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onewire.c revision 1.5 
      1 /* $NetBSD: onewire.c,v 1.5 2007/07/09 21:00:52 ad Exp $ */
      2 /*	$OpenBSD: onewire.c,v 1.1 2006/03/04 16:27:03 grange Exp $	*/
      3 
      4 /*
      5  * Copyright (c) 2006 Alexander Yurchenko <grange (at) openbsd.org>
      6  *
      7  * Permission to use, copy, modify, and distribute this software for any
      8  * purpose with or without fee is hereby granted, provided that the above
      9  * copyright notice and this permission notice appear in all copies.
     10  *
     11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     18  */
     19 
     20 #include <sys/cdefs.h>
     21 __KERNEL_RCSID(0, "$NetBSD: onewire.c,v 1.5 2007/07/09 21:00:52 ad Exp $");
     22 
     23 /*
     24  * 1-Wire bus driver.
     25  */
     26 
     27 #include <sys/param.h>
     28 #include <sys/systm.h>
     29 #include <sys/conf.h>
     30 #include <sys/device.h>
     31 #include <sys/kernel.h>
     32 #include <sys/kthread.h>
     33 #include <sys/lock.h>
     34 #include <sys/malloc.h>
     35 #include <sys/proc.h>
     36 #include <sys/queue.h>
     37 
     38 #include <dev/onewire/onewirereg.h>
     39 #include <dev/onewire/onewirevar.h>
     40 
     41 #ifdef ONEWIRE_DEBUG
     42 #define DPRINTF(x) printf x
     43 #else
     44 #define DPRINTF(x)
     45 #endif
     46 
     47 //#define ONEWIRE_MAXDEVS		256
     48 #define ONEWIRE_MAXDEVS		8
     49 #define ONEWIRE_SCANTIME	3
     50 
     51 struct onewire_softc {
     52 	struct device			sc_dev;
     53 
     54 	struct onewire_bus *		sc_bus;
     55 	struct lock			sc_lock;
     56 	struct lwp *			sc_thread;
     57 	TAILQ_HEAD(, onewire_device)	sc_devs;
     58 
     59 	int				sc_dying;
     60 };
     61 
     62 struct onewire_device {
     63 	TAILQ_ENTRY(onewire_device)	d_list;
     64 	struct device *			d_dev;
     65 	u_int64_t			d_rom;
     66 	int				d_present;
     67 };
     68 
     69 int	onewire_match(struct device *, struct cfdata *, void *);
     70 void	onewire_attach(struct device *, struct device *, void *);
     71 int	onewire_detach(struct device *, int);
     72 int	onewire_activate(struct device *, enum devact);
     73 int	onewire_print(void *, const char *);
     74 
     75 void	onewire_thread(void *);
     76 void	onewire_scan(struct onewire_softc *);
     77 
     78 CFATTACH_DECL(onewire, sizeof(struct onewire_softc),
     79 	onewire_match, onewire_attach, onewire_detach, onewire_activate);
     80 
     81 const struct cdevsw onewire_cdevsw = {
     82 	noopen, noclose, noread, nowrite, noioctl, nostop, notty,
     83 	nopoll, nommap, nokqfilter, D_OTHER,
     84 };
     85 
     86 extern struct cfdriver onewire_cd;
     87 
     88 int
     89 onewire_match(struct device *parent, struct cfdata *cf,
     90     void *aux)
     91 {
     92 	return 1;
     93 }
     94 
     95 void
     96 onewire_attach(struct device *parent, struct device *self, void *aux)
     97 {
     98 	struct onewire_softc *sc = device_private(self);
     99 	struct onewirebus_attach_args *oba = aux;
    100 
    101 	sc->sc_bus = oba->oba_bus;
    102 	lockinit(&sc->sc_lock, PRIBIO, "owlock", 0, 0);
