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button.c revision 1.2
      1 /*	$NetBSD: button.c,v 1.2 2007/03/04 06:00:03 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2003 Wasabi Systems, Inc.
      5  * All rights reserved.
      6  *
      7  * Written by Jason R. Thorpe for Wasabi Systems, Inc.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. All advertising materials mentioning features or use of this software
     18  *    must display the following acknowledgement:
     19  *	This product includes software developed for the NetBSD Project by
     20  *	Wasabi Systems, Inc.
     21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
     22  *    or promote products derived from this software without specific prior
     23  *    written permission.
     24  *
     25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
     26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
     29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     35  * POSSIBILITY OF SUCH DAMAGE.
     36  */
     37 
     38 #include <sys/cdefs.h>
     39 __KERNEL_RCSID(0, "$NetBSD: button.c,v 1.2 2007/03/04 06:00:03 christos Exp $");
     40 
     41 #include <sys/param.h>
     42 #include <sys/conf.h>
     43 #include <sys/systm.h>
     44 #include <sys/malloc.h>
     45 #include <sys/lock.h>
     46 #include <sys/queue.h>
     47 #include <sys/proc.h>
     48 #include <sys/kthread.h>
     49 #include <sys/errno.h>
     50 #include <sys/fcntl.h>
     51 #include <sys/callout.h>
     52 #include <sys/kernel.h>
     53 #include <sys/poll.h>
     54 #include <sys/select.h>
     55 #include <sys/vnode.h>
     56 
     57 #include <machine/button.h>
     58 
     59 #include <landisk/dev/buttonvar.h>
     60 
     61 /*
     62  * event handler
     63  */
     64 static LIST_HEAD(, btn_event) btn_event_list =
     65     LIST_HEAD_INITIALIZER(btn_event_list);
     66 static struct simplelock btn_event_list_slock =
     67     SIMPLELOCK_INITIALIZER;
     68 
     69 static struct lwp *btn_daemon;
     70 
     71 #define	BTN_MAX_EVENTS		32
     72 
     73 static struct simplelock btn_event_queue_slock =
     74     SIMPLELOCK_INITIALIZER;
     75 static button_event_t btn_event_queue[BTN_MAX_EVENTS];
     76 static int btn_event_queue_head;
     77 static int btn_event_queue_tail;
     78 static int btn_event_queue_count;
     79 static int btn_event_queue_flags;
     80 static struct selinfo btn_event_queue_selinfo;
     81 
     82 static char btn_type[32];
     83 
     84 #define	BEVQ_F_WAITING		0x01	/* daemon waiting for event */
     85 
     86 #define	BTN_NEXT_EVENT(x)	(((x) + 1) / BTN_MAX_EVENTS)
     87 
     88 dev_type_open(btnopen);
     89 dev_type_close(btnclose);
     90 dev_type_ioctl(btnioctl);
     91 dev_type_read(btnread);
     92 dev_type_poll(btnpoll);
     93 dev_type_kqfilter(btnkqfilter);
     94 
     95 const struct cdevsw button_cdevsw = {
     96 	btnopen, btnclose, btnread, nowrite, btnioctl,
     97 	nostop, notty, btnpoll, nommap, btnkqfilter,
     98 };
     99 
    100 static int
    101 btn_queue_event(button_event_t *bev)
    102 {
    103 
    104 	LOCK_ASSERT(simple_lock_held(&btn_event_queue_slock));
    105 
    106 	if (btn_event_queue_count == BTN_MAX_EVENTS)
    107 		return (0);
    108 
    109 	btn_event_queue[btn_event_queue_head] = *bev;
    110 	btn_event_queue_head = BTN_NEXT_EVENT(btn_event_queue_head);
    111 	btn_event_queue_count++;
    112 
    113 	return (1);
    114 }
    115 
    116 static int
    117 btn_get_event(button_event_t *bev)
    118 {
    119 
    120 	LOCK_ASSERT(simple_lock_held(&btn_event_queue_slock));
    121 
    122 	if (btn_event_queue_count == 0)
