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onewire.c revision 1.9 
      1 /* $NetBSD: onewire.c,v 1.9 2008/05/05 13:58:58 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 1.9 2008/05/05 13:58:58 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 	device_t			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 	device_t			d_dev;
     65 	u_int64_t			d_rom;
     66 	int				d_present;
     67 };
     68 
     69 static int	onewire_match(device_t, cfdata_t, void *);
     70 static void	onewire_attach(device_t, device_t, void *);
     71 static int	onewire_detach(device_t, int);
     72 static int	onewire_activate(device_t, enum devact);
     73 int		onewire_print(void *, const char *);
     74 
     75 static void	onewire_thread(void *);
     76 static void	onewire_scan(struct onewire_softc *);
     77 
     78 CFATTACH_DECL_NEW(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 static int
     89 onewire_match(device_t parent, cfdata_t cf, void *aux)
     90 {
     91 	return 1;
     92 }
     93 
     94 static void
     95 onewire_attach(device_t parent, device_t self, void *aux)
     96 {
     97 	struct onewire_softc *sc = device_private(self);
     98 	struct onewirebus_attach_args *oba = aux;
     99 
    100 	sc->sc_dev = self;
    101 	sc->sc_bus = oba->oba_bus;
    102 	rw_init(&sc->sc_rwlock);
    103 	TAILQ_INIT(&sc->sc_devs);
    104 
    105 	aprint_naive("\n");
    106 	aprint_normal("\n");
    107 
    108 	if (kthread_create(PRI_NONE, 0, NULL, onewire_thread, sc,
    109 	    &sc->sc_thread, "%s", device_xname(self)) != 0)
    110 		aprint_error_dev(self, "can't create kernel thread\n");
    111 }
    112 
    113 static int
    114 onewire_detach(device_t 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);
    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 static int
    135 onewire_activate(device_t 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 void
    186 onewire_lock(void *arg)
    187 {
    188 	struct onewire_softc *sc = arg;
    189 
    190 	rw_enter(&sc->sc_rwlock, RW_WRITER);
    191 }
    192 
    193 void
    194 onewire_unlock(void *arg)
    195 {
    196 	struct onewire_softc *sc = arg;
    197 
    198 	rw_exit(&sc->sc_rwlock);
    199 }
    200 
    201 int
    202 onewire_reset(void *arg)
    203 {
    204 	struct onewire_softc *sc = arg;
    205 	struct onewire_bus *bus = sc->sc_bus;
    206 
    207 	return bus->bus_reset(bus->bus_cookie);
    208 }
    209 
    210 int
    211 onewire_bit(void *arg, int value)
    212 {
    213 	struct onewire_softc *sc = arg;
    214 	struct onewire_bus *bus = sc->sc_bus;
    215 
    216 	return bus->bus_bit(bus->bus_cookie, value);
    217 }
    218 
    219 int
    220 onewire_read_byte(void *arg)
    221 {
    222 	struct onewire_softc *sc = arg;
    223 	struct onewire_bus *bus = sc->sc_bus;
    224 	uint8_t value = 0;
    225 	int i;
    226 
    227 	if (bus->bus_read_byte != NULL)
    228 		return bus->bus_read_byte(bus->bus_cookie);
    229 
    230 	for (i = 0; i < 8; i++)
    231 		value |= (bus->bus_bit(bus->bus_cookie, 1) << i);
    232 
    233 	return value;
    234 }
    235 
    236 void
    237 onewire_write_byte(void *arg, int value)
    238 {
    239 	struct onewire_softc *sc = arg;
    240 	struct onewire_bus *bus = sc->sc_bus;
    241 	int i;
    242 
    243 	if (bus->bus_write_byte != NULL)
    244 		return bus->bus_write_byte(bus->bus_cookie, value);
    245 
    246 	for (i = 0; i < 8; i++)
    247 		bus->bus_bit(bus->bus_cookie, (value >> i) & 0x1);
    248 }
    249 
    250 int
    251 onewire_triplet(void *arg, int dir)
    252 {
    253 	struct onewire_softc *sc = arg;
    254 	struct onewire_bus *bus = sc->sc_bus;
    255 	int rv;
    256 
    257 	if (bus->bus_triplet != NULL)
    258 		return bus->bus_triplet(bus->bus_cookie, dir);
    259 
    260 	rv = bus->bus_bit(bus->bus_cookie, 1);
    261 	rv <<= 1;
    262 	rv |= bus->bus_bit(bus->bus_cookie, 1);
    263 
    264 	switch (rv) {
    265 	case 0x0:
    266 		bus->bus_bit(bus->bus_cookie, dir);
    267 		break;
    268 	case 0x1:
    269 		bus->bus_bit(bus->bus_cookie, 0);
    270 		break;
    271 	default:
    272 		bus->bus_bit(bus->bus_cookie, 1);
    273 	}
    274 
    275 	return rv;
    276 }
    277 
    278 void
    279 onewire_read_block(void *arg, void *buf, int len)
    280 {
    281 	uint8_t *p = buf;
    282 
    283 	while (len--)
    284 		*p++ = onewire_read_byte(arg);
    285 }
    286 
    287 void
    288 onewire_write_block(void *arg, const void *buf, int len)
    289 {
    290 	const uint8_t *p = buf;
    291 
    292 	while (len--)
    293 		onewire_write_byte(arg, *p++);
    294 }
    295 
    296 void
    297 onewire_matchrom(void *arg, u_int64_t rom)
    298 {
    299 	int i;
    300 
    301 	onewire_write_byte(arg, ONEWIRE_CMD_MATCH_ROM);
    302 	for (i = 0; i < 8; i++)
    303 		onewire_write_byte(arg, (rom >> (i * 8)) & 0xff);
    304 }
    305 
    306 static void
    307 onewire_thread(void *arg)
    308 {
    309 	struct onewire_softc *sc = arg;
    310 
    311 	while (!sc->sc_dying) {
    312 		onewire_scan(sc);
    313 		tsleep(sc->sc_thread, PWAIT, "owidle", ONEWIRE_SCANTIME * hz);
    314 	}
    315 
    316 	sc->sc_thread = NULL;
    317 	wakeup(&sc->sc_dying);
    318 	kthread_exit(0);
    319 }
    320 
    321 static void
    322 onewire_scan(struct onewire_softc *sc)
    323 {
    324 	struct onewire_device *d, *next, *nd;
    325 	struct onewire_attach_args oa;
    326 	struct device *dev;
    327 	int search = 1, count = 0, present;
    328 	int dir, rv;
    329 	uint64_t mask, rom = 0, lastrom;
    330 	uint8_t data[8];
    331 	int i, i0 = -1, lastd = -1;
    332 
    333 	TAILQ_FOREACH(d, &sc->sc_devs, d_list)
    334 		d->d_present = 0;
    335 
    336 	while (search && count++ < ONEWIRE_MAXDEVS) {
    337 		/* XXX: yield processor */
    338 		tsleep(sc, PWAIT, "owscan", hz / 10);
    339 
    340 		/*
    341 		 * Reset the bus. If there's no presence pulse
    342 		 * don't search for any devices.
