Rework bus scanning code so that most of work could be offloaded

the hardware. And fix another bug in the search algorithm.

2 files changed, 93 insertions, 68 deletions

diff --git a/sys/dev/onewire/onewire.c b/sys/dev/onewire/onewire.c
index 9b914bf099e..8a417e36332 100644
--- a/sys/dev/onewire/onewire.c
+++ b/sys/dev/onewire/onewire.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: onewire.c,v 1.6 2006/09/30 17:45:31 grange Exp $	*/
+/*	$OpenBSD: onewire.c,v 1.7 2006/10/08 21:12:51 grange Exp $	*/
 
 /*
  * Copyright (c) 2006 Alexander Yurchenko <grange@openbsd.org>
@@ -51,6 +51,7 @@ struct onewire_softc {
 	TAILQ_HEAD(, onewire_device)	sc_devs;
 
 	int				sc_dying;
+	u_int64_t			sc_rombuf[ONEWIRE_MAXDEVS];
 };
 
 struct onewire_device {
@@ -109,7 +110,6 @@ int
 onewire_detach(struct device *self, int flags)
 {
 	struct onewire_softc *sc = (struct onewire_softc *)self;
-	int rv;
 
 	sc->sc_dying = 1;
 	if (sc->sc_thread != NULL) {
@@ -117,11 +117,7 @@ onewire_detach(struct device *self, int flags)
 		tsleep(&sc->sc_dying, PWAIT, "owdt", 0);
 	}
 
-	onewire_lock(sc, 0);
-	rv = config_detach_children(self, flags);
-	onewire_unlock(sc);
-
-	return (rv);
+	return (config_detach_children(self, flags));
 }
 
 int
@@ -311,72 +307,32 @@ onewire_matchrom(void *arg, u_int64_t rom)
 		onewire_write_byte(arg, (rom >> (i * 8)) & 0xff);
 }
 
-void
-onewire_thread(void *arg)
-{
-	struct onewire_softc *sc = arg;
-
-	while (!sc->sc_dying) {
-		onewire_scan(sc);
-		tsleep(sc->sc_thread, PWAIT, "owidle", ONEWIRE_SCANTIME * hz);
-	}
-
-	sc->sc_thread = NULL;
-	wakeup(&sc->sc_dying);
-	kthread_exit(0);
-}
-
-void
-onewire_createthread(void *arg)
+int
+onewire_search(void *arg, u_int64_t *buf, int size, u_int64_t startrom)
 {
 	struct onewire_softc *sc = arg;
-
-	if (kthread_create(onewire_thread, sc, &sc->sc_thread,
-	    "%s", sc->sc_dev.dv_xname) != 0)
-		printf("%s: can't create kernel thread\n",
-		    sc->sc_dev.dv_xname);
-}
-
-void
-onewire_scan(struct onewire_softc *sc)
-{
-	struct onewire_device *d, *next, *nd;
-	struct onewire_attach_args oa;
-	struct device *dev;
-	int search = 1, count = 0, present;
-	int dir, rv;
-	u_int64_t mask, rom = 0, lastrom;
+	struct onewire_bus *bus = sc->sc_bus;
+	int search = 1, count = 0, lastd = -1, dir, rv, i, i0;
+	u_int64_t mask, rom = startrom, lastrom;
 	u_int8_t data[8];
-	int i, i0, lastd = -1;
 
-	TAILQ_FOREACH(d, &sc->sc_devs, d_list)
-		d->d_present = 0;
+	if (bus->bus_search != NULL)
+		return (bus->bus_search(bus->bus_cookie, buf, size, rom));
 
-	while (search && count++ < ONEWIRE_MAXDEVS) {
+	while (search && count < size) {
 		/* XXX: yield processor */
 		tsleep(sc, PWAIT, "owscan", hz / 10);
 
 		/*
-		 * Reset the bus. If there's no presence pulse
-		 * don't search for any devices.
-		 */
-		onewire_lock(sc, 0);
-		if (onewire_reset(sc) != 0) {
-			DPRINTF(("%s: scan: no presence pulse\n",
-			    sc->sc_dev.dv_xname));
-			onewire_unlock(sc);
-			break;
-		}
-
-		/*
 		 * Start new search. Go through the previous path to
 		 * the point we made a decision last time and make an
 		 * opposite decision. If we didn't make any decision
 		 * stop searching.
 		 */
-		search = 0;
 		lastrom = rom;
 		rom = 0;
+		onewire_lock(sc, 0);
+		onewire_reset(sc);
 		onewire_write_byte(sc, ONEWIRE_CMD_SEARCH_ROM);
 		for (i = 0, i0 = -1; i < 64; i++) {
 			dir = (lastrom >> i) & 0x1;
@@ -387,11 +343,8 @@ onewire_scan(struct onewire_softc *sc)
 			rv = onewire_triplet(sc, dir);
 			switch (rv) {
 			case 0x0:
-				if (i != lastd) {
-					if (dir == 0)
-						i0 = i;
-					search = 1;
-				}
+				if (i != lastd && dir == 0)
+					i0 = i;
 				mask = dir;
 				break;
 			case 0x1:
@@ -401,17 +354,19 @@ onewire_scan(struct onewire_softc *sc)
 				mask = 1;
 				break;
 			default:
-				DPRINTF(("%s: scan: triplet error 0x%x, "
+				DPRINTF(("%s: search triplet error 0x%x, "
 				    "step %d\n",
 				    sc->sc_dev.dv_xname, rv, i));
 				onewire_unlock(sc);
-				return;
+				return (-1);
 			}
 			rom |= (mask << i);
 		}
-		lastd = i0;
 		onewire_unlock(sc);
 