    123 		return (0);
    124 
    125 	*bev = btn_event_queue[btn_event_queue_tail];
    126 	btn_event_queue_tail = BTN_NEXT_EVENT(btn_event_queue_tail);
    127 	btn_event_queue_count--;
    128 
    129 	return (1);
    130 }
    131 
    132 static void
    133 btn_event_queue_flush(void)
    134 {
    135 
    136 	btn_event_queue_head = 0;
    137 	btn_event_queue_tail = 0;
    138 	btn_event_queue_count = 0;
    139 	btn_event_queue_flags = 0;
    140 }
    141 
    142 int
    143 btnopen(dev_t dev, int flag, int mode, struct lwp *l)
    144 {
    145 	int error;
    146 
    147 	if (minor(dev) != 0) {
    148 		return (ENODEV);
    149 	}
    150 
    151 	simple_lock(&btn_event_queue_slock);
    152 	if (btn_daemon != NULL) {
    153 		error = EBUSY;
    154 	} else {
    155 		error = 0;
    156 		btn_daemon = l;
    157 		btn_event_queue_flush();
    158 	}
    159 	simple_unlock(&btn_event_queue_slock);
    160 
    161 	return (error);
    162 }
    163 
    164 int
    165 btnclose(dev_t dev, int flag, int mode, struct lwp *l)
    166 {
    167 	int count;
    168 
    169 	if (minor(dev) != 0) {
    170 		return (ENODEV);
    171 	}
    172 
    173 	simple_lock(&btn_event_queue_slock);
    174 	count = btn_event_queue_count;
    175 	btn_daemon = NULL;
    176 	btn_event_queue_flush();
    177 	simple_unlock(&btn_event_queue_slock);
    178 
    179 	if (count) {
    180 		printf("WARNING: %d events lost by exiting daemon\n", count);
    181 	}
    182 
    183 	return (0);
    184 }
    185 
    186 int
    187 btnioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
    188 {
    189 	int error = 0;
    190 
    191 	if (minor(dev) != 0) {
    192 		return (ENODEV);
    193 	}
    194 
    195 	switch (cmd) {
    196 	case BUTTON_IOC_GET_TYPE:
    197 	    {
    198 		struct button_type *button_type = (void *)data;
    199 		strcpy(button_type->button_type, btn_type);
    200 		break;
    201 	    }
    202 
    203 	default:
    204 		error = ENOTTY;
    205 		break;
    206 	}
    207 
    208 	return (error);
    209 }
    210 
    211 int
    212 btnread(dev_t dev, struct uio *uio, int flags)
    213 {
    214 	button_event_t bev;
    215 	int error;
    216 
    217 	if (minor(dev) != 0) {
    218 		return (ENODEV);
    219 	}
    220 
    221 	if (uio->uio_resid != BUTTON_EVENT_MSG_SIZE) {
    222 		return (EINVAL);
    223 	}
    224 
    225 	simple_lock(&btn_event_queue_slock);
    226 	for (;;) {
    227 		if (btn_get_event(&bev)) {
    228 			simple_unlock(&btn_event_queue_slock);
    229 			return (uiomove(&bev, BUTTON_EVENT_MSG_SIZE, uio));
    230 		}
    231 
    232 		if (flags & IO_NDELAY) {
    233 			simple_unlock(&btn_event_queue_slock);
    234 			return (EWOULDBLOCK);
    235 		}
    236 
    237 		btn_event_queue_flags |= BEVQ_F_WAITING;
    238 		error = ltsleep(&btn_event_queue_count,
    239 		    (PRIBIO|PCATCH), "btnread", 0, &btn_event_queue_slock);
    240 		if (error) {
    241 			simple_unlock(&btn_event_queue_slock);
    242 			return (error);
    243 		}
    244 	}
    245 }
    246 
    247 int
    248 btnpoll(dev_t dev, int events, struct lwp *l)
    249 {
    250 	int revents;
    251 
    252 	if (minor(dev) != 0) {
    253 		return (ENODEV);
    254 	}
    255 
    256 	revents = events & (POLLOUT | POLLWRNORM);
    257 
    258 	/* Attempt to save some work. */
    259 	if ((events & (POLLIN | POLLRDNORM)) == 0)
    260 		return (revents);
    261 
    262 	simple_lock(&btn_event_queue_slock);
    263 	if (btn_event_queue_count) {
    264 		revents |= events & (POLLIN | POLLRDNORM);
    265 	} else {
    266 		selrecord(l, &btn_event_queue_selinfo);
    267 	}
