287 lines
7.7 KiB
C
287 lines
7.7 KiB
C
/*-
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* Copyright (c) 2016 Ian Lepore <ian@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#include <sys/param.h>
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#include <sys/gpio.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/module.h>
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#include <sys/bus.h>
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#include <sys/conf.h>
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#include <sys/timepps.h>
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#include <dev/gpio/gpiobusvar.h>
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#include "opt_platform.h"
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#ifdef FDT
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#include <dev/ofw/ofw_bus.h>
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static struct ofw_compat_data compat_data[] = {
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{"pps-gpio", 1},
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{NULL, 0}
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};
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SIMPLEBUS_PNP_INFO(compat_data);
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#endif /* FDT */
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struct pps_softc {
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device_t dev;
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gpio_pin_t gpin;
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void *ihandler;
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struct resource *ires;
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int irid;
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struct cdev *pps_cdev;
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struct pps_state pps_state;
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struct mtx pps_mtx;
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bool falling_edge;
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};
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#define PPS_CDEV_NAME "gpiopps"
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static int
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gpiopps_open(struct cdev *dev, int flags, int fmt, struct thread *td)
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{
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struct pps_softc *sc = dev->si_drv1;
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/* We can't be unloaded while open, so mark ourselves BUSY. */
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mtx_lock(&sc->pps_mtx);
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device_busy(sc->dev);
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mtx_unlock(&sc->pps_mtx);
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return 0;
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}
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static int
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gpiopps_close(struct cdev *dev, int flags, int fmt, struct thread *td)
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{
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struct pps_softc *sc = dev->si_drv1;
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mtx_lock(&sc->pps_mtx);
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device_unbusy(sc->dev);
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mtx_unlock(&sc->pps_mtx);
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return 0;
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}
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static int
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gpiopps_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags, struct thread *td)
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{
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struct pps_softc *sc = dev->si_drv1;
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int err;
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/* Let the kernel do the heavy lifting for ioctl. */
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mtx_lock(&sc->pps_mtx);
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err = pps_ioctl(cmd, data, &sc->pps_state);
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mtx_unlock(&sc->pps_mtx);
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return err;
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}
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static struct cdevsw pps_cdevsw = {
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.d_version = D_VERSION,
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.d_flags = D_TRACKCLOSE,
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.d_open = gpiopps_open,
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.d_close = gpiopps_close,
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.d_ioctl = gpiopps_ioctl,
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.d_name = PPS_CDEV_NAME,
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};
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static int
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gpiopps_ifltr(void *arg)
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{
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struct pps_softc *sc = arg;
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/*
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* There is no locking here by design... The kernel cleverly captures
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* the current time into an area of the pps_state structure which is
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* written only by the pps_capture() routine and read only by the
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* pps_event() routine. We don't need lock-based management of access
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* to the capture area because we have time-based access management: we
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* can't be reading and writing concurrently because we can't be running
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* both the threaded and filter handlers concurrently (because a new
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* hardware interrupt can't happen until the threaded handler for the
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* current interrupt exits, after which the system does the EOI that
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* enables a new hardware interrupt).
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*/
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pps_capture(&sc->pps_state);
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return (FILTER_SCHEDULE_THREAD);
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}
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static void
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gpiopps_ithrd(void *arg)
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{
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struct pps_softc *sc = arg;
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/*
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* Go create a pps event from the data captured in the filter handler.
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*
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* Note that we DO need locking here, unlike the case with the filter
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* handler. The pps_event() routine updates the non-capture part of the
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* pps_state structure, and the ioctl() code could be accessing that
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* data right now in a non-interrupt context, so we need an interlock.
