drivers/hid/usbhid/hiddev.c

   1 /*
   2  *  Copyright (c) 2001 Paul Stewart
   3  *  Copyright (c) 2001 Vojtech Pavlik
   4  *
   5  *  HID char devices, giving access to raw HID device events.
   6  *
   7  */
   8
   9 /*
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  *
  24  * Should you need to contact me, the author, you can do so either by
  25  * e-mail - mail your message to Paul Stewart <stewart@wetlogic.net>
  26  */
  27
  28 #include <linux/poll.h>
  29 #include <linux/slab.h>
  30 #include <linux/module.h>
  31 #include <linux/init.h>
  32 #include <linux/smp_lock.h>
  33 #include <linux/input.h>
  34 #include <linux/usb.h>
  35 #include <linux/hid.h>
  36 #include <linux/hiddev.h>
  37 #include <linux/compat.h>
  38 #include "usbhid.h"
  39
  40 #ifdef CONFIG_USB_DYNAMIC_MINORS
  41 #define HIDDEV_MINOR_BASE       0
  42 #define HIDDEV_MINORS           256
  43 #else
  44 #define HIDDEV_MINOR_BASE       96
  45 #define HIDDEV_MINORS           16
  46 #endif
  47 #define HIDDEV_BUFFER_SIZE      2048
  48
  49 struct hiddev {
  50         int exist;
  51         int open;
  52         struct mutex existancelock;
  53         wait_queue_head_t wait;
  54         struct hid_device *hid;
  55         struct list_head list;
  56         spinlock_t list_lock;
  57 };
  58
  59 struct hiddev_list {
  60         struct hiddev_usage_ref buffer[HIDDEV_BUFFER_SIZE];
  61         int head;
  62         int tail;
  63         unsigned flags;
  64         struct fasync_struct *fasync;
  65         struct hiddev *hiddev;
  66         struct list_head node;
  67         struct mutex thread_lock;
  68 };
  69
  70 static struct hiddev *hiddev_table[HIDDEV_MINORS];
  71
  72 /*
  73  * Find a report, given the report's type and ID.  The ID can be specified
  74  * indirectly by REPORT_ID_FIRST (which returns the first report of the given
  75  * type) or by (REPORT_ID_NEXT | old_id), which returns the next report of the
  76  * given type which follows old_id.
  77  */
  78 static struct hid_report *
  79 hiddev_lookup_report(struct hid_device *hid, struct hiddev_report_info *rinfo)
  80 {
  81         unsigned int flags = rinfo->report_id & ~HID_REPORT_ID_MASK;
  82         unsigned int rid = rinfo->report_id & HID_REPORT_ID_MASK;
  83         struct hid_report_enum *report_enum;
  84         struct hid_report *report;
  85         struct list_head *list;
  86
  87         if (rinfo->report_type < HID_REPORT_TYPE_MIN ||
  88             rinfo->report_type > HID_REPORT_TYPE_MAX)
  89                 return NULL;
  90
  91         report_enum = hid->report_enum +
  92                 (rinfo->report_type - HID_REPORT_TYPE_MIN);
  93
  94         switch (flags) {
  95         case 0: /* Nothing to do -- report_id is already set correctly */
  96                 break;
  97
  98         case HID_REPORT_ID_FIRST:
  99                 if (list_empty(&report_enum->report_list))
 100                         return NULL;
 101
 102                 list = report_enum->report_list.next;
 103                 report = list_entry(list, struct hid_report, list);
 104                 rinfo->report_id = report->id;
 105                 break;
 106
 107         case HID_REPORT_ID_NEXT:
 108                 report = report_enum->report_id_hash[rid];
 109                 if (!report)
 110                         return NULL;
 111
 112                 list = report->list.next;
 113                 if (list == &report_enum->report_list)
 114                         return NULL;
 115
 116                 report = list_entry(list, struct hid_report, list);
 117                 rinfo->report_id = report->id;
 118                 break;
 119
 120         default:
 121                 return NULL;
 122         }
 123
 124         return report_enum->report_id_hash[rinfo->report_id];
 125 }
 126
 127 /*
 128  * Perform an exhaustive search of the report table for a usage, given its
 129  * type and usage id.
