                                                         usb_rcvintpipe(dev->udev,
 433                                                                 dev->interrupt_in_endpoint->bEndpointAddress),
 434                                                          dev->interrupt_in_buffer,
 435                                                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 436                                                          adu_interrupt_in_callback,
 437                                                          dev,
 438                                                          dev->interrupt_in_endpoint->bInterval);
 439                                         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 440                                         if (retval) {
 441                                                 dev->read_urb_finished = 1;
 442                                                 if (retval == -ENOMEM) {
 443                                                         retval = bytes_read ? bytes_read : -ENOMEM;
 444                                                 }
 445                                                 dev_dbg(&dev->udev->dev,
 446                                                         "%s : submit failed\n",
 447                                                         __func__);
 448                                                 goto exit;
 449                                         }
 450                                 }
 451
 452                                 /* we wait for I/O to complete */
 453                                 set_current_state(TASK_INTERRUPTIBLE);
 454                                 add_wait_queue(&dev->read_wait, &wait);
 455                                 spin_lock_irqsave(&dev->buflock, flags);
 456                                 if (!dev->read_urb_finished) {
 457                                         spin_unlock_irqrestore(&dev->buflock, flags);
 458                                         timeout = schedule_timeout(COMMAND_TIMEOUT);
 459                                 } else {
 460                                         spin_unlock_irqrestore(&dev->buflock, flags);
 461                                         set_current_state(TASK_RUNNING);
 462                                 }
 463                                 remove_wait_queue(&dev->read_wait, &wait);
 464
 465                                 if (timeout <= 0) {
 466                                         dev_dbg(&dev->udev->dev,
 467                                                 "%s : timeout\n", __func__);
 468                                         retval = bytes_read ? bytes_read : -ETIMEDOUT;
 469                                         goto exit;
 470                                 }
 471
 472                                 if (signal_pending(current)) {
 473                                         dev_dbg(&dev->udev->dev,
 474                                                 "%s : signal pending\n",
 475                                                 __func__);
 476                                         retval = bytes_read ? bytes_read : -EINTR;
 477                                         goto exit;
 478                                 }
 479                         }
 480                 }
 481         }
 482
 483         retval = bytes_read;
 484         /* if the primary buffer is empty then use it */
 485         spin_lock_irqsave(&dev->buflock, flags);
 486         if (should_submit && dev->read_urb_finished) {
 487                 dev->read_urb_finished = 0;
 488                 spin_unlock_irqrestore(&dev->buflock, flags);
 489                 usb_fill_int_urb(dev->interrupt_in_urb, dev->udev,
 490                                  usb_rcvintpipe(dev->udev,
 491                                         dev->interrupt_in_endpoint->bEndpointAddress),
 492                                 dev->interrupt_in_buffer,
 493                                 usb_endpoint_maxp(dev->interrupt_in_endpoint),
 494                                 adu_interrupt_in_callback,
 495                                 dev,
 496                                 dev->interrupt_in_endpoint->bInterval);
 497                 if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL) != 0)
 498                         dev->read_urb_finished = 1;
 499                 /* we ignore failure */
 500         } else {
 501                 spin_unlock_irqrestore(&dev->buflock, flags);
 502         }
 503
 504 exit:
 505         /* unlock the device */
 506         mutex_unlock(&dev->mtx);
 507
 508         return retval;
 509 }
 510
 511 static ssize_t adu_write(struct file *file, const __user char *buffer,
 512                          size_t count, loff_t *ppos)
 513 {
 514         DECLARE_WAITQUEUE(waita, current);
 515         struct adu_device *dev;
 516         size_t bytes_written = 0;
 517         size_t bytes_to_write;
 518         size_t buffer_size;
 519         unsigned long flags;
 520         int retval;
 521
 522         dev = file->private_data;
 523
 524         retval = mutex_lock_interruptible(&dev->mtx);
 525         if (retval)
 526                 goto exit_nolock;
 527
 528         /* verify that the device wasn't unplugged */
 529         if (dev->udev == NULL) {
 530                 retval = -ENODEV;
 531                 pr_err("No device or device unplugged %d\n", retval);
 532                 goto exit;
 533         }
 534
 535         /* verify that we actually have some data to write */
