xref: /netbsd-src/sys/dev/usb/uhid.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*	$NetBSD: uhid.c,v 1.83 2009/12/06 21:40:31 dyoung Exp $	*/
2 
3 /*
4  * Copyright (c) 1998, 2004, 2008 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Lennart Augustsson (lennart@augustsson.net) at
9  * Carlstedt Research & Technology.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30  * POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 /*
34  * HID spec: http://www.usb.org/developers/devclass_docs/HID1_11.pdf
35  */
36 
37 #include <sys/cdefs.h>
38 __KERNEL_RCSID(0, "$NetBSD: uhid.c,v 1.83 2009/12/06 21:40:31 dyoung Exp $");
39 
40 #include "opt_compat_netbsd.h"
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
45 #include <sys/malloc.h>
46 #include <sys/signalvar.h>
47 #include <sys/device.h>
48 #include <sys/ioctl.h>
49 #include <sys/conf.h>
50 #include <sys/tty.h>
51 #include <sys/file.h>
52 #include <sys/select.h>
53 #include <sys/proc.h>
54 #include <sys/vnode.h>
55 #include <sys/poll.h>
56 #include <sys/intr.h>
57 
58 #include <dev/usb/usb.h>
59 #include <dev/usb/usbhid.h>
60 
61 #include <dev/usb/usbdevs.h>
62 #include <dev/usb/usbdi.h>
63 #include <dev/usb/usbdi_util.h>
64 #include <dev/usb/hid.h>
65 #include <dev/usb/usb_quirks.h>
66 
67 #include <dev/usb/uhidev.h>
68 
69 #ifdef UHID_DEBUG
70 #define DPRINTF(x)	if (uhiddebug) logprintf x
71 #define DPRINTFN(n,x)	if (uhiddebug>(n)) logprintf x
72 int	uhiddebug = 0;
73 #else
74 #define DPRINTF(x)
75 #define DPRINTFN(n,x)
76 #endif
77 
78 struct uhid_softc {
79 	struct uhidev sc_hdev;
80 
81 	int sc_isize;
82 	int sc_osize;
83 	int sc_fsize;
84 
85 	u_char *sc_obuf;
86 
87 	struct clist sc_q;
88 	struct selinfo sc_rsel;
89 	usb_proc_ptr sc_async;	/* process that wants SIGIO */
90 	void *sc_sih;
91 	u_char sc_state;	/* driver state */
92 #define	UHID_ASLP	0x01	/* waiting for device data */
93 #define UHID_IMMED	0x02	/* return read data immediately */
94 
95 	int sc_refcnt;
96 	u_char sc_dying;
97 };
98 
99 #define	UHIDUNIT(dev)	(minor(dev))
100 #define	UHID_CHUNK	128	/* chunk size for read */
101 #define	UHID_BSIZE	1020	/* buffer size */
102 
103 dev_type_open(uhidopen);
104 dev_type_close(uhidclose);
105 dev_type_read(uhidread);
106 dev_type_write(uhidwrite);
107 dev_type_ioctl(uhidioctl);
108 dev_type_poll(uhidpoll);
109 dev_type_kqfilter(uhidkqfilter);
110 
111 const struct cdevsw uhid_cdevsw = {
112 	uhidopen, uhidclose, uhidread, uhidwrite, uhidioctl,
113 	nostop, notty, uhidpoll, nommap, uhidkqfilter, D_OTHER,
114 };
115 
116 Static void uhid_intr(struct uhidev *, void *, u_int len);
117 Static void uhid_softintr(void *);
118 
119 Static int uhid_do_read(struct uhid_softc *, struct uio *uio, int);
120 Static int uhid_do_write(struct uhid_softc *, struct uio *uio, int);
121 Static int uhid_do_ioctl(struct uhid_softc*, u_long, void *, int, struct lwp *);
122 
