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button.c revision 1.6 
      1 /*	$NetBSD: button.c,v 1.6 2011/05/14 02:27:35 rmind 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 1.6 2011/05/14 02:27:35 rmind Exp $");
     40 
     41 #include <sys/param.h>
     42 #include <sys/conf.h>
     43 #include <sys/systm.h>
     44 #include <sys/queue.h>
     45 #include <sys/mutex.h>
     46 #include <sys/errno.h>
     47 #include <sys/fcntl.h>
     48 #include <sys/callout.h>
     49 #include <sys/kernel.h>
     50 #include <sys/once.h>
     51 #include <sys/poll.h>
     52 #include <sys/select.h>
     53 #include <sys/vnode.h>
     54 
     55 #include <machine/button.h>
     56 
     57 #include <landisk/dev/buttonvar.h>
     58 
     59 /*
     60  * event handler
     61  */
     62 static ONCE_DECL(btn_once);
     63 static LIST_HEAD(, btn_event) btn_event_list;
     64 static kmutex_t btn_event_list_lock;
     65 
     66 static struct lwp *btn_daemon;
     67 
     68 #define	BTN_MAX_EVENTS		32
     69 
     70 static kmutex_t btn_event_queue_lock;
     71 static kcondvar_t btn_event_queue_cv;
     72 
     73 static button_event_t btn_event_queue[BTN_MAX_EVENTS];
     74 static int btn_event_queue_head;
     75 static int btn_event_queue_tail;
     76 static int btn_event_queue_count;
     77 static int btn_event_queue_flags;
     78 static struct selinfo btn_event_queue_selinfo;
     79 
     80 static char btn_type[32];
     81 
     82 #define	BEVQ_F_WAITING		0x01	/* daemon waiting for event */
     83 
     84 #define	BTN_NEXT_EVENT(x)	(((x) + 1) / BTN_MAX_EVENTS)
     85 
     86 dev_type_open(btnopen);
     87 dev_type_close(btnclose);
     88 dev_type_ioctl(btnioctl);
     89 dev_type_read(btnread);
     90 dev_type_poll(btnpoll);
     91 dev_type_kqfilter(btnkqfilter);
     92 
     93 const struct cdevsw button_cdevsw = {
     94 	btnopen, btnclose, btnread, nowrite, btnioctl,
     95 	nostop, notty, btnpoll, nommap, btnkqfilter,
     96 };
     97 
     98 static int
     99 btn_init(void)
    100 {
    101 
    102 	LIST_INIT(&btn_event_list);
    103 	mutex_init(&btn_event_list_lock, MUTEX_DEFAULT, IPL_NONE);
    104 	mutex_init(&btn_event_queue_lock, MUTEX_DEFAULT, IPL_NONE);
    105 	cv_init(&btn_event_queue_cv, "btncv");
    106 	selinit(&btn_event_queue_selinfo);
    107 
    108 	return 0;
    109 }
    110 
    111 static int
    112 btn_queue_event(button_event_t *bev)
    113 {
    114 
    115 	if (btn_event_queue_count == BTN_MAX_EVENTS)
    116 		return (0);
    117 
    118 	btn_event_queue[btn_event_queue_head] = *bev;
    119 	btn_event_queue_head = BTN_NEXT_EVENT(btn_event_queue_head);
    120 	btn_event_queue_count++;
    121 
    122 	return (1);
    123 }
    124 
    125 static int
    126 btn_get_event(button_event_t *bev)
    127 {
    128 
    129 	if (btn_event_queue_count == 0)
    130 		return (0);
    131 
    132 	*bev = btn_event_queue[btn_event_queue_tail];
    133 	btn_event_queue_tail = BTN_NEXT_EVENT(btn_event_queue_tail);
    134 	btn_event_queue_count--;
    135 
    136 	return (1);
    137 }
    138 
    139 static void
    140 btn_event_queue_flush(void)
    141 {
    142 
    143 	btn_event_queue_head = 0;
    144 	btn_event_queue_tail = 0;
    145 	btn_event_queue_count = 0;
    146 	btn_event_queue_flags = 0;
    147 }
    148 
    149 int
    150 btnopen(dev_t dev, int flag, int mode, struct lwp *l)