 536         if (count == 0) {
 537                 dev_dbg(&dev->udev->dev, "%s : write request of 0 bytes\n",
 538                         __func__);
 539                 goto exit;
 540         }
 541
 542         while (count > 0) {
 543                 add_wait_queue(&dev->write_wait, &waita);
 544                 set_current_state(TASK_INTERRUPTIBLE);
 545                 spin_lock_irqsave(&dev->buflock, flags);
 546                 if (!dev->out_urb_finished) {
 547                         spin_unlock_irqrestore(&dev->buflock, flags);
 548
 549                         mutex_unlock(&dev->mtx);
 550                         if (signal_pending(current)) {
 551                                 dev_dbg(&dev->udev->dev, "%s : interrupted\n",
 552                                         __func__);
 553                                 set_current_state(TASK_RUNNING);
 554                                 retval = -EINTR;
 555                                 goto exit_onqueue;
 556                         }
 557                         if (schedule_timeout(COMMAND_TIMEOUT) == 0) {
 558                                 dev_dbg(&dev->udev->dev,
 559                                         "%s - command timed out.\n", __func__);
 560                                 retval = -ETIMEDOUT;
 561                                 goto exit_onqueue;
 562                         }
 563                         remove_wait_queue(&dev->write_wait, &waita);
 564                         retval = mutex_lock_interruptible(&dev->mtx);
 565                         if (retval) {
 566                                 retval = bytes_written ? bytes_written : retval;
 567                                 goto exit_nolock;
 568                         }
 569
 570                         dev_dbg(&dev->udev->dev,
 571                                 "%s : in progress, count = %Zd\n",
 572                                 __func__, count);
 573                 } else {
 574                         spin_unlock_irqrestore(&dev->buflock, flags);
 575                         set_current_state(TASK_RUNNING);
 576                         remove_wait_queue(&dev->write_wait, &waita);
 577                         dev_dbg(&dev->udev->dev, "%s : sending, count = %Zd\n",
 578                                 __func__, count);
 579
 580                         /* write the data into interrupt_out_buffer from userspace */
 581                         buffer_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 582                         bytes_to_write = count > buffer_size ? buffer_size : count;
 583                         dev_dbg(&dev->udev->dev,
 584                                 "%s : buffer_size = %Zd, count = %Zd, bytes_to_write = %Zd\n",
 585                                 __func__, buffer_size, count, bytes_to_write);
 586
 587                         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
 588                                 retval = -EFAULT;
 589                                 goto exit;
 590                         }
 591
 592                         /* send off the urb */
 593                         usb_fill_int_urb(
 594                                 dev->interrupt_out_urb,
 595                                 dev->udev,
 596                                 usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 597                                 dev->interrupt_out_buffer,
 598                                 bytes_to_write,
 599                                 adu_interrupt_out_callback,
 600                                 dev,
 601                                 dev->interrupt_out_endpoint->bInterval);
 602                         dev->interrupt_out_urb->actual_length = bytes_to_write;
 603                         dev->out_urb_finished = 0;
 604                         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 605                         if (retval < 0) {
 606                                 dev->out_urb_finished = 1;
 607                                 dev_err(&dev->udev->dev, "Couldn't submit "
 608                                         "interrupt_out_urb %d\n", retval);
 609                                 goto exit;
 610                         }
 611
 612                         buffer += bytes_to_write;
 613                         count -= bytes_to_write;
 614
 615                         bytes_written += bytes_to_write;
 616                 }
 617         }
 618         mutex_unlock(&dev->mtx);
 619         return bytes_written;
 620
 621 exit:
 622         mutex_unlock(&dev->mtx);
 623 exit_nolock:
 624         return retval;
 625
 626 exit_onqueue:
 627         remove_wait_queue(&dev->write_wait, &waita);
 628         return retval;
 629 }
 630
 631 /* file operations needed when we register this driver */
 632 static const struct file_operations adu_fops = {
 633         .owner = THIS_MODULE,
 634         .read  = adu_read,
 635         .write = adu_write,
 636         .open = adu_open,
 637         .release = adu_release,
 638         .llseek = noop_llseek,
 639 };
 640
 641 /*
 642  * usb class driver info in order to get a minor number from the usb core,
 643  * and to have the device registered with devfs and the driver core
 644  */
 645 static struct usb_class_driver adu_class = {
 646         .name = "usb/adutux%d",
 647         .fops = &adu_fops,
 648         .minor_base = ADU_MINOR_BASE,
 649 };
 650
 651 /**
 652  * adu_probe
 653  *
 654  * Called by the usb core when a new device is connected that it thinks
 655  * this driver might be interested in.
