xref: /netbsd-src/sys/dev/usb/uhid.c (revision 8ac07aec990b9d2e483062509d0a9fa5b4f57cf2)
1 /*	$NetBSD: uhid.c,v 1.80 2008/04/24 15:35:28 ad 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  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *        This product includes software developed by the NetBSD
22  *        Foundation, Inc. and its contributors.
23  * 4. Neither the name of The NetBSD Foundation nor the names of its
24  *    contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37  * POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 /*
41  * HID spec: http://www.usb.org/developers/devclass_docs/HID1_11.pdf
42  */
43 
44 #include <sys/cdefs.h>
45 __KERNEL_RCSID(0, "$NetBSD: uhid.c,v 1.80 2008/04/24 15:35:28 ad Exp $");
46 
47 #include "opt_compat_netbsd.h"
48 
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/kernel.h>
52 #include <sys/malloc.h>
53 #include <sys/signalvar.h>
54 #include <sys/device.h>
55 #include <sys/ioctl.h>
56 #include <sys/conf.h>
57 #include <sys/tty.h>
58 #include <sys/file.h>
59 #include <sys/select.h>
60 #include <sys/proc.h>
61 #include <sys/vnode.h>
62 #include <sys/poll.h>
63 #include <sys/intr.h>
64 
65 #include <dev/usb/usb.h>
66 #include <dev/usb/usbhid.h>
67 
68 #include <dev/usb/usbdevs.h>
69 #include <dev/usb/usbdi.h>
70 #include <dev/usb/usbdi_util.h>
71 #include <dev/usb/hid.h>
72 #include <dev/usb/usb_quirks.h>
73 
74 #include <dev/usb/uhidev.h>
75 
76 #ifdef UHID_DEBUG
77 #define DPRINTF(x)	if (uhiddebug) logprintf x
78 #define DPRINTFN(n,x)	if (uhiddebug>(n)) logprintf x
79 int	uhiddebug = 0;
80 #else
81 #define DPRINTF(x)
82 #define DPRINTFN(n,x)
83 #endif
84 
85 struct uhid_softc {
86 	struct uhidev sc_hdev;
87 
88 	int sc_isize;
89 	int sc_osize;
90 	int sc_fsize;
91 
92 	u_char *sc_obuf;
93 
94 	struct clist sc_q;
95 	struct selinfo sc_rsel;
96 	usb_proc_ptr sc_async;	/* process that wants SIGIO */
97 	void *sc_sih;
98 	u_char sc_state;	/* driver state */
99 #define	UHID_ASLP	0x01	/* waiting for device data */
100 #define UHID_IMMED	0x02	/* return read data immediately */
101 
102 	int sc_refcnt;
103 	u_char sc_dying;
104 };
105 
106 #define	UHIDUNIT(dev)	(minor(dev))
107 #define	UHID_CHUNK	128	/* chunk size for read */
108 #define	UHID_BSIZE	1020	/* buffer size */
109 
110 dev_type_open(uhidopen);
111 dev_type_close(uhidclose);
112 dev_type_read(uhidread);
113 dev_type_write(uhidwrite);
114 dev_type_ioctl(uhidioctl);
115 dev_type_poll(uhidpoll);
116 dev_type_kqfilter(uhidkqfilter);
117 
118 const struct cdevsw uhid_cdevsw = {
119 	uhidopen, uhidclose, uhidread, uhidwrite, uhidioctl,
120 	nostop, notty, uhidpoll, nommap, uhidkqfilter, D_OTHER,
121 };
122 
123 Static void uhid_intr(struct uhidev *, void *, u_int len);
124 Static void uhid_softintr(void *);
125 
126 Static int uhid_do_read(struct uhid_softc *, struct uio *uio, int);
127 Static int uhid_do_write(struct uhid_softc *, struct uio *uio, int);
