Add a PPS driver that takes the timing pulse from a gpio pin. Currently

supports only ofw/fdt systems.  Some day, hinted attachment for non-fdt
systems should be possible too.

sys/conf/files

@@ -1534,6 +1534,7 @@ dev/gpio/gpioled.c		optional gpioled
 dev/gpio/gpiospi.c		optional gpiospi
 dev/gpio/gpio_if.m		optional gpio
 dev/gpio/gpiobus_if.m		optional gpio
+dev/gpio/gpiopps.c		optional gpiopps
 dev/gpio/ofw_gpiobus.c		optional fdt gpio
 dev/hatm/if_hatm.c		optional hatm pci
 dev/hatm/if_hatm_intr.c		optional hatm pci

sys/dev/gpio/gpiopps.c

@@ -0,0 +1,294 @@
+/*-
+ * Copyright (c) 2016 Ian Lepore <ian@FreeBSD.org>
+ * All rights reserved.
+ *
+ * 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 AUTHOR 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 AUTHOR 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/gpio.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/module.h>
+#include <sys/bus.h>
+#include <sys/conf.h>
+#include <sys/timepps.h>
+
+#include <dev/gpio/gpiobusvar.h>
+
+#include "opt_platform.h"
+
+#ifdef FDT
+#include <dev/ofw/ofw_bus.h>
+
+static struct ofw_compat_data compat_data[] = {
+	{"pps-gpio", 	1},
+	{NULL,          0}
+};
+#endif /* FDT */
+
+static devclass_t pps_devclass;
+
+struct pps_softc {
+	device_t         dev;
+	gpio_pin_t	 gpin;
+	void            *ihandler;
+	struct resource *ires;
+	int		 irid;
+	struct cdev     *pps_cdev;
+	struct pps_state pps_state;
+	struct mtx       pps_mtx;
+	bool		 falling_edge;
+};
+
+#define PPS_CDEV_NAME   "gpiopps"
+
+static int
+gpiopps_open(struct cdev *dev, int flags, int fmt, struct thread *td)
+{
+	struct pps_softc *sc = dev->si_drv1;
+
+	/* We can't be unloaded while open, so mark ourselves BUSY. */
+	mtx_lock(&sc->pps_mtx);
+	if (device_get_state(sc->dev) < DS_BUSY) {
+		device_busy(sc->dev);
+	}
+	mtx_unlock(&sc->pps_mtx);
+
+	return 0;
+}
+
+static	int
+gpiopps_close(struct cdev *dev, int flags, int fmt, struct thread *td)
+{
+	struct pps_softc *sc = dev->si_drv1;
+
+	/*
+	 * Un-busy on last close. We rely on the vfs counting stuff to only call
+	 * this routine on last-close, so we don't need any open-count logic.
+	 */
+	mtx_lock(&sc->pps_mtx);
+	device_unbusy(sc->dev);
+	mtx_unlock(&sc->pps_mtx);
+
+	return 0;
+}
+
+static int
+gpiopps_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags, struct thread *td)
+{
+	struct pps_softc *sc = dev->si_drv1;
+	int err;
+
+	/* Let the kernel do the heavy lifting for ioctl. */
+	mtx_lock(&sc->pps_mtx);
+	err = pps_ioctl(cmd, data, &sc->pps_state);
+	mtx_unlock(&sc->pps_mtx);
+
+	return err;
+}
+
+static struct cdevsw pps_cdevsw = {
+	.d_version =    D_VERSION,
+	.d_open =       gpiopps_open,
+	.d_close =      gpiopps_close,
+	.d_ioctl =      gpiopps_ioctl,
+	.d_name =       PPS_CDEV_NAME,
+};
+
+static int
+gpiopps_ifltr(void *arg)
+{
+	struct pps_softc *sc = arg;
+
+	/*
+	 * There is no locking here by design... The kernel cleverly captures
+	 * the current time into an area of the pps_state structure which is
+	 * written only by the pps_capture() routine and read only by the
+	 * pps_event() routine.  We don't need lock-based management of access
+	 * to the capture area because we have time-based access management:  we
+	 * can't be reading and writing concurently because we can't be running
+	 * both the threaded and filter handlers concurrently (because a new
+	 * hardware interrupt can't happen until the threaded handler for the
+	 * current interrupt exits, after which the system does the EOI that
+	 * enables a new hardware interrupt).
+	 */
+	pps_capture(&sc->pps_state);
+	return (FILTER_SCHEDULE_THREAD);
+}
+
+static void
+gpiopps_ithrd(void *arg)
+{
+	struct pps_softc *sc = arg;
+
+	/*
+	 * Go create a pps event from the data captured in the filter handler.
+	 *
+	 * Note that we DO need locking here, unlike the case with the filter
