drivers/hid/uhid.c

   1 /*
   2  * User-space I/O driver support for HID subsystem
   3  * Copyright (c) 2012 David Herrmann
   4  */
   5
   6 /*
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the Free
   9  * Software Foundation; either version 2 of the License, or (at your option)
  10  * any later version.
  11  */
  12
  13 #include <linux/atomic.h>
  14 #include <linux/compat.h>
  15 #include <linux/device.h>
  16 #include <linux/fs.h>
  17 #include <linux/hid.h>
  18 #include <linux/input.h>
  19 #include <linux/miscdevice.h>
  20 #include <linux/module.h>
  21 #include <linux/mutex.h>
  22 #include <linux/poll.h>
  23 #include <linux/sched.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/uhid.h>
  26 #include <linux/wait.h>
  27
  28 #define UHID_NAME       "uhid"
  29 #define UHID_BUFSIZE    32
  30
  31 struct uhid_device {
  32         struct mutex devlock;
  33         bool running;
  34
  35         __u8 *rd_data;
  36         uint rd_size;
  37
  38         struct hid_device *hid;
  39         struct uhid_event input_buf;
  40
  41         wait_queue_head_t waitq;
  42         spinlock_t qlock;
  43         __u8 head;
  44         __u8 tail;
  45         struct uhid_event *outq[UHID_BUFSIZE];
  46
  47         /* blocking GET_REPORT support; state changes protected by qlock */
  48         struct mutex report_lock;
  49         wait_queue_head_t report_wait;
  50         bool report_running;
  51         u32 report_id;
  52         u32 report_type;
  53         struct uhid_event report_buf;
  54 };
  55
  56 static struct miscdevice uhid_misc;
  57
  58 static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev)
  59 {
  60         __u8 newhead;
  61
  62         newhead = (uhid->head + 1) % UHID_BUFSIZE;
  63
  64         if (newhead != uhid->tail) {
  65                 uhid->outq[uhid->head] = ev;
  66                 uhid->head = newhead;
  67                 wake_up_interruptible(&uhid->waitq);
  68         } else {
  69                 hid_warn(uhid->hid, "Output queue is full\n");
  70                 kfree(ev);
  71         }
  72 }
  73
  74 static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
  75 {
  76         unsigned long flags;
  77         struct uhid_event *ev;
  78
  79         ev = kzalloc(sizeof(*ev), GFP_KERNEL);
  80         if (!ev)
  81                 return -ENOMEM;
  82
  83         ev->type = event;
  84
  85         spin_lock_irqsave(&uhid->qlock, flags);
  86         uhid_queue(uhid, ev);
  87         spin_unlock_irqrestore(&uhid->qlock, flags);
  88
  89         return 0;
  90 }
  91
  92 static int uhid_hid_start(struct hid_device *hid)
  93 {
  94         struct uhid_device *uhid = hid->driver_data;
  95         struct uhid_event *ev;
  96         unsigned long flags;
  97
  98         ev = kzalloc(sizeof(*ev), GFP_KERNEL);
  99         if (!ev)
 100                 return -ENOMEM;
 101
 102         ev->type = UHID_START;
 103
 104         if (hid->report_enum[HID_FEATURE_REPORT].numbered)
 105                 ev->u.start.dev_flags |= UHID_DEV_NUMBERED_FEATURE_REPORTS;
 106         if (hid->report_enum[HID_OUTPUT_REPORT].numbered)
 107                 ev->u.start.dev_flags |= UHID_DEV_NUMBERED_OUTPUT_REPORTS;
 108         if (hid->report_enum[HID_INPUT_REPORT].numbered)
 109                 ev->u.start.dev_flags |= UHID_DEV_NUMBERED_INPUT_REPORTS;
 110
 111         spin_lock_irqsave(&uhid->qlock, flags);
 112         uhid_queue(uhid, ev);
 113         spin_unlock_irqrestore(&uhid->qlock, flags);
 114
 115         return 0;
 116 }
 117
 118 static void uhid_hid_stop(struct hid_device *hid)
 119 {
 120         struct uhid_device *uhid = hid->driver_data;
 121
 122         hid->claimed = 0;
 123         uhid_queue_event(uhid, UHID_STOP);
 124 }
 125
 126 static int uhid_hid_open(struct hid_device *hid)
 127 {
 128         struct uhid_device *uhid = hid->driver_data;
 129
 130         return uhid_queue_event(uhid, UHID_OPEN);
 131 }
 132
 133 static void uhid_hid_close(struct hid_device *hid)
 134 {
 135         struct uhid_device *uhid = hid->driver_data;
 136
 137         uhid_queue_event(uhid, UHID_CLOSE);
 138 }
 139
 140 static int uhid_hid_parse(struct hid_device *hid)
 141 {
 142         struct uhid_device *uhid = hid->driver_data;
