/*-
* 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 */
