Module Name: src Committed By: ad Date: Sat Nov 30 23:04:12 UTC 2019
Modified Files: src/sys/dev/gpio: gpioow.c src/sys/dev/onewire: onewire.c onewire_bitbang.c onewirevar.h Log Message: onewire: - Re-do the signalling to be a little more forgiving and efficient. - If bus reset fails during probe, try a second time. - Spread out kernel threads for many busses to avoid thundering herd effect. To generate a diff of this commit: cvs rdiff -u -r1.15 -r1.16 src/sys/dev/gpio/gpioow.c cvs rdiff -u -r1.17 -r1.18 src/sys/dev/onewire/onewire.c cvs rdiff -u -r1.1 -r1.2 src/sys/dev/onewire/onewire_bitbang.c cvs rdiff -u -r1.5 -r1.6 src/sys/dev/onewire/onewirevar.h Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.
Modified files: Index: src/sys/dev/gpio/gpioow.c diff -u src/sys/dev/gpio/gpioow.c:1.15 src/sys/dev/gpio/gpioow.c:1.16 --- src/sys/dev/gpio/gpioow.c:1.15 Sat Oct 28 04:53:56 2017 +++ src/sys/dev/gpio/gpioow.c Sat Nov 30 23:04:12 2019 @@ -1,4 +1,4 @@ -/* $NetBSD: gpioow.c,v 1.15 2017/10/28 04:53:56 riastradh Exp $ */ +/* $NetBSD: gpioow.c,v 1.16 2019/11/30 23:04:12 ad Exp $ */ /* $OpenBSD: gpioow.c,v 1.1 2006/03/04 16:27:03 grange Exp $ */ /* @@ -18,7 +18,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: gpioow.c,v 1.15 2017/10/28 04:53:56 riastradh Exp $"); +__KERNEL_RCSID(0, "$NetBSD: gpioow.c,v 1.16 2019/11/30 23:04:12 ad Exp $"); /* * 1-Wire bus bit-banging through GPIO pin. @@ -57,7 +57,8 @@ int gpioow_detach(device_t, int); int gpioow_activate(device_t, enum devact); int gpioow_ow_reset(void *); -int gpioow_ow_bit(void *, int); +int gpioow_ow_read_bit(void *); +void gpioow_ow_write_bit(void *, int); void gpioow_bb_rx(void *); void gpioow_bb_tx(void *); @@ -143,7 +144,8 @@ gpioow_attach(device_t parent, device_t /* Attach 1-Wire bus */ sc->sc_ow_bus.bus_cookie = sc; sc->sc_ow_bus.bus_reset = gpioow_ow_reset; - sc->sc_ow_bus.bus_bit = gpioow_ow_bit; + sc->sc_ow_bus.bus_read_bit = gpioow_ow_read_bit; + sc->sc_ow_bus.bus_write_bit = gpioow_ow_write_bit; memset(&oba, 0, sizeof(oba)); oba.oba_bus = &sc->sc_ow_bus; @@ -193,9 +195,15 @@ gpioow_ow_reset(void *arg) } int -gpioow_ow_bit(void *arg, int value) +gpioow_ow_read_bit(void *arg) { - return (onewire_bb_bit(&gpioow_bbops, arg, value)); + return (onewire_bb_read_bit(&gpioow_bbops, arg)); +} + +void +gpioow_ow_write_bit(void *arg, int value) +{ + onewire_bb_write_bit(&gpioow_bbops, arg, value); } void Index: src/sys/dev/onewire/onewire.c diff -u src/sys/dev/onewire/onewire.c:1.17 src/sys/dev/onewire/onewire.c:1.18 --- src/sys/dev/onewire/onewire.c:1.17 Fri Oct 25 16:25:14 2019 +++ src/sys/dev/onewire/onewire.c Sat Nov 30 23:04:12 2019 @@ -1,6 +1,35 @@ -/* $NetBSD: onewire.c,v 1.17 2019/10/25 16:25:14 martin Exp $ */ +/* $NetBSD: onewire.c,v 1.18 2019/11/30 23:04:12 ad Exp $ */ /* $OpenBSD: onewire.c,v 1.1 2006/03/04 16:27:03 grange Exp $ */ +/*- + * Copyright (c) 2019 The NetBSD Foundation, Inc. + * All rights reserved. + * + * This code is derived from software contributed to The NetBSD Foundation + * by Andrew Doran. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + /* * Copyright (c) 2006 Alexander Yurchenko <gra...