123 USB_DECLARE_DRIVER(uhid);
124 
125 int
126 uhid_match(device_t parent, cfdata_t match, void *aux)
127 {
128 #ifdef UHID_DEBUG
129 	struct uhidev_attach_arg *uha = aux;
130 #endif
131 
132 	DPRINTF(("uhid_match: report=%d\n", uha->reportid));
133 
134 	if (match->cf_flags & 1)
135 		return (UMATCH_HIGHEST);
136 	else
137 		return (UMATCH_IFACECLASS_GENERIC);
138 }
139 
140 void
141 uhid_attach(device_t parent, device_t self, void *aux)
142 {
143 	struct uhid_softc *sc = device_private(self);
144 	struct uhidev_attach_arg *uha = aux;
145 	int size, repid;
146 	void *desc;
147 
148 	sc->sc_hdev.sc_dev = self;
149 	selinit(&sc->sc_rsel);
150 	sc->sc_hdev.sc_intr = uhid_intr;
151 	sc->sc_hdev.sc_parent = uha->parent;
152 	sc->sc_hdev.sc_report_id = uha->reportid;
153 	sc->sc_sih = softint_establish(SOFTINT_MPSAFE | SOFTINT_CLOCK,
154 	    uhid_softintr, sc);
155 
156 	uhidev_get_report_desc(uha->parent, &desc, &size);
157 	repid = uha->reportid;
158 	sc->sc_isize = hid_report_size(desc, size, hid_input,   repid);
159 	sc->sc_osize = hid_report_size(desc, size, hid_output,  repid);
160 	sc->sc_fsize = hid_report_size(desc, size, hid_feature, repid);
161 
162 	aprint_naive("\n");
163 	aprint_normal(": input=%d, output=%d, feature=%d\n",
164 	       sc->sc_isize, sc->sc_osize, sc->sc_fsize);
165 
166 	if (!pmf_device_register(self, NULL, NULL))
167 		aprint_error_dev(self, "couldn't establish power handler\n");
168 
169 	USB_ATTACH_SUCCESS_RETURN;
170 }
171 
172 int
173 uhid_activate(device_ptr_t self, enum devact act)
174 {
175 	struct uhid_softc *sc = device_private(self);
176 
177 	switch (act) {
178 	case DVACT_DEACTIVATE:
179 		sc->sc_dying = 1;
180 		return 0;
181 	default:
182 		return EOPNOTSUPP;
183 	}
184 }
185 
186 int
187 uhid_detach(device_t self, int flags)
188 {
189 	struct uhid_softc *sc = device_private(self);
190 	int s;
191 	int maj, mn;
192 
193 	DPRINTF(("uhid_detach: sc=%p flags=%d\n", sc, flags));
194 
195 	sc->sc_dying = 1;
196 
197 	if (sc->sc_hdev.sc_state & UHIDEV_OPEN) {
198 		s = splusb();
199 		if (--sc->sc_refcnt >= 0) {
200 			/* Wake everyone */
201 			wakeup(&sc->sc_q);
202 			/* Wait for processes to go away. */
203 			usb_detach_wait(USBDEV(sc->sc_hdev.sc_dev));
204 		}
205 		splx(s);
206 	}
207 
208 	/* locate the major number */
209 #if defined(__NetBSD__)
210 	maj = cdevsw_lookup_major(&uhid_cdevsw);
211 #elif defined(__OpenBSD__)
212 	for (maj = 0; maj < nchrdev; maj++)
213 		if (cdevsw[maj].d_open == uhidopen)
214 			break;
215 #endif
216 
217 	/* Nuke the vnodes for any open instances (calls close). */
218 	mn = device_unit(self);
219 	vdevgone(maj, mn, mn, VCHR);
220 
221 #if 0
222 	usbd_add_drv_event(USB_EVENT_DRIVER_DETACH,
223 			   sc->sc_hdev.sc_parent->sc_udev,
224 			   USBDEV(sc->sc_hdev.sc_dev));
225 #endif
226 	seldestroy(&sc->sc_rsel);
227 	softint_disestablish(sc->sc_sih);
228 