 130  */
 131 static struct hid_field *
 132 hiddev_lookup_usage(struct hid_device *hid, struct hiddev_usage_ref *uref)
 133 {
 134         int i, j;
 135         struct hid_report *report;
 136         struct hid_report_enum *report_enum;
 137         struct hid_field *field;
 138
 139         if (uref->report_type < HID_REPORT_TYPE_MIN ||
 140             uref->report_type > HID_REPORT_TYPE_MAX)
 141                 return NULL;
 142
 143         report_enum = hid->report_enum +
 144                 (uref->report_type - HID_REPORT_TYPE_MIN);
 145
 146         list_for_each_entry(report, &report_enum->report_list, list) {
 147                 for (i = 0; i < report->maxfield; i++) {
 148                         field = report->field[i];
 149                         for (j = 0; j < field->maxusage; j++) {
 150                                 if (field->usage[j].hid == uref->usage_code) {
 151                                         uref->report_id = report->id;
 152                                         uref->field_index = i;
 153                                         uref->usage_index = j;
 154                                         return field;
 155                                 }
 156                         }
 157                 }
 158         }
 159
 160         return NULL;
 161 }
 162
 163 static void hiddev_send_event(struct hid_device *hid,
 164                               struct hiddev_usage_ref *uref)
 165 {
 166         struct hiddev *hiddev = hid->hiddev;
 167         struct hiddev_list *list;
 168         unsigned long flags;
 169
 170         spin_lock_irqsave(&hiddev->list_lock, flags);
 171         list_for_each_entry(list, &hiddev->list, node) {
 172                 if (uref->field_index != HID_FIELD_INDEX_NONE ||
 173                     (list->flags & HIDDEV_FLAG_REPORT) != 0) {
 174                         list->buffer[list->head] = *uref;
 175                         list->head = (list->head + 1) &
 176                                 (HIDDEV_BUFFER_SIZE - 1);
 177                         kill_fasync(&list->fasync, SIGIO, POLL_IN);
 178                 }
 179         }
 180         spin_unlock_irqrestore(&hiddev->list_lock, flags);
 181
 182         wake_up_interruptible(&hiddev->wait);
 183 }
 184
 185 /*
 186  * This is where hid.c calls into hiddev to pass an event that occurred over
 187  * the interrupt pipe
 188  */
 189 void hiddev_hid_event(struct hid_device *hid, struct hid_field *field,
 190                       struct hid_usage *usage, __s32 value)
 191 {
 192         unsigned type = field->report_type;
 193         struct hiddev_usage_ref uref;
 194
 195         uref.report_type =
 196           (type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
 197           ((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT :
 198            ((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE : 0));
 199         uref.report_id = field->report->id;
 200         uref.field_index = field->index;
 201         uref.usage_index = (usage - field->usage);
 202         uref.usage_code = usage->hid;
 203         uref.value = value;
 204
 205         hiddev_send_event(hid, &uref);
 206 }
 207 EXPORT_SYMBOL_GPL(hiddev_hid_event);
 208
 209 void hiddev_report_event(struct hid_device *hid, struct hid_report *report)
 210 {
 211         unsigned type = report->type;
 212         struct hiddev_usage_ref uref;
 213
 214         memset(&uref, 0, sizeof(uref));
 215         uref.report_type =
 216           (type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
 217           ((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT :
 218            ((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE : 0));
 219         uref.report_id = report->id;
 220         uref.field_index = HID_FIELD_INDEX_NONE;
 221
 222         hiddev_send_event(hid, &uref);
 223 }
 224
 225 /*
 226  * fasync file op
 227  */
 228 static int hiddev_fasync(int fd, struct file *file, int on)
 229 {
 230         struct hiddev_list *list = file->private_data;
 231
 232         return fasync_helper(fd, file, on, &list->fasync);
 233 }
 234
 235
 236 /*
 237  * release file op
 238  */
 239 static int hiddev_release(struct inode * inode, struct file * file)
 240 {
 241         struct hiddev_list *list = file->private_data;
 242         unsigned long flags;
 243
 244         spin_lock_irqsave(&list->hiddev->list_lock, flags);
 245         list_del(&list->node);
 246         spin_unlock_irqrestore(&list->hiddev->list_lock, flags);
 247
 248         if (!--list->hiddev->open) {
 249                 if (list->hiddev->exist) {
 250                         usbhid_close(list->hiddev->hid);
 251                         usbhid_put_power(list->hiddev->hid);
 252                 } else {
 253                         kfree(list->hiddev);
 254                 }
 255         }
 256
 257         kfree(list);
 258
 259         return 0;
 260 }
 261
 262 /*
 263  * open file op
 264  */
 265 static int hiddev_open(struct inode *inode, struct file *file)
 266 {
 267         struct hiddev_list *list;
 268         int res, i;
 269