 656  */
 657 static int adu_probe(struct usb_interface *interface,
 658                      const struct usb_device_id *id)
 659 {
 660         struct usb_device *udev = interface_to_usbdev(interface);
 661         struct adu_device *dev = NULL;
 662         struct usb_host_interface *iface_desc;
 663         struct usb_endpoint_descriptor *endpoint;
 664         int retval = -ENODEV;
 665         int in_end_size;
 666         int out_end_size;
 667         int i;
 668
 669         if (udev == NULL) {
 670                 dev_err(&interface->dev, "udev is NULL.\n");
 671                 goto exit;
 672         }
 673
 674         /* allocate memory for our device state and initialize it */
 675         dev = kzalloc(sizeof(struct adu_device), GFP_KERNEL);
 676         if (dev == NULL) {
 677                 dev_err(&interface->dev, "Out of memory\n");
 678                 retval = -ENOMEM;
 679                 goto exit;
 680         }
 681
 682         mutex_init(&dev->mtx);
 683         spin_lock_init(&dev->buflock);
 684         dev->udev = udev;
 685         init_waitqueue_head(&dev->read_wait);
 686         init_waitqueue_head(&dev->write_wait);
 687
 688         iface_desc = &interface->altsetting[0];
 689
 690         /* set up the endpoint information */
 691         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 692                 endpoint = &iface_desc->endpoint[i].desc;
 693
 694                 if (usb_endpoint_is_int_in(endpoint))
 695                         dev->interrupt_in_endpoint = endpoint;
 696
 697                 if (usb_endpoint_is_int_out(endpoint))
 698                         dev->interrupt_out_endpoint = endpoint;
 699         }
 700         if (dev->interrupt_in_endpoint == NULL) {
 701                 dev_err(&interface->dev, "interrupt in endpoint not found\n");
 702                 goto error;
 703         }
 704         if (dev->interrupt_out_endpoint == NULL) {
 705                 dev_err(&interface->dev, "interrupt out endpoint not found\n");
 706                 goto error;
 707         }
 708
 709         in_end_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
 710         out_end_size = usb_endpoint_maxp(dev->interrupt_out_endpoint);
 711
 712         dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
 713         if (!dev->read_buffer_primary) {
 714                 dev_err(&interface->dev, "Couldn't allocate read_buffer_primary\n");
 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                 dev_err(&interface->dev, "Couldn't allocate read_buffer_secondary\n");
 728                 retval = -ENOMEM;
 729                 goto error;
 730         }
 731
 732         /* debug code prime the buffer */
 733         memset(dev->read_buffer_secondary, 'e', in_end_size);
 734         memset(dev->read_buffer_secondary + in_end_size, 'f', in_end_size);
 735         memset(dev->read_buffer_secondary + (2 * in_end_size), 'g', in_end_size);
 736         memset(dev->read_buffer_secondary + (3 * in_end_size), 'h', in_end_size);
 737
 738         dev->interrupt_in_buffer = kmalloc(in_end_size, GFP_KERNEL);
 739         if (!dev->interrupt_in_buffer) {
 740                 dev_err(&interface->dev, "Couldn't allocate interrupt_in_buffer\n");
 741                 goto error;
 742         }
 743
 744         /* debug code prime the buffer */
 745         memset(dev->interrupt_in_buffer, 'i', in_end_size);
 746
 747         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 748         if (!dev->interrupt_in_urb) {
