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onewire.c revision 1.6 
      1 /* $NetBSD: onewire.c,v 1.6 2007/09/02 00:55:33 xtraeme 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 1.6 2007/09/02 00:55:33 xtraeme 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/rwlock.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 	krwlock_t			sc_rwlock;
     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, void *aux)
     90 {
     91 	return 1;
     92 }
     93 
     94 void
     95 onewire_attach(struct device *parent, struct device *self, void *aux)
     96 {
     97 	struct onewire_softc *sc = device_private(self);
     98 	struct onewirebus_attach_args *oba = aux;
     99 
    100 	sc->sc_bus = oba->oba_bus;
    101 	rw_init(&sc->sc_rwlock);
    102 	TAILQ_INIT(&sc->sc_devs);
    103 
    104 	aprint_naive("\n");
    105 	aprint_normal("\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 		aprint_error("%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 	rw_destroy(&sc->sc_rwlock);
    130 
    131 	return rv;
    132 }
    133 
    134 int
    135 onewire_activate(struct device *self, enum devact act)
    136 {
    137 	struct onewire_softc *sc = device_private(self);
    138 	int rv = 0;
    139 
    140 	switch (act) {
    141 	case DVACT_ACTIVATE:
    142 		rv = EOPNOTSUPP;
    143 		break;
    144 	case DVACT_DEACTIVATE:
    145 		sc->sc_dying = 1;
    146 		break;
    147 	}
    148 
    149 	//return (config_activate_children(self, act));
    150 	return rv;
    151 }
    152 
    153 int
    154 onewire_print(void *aux, const char *pnp)
    155 {
    156 	struct onewire_attach_args *oa = aux;
    157 	const char *famname;
    158 
    159 	if (pnp == NULL)
    160 		aprint_normal(" ");
    161 
    162 	famname = onewire_famname(ONEWIRE_ROM_FAMILY_TYPE(oa->oa_rom));
    163 	if (famname == NULL)
    164 		aprint_normal("family 0x%02x",
    165 		    (uint)ONEWIRE_ROM_FAMILY_TYPE(oa->oa_rom));
    166 	else
    167 		aprint_normal("\"%s\"", famname);
    168 	aprint_normal(" sn %012llx", ONEWIRE_ROM_SN(oa->oa_rom));
    169 
    170 	if (pnp != NULL)
    171 		aprint_normal(" at %s", pnp);
    172 
    173 	return UNCONF;
    174 }
    175 
    176 int
    177 onewirebus_print(void *aux, const char *pnp)
    178 {
    179 	if (pnp != NULL)
    180 		aprint_normal("onewire at %s", pnp);
    181 
    182 	return UNCONF;
    183 }
    184 
    185 int
    186 onewire_lock(void *arg, int flags)
    187 {
    188 	struct onewire_softc *sc = arg;
    189 
    190 	if (flags & ONEWIRE_NOWAIT)
    191 		return rw_tryenter(&sc->sc_rwlock, RW_WRITER);
    192 
    193 	rw_enter(&sc->sc_rwlock, RW_WRITER);
    194 	return 0;
    195 }
    196 
    197 void
    198 onewire_unlock(void *arg)
    199 {
    200 	struct onewire_softc *sc = arg;
    201 
    202 	rw_exit(&sc->sc_rwlock);
    203 }
    204 
    205 int
    206 onewire_reset(void *arg)
    207 {
    208 	struct onewire_softc *sc = arg;
    209 	struct onewire_bus *bus = sc->sc_bus;
    210 
    211 	return bus->bus_reset(bus->bus_cookie);
    212 }
    213 
    214 int
    215 onewire_bit(void *arg, int value)
    216 {
    217 	struct onewire_softc *sc = arg;
    218 	struct onewire_bus *bus = sc->sc_bus;
    219 
    220 	return bus->bus_bit(bus->bus_cookie, value);
    221 }
    222 