 270         /* See comment in hiddev_connect() for BKL explanation */
 271         lock_kernel();
 272         i = iminor(inode) - HIDDEV_MINOR_BASE;
 273
 274         if (i >= HIDDEV_MINORS || i < 0 || !hiddev_table[i])
 275                 return -ENODEV;
 276
 277         if (!(list = kzalloc(sizeof(struct hiddev_list), GFP_KERNEL)))
 278                 return -ENOMEM;
 279         mutex_init(&list->thread_lock);
 280
 281         list->hiddev = hiddev_table[i];
 282
 283
 284         file->private_data = list;
 285
 286         /*
 287          * no need for locking because the USB major number
 288          * is shared which usbcore guards against disconnect
 289          */
 290         if (list->hiddev->exist) {
 291                 if (!list->hiddev->open++) {
 292                         res = usbhid_open(hiddev_table[i]->hid);
 293                         if (res < 0) {
 294                                 res = -EIO;
 295                                 goto bail;
 296                         }
 297                 }
 298         } else {
 299                 res = -ENODEV;
 300                 goto bail;
 301         }
 302
 303         spin_lock_irq(&list->hiddev->list_lock);
 304         list_add_tail(&list->node, &hiddev_table[i]->list);
 305         spin_unlock_irq(&list->hiddev->list_lock);
 306
 307         if (!list->hiddev->open++)
 308                 if (list->hiddev->exist) {
 309                         struct hid_device *hid = hiddev_table[i]->hid;
 310                         res = usbhid_get_power(hid);
 311                         if (res < 0) {
 312                                 res = -EIO;
 313                                 goto bail;
 314                         }
 315                         usbhid_open(hid);
 316                 }
 317
 318         unlock_kernel();
 319         return 0;
 320 bail:
 321         file->private_data = NULL;
 322         kfree(list);
 323         unlock_kernel();
 324         return res;
 325 }
 326
 327 /*
 328  * "write" file op
 329  */
 330 static ssize_t hiddev_write(struct file * file, const char __user * buffer, size_t count, loff_t *ppos)
 331 {
 332         return -EINVAL;
 333 }
 334
 335 /*
 336  * "read" file op
 337  */
 338 static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t count, loff_t *ppos)
 339 {
 340         DEFINE_WAIT(wait);
 341         struct hiddev_list *list = file->private_data;
 342         int event_size;
 343         int retval;
 344
 345         event_size = ((list->flags & HIDDEV_FLAG_UREF) != 0) ?
 346                 sizeof(struct hiddev_usage_ref) : sizeof(struct hiddev_event);
 347
 348         if (count < event_size)
 349                 return 0;
 350
 351         /* lock against other threads */
 352         retval = mutex_lock_interruptible(&list->thread_lock);
 353         if (retval)
 354                 return -ERESTARTSYS;
 355
 356         while (retval == 0) {
 357                 if (list->head == list->tail) {
 358                         prepare_to_wait(&list->hiddev->wait, &wait, TASK_INTERRUPTIBLE);
 359
 360                         while (list->head == list->tail) {
 361                                 if (file->f_flags & O_NONBLOCK) {
 362                                         retval = -EAGAIN;
 363                                         break;
 364                                 }
 365                                 if (signal_pending(current)) {
 366                                         retval = -ERESTARTSYS;
 367                                         break;
 368                                 }
 369                                 if (!list->hiddev->exist) {
 370                                         retval = -EIO;
 371                                         break;
 372                                 }
 373
 374                                 /* let O_NONBLOCK tasks run */
 375                                 mutex_unlock(&list->thread_lock);
 376                                 schedule();
 377                                 if (mutex_lock_interruptible(&list->thread_lock))
 378                                         return -EINTR;
 379                                 set_current_state(TASK_INTERRUPTIBLE);
 380                         }
 381                         finish_wait(&list->hiddev->wait, &wait);
 382
 383                 }
 384
 385                 if (retval) {
 386                         mutex_unlock(&list->thread_lock);
 387                         return retval;
 388                 }
 389
 390
 391                 while (list->head != list->tail &&
 392                        retval + event_size <= count) {
 393                         if ((list->flags & HIDDEV_FLAG_UREF) == 0) {
 394                                 if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE) {
 395                                         struct hiddev_event event;
 396
 397                                         event.hid = list->buffer[list->tail].usage_code;
 398                                         event.value = list->buffer[list->tail].value;