 749                 dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
 750                 goto error;
 751         }
 752         dev->interrupt_out_buffer = kmalloc(out_end_size, GFP_KERNEL);
 753         if (!dev->interrupt_out_buffer) {
 754                 dev_err(&interface->dev, "Couldn't allocate interrupt_out_buffer\n");
 755                 goto error;
 756         }
 757         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 758         if (!dev->interrupt_out_urb) {
 759                 dev_err(&interface->dev, "Couldn't allocate interrupt_out_urb\n");
 760                 goto error;
 761         }
 762
 763         if (!usb_string(udev, udev->descriptor.iSerialNumber, dev->serial_number,
 764                         sizeof(dev->serial_number))) {
 765                 dev_err(&interface->dev, "Could not retrieve serial number\n");
 766                 goto error;
 767         }
 768         dev_dbg(&interface->dev,"serial_number=%s", dev->serial_number);
 769
 770         /* we can register the device now, as it is ready */
 771         usb_set_intfdata(interface, dev);
 772
 773         retval = usb_register_dev(interface, &adu_class);
 774
 775         if (retval) {
 776                 /* something prevented us from registering this driver */
 777                 dev_err(&interface->dev, "Not able to get a minor for this device.\n");
 778                 usb_set_intfdata(interface, NULL);
 779                 goto error;
 780         }
 781
 782         dev->minor = interface->minor;
 783
 784         /* let the user know what node this device is now attached to */
 785         dev_info(&interface->dev, "ADU%d %s now attached to /dev/usb/adutux%d\n",
 786                  le16_to_cpu(udev->descriptor.idProduct), dev->serial_number,
 787                  (dev->minor - ADU_MINOR_BASE));
 788 exit:
 789         return retval;
 790
 791 error:
 792         adu_delete(dev);
 793         return retval;
 794 }
 795
 796 /**
 797  * adu_disconnect
 798  *
 799  * Called by the usb core when the device is removed from the system.
 800  */
 801 static void adu_disconnect(struct usb_interface *interface)
 802 {
 803         struct adu_device *dev;
 804         int minor;
 805
 806         dev = usb_get_intfdata(interface);
 807
 808         mutex_lock(&dev->mtx);  /* not interruptible */
 809         dev->udev = NULL;       /* poison */
 810         minor = dev->minor;
 811         usb_deregister_dev(interface, &adu_class);
 812         mutex_unlock(&dev->mtx);
 813
 814         mutex_lock(&adutux_mutex);
 815         usb_set_intfdata(interface, NULL);
 816
 817         /* if the device is not opened, then we clean up right now */
 818         dev_dbg(&dev->udev->dev, "%s : open count %d\n",
 819                 __func__, dev->open_count);
 820         if (!dev->open_count)
 821                 adu_delete(dev);
 822
 823         mutex_unlock(&adutux_mutex);
 824
 825         dev_info(&interface->dev, "ADU device adutux%d now disconnected\n",
 826                  (minor - ADU_MINOR_BASE));
 827 }
 828
 829 /* usb specific object needed to register this driver with the usb subsystem */
 830 static struct usb_driver adu_driver = {
 831         .name = "adutux",
 832         .probe = adu_probe,
 833         .disconnect = adu_disconnect,
 834         .id_table = device_table,
 835 };
 836
 837 module_usb_driver(adu_driver);
 838
 839 MODULE_AUTHOR(DRIVER_AUTHOR);
 840 MODULE_DESCRIPTION(DRIVER_DESC);
 841 MODULE_LICENSE("GPL");