    103 	TAILQ_INIT(&sc->sc_devs);
    104 
    105 	printf("\n");
    106 
    107 	if (kthread_create(PRI_NONE, 0, NULL, onewire_thread, sc,
    108 	    &sc->sc_thread, "%s", sc->sc_dev.dv_xname) != 0)
    109 		printf("%s: can't create kernel thread\n",
    110 		    sc->sc_dev.dv_xname);
    111 }
    112 
    113 int
    114 onewire_detach(struct device *self, int flags)
    115 {
    116 	struct onewire_softc *sc = device_private(self);
    117 	int rv;
    118 
    119 	sc->sc_dying = 1;
    120 	if (sc->sc_thread != NULL) {
    121 		wakeup(sc->sc_thread);
    122 		tsleep(&sc->sc_dying, PWAIT, "owdt", 0);
    123 	}
    124 
    125 	onewire_lock(sc, 0);
    126 	//rv = config_detach_children(self, flags);
    127 	rv = 0;  /* XXX riz */
    128 	onewire_unlock(sc);
    129 
    130 	return (rv);
    131 }
    132 
    133 int
    134 onewire_activate(struct device *self, enum devact act)
    135 {
    136 	struct onewire_softc *sc = device_private(self);
    137 	int rv = 0;
    138 
    139 	switch (act) {
    140 	case DVACT_ACTIVATE:
    141 		rv = EOPNOTSUPP;
    142 		break;
    143 	case DVACT_DEACTIVATE:
    144 		sc->sc_dying = 1;
    145 		break;
    146 	}
    147 
    148 	//return (config_activate_children(self, act));
    149 	return rv;
    150 }
    151 
    152 int
    153 onewire_print(void *aux, const char *pnp)
    154 {
    155 	struct onewire_attach_args *oa = aux;
    156 	const char *famname;
    157 
    158 	if (pnp == NULL)
    159 		printf(" ");
    160 
    161 	famname = onewire_famname(ONEWIRE_ROM_FAMILY_TYPE(oa->oa_rom));
    162 	if (famname == NULL)
    163 		printf("family 0x%02x", (uint)ONEWIRE_ROM_FAMILY_TYPE(oa->oa_rom));
    164 	else
    165 		printf("\"%s\"", famname);
    166 	printf(" sn %012llx", ONEWIRE_ROM_SN(oa->oa_rom));
    167 
    168 	if (pnp != NULL)
    169 		printf(" at %s", pnp);
    170 
    171 	return (UNCONF);
    172 }
    173 
    174 int
    175 onewirebus_print(void *aux, const char *pnp)
    176 {
    177 	if (pnp != NULL)
    178 		printf("onewire at %s", pnp);
    179 
    180 	return (UNCONF);
    181 }
    182 
    183 int
    184 onewire_lock(void *arg, int flags)
    185 {
    186 	struct onewire_softc *sc = arg;
    187 	int lflags = LK_EXCLUSIVE;
    188 
    189 	if (flags & ONEWIRE_NOWAIT)
    190 		lflags |= LK_NOWAIT;
    191 
    192 	return (lockmgr(&sc->sc_lock, lflags, NULL));
    193 }
    194 
    195 void
    196 onewire_unlock(void *arg)
    197 {
    198 	struct onewire_softc *sc = arg;
    199 
    200 	lockmgr(&sc->sc_lock, LK_RELEASE, NULL);
    201 }
    202 
    203 int
    204 onewire_reset(void *arg)
    205 {
    206 	struct onewire_softc *sc = arg;
    207 	struct onewire_bus *bus = sc->sc_bus;
    208 
    209 	return (bus->bus_reset(bus->bus_cookie));
    210 }
    211 
    212 int
    213 onewire_bit(void *arg, int value)
    214 {
    215 	struct onewire_softc *sc = arg;
    216 	struct onewire_bus *bus = sc->sc_bus;
    217 
    218 	return (bus->bus_bit(bus->bus_cookie, value));
    219 }
    220 
    221 int
    222 onewire_read_byte(void *arg)
    223 {
    224 	struct onewire_softc *sc = arg;
    225 	struct onewire_bus *bus = sc->sc_bus;