+	 * handler.  The pps_event() routine updates the non-capture part of the
+	 * pps_state structure, and the ioctl() code could be accessing that
+	 * data right now in a non-interrupt context, so we need an interlock.
+	 */
+	mtx_lock(&sc->pps_mtx);
+	pps_event(&sc->pps_state, PPS_CAPTUREASSERT);
+	mtx_unlock(&sc->pps_mtx);
+}
+
+static int
+gpiopps_detach(device_t dev)
+{
+	struct pps_softc *sc = device_get_softc(dev);
+
+	if (sc->pps_cdev != NULL)
+		destroy_dev(sc->pps_cdev);
+	if (sc->ihandler != NULL)
+		bus_teardown_intr(dev, sc->ires, sc->ihandler);
+	if (sc->ires != NULL)
+		bus_release_resource(dev, SYS_RES_IRQ, sc->irid, sc->ires);
+	if (sc->gpin != NULL)
+		gpiobus_release_pin(GPIO_GET_BUS(sc->gpin->dev), sc->gpin->pin);
+	return (0);
+}
+
+#ifdef FDT
+static int
+gpiopps_fdt_attach(device_t dev)
+{
+	struct pps_softc *sc;
+	struct make_dev_args devargs;
+	phandle_t node;
+	uint32_t edge, pincaps;
+	int err;
+
+	sc = device_get_softc(dev);
+	sc->dev = dev;
+
+	mtx_init(&sc->pps_mtx, device_get_nameunit(dev), NULL, MTX_DEF);
+
+	/* Initialize the pps_state struct. */
+	sc->pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
+	sc->pps_state.driver_abi = PPS_ABI_VERSION;
+	sc->pps_state.driver_mtx = &sc->pps_mtx;
+	pps_init_abi(&sc->pps_state);
+
+	/* Check which edge we're configured to capture (default is rising). */
+	if (ofw_bus_has_prop(dev, "assert-falling-edge"))
+		edge = GPIO_INTR_EDGE_FALLING;
+	else
+		edge = GPIO_INTR_EDGE_RISING;
+
+	/*
+	 * Look up the configured gpio pin and ensure it can be configured for
+	 * the interrupt mode we need.
+	 */
+	node = ofw_bus_get_node(dev);
+	if ((err = gpio_pin_get_by_ofw_idx(dev, node, 0, &sc->gpin)) != 0) {
+		device_printf(dev, "Cannot obtain gpio pin\n");
+		return (err);
+	}
+	device_printf(dev, "PPS input on %s pin %u\n",
+	    device_get_nameunit(sc->gpin->dev), sc->gpin->pin);
+
+	if ((err = gpio_pin_getcaps(sc->gpin, &pincaps)) != 0) {
+		device_printf(dev, "Cannot query capabilities of gpio pin\n");
+		gpiopps_detach(dev);
+		return (err);
+	}
+	if ((pincaps & edge) == 0) {
+		device_printf(dev, "Pin cannot be configured for the requested signal edge\n");
+		gpiopps_detach(dev);
+		return (ENOTSUP);
+	}
+
+	/*
+	 * Transform our 'gpios' property into an interrupt resource and set up
+	 * the interrupt.
+	 */
+	if ((sc->ires = gpio_alloc_intr_resource(dev, &sc->irid, RF_ACTIVE,
+	    sc->gpin, edge)) == NULL) {
+		device_printf(dev, "Cannot allocate an IRQ for the GPIO\n");
+		gpiopps_detach(dev);
+		return (err);
+	}
+
+	err = bus_setup_intr(dev, sc->ires, INTR_TYPE_CLK | INTR_MPSAFE, 
+	    gpiopps_ifltr, gpiopps_ithrd, sc, &sc->ihandler);
+	if (err != 0) {
+		device_printf(dev, "Unable to setup pps irq handler\n");
+		gpiopps_detach(dev);
+		return (err);
+	}
+
+	/* Create the RFC 2783 pps-api cdev. */
+	make_dev_args_init(&devargs);
+	devargs.mda_devsw = &pps_cdevsw;
+	devargs.mda_uid = UID_ROOT;
+	devargs.mda_gid = GID_WHEEL;
+	devargs.mda_mode = 0660;
+	devargs.mda_si_drv1 = sc;
+	err = make_dev_s(&devargs, &sc->pps_cdev, PPS_CDEV_NAME "%d", 
+	    device_get_unit(dev));
+	if (err != 0) {
+		device_printf(dev, "Unable to create pps cdev\n");
+		gpiopps_detach(dev);
+		return (err);
+	}
+
+	return (0);
+}
+
+static int
+gpiopps_fdt_probe(device_t dev)
+{
+
+	if (!ofw_bus_status_okay(dev))
+		return (ENXIO);
+
+	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data != 0) {
+		device_set_desc(dev, "GPIO PPS");
+		return (BUS_PROBE_DEFAULT);
+	}
+
+	return (ENXIO);
+}
+
+static device_method_t pps_fdt_methods[] = {
+	DEVMETHOD(device_probe,		gpiopps_fdt_probe),
+	DEVMETHOD(device_attach,	gpiopps_fdt_attach),
+	DEVMETHOD(device_detach,	gpiopps_detach),
+
+	DEVMETHOD_END
+};
+
+static driver_t pps_fdt_driver = {
+	"gpiopps",
+	pps_fdt_methods,
+	sizeof(struct pps_softc),
+};
+
+DRIVER_MODULE(gpiopps, simplebus, pps_fdt_driver, pps_devclass, 0, 0);
+
+#endif /* FDT */

