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button.c revision 1.6.4.1 
      1 /*	$NetBSD: button.c,v 1.6.4.1 2014/05/22 11:39:54 yamt 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 1.6.4.1 2014/05/22 11:39:54 yamt 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 	.d_open = btnopen,
     95 	.d_close = btnclose,
     96 	.d_read = btnread,
     97 	.d_write = nowrite,
     98 	.d_ioctl = btnioctl,
     99 	.d_stop = nostop,
    100 	.d_tty = notty,
    101 	.d_poll = btnpoll,
    102 	.d_mmap = nommap,
    103 	.d_kqfilter = btnkqfilter,
    104 	.d_flag = 0
    105 };
    106 
    107 static int
    108 btn_init(void)
    109 {
    110 
    111 	LIST_INIT(&btn_event_list);
    112 	mutex_init(&btn_event_list_lock, MUTEX_DEFAULT, IPL_NONE);
    113 	mutex_init(&btn_event_queue_lock, MUTEX_DEFAULT, IPL_NONE);
    114 	cv_init(&btn_event_queue_cv, "btncv");
    115 	selinit(&btn_event_queue_selinfo);
    116 
    117 	return 0;
    118 }
    119 
    120 static int
    121 btn_queue_event(button_event_t *bev)
    122 {
    123 
    124 	if (btn_event_queue_count == BTN_MAX_EVENTS)
    125 		return (0);
    126 
    127 	btn_event_queue[btn_event_queue_head] = *bev;
    128 	btn_event_queue_head = BTN_NEXT_EVENT(btn_event_queue_head);
    129 	btn_event_queue_count++;
    130 
    131 	return (1);
    132 }
    133 
    134 static int
    135 btn_get_event(button_event_t *bev)
    136 {
    137 
    138 	if (btn_event_queue_count == 0)
    139 		return (0);
    140 
    141 	*bev = btn_event_queue[btn_event_queue_tail];
    142 	btn_event_queue_tail = BTN_NEXT_EVENT(btn_event_queue_tail);
    143 	btn_event_queue_count--;
    144 
    145 	return (1);
    146 }
    147 
    148 static void
    149 btn_event_queue_flush(void)
    150 {
    151 
    152 	btn_event_queue_head = 0;
    153 	btn_event_queue_tail = 0;
    154 	btn_event_queue_count = 0;
    155 	btn_event_queue_flags = 0;
    156 }
    157 
    158 int
    159 btnopen(dev_t dev, int flag, int mode, struct lwp *l)
    160 {
    161 	int error;
    162 
    163 	error = RUN_ONCE(&btn_once, btn_init);
    164 	if (error) {
    165 		return error;
    166 	}
    167 
    168 	if (minor(dev) != 0) {
    169 		return (ENODEV);
    170 	}
    171 
    172 	mutex_enter(&btn_event_queue_lock);
    173 	if (btn_daemon != NULL) {
    174 		error = EBUSY;
    175 	} else {
    176 		error = 0;
    177 		btn_daemon = l;
    178 		btn_event_queue_flush();
    179 	}
    180 	mutex_exit(&btn_event_queue_lock);
    181 
    182 	return (error);
    183 }
    184 
    185 int
    186 btnclose(dev_t dev, int flag, int mode, struct lwp *l)
    187 {
    188 	int count;
    189 
    190 	if (minor(dev) != 0) {
    191 		return (ENODEV);
    192 	}
    193 
    194 	mutex_enter(&btn_event_queue_lock);
    195 	count = btn_event_queue_count;
    196 	btn_daemon = NULL;
    197 	btn_event_queue_flush();
    198 	mutex_exit(&btn_event_queue_lock);
    199 
    200 	if (count) {
    201 		printf("WARNING: %d events lost by exiting daemon\n", count);
    202 	}
    203 
    204 	return (0);
    205 }
    206 
    207 int
    208 btnioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
    209 {
    210 	int error = 0;
    211 
    212 	if (minor(dev) != 0) {
    213 		return (ENODEV);
    214 	}
    215 
    216 	switch (cmd) {
    217 	case BUTTON_IOC_GET_TYPE:
    218 	    {
    219 		struct button_type *button_type = (void *)data;
    220 		strcpy(button_type->button_type, btn_type);
    221 		break;
    222 	    }
    223 
    224 	default:
    225 		error = ENOTTY;
    226 		break;
    227 	}
    228 
    229 	return (error);
    230 }
    231 
    232 int
    233 btnread(dev_t dev, struct uio *uio, int flags)
    234 {
    235 	button_event_t bev;
    236 	int error;
    237 
    238 	if (minor(dev) != 0) {
    239 		return (ENODEV);
    240 	}
    241 
    242 	if (uio->uio_resid != BUTTON_EVENT_MSG_SIZE) {
    243 		return (EINVAL);
    244 	}
    245 
    246 	mutex_enter(&btn_event_queue_lock);
    247 	for (;;) {
    248 		if (btn_get_event(&bev)) {
    249 			mutex_exit(&btn_event_queue_lock);
    250 			return (uiomove(&bev, BUTTON_EVENT_MSG_SIZE, uio));
    251 		}
    252 
    253 		if (flags & IO_NDELAY) {
    254 			mutex_exit(&btn_event_queue_lock);
    255 			return (EWOULDBLOCK);
    256 		}
    257 
    258 		btn_event_queue_flags |= BEVQ_F_WAITING;