    226 	u_int8_t value = 0;
    227 	int i;
    228 
    229 	if (bus->bus_read_byte != NULL)
    230 		return (bus->bus_read_byte(bus->bus_cookie));
    231 
    232 	for (i = 0; i < 8; i++)
    233 		value |= (bus->bus_bit(bus->bus_cookie, 1) << i);
    234 
    235 	return (value);
    236 }
    237 
    238 void
    239 onewire_write_byte(void *arg, int value)
    240 {
    241 	struct onewire_softc *sc = arg;
    242 	struct onewire_bus *bus = sc->sc_bus;
    243 	int i;
    244 
    245 	if (bus->bus_write_byte != NULL)
    246 		return (bus->bus_write_byte(bus->bus_cookie, value));
    247 
    248 	for (i = 0; i < 8; i++)
    249 		bus->bus_bit(bus->bus_cookie, (value >> i) & 0x1);
    250 }
    251 
    252 int
    253 onewire_triplet(void *arg, int dir)
    254 {
    255 	struct onewire_softc *sc = arg;
    256 	struct onewire_bus *bus = sc->sc_bus;
    257 	int rv;
    258 
    259 	if (bus->bus_triplet != NULL)
    260 		return (bus->bus_triplet(bus->bus_cookie, dir));
    261 
    262 	rv = bus->bus_bit(bus->bus_cookie, 1);
    263 	rv <<= 1;
    264 	rv |= bus->bus_bit(bus->bus_cookie, 1);
    265 
    266 	switch (rv) {
    267 	case 0x0:
    268 		bus->bus_bit(bus->bus_cookie, dir);
    269 		break;
    270 	case 0x1:
    271 		bus->bus_bit(bus->bus_cookie, 0);
    272 		break;
    273 	default:
    274 		bus->bus_bit(bus->bus_cookie, 1);
    275 	}
    276 
    277 	return (rv);
    278 }
    279 
    280 void
    281 onewire_read_block(void *arg, void *buf, int len)
    282 {
    283 	u_int8_t *p = buf;
    284 
    285 	while (len--)
    286 		*p++ = onewire_read_byte(arg);
    287 }
    288 
    289 void
    290 onewire_write_block(void *arg, const void *buf, int len)
    291 {
    292 	const u_int8_t *p = buf;
    293 
    294 	while (len--)
    295 		onewire_write_byte(arg, *p++);
    296 }
    297 
    298 void
    299 onewire_matchrom(void *arg, u_int64_t rom)
    300 {
    301 	int i;
    302 
    303 	onewire_write_byte(arg, ONEWIRE_CMD_MATCH_ROM);
    304 	for (i = 0; i < 8; i++)
    305 		onewire_write_byte(arg, (rom >> (i * 8)) & 0xff);
    306 }
    307 
    308 void
    309 onewire_thread(void *arg)
    310 {
    311 	struct onewire_softc *sc = arg;
    312 
    313 	while (!sc->sc_dying) {
    314 		onewire_scan(sc);
    315 		tsleep(sc->sc_thread, PWAIT, "owidle", ONEWIRE_SCANTIME * hz);
    316 	}
    317 
    318 	sc->sc_thread = NULL;
    319 	wakeup(&sc->sc_dying);
    320 	kthread_exit(0);
    321 }
    322 void
    323 onewire_scan(struct onewire_softc *sc)
    324 {
    325 	struct onewire_device *d, *next, *nd;
    326 	struct onewire_attach_args oa;
    327 	struct device *dev;
    328 	int search = 1, count = 0, present;
    329 	int dir, rv;
    330 	u_int64_t mask, rom = 0, lastrom;
    331 	u_int8_t data[8];
    332 	int i, i0 = -1, lastd = -1;
    333 
    334 	TAILQ_FOREACH(d, &sc->sc_devs, d_list)
    335 		d->d_present = 0;
    336 
    337 	while (search && count++ < ONEWIRE_MAXDEVS) {
    338 		/* XXX: yield processor */
    339 		tsleep(sc, PWAIT, "owscan", hz / 10);
    340 
    341 		/*
    342 		 * Reset the bus. If there's no presence pulse
    343 		 * don't search for any devices.