sys/gnu/dts/arm/imx6qdl-wandboard.dtsi

@@ -262,3 +262,12 @@
 	cd-gpios = <&gpio3 9 GPIO_ACTIVE_LOW>;
 	status = "okay";
 };
+
+/ {
+	pps@0 {
+		compatible = "pps-gpio";
+		gpios = <&gpio3 27 GPIO_ACTIVE_HIGH>;
+		status = "okay";
+	};
+};
+

sys/modules/Makefile

@@ -125,6 +125,7 @@ SUBDIR=	\
 	geom \
 	${_glxiic} \
 	${_glxsb} \
+	gpio \
 	hatm \
 	hifn \
 	hme \

sys/modules/gpio/Makefile

@@ -25,6 +25,6 @@
 # SUCH DAMAGE.
 #
 
-SUBDIR = gpiobus gpioiic gpioled
+SUBDIR = gpiobus gpioiic gpioled gpiopps
 
 .include <bsd.subdir.mk>

sys/modules/gpio/gpiopps/Makefile

@@ -0,0 +1,40 @@
+#
+# Copyright (c) 2016 Ian Lepore <ian@FreeBSD.org>
+# All rights reserved.
+#
+# 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,
+#    without modification.
+# 2. Redistributions in binary form must reproduce at minimum a disclaimer
+#    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
+#    redistribution must be conditioned upon including a substantially
+#    similar Disclaimer requirement for further binary redistribution.
+#
+# NO WARRANTY
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
+# AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+# THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR 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 DAMAGES.
+#
+# $FreeBSD$
+#
+
+.PATH:	${.CURDIR}/../../../dev/gpio/
+
+KMOD=	gpiopps
+SRCS=	gpiopps.c
+SRCS+=	device_if.h bus_if.h gpio_if.h gpiobus_if.h opt_platform.h
+
+CFLAGS+=  -I. -I${.CURDIR}/../../../dev/gpio/
+
+.include <bsd.kmod.mk>