    259 		error = cv_wait_sig(&btn_event_queue_cv, &btn_event_queue_lock);
    260 		if (error) {
    261 			mutex_exit(&btn_event_queue_lock);
    262 			return (error);
    263 		}
    264 	}
    265 }
    266 
    267 int
    268 btnpoll(dev_t dev, int events, struct lwp *l)
    269 {
    270 	int revents;
    271 
    272 	if (minor(dev) != 0) {
    273 		return (ENODEV);
    274 	}
    275 
    276 	revents = events & (POLLOUT | POLLWRNORM);
    277 
    278 	/* Attempt to save some work. */
    279 	if ((events & (POLLIN | POLLRDNORM)) == 0)
    280 		return (revents);
    281 
    282 	mutex_enter(&btn_event_queue_lock);
    283 	if (btn_event_queue_count) {
    284 		revents |= events & (POLLIN | POLLRDNORM);
    285 	} else {
    286 		selrecord(l, &btn_event_queue_selinfo);
    287 	}
    288 	mutex_exit(&btn_event_queue_lock);
    289 
    290 	return (revents);
    291 }
    292 
    293 static void
    294 filt_btn_rdetach(struct knote *kn)
    295 {
    296 
    297 	mutex_enter(&btn_event_queue_lock);
    298 	SLIST_REMOVE(&btn_event_queue_selinfo.sel_klist,
    299 	    kn, knote, kn_selnext);
    300 	mutex_exit(&btn_event_queue_lock);
    301 }
    302 
    303 static int
    304 filt_btn_read(struct knote *kn, long hint)
    305 {
    306 
    307 	mutex_enter(&btn_event_queue_lock);
    308 	kn->kn_data = btn_event_queue_count;
    309 	mutex_exit(&btn_event_queue_lock);
    310 
    311 	return (kn->kn_data > 0);
    312 }
    313 
    314 static const struct filterops btn_read_filtops =
    315     { 1, NULL, filt_btn_rdetach, filt_btn_read };
    316 
    317 static const struct filterops btn_write_filtops =
    318     { 1, NULL, filt_btn_rdetach, filt_seltrue };
    319 
    320 int
    321 btnkqfilter(dev_t dev, struct knote *kn)
    322 {
    323 	struct klist *klist;
    324 
    325 	if (minor(dev) != 0) {
    326 		return (ENODEV);
    327 	}
    328 
    329 	switch (kn->kn_filter) {
    330 	case EVFILT_READ:
    331 		klist = &btn_event_queue_selinfo.sel_klist;
    332 		kn->kn_fop = &btn_read_filtops;
    333 		break;
    334 
    335 	case EVFILT_WRITE:
    336 		klist = &btn_event_queue_selinfo.sel_klist;
    337 		kn->kn_fop = &btn_write_filtops;
    338 		break;
    339 
    340 	default:
    341 		return (1);
    342 	}
    343 
    344 	mutex_enter(&btn_event_queue_lock);
    345 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
    346 	mutex_exit(&btn_event_queue_lock);
    347 
    348 	return (0);
    349 }
    350 
    351 void
    352 btn_settype(const char *type)
    353 {
    354 
    355 	/*
    356 	 * Don't bother locking this; it's going to be set
    357 	 * during autoconfiguration, and then only read from
    358 	 * then on.
    359 	 */
    360 	strlcpy(btn_type, type, sizeof(btn_type));
    361 }
    362 
    363 int
    364 btn_event_register(struct btn_event *bev)
    365 {
    366 
    367 	mutex_enter(&btn_event_list_lock);
    368 	LIST_INSERT_HEAD(&btn_event_list, bev, bev_list);
    369 	mutex_exit(&btn_event_list_lock);
    370 
    371 	return (0);
    372 }
    373 
    374 void
    375 btn_event_unregister(struct btn_event *bev)
    376 {
    377 
    378 	mutex_enter(&btn_event_list_lock);
    379 	LIST_REMOVE(bev, bev_list);
    380 	mutex_exit(&btn_event_list_lock);
    381 }
    382 
    383 void
    384 btn_event_send(struct btn_event *bev, int event)
    385 {
    386 	button_event_t btnev;
    387 	int rv;
    388 
    389 	mutex_enter(&btn_event_queue_lock);
    390 	if (btn_daemon == NULL) {
    391 		mutex_exit(&btn_event_queue_lock);
    392 		printf("%s: btn_event_send can't handle me.\n", bev->bev_name);
    393 		return;
    394 	}
    395 
    396 	btnev.bev_type = BUTTON_EVENT_STATE_CHANGE;
    397 	btnev.bev_event.bs_state = event;
    398 	strcpy(btnev.bev_event.bs_name, bev->bev_name);
    399 
    400 	rv = btn_queue_event(&btnev);
    401 	if (rv == 0) {
    402 		mutex_exit(&btn_event_queue_lock);
    403 		printf("%s: WARNING: state change event %d lost; "
    404 		    "queue full\n", bev->bev_name, btnev.bev_type);
    405 		return;
    406 	}
    407 	if (btn_event_queue_flags & BEVQ_F_WAITING) {
    408 		btn_event_queue_flags &= ~BEVQ_F_WAITING;
    409 		cv_broadcast(&btn_event_queue_cv);
    410 	}
    411 	selnotify(&btn_event_queue_selinfo, 0, 0);
    412 	mutex_exit(&btn_event_queue_lock);
    413 }
    414