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*/
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mtx_lock(&sc->pps_mtx);
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pps_event(&sc->pps_state, PPS_CAPTUREASSERT);
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mtx_unlock(&sc->pps_mtx);
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}
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static int
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gpiopps_detach(device_t dev)
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{
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struct pps_softc *sc = device_get_softc(dev);
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if (sc->pps_cdev != NULL)
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destroy_dev(sc->pps_cdev);
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if (sc->ihandler != NULL)
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bus_teardown_intr(dev, sc->ires, sc->ihandler);
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if (sc->ires != NULL)
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bus_release_resource(dev, SYS_RES_IRQ, sc->irid, sc->ires);
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if (sc->gpin != NULL)
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gpiobus_release_pin(GPIO_GET_BUS(sc->gpin->dev), sc->gpin->pin);
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return (0);
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}
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#ifdef FDT
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static int
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gpiopps_fdt_attach(device_t dev)
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{
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struct pps_softc *sc;
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struct make_dev_args devargs;
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phandle_t node;
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uint32_t edge, pincaps;
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int err;
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sc = device_get_softc(dev);
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sc->dev = dev;
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mtx_init(&sc->pps_mtx, device_get_nameunit(dev), NULL, MTX_DEF);
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/* Initialize the pps_state struct. */
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sc->pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
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sc->pps_state.driver_abi = PPS_ABI_VERSION;
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sc->pps_state.driver_mtx = &sc->pps_mtx;
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pps_init_abi(&sc->pps_state);
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/* Check which edge we're configured to capture (default is rising). */
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if (ofw_bus_has_prop(dev, "assert-falling-edge"))
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edge = GPIO_INTR_EDGE_FALLING;
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else
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edge = GPIO_INTR_EDGE_RISING;
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/*
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* Look up the configured gpio pin and ensure it can be configured for
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* the interrupt mode we need.
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*/
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node = ofw_bus_get_node(dev);
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if ((err = gpio_pin_get_by_ofw_idx(dev, node, 0, &sc->gpin)) != 0) {
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device_printf(dev, "Cannot obtain gpio pin\n");
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return (err);
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}
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device_printf(dev, "PPS input on %s pin %u\n",
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device_get_nameunit(sc->gpin->dev), sc->gpin->pin);
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if ((err = gpio_pin_getcaps(sc->gpin, &pincaps)) != 0) {
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device_printf(dev, "Cannot query capabilities of gpio pin\n");
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gpiopps_detach(dev);
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return (err);
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}
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if ((pincaps & edge) == 0) {
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device_printf(dev, "Pin cannot be configured for the requested signal edge\n");
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gpiopps_detach(dev);
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return (ENOTSUP);
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}
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/*
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* Transform our 'gpios' property into an interrupt resource and set up
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* the interrupt.
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*/
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if ((sc->ires = gpio_alloc_intr_resource(dev, &sc->irid, RF_ACTIVE,
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sc->gpin, edge)) == NULL) {
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device_printf(dev, "Cannot allocate an IRQ for the GPIO\n");
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gpiopps_detach(dev);
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return (err);
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}
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err = bus_setup_intr(dev, sc->ires, INTR_TYPE_CLK | INTR_MPSAFE,
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gpiopps_ifltr, gpiopps_ithrd, sc, &sc->ihandler);
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if (err != 0) {
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device_printf(dev, "Unable to setup pps irq handler\n");
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gpiopps_detach(dev);
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return (err);
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}
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/* Create the RFC 2783 pps-api cdev. */
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make_dev_args_init(&devargs);
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devargs.mda_devsw = &pps_cdevsw;
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devargs.mda_uid = UID_ROOT;
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devargs.mda_gid = GID_WHEEL;
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devargs.mda_mode = 0660;
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devargs.mda_si_drv1 = sc;
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err = make_dev_s(&devargs, &sc->pps_cdev, PPS_CDEV_NAME "%d",
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device_get_unit(dev));
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if (err != 0) {
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device_printf(dev, "Unable to create pps cdev\n");
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gpiopps_detach(dev);
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return (err);
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}
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return (0);
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}
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static int
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gpiopps_fdt_probe(device_t dev)
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{
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if (!ofw_bus_status_okay(dev))
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return (ENXIO);
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if (ofw_bus_search_compatible(dev, compat_data)->ocd_data != 0) {
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device_set_desc(dev, "GPIO PPS");
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return (BUS_PROBE_DEFAULT);
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}
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return (ENXIO);
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}
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static device_method_t pps_fdt_methods[] = {
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DEVMETHOD(device_probe, gpiopps_fdt_probe),
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DEVMETHOD(device_attach, gpiopps_fdt_attach),
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DEVMETHOD(device_detach, gpiopps_detach),
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DEVMETHOD_END
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};
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static driver_t pps_fdt_driver = {
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"gpiopps",
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pps_fdt_methods,
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sizeof(struct pps_softc),
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};
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DRIVER_MODULE(gpiopps, simplebus, pps_fdt_driver, 0, 0);
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#endif /* FDT */
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