@openbsd.org> * @@ -18,7 +47,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: onewire.c,v 1.17 2019/10/25 16:25:14 martin Exp $"); +__KERNEL_RCSID(0, "$NetBSD: onewire.c,v 1.18 2019/11/30 23:04:12 ad Exp $"); /* * 1-Wire bus driver. @@ -202,14 +231,25 @@ onewire_reset(void *arg) } int -onewire_bit(void *arg, int value) +onewire_read_bit(void *arg) { struct onewire_softc *sc = arg; struct onewire_bus *bus = sc->sc_bus; KASSERT(mutex_owned(&sc->sc_lock)); - return bus->bus_bit(bus->bus_cookie, value); + return bus->bus_read_bit(bus->bus_cookie); +} + +void +onewire_write_bit(void *arg, int value) +{ + struct onewire_softc *sc = arg; + struct onewire_bus *bus = sc->sc_bus; + + KASSERT(mutex_owned(&sc->sc_lock)); + + bus->bus_write_bit(bus->bus_cookie, value); } int @@ -226,7 +266,7 @@ onewire_read_byte(void *arg) return bus->bus_read_byte(bus->bus_cookie); for (i = 0; i < 8; i++) - value |= (bus->bus_bit(bus->bus_cookie, 1) << i); + value |= (bus->bus_read_bit(bus->bus_cookie) << i); return value; } @@ -244,7 +284,7 @@ onewire_write_byte(void *arg, int value) return bus->bus_write_byte(bus->bus_cookie, value); for (i = 0; i < 8; i++) - bus->bus_bit(bus->bus_cookie, (value >> i) & 0x1); + bus->bus_write_bit(bus->bus_cookie, (value >> i) & 0x1); } int @@ -259,19 +299,19 @@ onewire_triplet(void *arg, int dir) if (bus->bus_triplet != NULL) return bus->bus_triplet(bus->bus_cookie, dir); - rv = bus->bus_bit(bus->bus_cookie, 1); + rv = bus->bus_read_bit(bus->bus_cookie); rv <<= 1; - rv |= bus->bus_bit(bus->bus_cookie, 1); + rv |= bus->bus_read_bit(bus->bus_cookie); switch (rv) { case 0x0: - bus->bus_bit(bus->bus_cookie, dir); + bus->bus_write_bit(bus->bus_cookie, dir); break; case 0x1: - bus->bus_bit(bus->bus_cookie, 0); + bus->bus_write_bit(bus->bus_cookie, 0); break; default: - bus->bus_bit(bus->bus_cookie, 1); + bus->bus_write_bit(bus->bus_cookie, 1); } return rv; @@ -318,6 +358,18 @@ static void onewire_thread(void *arg) { struct onewire_softc *sc = arg; + int unit, dly; + + /* + * There can be many onewire busses, potentially funneled through + * few GPIO controllers. To avoid a thundering herd of kthreads and + * resulting contention for the GPIO controller, spread the probes + * out across an 8 second window. The kthreads could converge later + * due to timing effects. + */ + unit = device_unit(sc->sc_dev); + dly = (unit & 0x07) * hz + ((unit >> 3) * hz >> 3) + 1; + (void)kpause("owdly", false, dly, NULL); mutex_enter(&sc->sc_lock); while (!sc->sc_dying) { @@ -354,13 +406,17 @@ onewire_scan(struct onewire_softc *sc) while (search && count++ < onewire_maxdevs) { /* - * Reset the bus. If there's no presence pulse - * don't search for any devices. + * Reset the bus, allowing for one retry if reset fails. If + * there's no presence pulse don't search for any devices. */ if (onewire_reset(sc) != 0) { DPRINTF(("%s: scan: no presence pulse\n", device_xname(sc->sc_dev))); - break; + if (onewire_reset(sc) != 0) { + DPRINTF(("%s: scan: retry failed\n", + device_xname(sc->sc_dev))); + break; + } } /* @@ -405,6 +461,12 @@ onewire_scan(struct onewire_softc *sc) } lastd = i0; + /* + * Yield processor, but continue to hold the lock + * so that scan is not interrupted. + */ + (void)kpause("owscan", false, 