    344 		 */
    345 		onewire_lock(sc, 0);
    346 		if (onewire_reset(sc) != 0) {
    347 			DPRINTF(("%s: scan: no presence pulse\n",
    348 			    sc->sc_dev.dv_xname));
    349 			onewire_unlock(sc);
    350 			break;
    351 		}
    352 
    353 		/*
    354 		 * Start new search. Go through the previous path to
    355 		 * the point we made a decision last time and make an
    356 		 * opposite decision. If we didn't make any decision
    357 		 * stop searching.
    358 		 */
    359 		search = 0;
    360 		lastrom = rom;
    361 		rom = 0;
    362 		onewire_write_byte(sc, ONEWIRE_CMD_SEARCH_ROM);
    363 		for (i = 0,i0 = -1; i < 64; i++) {
    364 			dir = (lastrom >> i) & 0x1;
    365 			if (i == lastd)
    366 				dir = 1;
    367 			else if (i > lastd)
    368 				dir = 0;
    369 			rv = onewire_triplet(sc, dir);
    370 			switch (rv) {
    371 			case 0x0:
    372 				if (i != lastd) {
    373 					if (dir == 0)
    374 						i0 = i;
    375 					search = 1;
    376 				}
    377 				mask = dir;
    378 				break;
    379 			case 0x1:
    380 				mask = 0;
    381 				break;
    382 			case 0x2:
    383 				mask = 1;
    384 				break;
    385 			default:
    386 				DPRINTF(("%s: scan: triplet error 0x%x, "
    387 				    "step %d\n",
    388 				    sc->sc_dev.dv_xname, rv, i));
    389 				onewire_unlock(sc);
    390 				return;
    391 			}
    392 			rom |= (mask << i);
    393 		}
    394 		lastd = i0;
    395 		onewire_unlock(sc);
    396 
    397 		if (rom == 0)
    398 			continue;
    399 
    400 		/*
    401 		 * The last byte of the ROM code contains a CRC calculated
    402 		 * from the first 7 bytes. Re-calculate it to make sure
    403 		 * we found a valid device.
    404 		 */
    405 		for (i = 0; i < 8; i++)
    406 			data[i] = (rom >> (i * 8)) & 0xff;
    407 		if (onewire_crc(data, 7) != data[7])
    408 			continue;
    409 
    410 		/*
    411 		 * Go through the list of attached devices to see if we
    412 		 * found a new one.
    413 		 */
    414 		present = 0;
    415 		TAILQ_FOREACH(d, &sc->sc_devs, d_list) {
    416 			if (d->d_rom == rom) {
    417 				d->d_present = 1;
    418 				present = 1;
    419 				break;
    420 			}
    421 		}
    422 		if (!present) {
    423 			bzero(&oa, sizeof(oa));
    424 			oa.oa_onewire = sc;
    425 			oa.oa_rom = rom;
    426 			if ((dev = config_found(&sc->sc_dev, &oa,
    427 			    onewire_print)) == NULL)
    428 				continue;
    429 
    430 			MALLOC(nd, struct onewire_device *,
    431 			    sizeof(struct onewire_device), M_DEVBUF, M_NOWAIT);
    432 			if (nd == NULL)
    433 				continue;
    434 			nd->d_dev = dev;
    435 			nd->d_rom = rom;
    436 			nd->d_present = 1;
    437 			TAILQ_INSERT_TAIL(&sc->sc_devs, nd, d_list);
    438 		}
    439 	}
    440 
    441 	/* Detach disappeared devices */
    442 	onewire_lock(sc, 0);
    443 	for (d = TAILQ_FIRST(&sc->sc_devs);
    444 	    d != NULL; d = next) {
    445 		next = TAILQ_NEXT(d, d_list);
    446 		if (!d->d_present) {
    447 			config_detach(d->d_dev, DETACH_FORCE);
    448 			TAILQ_REMOVE(&sc->sc_devs, d, d_list);
    449 			FREE(d, M_DEVBUF);
    450 		}
    451 	}
    452 	onewire_unlock(sc);
    453 }
    454