 399                                         if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event))) {
 400                                                 mutex_unlock(&list->thread_lock);
 401                                                 return -EFAULT;
 402                                         }
 403                                         retval += sizeof(struct hiddev_event);
 404                                 }
 405                         } else {
 406                                 if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE ||
 407                                     (list->flags & HIDDEV_FLAG_REPORT) != 0) {
 408
 409                                         if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref))) {
 410                                                 mutex_unlock(&list->thread_lock);
 411                                                 return -EFAULT;
 412                                         }
 413                                         retval += sizeof(struct hiddev_usage_ref);
 414                                 }
 415                         }
 416                         list->tail = (list->tail + 1) & (HIDDEV_BUFFER_SIZE - 1);
 417                 }
 418
 419         }
 420         mutex_unlock(&list->thread_lock);
 421
 422         return retval;
 423 }
 424
 425 /*
 426  * "poll" file op
 427  * No kernel lock - fine
 428  */
 429 static unsigned int hiddev_poll(struct file *file, poll_table *wait)
 430 {
 431         struct hiddev_list *list = file->private_data;
 432
 433         poll_wait(file, &list->hiddev->wait, wait);
 434         if (list->head != list->tail)
 435                 return POLLIN | POLLRDNORM;
 436         if (!list->hiddev->exist)
 437                 return POLLERR | POLLHUP;
 438         return 0;
 439 }
 440
 441 /*
 442  * "ioctl" file op
 443  */
 444 static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
 445 {
 446         struct hid_device *hid = hiddev->hid;
 447         struct hiddev_report_info rinfo;
 448         struct hiddev_usage_ref_multi *uref_multi = NULL;
 449         struct hiddev_usage_ref *uref;
 450         struct hid_report *report;
 451         struct hid_field *field;
 452         int i;
 453
 454         uref_multi = kmalloc(sizeof(struct hiddev_usage_ref_multi), GFP_KERNEL);
 455         if (!uref_multi)
 456                 return -ENOMEM;
 457         uref = &uref_multi->uref;
 458         if (cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) {
 459                 if (copy_from_user(uref_multi, user_arg,
 460                                    sizeof(*uref_multi)))
 461                         goto fault;
 462         } else {
 463                 if (copy_from_user(uref, user_arg, sizeof(*uref)))
 464                         goto fault;
 465         }
 466
 467         switch (cmd) {
 468         case HIDIOCGUCODE:
 469                 rinfo.report_type = uref->report_type;
 470                 rinfo.report_id = uref->report_id;
 471                 if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
 472                         goto inval;
 473
 474                 if (uref->field_index >= report->maxfield)
 475                         goto inval;
 476
 477                 field = report->field[uref->field_index];
 478                 if (uref->usage_index >= field->maxusage)
 479                         goto inval;
 480
 481                 uref->usage_code = field->usage[uref->usage_index].hid;
 482
 483                 if (copy_to_user(user_arg, uref, sizeof(*uref)))
 484                         goto fault;
 485
 486                 goto goodreturn;
 487
 488         default:
 489                 if (cmd != HIDIOCGUSAGE &&
 490                     cmd != HIDIOCGUSAGES &&
 491                     uref->report_type == HID_REPORT_TYPE_INPUT)
 492                         goto inval;
 493
 494                 if (uref->report_id == HID_REPORT_ID_UNKNOWN) {
 495                         field = hiddev_lookup_usage(hid, uref);
 496                         if (field == NULL)
 497                                 goto inval;
 498                 } else {
 499                         rinfo.report_type = uref->report_type;
 500                         rinfo.report_id = uref->report_id;
 501                         if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
 502                                 goto inval;
 503
 504                         if (uref->field_index >= report->maxfield)
 505                                 goto inval;
 506
 507                         field = report->field[uref->field_index];
 508
 509                         if (cmd == HIDIOCGCOLLECTIONINDEX) {
 510                                 if (uref->usage_index >= field->maxusage)
 511                                         goto inval;
 512                         } else if (uref->usage_index >= field->report_count)
 513                                 goto inval;
 514
 515                         else if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
 516                                  (uref_multi->num_values > HID_MAX_MULTI_USAGES ||