1, NULL); + if (rom == 0) continue; @@ -437,12 +499,6 @@ onewire_scan(struct onewire_softc *sc) nd->d_present = true; TAILQ_INSERT_TAIL(&sc->sc_devs, nd, d_list); } - - /* - * Yield processor, but continue to hold the lock - * so that scan is not interrupted. - */ - kpause("owscan", false, 1, NULL); } /* Index: src/sys/dev/onewire/onewire_bitbang.c diff -u src/sys/dev/onewire/onewire_bitbang.c:1.1 src/sys/dev/onewire/onewire_bitbang.c:1.2 --- src/sys/dev/onewire/onewire_bitbang.c:1.1 Fri Apr 7 18:55:22 2006 +++ src/sys/dev/onewire/onewire_bitbang.c Sat Nov 30 23:04:12 2019 @@ -1,6 +1,35 @@ -/* $NetBSD: onewire_bitbang.c,v 1.1 2006/04/07 18:55:22 riz Exp $ */ +/* $NetBSD: onewire_bitbang.c,v 1.2 2019/11/30 23:04:12 ad Exp $ */ /* $OpenBSD: onewire_bitbang.c,v 1.1 2006/03/04 16:27:03 grange Exp $ */ +/*- + * Copyright (c) 2019 The NetBSD Foundation, Inc. + * All rights reserved. + * + * This code is derived from software contributed to The NetBSD Foundation + * by Andrew Doran. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + /* * Copyright (c) 2006 Alexander Yurchenko <gra...@openbsd.org> * @@ -18,7 +47,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: onewire_bitbang.c,v 1.1 2006/04/07 18:55:22 riz Exp $"); +__KERNEL_RCSID(0, "$NetBSD: onewire_bitbang.c,v 1.2 2019/11/30 23:04:12 ad Exp $"); /* * 1-Wire bus bit-banging routines. @@ -27,55 +56,131 @@ __KERNEL_RCSID(0, "$NetBSD: onewire_bitb #include <sys/param.h> #include <sys/systm.h> #include <sys/device.h> +#include <sys/proc.h> #include <dev/onewire/onewirevar.h> + /* + * Reset the bus. Sequence from DS18B20 datasheet: + * + * 1: Master pulls bus low for a minimum of 480us. + * 2: Bus pulled up by resistor. DS18B20 detects rising edge, waits 15-60us. + * 3: DS18B20 pulls bus low for 60-240us. + * 4: Bus pulled up by resistor. Master must wait at least 450us. + * + * 111111111112222233333444444444 + * + * Vpu | +-+ +-----> + * | / | / + * GND +----------+ +-----+ + */ int onewire_bb_reset(const struct onewire_bbops *ops, void *arg) { - int s, rv = 0, i; + int s, rv, i; + rv = 0; s = splhigh(); ops->bb_tx(arg); ops->bb_set(arg, 0); - DELAY(480); + delay(500); ops->bb_set(arg, 1); ops->bb_rx(arg); - DELAY(30); - for (i = 0; i < 6; i++) { + for (i = 0; i < 240 / 5; i++) { + delay(5); if ((rv = ops->bb_get(arg)) == 0) break; - DELAY(20); } - DELAY(450); + splx(s); + + /* + * After a bus reset, we must wait for at least 450us before any + * further device access. There is no upper bound on this time, so + * rather than burning CPU, sleep for 1 tick. + */ + KASSERT(2001 > hz); + (void)kpause("owreset", false, 1, NULL); + + /* + * With a push-pull GPIO, bring the bus high to supply + * parasite-powered devices. With either PP or open drain, + * past this point on entry to onewire_bb_write_bit() and + * onewire_bb_read_bit() we assume that the line is set to + * output and not being held low. + */ + s = splhigh(); + ops->bb_tx(arg); + ops->bb_set(arg, 1); splx(s); - return (rv); + return rv; } +/* + * Onewire bit write. + * + * Method: pull the bus low. Then let the pull up resistor settle the bus. + * ZERO is signalled by the bus being held low for minimum 60us. + * ONE is signalled