 143
 144         return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);
 145 }
 146
 147 /* must be called with report_lock held */
 148 static int __uhid_report_queue_and_wait(struct uhid_device *uhid,
 149                                         struct uhid_event *ev,
 150                                         __u32 *report_id)
 151 {
 152         unsigned long flags;
 153         int ret;
 154
 155         spin_lock_irqsave(&uhid->qlock, flags);
 156         *report_id = ++uhid->report_id;
 157         uhid->report_type = ev->type + 1;
 158         uhid->report_running = true;
 159         uhid_queue(uhid, ev);
 160         spin_unlock_irqrestore(&uhid->qlock, flags);
 161
 162         ret = wait_event_interruptible_timeout(uhid->report_wait,
 163                                 !uhid->report_running || !uhid->running,
 164                                 5 * HZ);
 165         if (!ret || !uhid->running || uhid->report_running)
 166                 ret = -EIO;
 167         else if (ret < 0)
 168                 ret = -ERESTARTSYS;
 169         else
 170                 ret = 0;
 171
 172         uhid->report_running = false;
 173
 174         return ret;
 175 }
 176
 177 static void uhid_report_wake_up(struct uhid_device *uhid, u32 id,
 178                                 const struct uhid_event *ev)
 179 {
 180         unsigned long flags;
 181
 182         spin_lock_irqsave(&uhid->qlock, flags);
 183
 184         /* id for old report; drop it silently */
 185         if (uhid->report_type != ev->type || uhid->report_id != id)
 186                 goto unlock;
 187         if (!uhid->report_running)
 188                 goto unlock;
 189
 190         memcpy(&uhid->report_buf, ev, sizeof(*ev));
 191         uhid->report_running = false;
 192         wake_up_interruptible(&uhid->report_wait);
 193
 194 unlock:
 195         spin_unlock_irqrestore(&uhid->qlock, flags);
 196 }
 197
 198 static int uhid_hid_get_report(struct hid_device *hid, unsigned char rnum,
 199                                u8 *buf, size_t count, u8 rtype)
 200 {
 201         struct uhid_device *uhid = hid->driver_data;
 202         struct uhid_get_report_reply_req *req;
 203         struct uhid_event *ev;
 204         int ret;
 205
 206         if (!uhid->running)
 207                 return -EIO;
 208
 209         ev = kzalloc(sizeof(*ev), GFP_KERNEL);
 210         if (!ev)
 211                 return -ENOMEM;
 212
 213         ev->type = UHID_GET_REPORT;
 214         ev->u.get_report.rnum = rnum;
 215         ev->u.get_report.rtype = rtype;
 216
 217         ret = mutex_lock_interruptible(&uhid->report_lock);
 218         if (ret) {
 219                 kfree(ev);
 220                 return ret;
 221         }
 222
 223         /* this _always_ takes ownership of @ev */
 224         ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.get_report.id);
 225         if (ret)
 226                 goto unlock;
 227
 228         req = &uhid->report_buf.u.get_report_reply;
 229         if (req->err) {
 230                 ret = -EIO;
 231         } else {
 232                 ret = min3(count, (size_t)req->size, (size_t)UHID_DATA_MAX);
 233                 memcpy(buf, req->data, ret);
 234         }
 235
 236 unlock:
 237         mutex_unlock(&uhid->report_lock);
 238         return ret;
 239 }
 240
 241 static int uhid_hid_set_report(struct hid_device *hid, unsigned char rnum,
 242                                const u8 *buf, size_t count, u8 rtype)
 243 {
 244         struct uhid_device *uhid = hid->driver_data;
 245         struct uhid_event *ev;
 246         int ret;
 247
 248         if (!uhid->running || count > UHID_DATA_MAX)
 249                 return -EIO;
 250
 251         ev = kzalloc(sizeof(*ev), GFP_KERNEL);
 252         if (!ev)
 253                 return -ENOMEM;
 254
 255         ev->type = UHID_SET_REPORT;
 256         ev->u.set_report.rnum = rnum;
 257         ev->u.set_report.rtype = rtype;
 258         ev->u.set_report.size = count;
 259         memcpy(ev->u.set_report.data, buf, count);
 260
 261         ret = mutex_lock_interruptible(&uhid->report_lock);
 262         if (ret) {
 263                 kfree(ev);
 264                 return ret;
 265         }