    223 int
    224 onewire_read_byte(void *arg)
    225 {
    226 	struct onewire_softc *sc = arg;
    227 	struct onewire_bus *bus = sc->sc_bus;
    228 	uint8_t value = 0;
    229 	int i;
    230 
    231 	if (bus->bus_read_byte != NULL)
    232 		return bus->bus_read_byte(bus->bus_cookie);
    233 
    234 	for (i = 0; i < 8; i++)
    235 		value |= (bus->bus_bit(bus->bus_cookie, 1) << i);
    236 
    237 	return value;
    238 }
    239 
    240 void
    241 onewire_write_byte(void *arg, int value)
    242 {
    243 	struct onewire_softc *sc = arg;
    244 	struct onewire_bus *bus = sc->sc_bus;
    245 	int i;
    246 
    247 	if (bus->bus_write_byte != NULL)
    248 		return bus->bus_write_byte(bus->bus_cookie, value);
    249 
    250 	for (i = 0; i < 8; i++)
    251 		bus->bus_bit(bus->bus_cookie, (value >> i) & 0x1);
    252 }
    253 
    254 int
    255 onewire_triplet(void *arg, int dir)
    256 {
    257 	struct onewire_softc *sc = arg;
    258 	struct onewire_bus *bus = sc->sc_bus;
    259 	int rv;
    260 
    261 	if (bus->bus_triplet != NULL)
    262 		return bus->bus_triplet(bus->bus_cookie, dir);
    263 
    264 	rv = bus->bus_bit(bus->bus_cookie, 1);
    265 	rv <<= 1;
    266 	rv |= bus->bus_bit(bus->bus_cookie, 1);
    267 
    268 	switch (rv) {
    269 	case 0x0:
    270 		bus->bus_bit(bus->bus_cookie, dir);
    271 		break;
    272 	case 0x1:
    273 		bus->bus_bit(bus->bus_cookie, 0);
    274 		break;
    275 	default:
    276 		bus->bus_bit(bus->bus_cookie, 1);
    277 	}
    278 
    279 	return rv;
    280 }
    281 
    282 void
    283 onewire_read_block(void *arg, void *buf, int len)
    284 {
    285 	uint8_t *p = buf;
    286 
    287 	while (len--)
    288 		*p++ = onewire_read_byte(arg);
    289 }
    290 
    291 void
    292 onewire_write_block(void *arg, const void *buf, int len)
    293 {
    294 	const uint8_t *p = buf;
    295 
    296 	while (len--)
    297 		onewire_write_byte(arg, *p++);
    298 }
    299 
    300 void
    301 onewire_matchrom(void *arg, u_int64_t rom)
    302 {
    303 	int i;
    304 
    305 	onewire_write_byte(arg, ONEWIRE_CMD_MATCH_ROM);
    306 	for (i = 0; i < 8; i++)
    307 		onewire_write_byte(arg, (rom >> (i * 8)) & 0xff);
    308 }
    309 
    310 void
    311 onewire_thread(void *arg)
    312 {
    313 	struct onewire_softc *sc = arg;
    314 
    315 	while (!sc->sc_dying) {
    316 		onewire_scan(sc);
    317 		tsleep(sc->sc_thread, PWAIT, "owidle", ONEWIRE_SCANTIME * hz);
    318 	}
    319 
    320 	sc->sc_thread = NULL;
    321 	wakeup(&sc->sc_dying);
    322 	kthread_exit(0);
    323 }
    324 void
    325 onewire_scan(struct onewire_softc *sc)
    326 {
    327 	struct onewire_device *d, *next, *nd;
    328 	struct onewire_attach_args oa;
    329 	struct device *dev;
    330 	int search = 1, count = 0, present;
    331 	int dir, rv;
    332 	uint64_t mask, rom = 0, lastrom;
    333 	uint8_t data[8];
    334 	int i, i0 = -1, lastd = -1;
    335 
    336 	TAILQ_FOREACH(d, &sc->sc_devs, d_list)
    337 		d->d_present = 0;
    338 
    339 	while (search && count++ < ONEWIRE_MAXDEVS) {
    340 		/* XXX: yield processor */
    341 		tsleep(sc, PWAIT, "owscan", hz / 10);
    342 
    343 		/*
    344 		 * Reset the bus. If there's no presence pulse
    345 		 * don't search for any devices.