    151 {
    152 	int error;
    153 
    154 	error = RUN_ONCE(&btn_once, btn_init);
    155 	if (error) {
    156 		return error;
    157 	}
    158 
    159 	if (minor(dev) != 0) {
    160 		return (ENODEV);
    161 	}
    162 
    163 	mutex_enter(&btn_event_queue_lock);
    164 	if (btn_daemon != NULL) {
    165 		error = EBUSY;
    166 	} else {
    167 		error = 0;
    168 		btn_daemon = l;
    169 		btn_event_queue_flush();
    170 	}
    171 	mutex_exit(&btn_event_queue_lock);
    172 
    173 	return (error);
    174 }
    175 
    176 int
    177 btnclose(dev_t dev, int flag, int mode, struct lwp *l)
    178 {
    179 	int count;
    180 
    181 	if (minor(dev) != 0) {
    182 		return (ENODEV);
    183 	}
    184 
    185 	mutex_enter(&btn_event_queue_lock);
    186 	count = btn_event_queue_count;
    187 	btn_daemon = NULL;
    188 	btn_event_queue_flush();
    189 	mutex_exit(&btn_event_queue_lock);
    190 
    191 	if (count) {
    192 		printf("WARNING: %d events lost by exiting daemon\n", count);
    193 	}
    194 
    195 	return (0);
    196 }
    197 
    198 int
    199 btnioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
    200 {
    201 	int error = 0;
    202 
    203 	if (minor(dev) != 0) {
    204 		return (ENODEV);
    205 	}
    206 
    207 	switch (cmd) {
    208 	case BUTTON_IOC_GET_TYPE:
    209 	    {
    210 		struct button_type *button_type = (void *)data;
    211 		strcpy(button_type->button_type, btn_type);
    212 		break;
    213 	    }
    214 
    215 	default:
    216 		error = ENOTTY;
    217 		break;
    218 	}
    219 
    220 	return (error);
    221 }
    222 
    223 int
    224 btnread(dev_t dev, struct uio *uio, int flags)
    225 {
    226 	button_event_t bev;
    227 	int error;
    228 
    229 	if (minor(dev) != 0) {
    230 		return (ENODEV);
    231 	}
    232 
    233 	if (uio->uio_resid != BUTTON_EVENT_MSG_SIZE) {
    234 		return (EINVAL);
    235 	}
    236 
    237 	mutex_enter(&btn_event_queue_lock);
    238 	for (;;) {
    239 		if (btn_get_event(&bev)) {
    240 			mutex_exit(&btn_event_queue_lock);
    241 			return (uiomove(&bev, BUTTON_EVENT_MSG_SIZE, uio));
    242 		}
    243 
    244 		if (flags & IO_NDELAY) {
    245 			mutex_exit(&btn_event_queue_lock);
    246 			return (EWOULDBLOCK);
    247 		}
    248 
    249 		btn_event_queue_flags |= BEVQ_F_WAITING;
    250 		error = cv_wait_sig(&btn_event_queue_cv, &btn_event_queue_lock);
    251 		if (error) {
    252 			mutex_exit(&btn_event_queue_lock);
    253 			return (error);
    254 		}
    255 	}
    256 }
    257 
    258 int
    259 btnpoll(dev_t dev, int events, struct lwp *l)
    260 {
    261 	int revents;
    262 
    263 	if (minor(dev) != 0) {
    264 		return (ENODEV);
    265 	}
    266 
    267 	revents = events & (POLLOUT | POLLWRNORM);
    268 
    269 	/* Attempt to save some work. */
    270 	if ((events & (POLLIN | POLLRDNORM)) == 0)
    271 		return (revents);
    272 
    273 	mutex_enter(&btn_event_queue_lock);
    274 	if (btn_event_queue_count) {
    275 		revents |= events & (POLLIN | POLLRDNORM);
    276 	} else {
    277 		selrecord(l, &btn_event_queue_selinfo);
    278 	}
    279 	mutex_exit(&btn_event_queue_lock);
    280 
    281 	return (revents);
    282 }
    283 
    284 static void
    285 filt_btn_rdetach(struct knote *kn)
    286 {
    287 