128 Static int uhid_do_ioctl(struct uhid_softc*, u_long, void *, int, struct lwp *);
129 
130 USB_DECLARE_DRIVER(uhid);
131 
132 int
133 uhid_match(struct device *parent, struct cfdata *match,
134     void *aux)
135 {
136 #ifdef UHID_DEBUG
137 	struct uhidev_attach_arg *uha = aux;
138 #endif
139 
140 	DPRINTF(("uhid_match: report=%d\n", uha->reportid));
141 
142 	if (match->cf_flags & 1)
143 		return (UMATCH_HIGHEST);
144 	else
145 		return (UMATCH_IFACECLASS_GENERIC);
146 }
147 
148 void
149 uhid_attach(struct device *parent, struct device *self, void *aux)
150 {
151 	struct uhid_softc *sc = (struct uhid_softc *)self;
152 	struct uhidev_attach_arg *uha = aux;
153 	int size, repid;
154 	void *desc;
155 
156 	selinit(&sc->sc_rsel);
157 	sc->sc_hdev.sc_intr = uhid_intr;
158 	sc->sc_hdev.sc_parent = uha->parent;
159 	sc->sc_hdev.sc_report_id = uha->reportid;
160 	sc->sc_sih = softint_establish(SOFTINT_MPSAFE | SOFTINT_CLOCK,
161 	    uhid_softintr, sc);
162 
163 	uhidev_get_report_desc(uha->parent, &desc, &size);
164 	repid = uha->reportid;
165 	sc->sc_isize = hid_report_size(desc, size, hid_input,   repid);
166 	sc->sc_osize = hid_report_size(desc, size, hid_output,  repid);
167 	sc->sc_fsize = hid_report_size(desc, size, hid_feature, repid);
168 
169 	printf(": input=%d, output=%d, feature=%d\n",
170 	       sc->sc_isize, sc->sc_osize, sc->sc_fsize);
171 
172 	if (!pmf_device_register(self, NULL, NULL))
173 		aprint_error_dev(self, "couldn't establish power handler\n");
174 
175 	USB_ATTACH_SUCCESS_RETURN;
176 }
177 
178 int
179 uhid_activate(device_ptr_t self, enum devact act)
180 {
181 	struct uhid_softc *sc = (struct uhid_softc *)self;
182 
183 	switch (act) {
184 	case DVACT_ACTIVATE:
185 		return (EOPNOTSUPP);
186 
187 	case DVACT_DEACTIVATE:
188 		sc->sc_dying = 1;
189 		break;
190 	}
191 	return (0);
192 }
193 
194 int
195 uhid_detach(struct device *self, int flags)
196 {
197 	struct uhid_softc *sc = (struct uhid_softc *)self;
198 	int s;
199 	int maj, mn;
200 
201 	DPRINTF(("uhid_detach: sc=%p flags=%d\n", sc, flags));
202 
203 	sc->sc_dying = 1;
204 
205 	if (sc->sc_hdev.sc_state & UHIDEV_OPEN) {
206 		s = splusb();
207 		if (--sc->sc_refcnt >= 0) {
208 			/* Wake everyone */
209 			wakeup(&sc->sc_q);
210 			/* Wait for processes to go away. */
211 			usb_detach_wait(USBDEV(sc->sc_hdev.sc_dev));
212 		}
213 		splx(s);
214 	}
215 
216 	/* locate the major number */
217 #if defined(__NetBSD__)
218 	maj = cdevsw_lookup_major(&uhid_cdevsw);
219 #elif defined(__OpenBSD__)
220 	for (maj = 0; maj < nchrdev; maj++)
221 		if (cdevsw[maj].d_open == uhidopen)
222 			break;
223 #endif
224 
225 	/* Nuke the vnodes for any open instances (calls close). */
226 	mn = device_unit(self);
227 	vdevgone(maj, mn, mn, VCHR);
228 
229 #if 0
230 	usbd_add_drv_event(USB_EVENT_DRIVER_DETACH,
231 			   sc->sc_hdev.sc_parent->sc_udev,
232 			   USBDEV(sc->sc_hdev.sc_dev));