+		if ((lastd = i0) == -1)
+			search = 0;
+
 		if (rom == 0)
 			continue;
 
@@ -425,6 +380,75 @@ onewire_scan(struct onewire_softc *sc)
 		if (onewire_crc(data, 7) != data[7])
 			continue;
 
+		buf[count++] = rom;
+	}
+
+	return (count);
+}
+
+void
+onewire_thread(void *arg)
+{
+	struct onewire_softc *sc = arg;
+
+	while (!sc->sc_dying) {
+		onewire_scan(sc);
+		tsleep(sc->sc_thread, PWAIT, "owidle", ONEWIRE_SCANTIME * hz);
+	}
+
+	sc->sc_thread = NULL;
+	wakeup(&sc->sc_dying);
+	kthread_exit(0);
+}
+
+void
+onewire_createthread(void *arg)
+{
+	struct onewire_softc *sc = arg;
+
+	if (kthread_create(onewire_thread, sc, &sc->sc_thread,
+	    "%s", sc->sc_dev.dv_xname) != 0)
+		printf("%s: can't create kernel thread\n",
+		    sc->sc_dev.dv_xname);
+}
+
+void
+onewire_scan(struct onewire_softc *sc)
+{
+	struct onewire_device *d, *next, *nd;
+	struct onewire_attach_args oa;
+	struct device *dev;
+	int present;
+	u_int64_t rom;
+	int i, rv;
+
+	/*
+	 * Mark all currently present devices as absent before
+	 * scanning. This allows to find out later which devices
+	 * have been disappeared.
+	 */
+	TAILQ_FOREACH(d, &sc->sc_devs, d_list)
+		d->d_present = 0;
+
+	/*
+	 * Reset the bus. If there's no presence pulse don't search
+	 * for any devices.
+	 */
+	onewire_lock(sc, 0);
+	rv = onewire_reset(sc);
+	onewire_unlock(sc);
+	if (rv != 0) {
+		DPRINTF(("%s: no presence pulse\n", sc->sc_dev.dv_xname));
+		goto out;
+	}
+
+	/* Scan the bus */
+	if ((rv = onewire_search(sc, sc->sc_rombuf, ONEWIRE_MAXDEVS, 0)) == -1)
+		return;
+
+	for (i = 0; i < rv; i++) {
+		rom = sc->sc_rombuf[i];
+
 		/*
 		 * Go through the list of attached devices to see if we
 		 * found a new one.
@@ -456,8 +480,8 @@ onewire_scan(struct onewire_softc *sc)
 		}
 	}
 
+out:
 	/* Detach disappeared devices */
-	onewire_lock(sc, 0);
 	for (d = TAILQ_FIRST(&sc->sc_devs);
 	    d != TAILQ_END(&sc->sc_dev); d = next) {
 		next = TAILQ_NEXT(d, d_list);
@@ -467,5 +491,4 @@ onewire_scan(struct onewire_softc *sc)
 			FREE(d, M_DEVBUF);
 		}
 	}
-	onewire_unlock(sc);
 }
diff --git a/sys/dev/onewire/onewirevar.h b/sys/dev/onewire/onewirevar.h
index ad75d929e4d..3aaeb3bffd3 100644
--- a/sys/dev/onewire/onewirevar.h
+++ b/sys/dev/onewire/onewirevar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: onewirevar.h,v 1.3 2006/09/30 15:52:21 grange Exp $	*/
+/*	$OpenBSD: onewirevar.h,v 1.4 2006/10/08 21:12:51 grange Exp $	*/
 
 /*
  * Copyright (c) 2006 Alexander Yurchenko <grange@openbsd.org>
@@ -35,6 +35,7 @@ struct onewire_bus {
 	void	(*bus_write_block)(void *, const void *, int);
 	int	(*bus_triplet)(void *, int);
 	void	(*bus_matchrom)(void *, u_int64_t);
+	int	(*bus_search)(void *, u_int64_t *, int, u_int64_t);
 };
 
 /* Bus methods */
@@ -49,6 +50,7 @@ void		onewire_read_block(void *, void *, int);
 void		onewire_write_block(void *, const void *, int);
 int		onewire_triplet(void *, int);
 void		onewire_matchrom(void *, u_int64_t);
+int		onewire_search(void *, u_int64_t *, int, u_int64_t);
 
 #define ONEWIRE_NOWAIT		0x0001