229 	return (0);
230 }
231 
232 void
233 uhid_intr(struct uhidev *addr, void *data, u_int len)
234 {
235 	struct uhid_softc *sc = (struct uhid_softc *)addr;
236 
237 #ifdef UHID_DEBUG
238 	if (uhiddebug > 5) {
239 		u_int32_t i;
240 
241 		DPRINTF(("uhid_intr: data ="));
242 		for (i = 0; i < len; i++)
243 			DPRINTF((" %02x", ((u_char *)data)[i]));
244 		DPRINTF(("\n"));
245 	}
246 #endif
247 
248 	(void)b_to_q(data, len, &sc->sc_q);
249 
250 	if (sc->sc_state & UHID_ASLP) {
251 		sc->sc_state &= ~UHID_ASLP;
252 		DPRINTFN(5, ("uhid_intr: waking %p\n", &sc->sc_q));
253 		wakeup(&sc->sc_q);
254 	}
255 	selnotify(&sc->sc_rsel, 0, 0);
256 	if (sc->sc_async != NULL) {
257 		DPRINTFN(3, ("uhid_intr: sending SIGIO %p\n", sc->sc_async));
258 		softint_schedule(sc->sc_sih);
259 	}
260 }
261 
262 void
263 uhid_softintr(void *cookie)
264 {
265 	struct uhid_softc *sc;
266 
267 	sc = cookie;
268 
269 	mutex_enter(proc_lock);
270 	if (sc->sc_async != NULL)
271 		 psignal(sc->sc_async, SIGIO);
272 	mutex_exit(proc_lock);
273 }
274 
275 int
276 uhidopen(dev_t dev, int flag, int mode,
277     struct lwp *l)
278 {
279 	struct uhid_softc *sc;
280 	int error;
281 
282 	USB_GET_SC_OPEN(uhid, UHIDUNIT(dev), sc);
283 
284 	DPRINTF(("uhidopen: sc=%p\n", sc));
285 
286 	if (sc->sc_dying)
287 		return (ENXIO);
288 
289 	error = uhidev_open(&sc->sc_hdev);
290 	if (error)
291 		return (error);
292 
293 	if (clalloc(&sc->sc_q, UHID_BSIZE, 0) == -1) {
294 		uhidev_close(&sc->sc_hdev);
295 		return (ENOMEM);
296 	}
297 	sc->sc_obuf = malloc(sc->sc_osize, M_USBDEV, M_WAITOK);
298 	sc->sc_state &= ~UHID_IMMED;
299 	mutex_enter(proc_lock);
300 	sc->sc_async = NULL;
301 	mutex_exit(proc_lock);
302 
303 	return (0);
304 }
305 
306 int
307 uhidclose(dev_t dev, int flag, int mode,
308     struct lwp *l)
309 {
310 	struct uhid_softc *sc;
311 
312 	USB_GET_SC(uhid, UHIDUNIT(dev), sc);
313 
314 	DPRINTF(("uhidclose: sc=%p\n", sc));
315 
316 	clfree(&sc->sc_q);
317 	free(sc->sc_obuf, M_USBDEV);
318 	mutex_enter(proc_lock);
319 	sc->sc_async = NULL;
320 	mutex_exit(proc_lock);
321 	uhidev_close(&sc->sc_hdev);
322 
323 	return (0);
324 }
325 
326 int
327 uhid_do_read(struct uhid_softc *sc, struct uio *uio, int flag)
328 {
329 	int s;
330 	int error = 0;
331 	int extra;
332 	size_t length;
333 	u_char buffer[UHID_CHUNK];
334 	usbd_status err;
335 
336 	DPRINTFN(1, ("uhidread\n"));
337 	if (sc->sc_state & UHID_IMMED) {
338 		DPRINTFN(1, ("uhidread immed\n"));
339 		extra = sc->sc_hdev.sc_report_id != 0;
340 		err = uhidev_get_report(&sc->sc_hdev, UHID_INPUT_REPORT,
341 					buffer, sc->sc_isize + extra);
342 		if (err)
343 			return (EIO);
344 		return (uiomove(buffer+extra, sc->sc_isize, uio));
345 	}
346 
347 	s = splusb();
348 	while (sc->sc_q.c_cc == 0) {
349 		if (flag & IO_NDELAY) {
350 			splx(s);
351 			return (EWOULDBLOCK);
352 		}
353 		sc->sc_state |= UHID_ASLP;