233 #endif
234 	seldestroy(&sc->sc_rsel);
235 	softint_disestablish(sc->sc_sih);
236 
237 	return (0);
238 }
239 
240 void
241 uhid_intr(struct uhidev *addr, void *data, u_int len)
242 {
243 	struct uhid_softc *sc = (struct uhid_softc *)addr;
244 
245 #ifdef UHID_DEBUG
246 	if (uhiddebug > 5) {
247 		u_int32_t i;
248 
249 		DPRINTF(("uhid_intr: data ="));
250 		for (i = 0; i < len; i++)
251 			DPRINTF((" %02x", ((u_char *)data)[i]));
252 		DPRINTF(("\n"));
253 	}
254 #endif
255 
256 	(void)b_to_q(data, len, &sc->sc_q);
257 
258 	if (sc->sc_state & UHID_ASLP) {
259 		sc->sc_state &= ~UHID_ASLP;
260 		DPRINTFN(5, ("uhid_intr: waking %p\n", &sc->sc_q));
261 		wakeup(&sc->sc_q);
262 	}
263 	selnotify(&sc->sc_rsel, 0, 0);
264 	if (sc->sc_async != NULL) {
265 		DPRINTFN(3, ("uhid_intr: sending SIGIO %p\n", sc->sc_async));
266 		softint_schedule(sc->sc_sih);
267 	}
268 }
269 
270 void
271 uhid_softintr(void *cookie)
272 {
273 	struct uhid_softc *sc;
274 
275 	sc = cookie;
276 
277 	mutex_enter(proc_lock);
278 	if (sc->sc_async != NULL)
279 		 psignal(sc->sc_async, SIGIO);
280 	mutex_exit(proc_lock);
281 }
282 
283 int
284 uhidopen(dev_t dev, int flag, int mode,
285     struct lwp *l)
286 {
287 	struct uhid_softc *sc;
288 	int error;
289 
290 	USB_GET_SC_OPEN(uhid, UHIDUNIT(dev), sc);
291 
292 	DPRINTF(("uhidopen: sc=%p\n", sc));
293 
294 	if (sc->sc_dying)
295 		return (ENXIO);
296 
297 	error = uhidev_open(&sc->sc_hdev);
298 	if (error)
299 		return (error);
300 
301 	if (clalloc(&sc->sc_q, UHID_BSIZE, 0) == -1) {
302 		uhidev_close(&sc->sc_hdev);
303 		return (ENOMEM);
304 	}
305 	sc->sc_obuf = malloc(sc->sc_osize, M_USBDEV, M_WAITOK);
306 	sc->sc_state &= ~UHID_IMMED;
307 	mutex_enter(proc_lock);
308 	sc->sc_async = NULL;
309 	mutex_exit(proc_lock);
310 
311 	return (0);
312 }
313 
314 int
315 uhidclose(dev_t dev, int flag, int mode,
316     struct lwp *l)
317 {
318 	struct uhid_softc *sc;
319 
320 	USB_GET_SC(uhid, UHIDUNIT(dev), sc);
321 
322 	DPRINTF(("uhidclose: sc=%p\n", sc));
323 
324 	clfree(&sc->sc_q);
325 	free(sc->sc_obuf, M_USBDEV);
326 	mutex_enter(proc_lock);
327 	sc->sc_async = NULL;
328 	mutex_exit(proc_lock);
329 	uhidev_close(&sc->sc_hdev);
330 
331 	return (0);
332 }
333 
334 int
335 uhid_do_read(struct uhid_softc *sc, struct uio *uio, int flag)
336 {
337 	int s;
338 	int error = 0;
339 	int extra;
340 	size_t length;
341 	u_char buffer[UHID_CHUNK];
342 	usbd_status err;
343 
344 	DPRINTFN(1, ("uhidread\n"));
345 	if (sc->sc_state & UHID_IMMED) {
346 		DPRINTFN(1, ("uhidread immed\n"));
347 		extra = sc->sc_hdev.sc_report_id != 0;
348 		err = uhidev_get_report(&sc->sc_hdev, UHID_INPUT_REPORT,
349 					buffer, sc->sc_isize + extra);
350 		if (err)
351 			return (EIO);
352 		return (uiomove(buffer+extra, sc->sc_isize, uio));
353 	}
354 
355 	s = splusb();
356 	while (sc->sc_q.c_cc == 0) {
357 		if (flag & IO_NDELAY) {
358 			splx(s);