 517                                   uref->usage_index + uref_multi->num_values > field->report_count))
 518                                 goto inval;
 519                         }
 520
 521                 switch (cmd) {
 522                 case HIDIOCGUSAGE:
 523                         uref->value = field->value[uref->usage_index];
 524                         if (copy_to_user(user_arg, uref, sizeof(*uref)))
 525                                 goto fault;
 526                         goto goodreturn;
 527
 528                 case HIDIOCSUSAGE:
 529                         field->value[uref->usage_index] = uref->value;
 530                         goto goodreturn;
 531
 532                 case HIDIOCGCOLLECTIONINDEX:
 533                         i = field->usage[uref->usage_index].collection_index;
 534                         kfree(uref_multi);
 535                         return i;
 536                 case HIDIOCGUSAGES:
 537                         for (i = 0; i < uref_multi->num_values; i++)
 538                                 uref_multi->values[i] =
 539                                     field->value[uref->usage_index + i];
 540                         if (copy_to_user(user_arg, uref_multi,
 541                                          sizeof(*uref_multi)))
 542                                 goto fault;
 543                         goto goodreturn;
 544                 case HIDIOCSUSAGES:
 545                         for (i = 0; i < uref_multi->num_values; i++)
 546                                 field->value[uref->usage_index + i] =
 547                                     uref_multi->values[i];
 548                         goto goodreturn;
 549                 }
 550
 551 goodreturn:
 552                 kfree(uref_multi);
 553                 return 0;
 554 fault:
 555                 kfree(uref_multi);
 556                 return -EFAULT;
 557 inval:
 558                 kfree(uref_multi);
 559                 return -EINVAL;
 560         }
 561 }
 562
 563 static noinline int hiddev_ioctl_string(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
 564 {
 565         struct hid_device *hid = hiddev->hid;
 566         struct usb_device *dev = hid_to_usb_dev(hid);
 567         int idx, len;
 568         char *buf;
 569
 570         if (get_user(idx, (int __user *)user_arg))
 571                 return -EFAULT;
 572
 573         if ((buf = kmalloc(HID_STRING_SIZE, GFP_KERNEL)) == NULL)
 574                 return -ENOMEM;
 575
 576         if ((len = usb_string(dev, idx, buf, HID_STRING_SIZE-1)) < 0) {
 577                 kfree(buf);
 578                 return -EINVAL;
 579         }
 580
 581         if (copy_to_user(user_arg+sizeof(int), buf, len+1)) {
 582                 kfree(buf);
 583                 return -EFAULT;
 584         }
 585
 586         kfree(buf);
 587
 588         return len;
 589 }
 590
 591 static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 592 {
 593         struct hiddev_list *list = file->private_data;
 594         struct hiddev *hiddev = list->hiddev;
 595         struct hid_device *hid = hiddev->hid;
 596         struct usb_device *dev = hid_to_usb_dev(hid);
 597         struct hiddev_collection_info cinfo;
 598         struct hiddev_report_info rinfo;
 599         struct hiddev_field_info finfo;
 600         struct hiddev_devinfo dinfo;
 601         struct hid_report *report;
 602         struct hid_field *field;
 603         struct usbhid_device *usbhid = hid->driver_data;
 604         void __user *user_arg = (void __user *)arg;
 605         int i, r;
 606
 607         /* Called without BKL by compat methods so no BKL taken */
 608
 609         /* FIXME: Who or what stop this racing with a disconnect ?? */
 610         if (!hiddev->exist)
 611                 return -EIO;
 612
 613         switch (cmd) {
 614
 615         case HIDIOCGVERSION:
 616                 return put_user(HID_VERSION, (int __user *)arg);
 617
 618         case HIDIOCAPPLICATION:
 619                 if (arg < 0 || arg >= hid->maxapplication)
 620                         return -EINVAL;
 621
 622                 for (i = 0; i < hid->maxcollection; i++)
 623                         if (hid->collection[i].type ==
 624                             HID_COLLECTION_APPLICATION && arg-- == 0)
 625                                 break;
 626
 627                 if (i == hid->maxcollection)
 628                         return -EINVAL;
 629
 630                 return hid->collection[i].usage;
 631
 632         case HIDIOCGDEVINFO:
 633                 dinfo.bustype = BUS_USB;
 634                 dinfo.busnum = dev->bus->busnum;
 635                 dinfo.devnum = dev->devnum;
 636                 dinfo.ifnum = usbhid->ifnum;
 637                 dinfo.vendor = le16_to_cpu(dev->descriptor.idVendor);
 638                 dinfo.product = le16_to_cpu(dev->descriptor.idProduct);
 639                 dinfo.version = le16_to_cpu(dev->descriptor.bcdDevice);
 640                 dinfo.num_applications = hid->maxapplication;
 641                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 642                         return -EFAULT;