354 		DPRINTFN(5, ("uhidread: sleep on %p\n", &sc->sc_q));
355 		error = tsleep(&sc->sc_q, PZERO | PCATCH, "uhidrea", 0);
356 		DPRINTFN(5, ("uhidread: woke, error=%d\n", error));
357 		if (sc->sc_dying)
358 			error = EIO;
359 		if (error) {
360 			sc->sc_state &= ~UHID_ASLP;
361 			break;
362 		}
363 	}
364 	splx(s);
365 
366 	/* Transfer as many chunks as possible. */
367 	while (sc->sc_q.c_cc > 0 && uio->uio_resid > 0 && !error) {
368 		length = min(sc->sc_q.c_cc, uio->uio_resid);
369 		if (length > sizeof(buffer))
370 			length = sizeof(buffer);
371 
372 		/* Remove a small chunk from the input queue. */
373 		(void) q_to_b(&sc->sc_q, buffer, length);
374 		DPRINTFN(5, ("uhidread: got %lu chars\n", (u_long)length));
375 
376 		/* Copy the data to the user process. */
377 		if ((error = uiomove(buffer, length, uio)) != 0)
378 			break;
379 	}
380 
381 	return (error);
382 }
383 
384 int
385 uhidread(dev_t dev, struct uio *uio, int flag)
386 {
387 	struct uhid_softc *sc;
388 	int error;
389 
390 	USB_GET_SC(uhid, UHIDUNIT(dev), sc);
391 
392 	sc->sc_refcnt++;
393 	error = uhid_do_read(sc, uio, flag);
394 	if (--sc->sc_refcnt < 0)
395 		usb_detach_wakeup(USBDEV(sc->sc_hdev.sc_dev));
396 	return (error);
397 }
398 
399 int
400 uhid_do_write(struct uhid_softc *sc, struct uio *uio, int flag)
401 {
402 	int error;
403 	int size;
404 	usbd_status err;
405 
406 	DPRINTFN(1, ("uhidwrite\n"));
407 
408 	if (sc->sc_dying)
409 		return (EIO);
410 
411 	size = sc->sc_osize;
412 	error = 0;
413 	if (uio->uio_resid != size)
414 		return (EINVAL);
415 	error = uiomove(sc->sc_obuf, size, uio);
416 	if (!error) {
417 		err = uhidev_set_report(&sc->sc_hdev, UHID_OUTPUT_REPORT,
418 					sc->sc_obuf, size);
419 		if (err)
420 			error = EIO;
421 	}
422 
423 	return (error);
424 }
425 
426 int
427 uhidwrite(dev_t dev, struct uio *uio, int flag)
428 {
429 	struct uhid_softc *sc;
430 	int error;
431 
432 	USB_GET_SC(uhid, UHIDUNIT(dev), sc);
433 
434 	sc->sc_refcnt++;
435 	error = uhid_do_write(sc, uio, flag);
436 	if (--sc->sc_refcnt < 0)
437 		usb_detach_wakeup(USBDEV(sc->sc_hdev.sc_dev));
438 	return (error);
439 }
440 
441 int
442 uhid_do_ioctl(struct uhid_softc *sc, u_long cmd, void *addr,
443     int flag, struct lwp *l)
444 {
445 	struct usb_ctl_report_desc *rd;
446 	struct usb_ctl_report *re;
447 	u_char buffer[UHID_CHUNK];
448 	int size, extra;
449 	usbd_status err;
450 	void *desc;
451 
452 	DPRINTFN(2, ("uhidioctl: cmd=%lx\n", cmd));
453 
454 	if (sc->sc_dying)
455 		return (EIO);
456 
457 	switch (cmd) {
458 	case FIONBIO:
459 		/* All handled in the upper FS layer. */
460 		break;
461 
462 	case FIOASYNC:
463 		mutex_enter(proc_lock);
464 		if (*(int *)addr) {
465 			if (sc->sc_async != NULL)
466 				return (EBUSY);
467 			sc->sc_async = l->l_proc;
468 			DPRINTF(("uhid_do_ioctl: FIOASYNC %p\n", l->l_proc));
469 		} else
470 			sc->sc_async = NULL;