359 			return (EWOULDBLOCK);
360 		}
361 		sc->sc_state |= UHID_ASLP;
362 		DPRINTFN(5, ("uhidread: sleep on %p\n", &sc->sc_q));
363 		error = tsleep(&sc->sc_q, PZERO | PCATCH, "uhidrea", 0);
364 		DPRINTFN(5, ("uhidread: woke, error=%d\n", error));
365 		if (sc->sc_dying)
366 			error = EIO;
367 		if (error) {
368 			sc->sc_state &= ~UHID_ASLP;
369 			break;
370 		}
371 	}
372 	splx(s);
373 
374 	/* Transfer as many chunks as possible. */
375 	while (sc->sc_q.c_cc > 0 && uio->uio_resid > 0 && !error) {
376 		length = min(sc->sc_q.c_cc, uio->uio_resid);
377 		if (length > sizeof(buffer))
378 			length = sizeof(buffer);
379 
380 		/* Remove a small chunk from the input queue. */
381 		(void) q_to_b(&sc->sc_q, buffer, length);
382 		DPRINTFN(5, ("uhidread: got %lu chars\n", (u_long)length));
383 
384 		/* Copy the data to the user process. */
385 		if ((error = uiomove(buffer, length, uio)) != 0)
386 			break;
387 	}
388 
389 	return (error);
390 }
391 
392 int
393 uhidread(dev_t dev, struct uio *uio, int flag)
394 {
395 	struct uhid_softc *sc;
396 	int error;
397 
398 	USB_GET_SC(uhid, UHIDUNIT(dev), sc);
399 
400 	sc->sc_refcnt++;
401 	error = uhid_do_read(sc, uio, flag);
402 	if (--sc->sc_refcnt < 0)
403 		usb_detach_wakeup(USBDEV(sc->sc_hdev.sc_dev));
404 	return (error);
405 }
406 
407 int
408 uhid_do_write(struct uhid_softc *sc, struct uio *uio, int flag)
409 {
410 	int error;
411 	int size;
412 	usbd_status err;
413 
414 	DPRINTFN(1, ("uhidwrite\n"));
415 
416 	if (sc->sc_dying)
417 		return (EIO);
418 
419 	size = sc->sc_osize;
420 	error = 0;
421 	if (uio->uio_resid != size)
422 		return (EINVAL);
423 	error = uiomove(sc->sc_obuf, size, uio);
424 	if (!error) {
425 		err = uhidev_set_report(&sc->sc_hdev, UHID_OUTPUT_REPORT,
426 					sc->sc_obuf, size);
427 		if (err)
428 			error = EIO;
429 	}
430 
431 	return (error);
432 }
433 
434 int
435 uhidwrite(dev_t dev, struct uio *uio, int flag)
436 {
437 	struct uhid_softc *sc;
438 	int error;
439 
440 	USB_GET_SC(uhid, UHIDUNIT(dev), sc);
441 
442 	sc->sc_refcnt++;
443 	error = uhid_do_write(sc, uio, flag);
444 	if (--sc->sc_refcnt < 0)
445 		usb_detach_wakeup(USBDEV(sc->sc_hdev.sc_dev));
446 	return (error);
447 }
448 
449 int
450 uhid_do_ioctl(struct uhid_softc *sc, u_long cmd, void *addr,
451     int flag, struct lwp *l)
452 {
453 	struct usb_ctl_report_desc *rd;
454 	struct usb_ctl_report *re;
455 	u_char buffer[UHID_CHUNK];
456 	int size, extra;
457 	usbd_status err;
458 	void *desc;
459 
460 	DPRINTFN(2, ("uhidioctl: cmd=%lx\n", cmd));
461 
462 	if (sc->sc_dying)
463 		return (EIO);
464 
465 	switch (cmd) {
466 	case FIONBIO:
467 		/* All handled in the upper FS layer. */
468 		break;
469 
470 	case FIOASYNC:
471 		mutex_enter(proc_lock);
472 		if (*(int *)addr) {
473 			if (sc->sc_async != NULL)
474 				return (EBUSY);
475 			sc->sc_async = l->l_proc;
476 			DPRINTF(("uhid_do_ioctl: FIOASYNC %p\n", l->l_proc));