by the hold being much shorter (minimum 1us). + * + * In any eventuality, pad the entire transaction to the minimum 60us, plus + * an additional bit of recovery time before the next transaction + */ +void +onewire_bb_write_bit(const struct onewire_bbops *ops, void *arg, int value) +{ + int s, d1, d2; + + if (value) { + d1 = 2; + d2 = 62; + } else { + d1 = 62; + d2 = 2; + } + + s = splhigh(); + ops->bb_set(arg, 0); + delay(d1); + ops->bb_set(arg, 1); + splx(s); + /* Timing no longer critical. */ + delay(d2); +} + +/* + * Onewire bit read. + * + * Method: pull the bus low for at least 1us. Then let the pull up resistor + * settle the bus. ZERO is signalled by the bus being pulled low again by + * the slave at some point between 15-45us of transaction start. ONE is + * signalled by the bus not being pulled low. + * + * In any eventuality, pad the entire transaction to the minimum 60us, plus + * an additional bit of recovery time before the next transaction. + */ int -onewire_bb_bit(const struct onewire_bbops *ops, void *arg, int value) +onewire_bb_read_bit(const struct onewire_bbops *ops, void *arg) { - int s, rv = 0, i; + int s, rv, us; s = splhigh(); - ops->bb_tx(arg); ops->bb_set(arg, 0); - DELAY(2); - if (value) { - ops->bb_set(arg, 1); - ops->bb_rx(arg); - for (i = 0; i < 15; i++) { - if ((rv = ops->bb_get(arg)) == 0) - break; - DELAY(2); + delay(2); + ops->bb_set(arg, 1); + ops->bb_rx(arg); + for (us = 62; us >= 60 - 45; us -= 5) { + delay(5); + if ((rv = ops->bb_get(arg)) == 0) { + break; } - ops->bb_tx(arg); } - DELAY(60); - ops->bb_set(arg, 1); - DELAY(5); splx(s); - - return (rv); + /* Timing no longer critical, and no further need to poll. */ + if (us > 0) { + delay(us); + } + ops->bb_tx(arg); + ops->bb_set(arg, 1); + return rv; } Index: src/sys/dev/onewire/onewirevar.h diff -u src/sys/dev/onewire/onewirevar.h:1.5 src/sys/dev/onewire/onewirevar.h:1.6 --- src/sys/dev/onewire/onewirevar.h:1.5 Wed Sep 5 15:39:22 2007 +++ src/sys/dev/onewire/onewirevar.h Sat Nov 30 23:04:12 2019 @@ -1,4 +1,4 @@ -/* $NetBSD: onewirevar.h,v 1.5 2007/09/05 15:39:22 xtraeme Exp $ */ +/* $NetBSD: onewirevar.h,v 1.6 2019/11/30 23:04:12 ad Exp $ */ /* $OpenBSD: onewirevar.h,v 1.1 2006/03/04 16:27:03 grange Exp $ */ /* @@ -29,7 +29,8 @@ struct onewire_bus { void * bus_cookie; int (*bus_reset)(void *); - int (*bus_bit)(void *, int); + int (*bus_read_bit)(void *); + void (*bus_write_bit)(void *, int); int (*bus_read_byte)(void *); void (*bus_write_byte)(void *, int); int (*bus_triplet)(void *, int); @@ -39,7 +40,8 @@ struct onewire_bus { void onewire_lock(void *); void onewire_unlock(void *); int onewire_reset(void *); -int onewire_bit(void *, int); +int onewire_read_bit(void *); +void onewire_write_bit(void *, int); int onewire_read_byte(void *); void onewire_write_byte(void *, int); int onewire_triplet(void *, int); @@ -80,6 +82,7 @@ struct onewire_bbops { }; int onewire_bb_reset(const struct onewire_bbops *, void *); -int onewire_bb_bit(const struct onewire_bbops *, void *, int); +int onewire_bb_read_bit(const struct onewire_bbops *, void *); +void onewire_bb_write_bit(const struct onewire_bbops *, void *, int); #endif /* !_DEV_ONEWIRE_ONEWIREVAR_H_ */