471 		mutex_exit(proc_lock);
472 		break;
473 
474 	/* XXX this is not the most general solution. */
475 	case TIOCSPGRP:
476 		mutex_enter(proc_lock);
477 		if (sc->sc_async == NULL) {
478 			mutex_exit(proc_lock);
479 			return (EINVAL);
480 		}
481 		if (*(int *)addr != sc->sc_async->p_pgid) {
482 			mutex_exit(proc_lock);
483 			return (EPERM);
484 		}
485 		mutex_exit(proc_lock);
486 		break;
487 
488 	case FIOSETOWN:
489 		mutex_enter(proc_lock);
490 		if (sc->sc_async == NULL) {
491 			mutex_exit(proc_lock);
492 			return (EINVAL);
493 		}
494 		if (-*(int *)addr != sc->sc_async->p_pgid
495 		    && *(int *)addr != sc->sc_async->p_pid) {
496 			mutex_exit(proc_lock);
497 			return (EPERM);
498 		}
499 		mutex_exit(proc_lock);
500 		break;
501 
502 	case USB_GET_REPORT_DESC:
503 		uhidev_get_report_desc(sc->sc_hdev.sc_parent, &desc, &size);
504 		rd = (struct usb_ctl_report_desc *)addr;
505 		size = min(size, sizeof rd->ucrd_data);
506 		rd->ucrd_size = size;
507 		memcpy(rd->ucrd_data, desc, size);
508 		break;
509 
510 	case USB_SET_IMMED:
511 		if (*(int *)addr) {
512 			extra = sc->sc_hdev.sc_report_id != 0;
513 			err = uhidev_get_report(&sc->sc_hdev, UHID_INPUT_REPORT,
514 						buffer, sc->sc_isize + extra);
515 			if (err)
516 				return (EOPNOTSUPP);
517 
518 			sc->sc_state |=  UHID_IMMED;
519 		} else
520 			sc->sc_state &= ~UHID_IMMED;
521 		break;
522 
523 	case USB_GET_REPORT:
524 		re = (struct usb_ctl_report *)addr;
525 		switch (re->ucr_report) {
526 		case UHID_INPUT_REPORT:
527 			size = sc->sc_isize;
528 			break;
529 		case UHID_OUTPUT_REPORT:
530 			size = sc->sc_osize;
531 			break;
532 		case UHID_FEATURE_REPORT:
533 			size = sc->sc_fsize;
534 			break;
535 		default:
536 			return (EINVAL);
537 		}
538 		extra = sc->sc_hdev.sc_report_id != 0;
539 		err = uhidev_get_report(&sc->sc_hdev, re->ucr_report,
540 		    re->ucr_data, size + extra);
541 		if (extra)
542 			memcpy(re->ucr_data, re->ucr_data+1, size);
543 		if (err)
544 			return (EIO);
545 		break;
546 
547 	case USB_SET_REPORT:
548 		re = (struct usb_ctl_report *)addr;
549 		switch (re->ucr_report) {
550 		case UHID_INPUT_REPORT:
551 			size = sc->sc_isize;
552 			break;
553 		case UHID_OUTPUT_REPORT:
554 			size = sc->sc_osize;
555 			break;
556 		case UHID_FEATURE_REPORT:
557 			size = sc->sc_fsize;
558 			break;
559 		default:
560 			return (EINVAL);
561 		}
562 		err = uhidev_set_report(&sc->sc_hdev, re->ucr_report,
563 		    re->ucr_data, size);
564 		if (err)
565 			return (EIO);
566 		break;
567 
568 	case USB_GET_REPORT_ID:
569 		*(int *)addr = sc->sc_hdev.sc_report_id;
570 		break;
571 
572 	case USB_GET_DEVICEINFO:
573 		usbd_fill_deviceinfo(sc->sc_hdev.sc_parent->sc_udev,
574 			             (struct usb_device_info *)addr, 0);
575 		break;
576 #ifdef COMPAT_30
577 	case USB_GET_DEVICEINFO_OLD:
578 		usbd_fill_deviceinfo_old(sc->sc_hdev.sc_parent->sc_udev,