 643
 644                 return 0;
 645
 646         case HIDIOCGFLAG:
 647                 if (put_user(list->flags, (int __user *)arg))
 648                         return -EFAULT;
 649
 650                 return 0;
 651
 652         case HIDIOCSFLAG:
 653                 {
 654                         int newflags;
 655                         if (get_user(newflags, (int __user *)arg))
 656                                 return -EFAULT;
 657
 658                         if ((newflags & ~HIDDEV_FLAGS) != 0 ||
 659                             ((newflags & HIDDEV_FLAG_REPORT) != 0 &&
 660                              (newflags & HIDDEV_FLAG_UREF) == 0))
 661                                 return -EINVAL;
 662
 663                         list->flags = newflags;
 664
 665                         return 0;
 666                 }
 667
 668         case HIDIOCGSTRING:
 669                 mutex_lock(&hiddev->existancelock);
 670                 if (hiddev->exist)
 671                         r = hiddev_ioctl_string(hiddev, cmd, user_arg);
 672                 else
 673                         r = -ENODEV;
 674                 mutex_unlock(&hiddev->existancelock);
 675                 return r;
 676
 677         case HIDIOCINITREPORT:
 678                 mutex_lock(&hiddev->existancelock);
 679                 if (!hiddev->exist) {
 680                         mutex_unlock(&hiddev->existancelock);
 681                         return -ENODEV;
 682                 }
 683                 usbhid_init_reports(hid);
 684                 mutex_unlock(&hiddev->existancelock);
 685
 686                 return 0;
 687
 688         case HIDIOCGREPORT:
 689                 if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
 690                         return -EFAULT;
 691
 692                 if (rinfo.report_type == HID_REPORT_TYPE_OUTPUT)
 693                         return -EINVAL;
 694
 695                 if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
 696                         return -EINVAL;
 697
 698                 mutex_lock(&hiddev->existancelock);
 699                 if (hiddev->exist) {
 700                         usbhid_submit_report(hid, report, USB_DIR_IN);
 701                         usbhid_wait_io(hid);
 702                 }
 703                 mutex_unlock(&hiddev->existancelock);
 704
 705                 return 0;
 706
 707         case HIDIOCSREPORT:
 708                 if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
 709                         return -EFAULT;
 710
 711                 if (rinfo.report_type == HID_REPORT_TYPE_INPUT)
 712                         return -EINVAL;
 713
 714                 if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
 715                         return -EINVAL;
 716
 717                 mutex_lock(&hiddev->existancelock);
 718                 if (hiddev->exist) {
 719                         usbhid_submit_report(hid, report, USB_DIR_OUT);
 720                         usbhid_wait_io(hid);
 721                 }
 722                 mutex_unlock(&hiddev->existancelock);
 723
 724                 return 0;
 725
 726         case HIDIOCGREPORTINFO:
 727                 if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))
 728                         return -EFAULT;
 729
 730                 if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
 731                         return -EINVAL;
 732
 733                 rinfo.num_fields = report->maxfield;
 734
 735                 if (copy_to_user(user_arg, &rinfo, sizeof(rinfo)))
 736                         return -EFAULT;
 737
 738                 return 0;
 739
 740         case HIDIOCGFIELDINFO:
 741                 if (copy_from_user(&finfo, user_arg, sizeof(finfo)))
 742                         return -EFAULT;
 743                 rinfo.report_type = finfo.report_type;
 744                 rinfo.report_id = finfo.report_id;
 745                 if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
 746                         return -EINVAL;
 747
 748                 if (finfo.field_index >= report->maxfield)
 749                         return -EINVAL;
 750
 751                 field = report->field[finfo.field_index];
 752                 memset(&finfo, 0, sizeof(finfo));
 753                 finfo.report_type = rinfo.report_type;
 754                 finfo.report_id = rinfo.report_id;
 755                 finfo.field_index = field->report_count - 1;
 756                 finfo.maxusage = field->maxusage;
 757                 finfo.flags = field->flags;
 758                 finfo.physical = field->physical;
 759                 finfo.logical = field->logical;
 760                 finfo.application = field->application;
 761                 finfo.logical_minimum = field->logical_minimum;
 762                 finfo.logical_maximum = field->logical_maximum;
 763                 finfo.physical_minimum = field->physical_minimum;
 764                 finfo.physical_maximum = field->physical_maximum;
 765                 finfo.unit_exponent = field->unit_exponent;