 266
 267         /* this _always_ takes ownership of @ev */
 268         ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.set_report.id);
 269         if (ret)
 270                 goto unlock;
 271
 272         if (uhid->report_buf.u.set_report_reply.err)
 273                 ret = -EIO;
 274         else
 275                 ret = count;
 276
 277 unlock:
 278         mutex_unlock(&uhid->report_lock);
 279         return ret;
 280 }
 281
 282 static int uhid_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
 283                                 __u8 *buf, size_t len, unsigned char rtype,
 284                                 int reqtype)
 285 {
 286         u8 u_rtype;
 287
 288         switch (rtype) {
 289         case HID_FEATURE_REPORT:
 290                 u_rtype = UHID_FEATURE_REPORT;
 291                 break;
 292         case HID_OUTPUT_REPORT:
 293                 u_rtype = UHID_OUTPUT_REPORT;
 294                 break;
 295         case HID_INPUT_REPORT:
 296                 u_rtype = UHID_INPUT_REPORT;
 297                 break;
 298         default:
 299                 return -EINVAL;
 300         }
 301
 302         switch (reqtype) {
 303         case HID_REQ_GET_REPORT:
 304                 return uhid_hid_get_report(hid, reportnum, buf, len, u_rtype);
 305         case HID_REQ_SET_REPORT:
 306                 return uhid_hid_set_report(hid, reportnum, buf, len, u_rtype);
 307         default:
 308                 return -EIO;
 309         }
 310 }
 311
 312 static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
 313                                unsigned char report_type)
 314 {
 315         struct uhid_device *uhid = hid->driver_data;
 316         __u8 rtype;
 317         unsigned long flags;
 318         struct uhid_event *ev;
 319
 320         switch (report_type) {
 321         case HID_FEATURE_REPORT:
 322                 rtype = UHID_FEATURE_REPORT;
 323                 break;
 324         case HID_OUTPUT_REPORT:
 325                 rtype = UHID_OUTPUT_REPORT;
 326                 break;
 327         default:
 328                 return -EINVAL;
 329         }
 330
 331         if (count < 1 || count > UHID_DATA_MAX)
 332                 return -EINVAL;
 333
 334         ev = kzalloc(sizeof(*ev), GFP_KERNEL);
 335         if (!ev)
 336                 return -ENOMEM;
 337
 338         ev->type = UHID_OUTPUT;
 339         ev->u.output.size = count;
 340         ev->u.output.rtype = rtype;
 341         memcpy(ev->u.output.data, buf, count);
 342
 343         spin_lock_irqsave(&uhid->qlock, flags);
 344         uhid_queue(uhid, ev);
 345         spin_unlock_irqrestore(&uhid->qlock, flags);
 346
 347         return count;
 348 }
 349
 350 static int uhid_hid_output_report(struct hid_device *hid, __u8 *buf,
 351                                   size_t count)
 352 {
 353         return uhid_hid_output_raw(hid, buf, count, HID_OUTPUT_REPORT);
 354 }
 355
 356 static struct hid_ll_driver uhid_hid_driver = {
 357         .start = uhid_hid_start,
 358         .stop = uhid_hid_stop,
 359         .open = uhid_hid_open,
 360         .close = uhid_hid_close,
 361         .parse = uhid_hid_parse,
 362         .raw_request = uhid_hid_raw_request,
 363         .output_report = uhid_hid_output_report,
 364 };
 365
 366 #ifdef CONFIG_COMPAT
 367
 368 /* Apparently we haven't stepped on these rakes enough times yet. */
 369 struct uhid_create_req_compat {
 370         __u8 name[128];
 371         __u8 phys[64];
 372         __u8 uniq[64];
 373
 374         compat_uptr_t rd_data;
 375         __u16 rd_size;
 376
 377         __u16 bus;
 378         __u32 vendor;
 379         __u32 product;
 380         __u32 version;
 381         __u32 country;
 382 } __attribute__((__packed__));
 383
 384 static int uhid_event_from_user(const char __user *buffer, size_t len,
 385                                 struct uhid_event *event)
 386 {
 387         if (in_compat_syscall()) {
 388                 u32 type;
 389
 390                 if (get_user(type, buffer))
 391                         return -EFAULT;
 392
 393                 if (type == UHID_CREATE) {
 394                         /*
 395                          * This is our messed up request with compat pointer.