579 					 (struct usb_device_info_old *)addr, 0);
580 
581 		break;
582 #endif
583         case USB_GET_STRING_DESC:
584 	    {
585                 struct usb_string_desc *si = (struct usb_string_desc *)addr;
586                 err = usbd_get_string_desc(sc->sc_hdev.sc_parent->sc_udev,
587 			si->usd_string_index,
588                 	si->usd_language_id, &si->usd_desc, &size);
589                 if (err)
590                         return (EINVAL);
591                 break;
592 	    }
593 
594 	default:
595 		return (EINVAL);
596 	}
597 	return (0);
598 }
599 
600 int
601 uhidioctl(dev_t dev, u_long cmd, void *addr, int flag, struct lwp *l)
602 {
603 	struct uhid_softc *sc;
604 	int error;
605 
606 	USB_GET_SC(uhid, UHIDUNIT(dev), sc);
607 
608 	sc->sc_refcnt++;
609 	error = uhid_do_ioctl(sc, cmd, addr, flag, l);
610 	if (--sc->sc_refcnt < 0)
611 		usb_detach_wakeup(USBDEV(sc->sc_hdev.sc_dev));
612 	return (error);
613 }
614 
615 int
616 uhidpoll(dev_t dev, int events, struct lwp *l)
617 {
618 	struct uhid_softc *sc;
619 	int revents = 0;
620 	int s;
621 
622 	USB_GET_SC(uhid, UHIDUNIT(dev), sc);
623 
624 	if (sc->sc_dying)
625 		return (POLLHUP);
626 
627 	s = splusb();
628 	if (events & (POLLOUT | POLLWRNORM))
629 		revents |= events & (POLLOUT | POLLWRNORM);
630 	if (events & (POLLIN | POLLRDNORM)) {
631 		if (sc->sc_q.c_cc > 0)
632 			revents |= events & (POLLIN | POLLRDNORM);
633 		else
634 			selrecord(l, &sc->sc_rsel);
635 	}
636 
637 	splx(s);
638 	return (revents);
639 }
640 
641 static void
642 filt_uhidrdetach(struct knote *kn)
643 {
644 	struct uhid_softc *sc = kn->kn_hook;
645 	int s;
646 
647 	s = splusb();
648 	SLIST_REMOVE(&sc->sc_rsel.sel_klist, kn, knote, kn_selnext);
649 	splx(s);
650 }
651 
652 static int
653 filt_uhidread(struct knote *kn, long hint)
654 {
655 	struct uhid_softc *sc = kn->kn_hook;
656 
657 	kn->kn_data = sc->sc_q.c_cc;
658 	return (kn->kn_data > 0);
659 }
660 
661 static const struct filterops uhidread_filtops =
662 	{ 1, NULL, filt_uhidrdetach, filt_uhidread };
663 
664 static const struct filterops uhid_seltrue_filtops =
665 	{ 1, NULL, filt_uhidrdetach, filt_seltrue };
666 
667 int
668 uhidkqfilter(dev_t dev, struct knote *kn)
669 {
670 	struct uhid_softc *sc;
671 	struct klist *klist;
672 	int s;
673 
674 	USB_GET_SC(uhid, UHIDUNIT(dev), sc);
675 
676 	if (sc->sc_dying)
677 		return (ENXIO);
678 
679 	switch (kn->kn_filter) {
680 	case EVFILT_READ:
681 		klist = &sc->sc_rsel.sel_klist;
682 		kn->kn_fop = &uhidread_filtops;
683 		break;
684 
685 	case EVFILT_WRITE:
686 		klist = &sc->sc_rsel.sel_klist;
687 		kn->kn_fop = &uhid_seltrue_filtops;
688 		break;
689 
690 	default:
691 		return (EINVAL);
692 	}
693 
694 	kn->kn_hook = sc;
695 
696 	s = splusb();
697 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
698 	splx(s);
699 
700 	return (0);
701 }
702