    288 	mutex_enter(&btn_event_queue_lock);
    289 	SLIST_REMOVE(&btn_event_queue_selinfo.sel_klist,
    290 	    kn, knote, kn_selnext);
    291 	mutex_exit(&btn_event_queue_lock);
    292 }
    293 
    294 static int
    295 filt_btn_read(struct knote *kn, long hint)
    296 {
    297 
    298 	mutex_enter(&btn_event_queue_lock);
    299 	kn->kn_data = btn_event_queue_count;
    300 	mutex_exit(&btn_event_queue_lock);
    301 
    302 	return (kn->kn_data > 0);
    303 }
    304 
    305 static const struct filterops btn_read_filtops =
    306     { 1, NULL, filt_btn_rdetach, filt_btn_read };
    307 
    308 static const struct filterops btn_write_filtops =
    309     { 1, NULL, filt_btn_rdetach, filt_seltrue };
    310 
    311 int
    312 btnkqfilter(dev_t dev, struct knote *kn)
    313 {
    314 	struct klist *klist;
    315 
    316 	if (minor(dev) != 0) {
    317 		return (ENODEV);
    318 	}
    319 
    320 	switch (kn->kn_filter) {
    321 	case EVFILT_READ:
    322 		klist = &btn_event_queue_selinfo.sel_klist;
    323 		kn->kn_fop = &btn_read_filtops;
    324 		break;
    325 
    326 	case EVFILT_WRITE:
    327 		klist = &btn_event_queue_selinfo.sel_klist;
    328 		kn->kn_fop = &btn_write_filtops;
    329 		break;
    330 
    331 	default:
    332 		return (1);
    333 	}
    334 
    335 	mutex_enter(&btn_event_queue_lock);
    336 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
    337 	mutex_exit(&btn_event_queue_lock);
    338 
    339 	return (0);
    340 }
    341 
    342 void
    343 btn_settype(const char *type)
    344 {
    345 
    346 	/*
    347 	 * Don't bother locking this; it's going to be set
    348 	 * during autoconfiguration, and then only read from
    349 	 * then on.
    350 	 */
    351 	strlcpy(btn_type, type, sizeof(btn_type));
    352 }
    353 
    354 int
    355 btn_event_register(struct btn_event *bev)
    356 {
    357 
    358 	mutex_enter(&btn_event_list_lock);
    359 	LIST_INSERT_HEAD(&btn_event_list, bev, bev_list);
    360 	mutex_exit(&btn_event_list_lock);
    361 
    362 	return (0);
    363 }
    364 
    365 void
    366 btn_event_unregister(struct btn_event *bev)
    367 {
    368 
    369 	mutex_enter(&btn_event_list_lock);
    370 	LIST_REMOVE(bev, bev_list);
    371 	mutex_exit(&btn_event_list_lock);
    372 }
    373 
    374 void
    375 btn_event_send(struct btn_event *bev, int event)
    376 {
    377 	button_event_t btnev;
    378 	int rv;
    379 
    380 	mutex_enter(&btn_event_queue_lock);
    381 	if (btn_daemon == NULL) {
    382 		mutex_exit(&btn_event_queue_lock);
    383 		printf("%s: btn_event_send can't handle me.\n", bev->bev_name);
    384 		return;
    385 	}
    386 
    387 	btnev.bev_type = BUTTON_EVENT_STATE_CHANGE;
    388 	btnev.bev_event.bs_state = event;
    389 	strcpy(btnev.bev_event.bs_name, bev->bev_name);
    390 
    391 	rv = btn_queue_event(&btnev);
    392 	if (rv == 0) {
    393 		mutex_exit(&btn_event_queue_lock);
    394 		printf("%s: WARNING: state change event %d lost; "
    395 		    "queue full\n", bev->bev_name, btnev.bev_type);
    396 		return;
    397 	}
    398 	if (btn_event_queue_flags & BEVQ_F_WAITING) {
    399 		btn_event_queue_flags &= ~BEVQ_F_WAITING;
    400 		cv_broadcast(&btn_event_queue_cv);
    401 	}
    402 	selnotify(&btn_event_queue_selinfo, 0, 0);
    403 	mutex_exit(&btn_event_queue_lock);
    404 }
    405