    346 		 */
    347 		onewire_lock(sc, 0);
    348 		if (onewire_reset(sc) != 0) {
    349 			DPRINTF(("%s: scan: no presence pulse\n",
    350 			    sc->sc_dev.dv_xname));
    351 			onewire_unlock(sc);
    352 			break;
    353 		}
    354 
    355 		/*
    356 		 * Start new search. Go through the previous path to
    357 		 * the point we made a decision last time and make an
    358 		 * opposite decision. If we didn't make any decision
    359 		 * stop searching.
    360 		 */
    361 		search = 0;
    362 		lastrom = rom;
    363 		rom = 0;
    364 		onewire_write_byte(sc, ONEWIRE_CMD_SEARCH_ROM);
    365 		for (i = 0,i0 = -1; i < 64; i++) {
    366 			dir = (lastrom >> i) & 0x1;
    367 			if (i == lastd)
    368 				dir = 1;
    369 			else if (i > lastd)
    370 				dir = 0;
    371 			rv = onewire_triplet(sc, dir);
    372 			switch (rv) {
    373 			case 0x0:
    374 				if (i != lastd) {
    375 					if (dir == 0)
    376 						i0 = i;
    377 					search = 1;
    378 				}
    379 				mask = dir;
    380 				break;
    381 			case 0x1:
    382 				mask = 0;
    383 				break;
    384 			case 0x2:
    385 				mask = 1;
    386 				break;
    387 			default:
    388 				DPRINTF(("%s: scan: triplet error 0x%x, "
    389 				    "step %d\n",
    390 				    sc->sc_dev.dv_xname, rv, i));
    391 				onewire_unlock(sc);
    392 				return;
    393 			}
    394 			rom |= (mask << i);
    395 		}
    396 		lastd = i0;
    397 		onewire_unlock(sc);
    398 
    399 		if (rom == 0)
    400 			continue;
    401 
    402 		/*
    403 		 * The last byte of the ROM code contains a CRC calculated
    404 		 * from the first 7 bytes. Re-calculate it to make sure
    405 		 * we found a valid device.
    406 		 */
    407 		for (i = 0; i < 8; i++)
    408 			data[i] = (rom >> (i * 8)) & 0xff;
    409 		if (onewire_crc(data, 7) != data[7])
    410 			continue;
    411 
    412 		/*
    413 		 * Go through the list of attached devices to see if we
    414 		 * found a new one.
    415 		 */
    416 		present = 0;
    417 		TAILQ_FOREACH(d, &sc->sc_devs, d_list) {
    418 			if (d->d_rom == rom) {
    419 				d->d_present = 1;
    420 				present = 1;
    421 				break;
    422 			}
    423 		}
    424 		if (!present) {
    425 			bzero(&oa, sizeof(oa));
    426 			oa.oa_onewire = sc;
    427 			oa.oa_rom = rom;
    428 			if ((dev = config_found(&sc->sc_dev, &oa,
    429 			    onewire_print)) == NULL)
    430 				continue;
    431 
    432 			MALLOC(nd, struct onewire_device *,
    433 			    sizeof(struct onewire_device), M_DEVBUF, M_NOWAIT);
    434 			if (nd == NULL)
    435 				continue;
    436 			nd->d_dev = dev;
    437 			nd->d_rom = rom;
    438 			nd->d_present = 1;
    439 			TAILQ_INSERT_TAIL(&sc->sc_devs, nd, d_list);
    440 		}
    441 	}
    442 
    443 	/* Detach disappeared devices */
    444 	onewire_lock(sc, 0);
    445 	for (d = TAILQ_FIRST(&sc->sc_devs);
    446 	    d != NULL; d = next) {
    447 		next = TAILQ_NEXT(d, d_list);
    448 		if (!d->d_present) {
    449 			config_detach(d->d_dev, DETACH_FORCE);
    450 			TAILQ_REMOVE(&sc->sc_devs, d, d_list);
    451 			FREE(d, M_DEVBUF);
    452 		}
    453 	}
    454 	onewire_unlock(sc);
    455 }
    456