 396                          * It is largish (more than 256 bytes) so we better
 397                          * allocate it from the heap.
 398                          */
 399                         struct uhid_create_req_compat *compat;
 400
 401                         compat = kzalloc(sizeof(*compat), GFP_KERNEL);
 402                         if (!compat)
 403                                 return -ENOMEM;
 404
 405                         buffer += sizeof(type);
 406                         len -= sizeof(type);
 407                         if (copy_from_user(compat, buffer,
 408                                            min(len, sizeof(*compat)))) {
 409                                 kfree(compat);
 410                                 return -EFAULT;
 411                         }
 412
 413                         /* Shuffle the data over to proper structure */
 414                         event->type = type;
 415
 416                         memcpy(event->u.create.name, compat->name,
 417                                 sizeof(compat->name));
 418                         memcpy(event->u.create.phys, compat->phys,
 419                                 sizeof(compat->phys));
 420                         memcpy(event->u.create.uniq, compat->uniq,
 421                                 sizeof(compat->uniq));
 422
 423                         event->u.create.rd_data = compat_ptr(compat->rd_data);
 424                         event->u.create.rd_size = compat->rd_size;
 425
 426                         event->u.create.bus = compat->bus;
 427                         event->u.create.vendor = compat->vendor;
 428                         event->u.create.product = compat->product;
 429                         event->u.create.version = compat->version;
 430                         event->u.create.country = compat->country;
 431
 432                         kfree(compat);
 433                         return 0;
 434                 }
 435                 /* All others can be copied directly */
 436         }
 437
 438         if (copy_from_user(event, buffer, min(len, sizeof(*event))))
 439                 return -EFAULT;
 440
 441         return 0;
 442 }
 443 #else
 444 static int uhid_event_from_user(const char __user *buffer, size_t len,
 445                                 struct uhid_event *event)
 446 {
 447         if (copy_from_user(event, buffer, min(len, sizeof(*event))))
 448                 return -EFAULT;
 449
 450         return 0;
 451 }
 452 #endif
 453
 454 static int uhid_dev_create2(struct uhid_device *uhid,
 455                             const struct uhid_event *ev)
 456 {
 457         struct hid_device *hid;
 458         size_t rd_size, len;
 459         void *rd_data;
 460         int ret;
 461
 462         if (uhid->running)
 463                 return -EALREADY;
 464
 465         rd_size = ev->u.create2.rd_size;
 466         if (rd_size <= 0 || rd_size > HID_MAX_DESCRIPTOR_SIZE)
 467                 return -EINVAL;
 468
 469         rd_data = kmemdup(ev->u.create2.rd_data, rd_size, GFP_KERNEL);
 470         if (!rd_data)
 471                 return -ENOMEM;
 472
 473         uhid->rd_size = rd_size;
 474         uhid->rd_data = rd_data;
 475
 476         hid = hid_allocate_device();
 477         if (IS_ERR(hid)) {
 478                 ret = PTR_ERR(hid);
 479                 goto err_free;
 480         }
 481
 482         len = min(sizeof(hid->name), sizeof(ev->u.create2.name)) - 1;
 483         strncpy(hid->name, ev->u.create2.name, len);
 484         len = min(sizeof(hid->phys), sizeof(ev->u.create2.phys)) - 1;
 485         strncpy(hid->phys, ev->u.create2.phys, len);
 486         len = min(sizeof(hid->uniq), sizeof(ev->u.create2.uniq)) - 1;
 487         strncpy(hid->uniq, ev->u.create2.uniq, len);
 488
 489         hid->ll_driver = &uhid_hid_driver;
 490         hid->bus = ev->u.create2.bus;
 491         hid->vendor = ev->u.create2.vendor;
 492         hid->product = ev->u.create2.product;
 493         hid->version = ev->u.create2.version;
 494         hid->country = ev->u.create2.country;
 495         hid->driver_data = uhid;
 496         hid->dev.parent = uhid_misc.this_device;
 497
 498         uhid->hid = hid;
 499         uhid->running = true;
 500
 501         ret = hid_add_device(hid);
 502         if (ret) {
 503                 hid_err(hid, "Cannot register HID device\n");
 504                 goto err_hid;
 505         }
 506
 507         return 0;
 508
 509 err_hid:
 510         hid_destroy_device(hid);
 511         uhid->hid = NULL;
 512         uhid->running = false;