 766                 finfo.unit = field->unit;
 767
 768                 if (copy_to_user(user_arg, &finfo, sizeof(finfo)))
 769                         return -EFAULT;
 770
 771                 return 0;
 772
 773         case HIDIOCGUCODE:
 774                 /* fall through */
 775         case HIDIOCGUSAGE:
 776         case HIDIOCSUSAGE:
 777         case HIDIOCGUSAGES:
 778         case HIDIOCSUSAGES:
 779         case HIDIOCGCOLLECTIONINDEX:
 780                 mutex_lock(&hiddev->existancelock);
 781                 if (hiddev->exist)
 782                         r = hiddev_ioctl_usage(hiddev, cmd, user_arg);
 783                 else
 784                         r = -ENODEV;
 785                 mutex_unlock(&hiddev->existancelock);
 786                 return r;
 787
 788         case HIDIOCGCOLLECTIONINFO:
 789                 if (copy_from_user(&cinfo, user_arg, sizeof(cinfo)))
 790                         return -EFAULT;
 791
 792                 if (cinfo.index >= hid->maxcollection)
 793                         return -EINVAL;
 794
 795                 cinfo.type = hid->collection[cinfo.index].type;
 796                 cinfo.usage = hid->collection[cinfo.index].usage;
 797                 cinfo.level = hid->collection[cinfo.index].level;
 798
 799                 if (copy_to_user(user_arg, &cinfo, sizeof(cinfo)))
 800                         return -EFAULT;
 801                 return 0;
 802
 803         default:
 804
 805                 if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ)
 806                         return -EINVAL;
 807
 808                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGNAME(0))) {
 809                         int len;
 810                         if (!hid->name)
 811                                 return 0;
 812                         len = strlen(hid->name) + 1;
 813                         if (len > _IOC_SIZE(cmd))
 814                                  len = _IOC_SIZE(cmd);
 815                         return copy_to_user(user_arg, hid->name, len) ?
 816                                 -EFAULT : len;
 817                 }
 818
 819                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGPHYS(0))) {
 820                         int len;
 821                         if (!hid->phys)
 822                                 return 0;
 823                         len = strlen(hid->phys) + 1;
 824                         if (len > _IOC_SIZE(cmd))
 825                                 len = _IOC_SIZE(cmd);
 826                         return copy_to_user(user_arg, hid->phys, len) ?
 827                                 -EFAULT : len;
 828                 }
 829         }
 830         return -EINVAL;
 831 }
 832
 833 #ifdef CONFIG_COMPAT
 834 static long hiddev_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 835 {
 836         return hiddev_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
 837 }
 838 #endif
 839
 840 static const struct file_operations hiddev_fops = {
 841         .owner =        THIS_MODULE,
 842         .read =         hiddev_read,
 843         .write =        hiddev_write,
 844         .poll =         hiddev_poll,
 845         .open =         hiddev_open,
 846         .release =      hiddev_release,
 847         .unlocked_ioctl =       hiddev_ioctl,
 848         .fasync =       hiddev_fasync,
 849 #ifdef CONFIG_COMPAT
 850         .compat_ioctl   = hiddev_compat_ioctl,
 851 #endif
 852 };
 853
 854 static char *hiddev_devnode(struct device *dev, mode_t *mode)
 855 {
 856         return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
 857 }
 858
 859 static struct usb_class_driver hiddev_class = {
 860         .name =         "hiddev%d",
 861         .devnode =      hiddev_devnode,
 862         .fops =         &hiddev_fops,
 863         .minor_base =   HIDDEV_MINOR_BASE,
 864 };
 865
 866 /*
 867  * This is where hid.c calls us to connect a hid device to the hiddev driver
 868  */
 869 int hiddev_connect(struct hid_device *hid, unsigned int force)
 870 {
 871         struct hiddev *hiddev;
 872         struct usbhid_device *usbhid = hid->driver_data;
 873         int retval;
 874
 875         if (!force) {
 876                 unsigned int i;
 877                 for (i = 0; i < hid->maxcollection; i++)
 878                         if (hid->collection[i].type ==
 879                             HID_COLLECTION_APPLICATION &&
 880                             !IS_INPUT_APPLICATION(hid->collection[i].usage))
 881                                 break;
 882
 883                 if (i == hid->maxcollection)
 884                         return -1;
 885         }
 886
 887         if (!(hiddev = kzalloc(sizeof(struct hiddev), GFP_KERNEL)))
 888                 return -1;
 889
 890         init_waitqueue_head(&hiddev->wait);
 891         INIT_LIST_HEAD(&hiddev->list);
 892         spin_lock_init(&hiddev->list_lock);
 893         mutex_init(&hiddev->existancelock);
 894         hid->hiddev = hiddev;
 895         hiddev->hid = hid;
 896         hiddev->exist = 1;
 897
 898         /*
 899          * BKL here is used to avoid race after usb_register_dev().