477 		} else
478 			sc->sc_async = NULL;
479 		mutex_exit(proc_lock);
480 		break;
481 
482 	/* XXX this is not the most general solution. */
483 	case TIOCSPGRP:
484 		mutex_enter(proc_lock);
485 		if (sc->sc_async == NULL) {
486 			mutex_exit(proc_lock);
487 			return (EINVAL);
488 		}
489 		if (*(int *)addr != sc->sc_async->p_pgid) {
490 			mutex_exit(proc_lock);
491 			return (EPERM);
492 		}
493 		mutex_exit(proc_lock);
494 		break;
495 
496 	case FIOSETOWN:
497 		mutex_enter(proc_lock);
498 		if (sc->sc_async == NULL) {
499 			mutex_exit(proc_lock);
500 			return (EINVAL);
501 		}
502 		if (-*(int *)addr != sc->sc_async->p_pgid
503 		    && *(int *)addr != sc->sc_async->p_pid) {
504 			mutex_exit(proc_lock);
505 			return (EPERM);
506 		}
507 		mutex_exit(proc_lock);
508 		break;
509 
510 	case USB_GET_REPORT_DESC:
511 		uhidev_get_report_desc(sc->sc_hdev.sc_parent, &desc, &size);
512 		rd = (struct usb_ctl_report_desc *)addr;
513 		size = min(size, sizeof rd->ucrd_data);
514 		rd->ucrd_size = size;
515 		memcpy(rd->ucrd_data, desc, size);
516 		break;
517 
518 	case USB_SET_IMMED:
519 		if (*(int *)addr) {
520 			extra = sc->sc_hdev.sc_report_id != 0;
521 			err = uhidev_get_report(&sc->sc_hdev, UHID_INPUT_REPORT,
522 						buffer, sc->sc_isize + extra);
523 			if (err)
524 				return (EOPNOTSUPP);
525 
526 			sc->sc_state |=  UHID_IMMED;
527 		} else
528 			sc->sc_state &= ~UHID_IMMED;
529 		break;
530 
531 	case USB_GET_REPORT:
532 		re = (struct usb_ctl_report *)addr;
533 		switch (re->ucr_report) {
534 		case UHID_INPUT_REPORT:
535 			size = sc->sc_isize;
536 			break;
537 		case UHID_OUTPUT_REPORT:
538 			size = sc->sc_osize;
539 			break;
540 		case UHID_FEATURE_REPORT:
541 			size = sc->sc_fsize;
542 			break;
543 		default:
544 			return (EINVAL);
545 		}
546 		extra = sc->sc_hdev.sc_report_id != 0;
547 		err = uhidev_get_report(&sc->sc_hdev, re->ucr_report,
548 		    re->ucr_data, size + extra);
549 		if (extra)
550 			memcpy(re->ucr_data, re->ucr_data+1, size);
551 		if (err)
552 			return (EIO);
553 		break;
554 
555 	case USB_SET_REPORT:
556 		re = (struct usb_ctl_report *)addr;
557 		switch (re->ucr_report) {
558 		case UHID_INPUT_REPORT:
559 			size = sc->sc_isize;
560 			break;
561 		case UHID_OUTPUT_REPORT:
562 			size = sc->sc_osize;
563 			break;
564 		case UHID_FEATURE_REPORT:
565 			size = sc->sc_fsize;
566 			break;
567 		default:
568 			return (EINVAL);
569 		}
570 		err = uhidev_set_report(&sc->sc_hdev, re->ucr_report,
571 		    re->ucr_data, size);
572 		if (err)
573 			return (EIO);
574 		break;
575 
576 	case USB_GET_REPORT_ID:
577 		*(int *)addr = sc->sc_hdev.sc_report_id;
578 		break;
579 
580 	case USB_GET_DEVICEINFO:
581 		usbd_fill_deviceinfo(sc->sc_hdev.sc_parent->sc_udev,
582 			             (struct usb_device_info *)addr, 0);
583 		break;
584 #ifdef COMPAT_30
585 	case USB_GET_DEVICEINFO_OLD:
586 		usbd_fill_deviceinfo_old(sc->sc_hdev.sc_parent->sc_udev,
587 					 (struct usb_device_info_old *)addr, 0);
588 
589 		break;
590 #endif
591         case USB_GET_STRING_DESC:
592 	    {
593                 struct usb_string_desc *si = (struct usb_string_desc *)addr;
594                 err = usbd_get_string_desc(sc->sc_hdev.sc_parent->sc_udev,
595 			si->usd_string_index,
596                 	si->usd_language_id, &si->usd_desc, &size);
597                 if (err)
598                         return (EINVAL);
599                 break;
600 	    }
601 
602 	default:
603 		return (EINVAL);
604 	}
605 	return (0);
606 }
607 
608 int
609 uhidioctl(dev_t dev, u_long cmd, void *addr, int flag, struct lwp *l)
610 {
611 	struct uhid_softc *sc;
612 	int error;
613 
614 	USB_GET_SC(uhid, UHIDUNIT(dev), sc);
615 
616 	sc->sc_refcnt++;
617 	error = uhid_do_ioctl(sc, cmd, addr, flag, l);
618 	if (--sc->sc_refcnt < 0)
619 		usb_detach_wakeup(USBDEV(sc->sc_hdev.sc_dev));
620 	return (error);
621 }
622 
623 int
624 uhidpoll(dev_t dev, int events, struct lwp *l)
625 {
626 	struct uhid_softc *sc;
627 	int revents = 0;
628 	int s;
629 
630 	USB_GET_SC(uhid, UHIDUNIT(dev), sc);
631 
632 	if (sc->sc_dying)
633 		return (POLLHUP);
634 
635 	s = splusb();
636 	if (events & (POLLOUT | POLLWRNORM))
637 		revents |= events & (POLLOUT | POLLWRNORM);
638 	if (events & (POLLIN | POLLRDNORM)) {
639 		if (sc->sc_q.c_cc > 0)
640 			revents |= events & (POLLIN | POLLRDNORM);
641 		else
642 			selrecord(l, &sc->sc_rsel);
643 	}
644 
645 	splx(s);
646 	return (revents);
647 }
648 
649 static void
650 filt_uhidrdetach(struct knote *kn)
651 {
652 	struct uhid_softc *sc = kn->kn_hook;
653 	int s;
654 
655 	s = splusb();
656 	SLIST_REMOVE(&sc->sc_rsel.sel_klist, kn, knote, kn_selnext);
657 	splx(s);
658 }
659 
660 static int
661 filt_uhidread(struct knote *kn, long hint)
662 {
663 	struct uhid_softc *sc = kn->kn_hook;
664 
665 	kn->kn_data = sc->sc_q.c_cc;
666 	return (kn->kn_data > 0);
667 }
668 
669 static const struct filterops uhidread_filtops =
670 	{ 1, NULL, filt_uhidrdetach, filt_uhidread };
671 
672 static const struct filterops uhid_seltrue_filtops =
673 	{ 1, NULL, filt_uhidrdetach, filt_seltrue };
674 
675 int
676 uhidkqfilter(dev_t dev, struct knote *kn)
677 {
678 	struct uhid_softc *sc;
679 	struct klist *klist;
680 	int s;
681 
682 	USB_GET_SC(uhid, UHIDUNIT(dev), sc);
683 
684 	if (sc->sc_dying)
685 		return (ENXIO);
686 
687 	switch (kn->kn_filter) {
688 	case EVFILT_READ:
689 		klist = &sc->sc_rsel.sel_klist;
690 		kn->kn_fop = &uhidread_filtops;
691 		break;
692 
693 	case EVFILT_WRITE:
694 		klist = &sc->sc_rsel.sel_klist;
695 		kn->kn_fop = &uhid_seltrue_filtops;
696 		break;
697 
698 	default:
699 		return (EINVAL);
700 	}
701 
702 	kn->kn_hook = sc;
703 
704 	s = splusb();
705 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
706 	splx(s);
707 
708 	return (0);
709 }
710