 513 err_free:
 514         kfree(uhid->rd_data);
 515         uhid->rd_data = NULL;
 516         uhid->rd_size = 0;
 517         return ret;
 518 }
 519
 520 static int uhid_dev_create(struct uhid_device *uhid,
 521                            struct uhid_event *ev)
 522 {
 523         struct uhid_create_req orig;
 524
 525         orig = ev->u.create;
 526
 527         if (orig.rd_size <= 0 || orig.rd_size > HID_MAX_DESCRIPTOR_SIZE)
 528                 return -EINVAL;
 529         if (copy_from_user(&ev->u.create2.rd_data, orig.rd_data, orig.rd_size))
 530                 return -EFAULT;
 531
 532         memcpy(ev->u.create2.name, orig.name, sizeof(orig.name));
 533         memcpy(ev->u.create2.phys, orig.phys, sizeof(orig.phys));
 534         memcpy(ev->u.create2.uniq, orig.uniq, sizeof(orig.uniq));
 535         ev->u.create2.rd_size = orig.rd_size;
 536         ev->u.create2.bus = orig.bus;
 537         ev->u.create2.vendor = orig.vendor;
 538         ev->u.create2.product = orig.product;
 539         ev->u.create2.version = orig.version;
 540         ev->u.create2.country = orig.country;
 541
 542         return uhid_dev_create2(uhid, ev);
 543 }
 544
 545 static int uhid_dev_destroy(struct uhid_device *uhid)
 546 {
 547         if (!uhid->running)
 548                 return -EINVAL;
 549
 550         uhid->running = false;
 551         wake_up_interruptible(&uhid->report_wait);
 552
 553         hid_destroy_device(uhid->hid);
 554         kfree(uhid->rd_data);
 555
 556         return 0;
 557 }
 558
 559 static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
 560 {
 561         if (!uhid->running)
 562                 return -EINVAL;
 563
 564         hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
 565                          min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
 566
 567         return 0;
 568 }
 569
 570 static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev)
 571 {
 572         if (!uhid->running)
 573                 return -EINVAL;
 574
 575         hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data,
 576                          min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0);
 577
 578         return 0;
 579 }
 580
 581 static int uhid_dev_get_report_reply(struct uhid_device *uhid,
 582                                      struct uhid_event *ev)
 583 {
 584         if (!uhid->running)
 585                 return -EINVAL;
 586
 587         uhid_report_wake_up(uhid, ev->u.get_report_reply.id, ev);
 588         return 0;
 589 }
 590
 591 static int uhid_dev_set_report_reply(struct uhid_device *uhid,
 592                                      struct uhid_event *ev)
 593 {
 594         if (!uhid->running)
 595                 return -EINVAL;
 596
 597         uhid_report_wake_up(uhid, ev->u.set_report_reply.id, ev);
 598         return 0;
 599 }
 600
 601 static int uhid_char_open(struct inode *inode, struct file *file)
 602 {
 603         struct uhid_device *uhid;
 604
 605         uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
 606         if (!uhid)
 607                 return -ENOMEM;
 608
 609         mutex_init(&uhid->devlock);
 610         mutex_init(&uhid->report_lock);
 611         spin_lock_init(&uhid->qlock);
 612         init_waitqueue_head(&uhid->waitq);
 613         init_waitqueue_head(&uhid->report_wait);
 614         uhid->running = false;
 615
 616         file->private_data = uhid;
 617         nonseekable_open(inode, file);
 618
 619         return 0;
 620 }
 621
 622 static int uhid_char_release(struct inode *inode, struct file *file)
 623 {
 624         struct uhid_device *uhid = file->private_data;
 625         unsigned int i;
 626
 627         uhid_dev_destroy(uhid);
 628
 629         for (i = 0; i < UHID_BUFSIZE; ++i)
 630                 kfree(uhid->outq[i]);
 631
 632         kfree(uhid);
 633
 634         return 0;
 635 }
 636
 637 static ssize_t uhid_char_read(struct file *file, char __user *buffer,
 638                                 size_t count, loff_t *ppos)
 639 {
 640         struct uhid_device *uhid = file->private_data;
 641         int ret;
 642         unsigned long flags;
 643         size_t len;
 644
 645         /* they need at least the "type" member of uhid_event */
 646         if (count < sizeof(__u32))
 647                 return -EINVAL;
 648
 649 try_again:
 650         if (file->f_flags & O_NONBLOCK) {
 651                 if (uhid->head == uhid->tail)
 652                         return -EAGAIN;
 653         } else {
 654                 ret = wait_event_interruptible(uhid->waitq,