 900          * Once the device node has been created, open() could happen on it.
 901          * The code below will then fail, as hiddev_table hasn't been
 902          * updated.
 903          *
 904          * The obvious fix -- introducing mutex to guard hiddev_table[]
 905          * doesn't work, as usb_open() and usb_register_dev() both take
 906          * minor_rwsem, thus we'll have ABBA deadlock.
 907          *
 908          * Before BKL pushdown, usb_open() had been acquiring it in right
 909          * order, so _open() was safe to use it to protect from this race.
 910          * Now the order is different, but AB-BA deadlock still doesn't occur
 911          * as BKL is dropped on schedule() (i.e. while sleeping on
 912          * minor_rwsem). Fugly.
 913          */
 914         lock_kernel();
 915         retval = usb_register_dev(usbhid->intf, &hiddev_class);
 916         if (retval) {
 917                 err_hid("Not able to get a minor for this device.");
 918                 hid->hiddev = NULL;
 919                 unlock_kernel();
 920                 kfree(hiddev);
 921                 return -1;
 922         } else {
 923                 hid->minor = usbhid->intf->minor;
 924                 hiddev_table[usbhid->intf->minor - HIDDEV_MINOR_BASE] = hiddev;
 925         }
 926         unlock_kernel();
 927
 928         return 0;
 929 }
 930
 931 /*
 932  * This is where hid.c calls us to disconnect a hiddev device from the
 933  * corresponding hid device (usually because the usb device has disconnected)
 934  */
 935 static struct usb_class_driver hiddev_class;
 936 void hiddev_disconnect(struct hid_device *hid)
 937 {
 938         struct hiddev *hiddev = hid->hiddev;
 939         struct usbhid_device *usbhid = hid->driver_data;
 940
 941         mutex_lock(&hiddev->existancelock);
 942         hiddev->exist = 0;
 943         mutex_unlock(&hiddev->existancelock);
 944
 945         hiddev_table[hiddev->hid->minor - HIDDEV_MINOR_BASE] = NULL;
 946         usb_deregister_dev(usbhid->intf, &hiddev_class);
 947
 948         if (hiddev->open) {
 949                 usbhid_close(hiddev->hid);
 950                 wake_up_interruptible(&hiddev->wait);
 951         } else {
 952                 kfree(hiddev);
 953         }
 954 }
 955
 956 /* Currently this driver is a USB driver.  It's not a conventional one in
 957  * the sense that it doesn't probe at the USB level.  Instead it waits to
 958  * be connected by HID through the hiddev_connect / hiddev_disconnect
 959  * routines.  The reason to register as a USB device is to gain part of the
 960  * minor number space from the USB major.
 961  *
 962  * In theory, should the HID code be generalized to more than one physical
 963  * medium (say, IEEE 1384), this driver will probably need to register its
 964  * own major number, and in doing so, no longer need to register with USB.
 965  * At that point the probe routine and hiddev_driver struct below will no
 966  * longer be useful.
 967  */
 968
 969
 970 /* We never attach in this manner, and rely on HID to connect us.  This
 971  * is why there is no disconnect routine defined in the usb_driver either.
 972  */
 973 static int hiddev_usbd_probe(struct usb_interface *intf,
 974                              const struct usb_device_id *hiddev_info)
 975 {
 976         return -ENODEV;
 977 }
 978
 979 static /* const */ struct usb_driver hiddev_driver = {
 980         .name =         "hiddev",
 981         .probe =        hiddev_usbd_probe,
 982 };
 983
 984 int __init hiddev_init(void)
 985 {
 986         return usb_register(&hiddev_driver);
 987 }
 988
 989 void hiddev_exit(void)
 990 {
 991         usb_deregister(&hiddev_driver);
 992 }