    343 		 */
    344 		onewire_lock(sc);
    345 		if (onewire_reset(sc) != 0) {
    346 			DPRINTF(("%s: scan: no presence pulse\n",
    347 			    device_xname(sc->sc_dev)));
    348 			onewire_unlock(sc);
    349 			break;
    350 		}
    351 
    352 		/*
    353 		 * Start new search. Go through the previous path to
    354 		 * the point we made a decision last time and make an
    355 		 * opposite decision. If we didn't make any decision
    356 		 * stop searching.
    357 		 */
    358 		search = 0;
    359 		lastrom = rom;
    360 		rom = 0;
    361 		onewire_write_byte(sc, ONEWIRE_CMD_SEARCH_ROM);
    362 		for (i = 0,i0 = -1; i < 64; i++) {
    363 			dir = (lastrom >> i) & 0x1;
    364 			if (i == lastd)
    365 				dir = 1;
    366 			else if (i > lastd)
    367 				dir = 0;
    368 			rv = onewire_triplet(sc, dir);
    369 			switch (rv) {
    370 			case 0x0:
    371 				if (i != lastd) {
    372 					if (dir == 0)
    373 						i0 = i;
    374 					search = 1;
    375 				}
    376 				mask = dir;
    377 				break;
    378 			case 0x1:
    379 				mask = 0;
    380 				break;
    381 			case 0x2:
    382 				mask = 1;
    383 				break;
    384 			default:
    385 				DPRINTF(("%s: scan: triplet error 0x%x, "
    386 				    "step %d\n",
    387 				    device_xname(sc->sc_dev), rv, i));
    388 				onewire_unlock(sc);
    389 				return;
    390 			}
    391 			rom |= (mask << i);
    392 		}
    393 		lastd = i0;
    394 		onewire_unlock(sc);
    395 
    396 		if (rom == 0)
    397 			continue;
    398 
    399 		/*
    400 		 * The last byte of the ROM code contains a CRC calculated
    401 		 * from the first 7 bytes. Re-calculate it to make sure
    402 		 * we found a valid device.
    403 		 */
    404 		for (i = 0; i < 8; i++)
    405 			data[i] = (rom >> (i * 8)) & 0xff;
    406 		if (onewire_crc(data, 7) != data[7])
    407 			continue;
    408 
    409 		/*
    410 		 * Go through the list of attached devices to see if we
    411 		 * found a new one.
    412 		 */
    413 		present = 0;
    414 		TAILQ_FOREACH(d, &sc->sc_devs, d_list) {
    415 			if (d->d_rom == rom) {
    416 				d->d_present = 1;
    417 				present = 1;
    418 				break;
    419 			}
    420 		}
    421 		if (!present) {
    422 			bzero(&oa, sizeof(oa));
    423 			oa.oa_onewire = sc;
    424 			oa.oa_rom = rom;
    425 			if ((dev = config_found(sc->sc_dev, &oa,
    426 			    onewire_print)) == NULL)
    427 				continue;
    428 
    429 			MALLOC(nd, struct onewire_device *,
    430 			    sizeof(struct onewire_device), M_DEVBUF, M_NOWAIT);
    431 			if (nd == NULL)
    432 				continue;
    433 			nd->d_dev = dev;
    434 			nd->d_rom = rom;
    435 			nd->d_present = 1;
    436 			TAILQ_INSERT_TAIL(&sc->sc_devs, nd, d_list);
    437 		}
    438 	}
    439 
    440 	/* Detach disappeared devices */
    441 	onewire_lock(sc);
    442 	for (d = TAILQ_FIRST(&sc->sc_devs);
    443 	    d != NULL; d = next) {
    444 		next = TAILQ_NEXT(d, d_list);
    445 		if (!d->d_present) {
    446 			config_detach(d->d_dev, DETACH_FORCE);
    447 			TAILQ_REMOVE(&sc->sc_devs, d, d_list);
    448 			FREE(d, M_DEVBUF);
    449 		}
    450 	}
    451 	onewire_unlock(sc);
    452 }
    453