 655                                                 uhid->head != uhid->tail);
 656                 if (ret)
 657                         return ret;
 658         }
 659
 660         ret = mutex_lock_interruptible(&uhid->devlock);
 661         if (ret)
 662                 return ret;
 663
 664         if (uhid->head == uhid->tail) {
 665                 mutex_unlock(&uhid->devlock);
 666                 goto try_again;
 667         } else {
 668                 len = min(count, sizeof(**uhid->outq));
 669                 if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) {
 670                         ret = -EFAULT;
 671                 } else {
 672                         kfree(uhid->outq[uhid->tail]);
 673                         uhid->outq[uhid->tail] = NULL;
 674
 675                         spin_lock_irqsave(&uhid->qlock, flags);
 676                         uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
 677                         spin_unlock_irqrestore(&uhid->qlock, flags);
 678                 }
 679         }
 680
 681         mutex_unlock(&uhid->devlock);
 682         return ret ? ret : len;
 683 }
 684
 685 static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
 686                                 size_t count, loff_t *ppos)
 687 {
 688         struct uhid_device *uhid = file->private_data;
 689         int ret;
 690         size_t len;
 691
 692         /* we need at least the "type" member of uhid_event */
 693         if (count < sizeof(__u32))
 694                 return -EINVAL;
 695
 696         ret = mutex_lock_interruptible(&uhid->devlock);
 697         if (ret)
 698                 return ret;
 699
 700         memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
 701         len = min(count, sizeof(uhid->input_buf));
 702
 703         ret = uhid_event_from_user(buffer, len, &uhid->input_buf);
 704         if (ret)
 705                 goto unlock;
 706
 707         switch (uhid->input_buf.type) {
 708         case UHID_CREATE:
 709                 ret = uhid_dev_create(uhid, &uhid->input_buf);
 710                 break;
 711         case UHID_CREATE2:
 712                 ret = uhid_dev_create2(uhid, &uhid->input_buf);
 713                 break;
 714         case UHID_DESTROY:
 715                 ret = uhid_dev_destroy(uhid);
 716                 break;
 717         case UHID_INPUT:
 718                 ret = uhid_dev_input(uhid, &uhid->input_buf);
 719                 break;
 720         case UHID_INPUT2:
 721                 ret = uhid_dev_input2(uhid, &uhid->input_buf);
 722                 break;
 723         case UHID_GET_REPORT_REPLY:
 724                 ret = uhid_dev_get_report_reply(uhid, &uhid->input_buf);
 725                 break;
 726         case UHID_SET_REPORT_REPLY:
 727                 ret = uhid_dev_set_report_reply(uhid, &uhid->input_buf);
 728                 break;
 729         default:
 730                 ret = -EOPNOTSUPP;
 731         }
 732
 733 unlock:
 734         mutex_unlock(&uhid->devlock);
 735
 736         /* return "count" not "len" to not confuse the caller */
 737         return ret ? ret : count;
 738 }
 739
 740 static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
 741 {
 742         struct uhid_device *uhid = file->private_data;
 743
 744         poll_wait(file, &uhid->waitq, wait);
 745
 746         if (uhid->head != uhid->tail)
 747                 return POLLIN | POLLRDNORM;
 748
 749         return 0;
 750 }
 751
 752 static const struct file_operations uhid_fops = {
 753         .owner          = THIS_MODULE,
 754         .open           = uhid_char_open,
 755         .release        = uhid_char_release,
 756         .read           = uhid_char_read,
 757         .write          = uhid_char_write,
 758         .poll           = uhid_char_poll,
 759         .llseek         = no_llseek,
 760 };
 761
 762 static struct miscdevice uhid_misc = {
 763         .fops           = &uhid_fops,
 764         .minor          = UHID_MINOR,
 765         .name           = UHID_NAME,
 766 };
 767
 768 static int __init uhid_init(void)
 769 {
 770         return misc_register(&uhid_misc);
 771 }
 772
 773 static void __exit uhid_exit(void)
 774 {
 775         misc_deregister(&uhid_misc);
 776 }
 777
 778 module_init(uhid_init);
 779 module_exit(uhid_exit);
 780 MODULE_LICENSE("GPL");
 781 MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
 782 MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");
 783 MODULE_ALIAS_MISCDEV(UHID_MINOR);
 784 MODULE_ALIAS("devname:" UHID_NAME);