    268 	simple_unlock(&btn_event_queue_slock);
    269 
    270 	return (revents);
    271 }
    272 
    273 static void
    274 filt_btn_rdetach(struct knote *kn)
    275 {
    276 
    277 	simple_lock(&btn_event_queue_slock);
    278 	SLIST_REMOVE(&btn_event_queue_selinfo.sel_klist,
    279 	    kn, knote, kn_selnext);
    280 	simple_unlock(&btn_event_queue_slock);
    281 }
    282 
    283 static int
    284 filt_btn_read(struct knote *kn, long hint)
    285 {
    286 
    287 	simple_lock(&btn_event_queue_slock);
    288 	kn->kn_data = btn_event_queue_count;
    289 	simple_unlock(&btn_event_queue_slock);
    290 
    291 	return (kn->kn_data > 0);
    292 }
    293 
    294 static const struct filterops btn_read_filtops =
    295     { 1, NULL, filt_btn_rdetach, filt_btn_read };
    296 
    297 static const struct filterops btn_write_filtops =
    298     { 1, NULL, filt_btn_rdetach, filt_seltrue };
    299 
    300 int
    301 btnkqfilter(dev_t dev, struct knote *kn)
    302 {
    303 	struct klist *klist;
    304 
    305 	if (minor(dev) != 0) {
    306 		return (ENODEV);
    307 	}
    308 
    309 	switch (kn->kn_filter) {
    310 	case EVFILT_READ:
    311 		klist = &btn_event_queue_selinfo.sel_klist;
    312 		kn->kn_fop = &btn_read_filtops;
    313 		break;
    314 
    315 	case EVFILT_WRITE:
    316 		klist = &btn_event_queue_selinfo.sel_klist;
    317 		kn->kn_fop = &btn_write_filtops;
    318 		break;
    319 
    320 	default:
    321 		return (1);
    322 	}
    323 
    324 	simple_lock(&btn_event_queue_slock);
    325 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
    326 	simple_unlock(&btn_event_queue_slock);
    327 
    328 	return (0);
    329 }
    330 
    331 void
    332 btn_settype(const char *type)
    333 {
    334 
    335 	/*
    336 	 * Don't bother locking this; it's going to be set
    337 	 * during autoconfiguration, and then only read from
    338 	 * then on.
    339 	 */
    340 	strlcpy(btn_type, type, sizeof(btn_type));
    341 }
    342 
    343 int
    344 btn_event_register(struct btn_event *bev)
    345 {
    346 
    347 	simple_lock(&btn_event_list_slock);
    348 	LIST_INSERT_HEAD(&btn_event_list, bev, bev_list);
    349 	simple_unlock(&btn_event_list_slock);
    350 
    351 	return (0);
    352 }
    353 
    354 void
    355 btn_event_unregister(struct btn_event *bev)
    356 {
    357 
    358 	simple_lock(&btn_event_list_slock);
    359 	LIST_REMOVE(bev, bev_list);
    360 	simple_unlock(&btn_event_list_slock);
    361 }
    362 
    363 void
    364 btn_event_send(struct btn_event *bev, int event)
    365 {
    366 	button_event_t btnev;
    367 	int rv;
    368 
    369 	simple_lock(&btn_event_queue_slock);
    370 	if (btn_daemon != NULL) {
    371 		btnev.bev_type = BUTTON_EVENT_STATE_CHANGE;
    372 		btnev.bev_event.bs_state = event;
    373 		strcpy(btnev.bev_event.bs_name, bev->bev_name);
    374 
    375 		rv = btn_queue_event(&btnev);
    376 		if (rv == 0) {
    377 			simple_unlock(&btn_event_queue_slock);
    378 			printf("%s: WARNING: state change event %d lost; "
    379 			    "queue full\n", bev->bev_name, btnev.bev_type);
    380 		} else {
    381 			if (btn_event_queue_flags & BEVQ_F_WAITING) {
    382 				btn_event_queue_flags &= ~BEVQ_F_WAITING;
    383 				simple_unlock(&btn_event_queue_slock);
    384 				wakeup(&btn_event_queue_count);
    385 			} else {
    386 				simple_unlock(&btn_event_queue_slock);
    387 			}
    388 			selnotify(&btn_event_queue_selinfo, 0);
    389 		}
    390 		return;
    391 	}
    392 	simple_unlock(&btn_event_queue_slock);
    393 
    394 	printf("%s: btn_event_send can't handle me.\n", bev->bev_name);
    395 }
    396