2 * Copyright (c) 2016 Ian Lepore <ian@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
32 #include <sys/kernel.h>
34 #include <sys/module.h>
37 #include <sys/timepps.h>
39 #include <dev/gpio/gpiobusvar.h>
41 #include "opt_platform.h"
44 #include <dev/ofw/ofw_bus.h>
46 static struct ofw_compat_data compat_data[] = {
52 static devclass_t pps_devclass;
58 struct resource *ires;
60 struct cdev *pps_cdev;
61 struct pps_state pps_state;
66 #define PPS_CDEV_NAME "gpiopps"
69 gpiopps_open(struct cdev *dev, int flags, int fmt, struct thread *td)
71 struct pps_softc *sc = dev->si_drv1;
73 /* We can't be unloaded while open, so mark ourselves BUSY. */
74 mtx_lock(&sc->pps_mtx);
75 if (device_get_state(sc->dev) < DS_BUSY) {
78 mtx_unlock(&sc->pps_mtx);
84 gpiopps_close(struct cdev *dev, int flags, int fmt, struct thread *td)
86 struct pps_softc *sc = dev->si_drv1;
89 * Un-busy on last close. We rely on the vfs counting stuff to only call
90 * this routine on last-close, so we don't need any open-count logic.
92 mtx_lock(&sc->pps_mtx);
93 device_unbusy(sc->dev);
94 mtx_unlock(&sc->pps_mtx);
100 gpiopps_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags, struct thread *td)
102 struct pps_softc *sc = dev->si_drv1;
105 /* Let the kernel do the heavy lifting for ioctl. */
106 mtx_lock(&sc->pps_mtx);
107 err = pps_ioctl(cmd, data, &sc->pps_state);
108 mtx_unlock(&sc->pps_mtx);
113 static struct cdevsw pps_cdevsw = {
114 .d_version = D_VERSION,
115 .d_open = gpiopps_open,
116 .d_close = gpiopps_close,
117 .d_ioctl = gpiopps_ioctl,
118 .d_name = PPS_CDEV_NAME,
122 gpiopps_ifltr(void *arg)
124 struct pps_softc *sc = arg;
127 * There is no locking here by design... The kernel cleverly captures
128 * the current time into an area of the pps_state structure which is
129 * written only by the pps_capture() routine and read only by the
130 * pps_event() routine. We don't need lock-based management of access
131 * to the capture area because we have time-based access management: we
132 * can't be reading and writing concurently because we can't be running
133 * both the threaded and filter handlers concurrently (because a new
134 * hardware interrupt can't happen until the threaded handler for the
135 * current interrupt exits, after which the system does the EOI that
136 * enables a new hardware interrupt).
138 pps_capture(&sc->pps_state);
139 return (FILTER_SCHEDULE_THREAD);
143 gpiopps_ithrd(void *arg)
145 struct pps_softc *sc = arg;
148 * Go create a pps event from the data captured in the filter handler.
150 * Note that we DO need locking here, unlike the case with the filter
151 * handler. The pps_event() routine updates the non-capture part of the
152 * pps_state structure, and the ioctl() code could be accessing that
153 * data right now in a non-interrupt context, so we need an interlock.
155 mtx_lock(&sc->pps_mtx);
156 pps_event(&sc->pps_state, PPS_CAPTUREASSERT);
157 mtx_unlock(&sc->pps_mtx);
161 gpiopps_detach(device_t dev)
163 struct pps_softc *sc = device_get_softc(dev);
165 if (sc->pps_cdev != NULL)
166 destroy_dev(sc->pps_cdev);
167 if (sc->ihandler != NULL)
168 bus_teardown_intr(dev, sc->ires, sc->ihandler);
169 if (sc->ires != NULL)
170 bus_release_resource(dev, SYS_RES_IRQ, sc->irid, sc->ires);
171 if (sc->gpin != NULL)
172 gpiobus_release_pin(GPIO_GET_BUS(sc->gpin->dev), sc->gpin->pin);
178 gpiopps_fdt_attach(device_t dev)
180 struct pps_softc *sc;
181 struct make_dev_args devargs;
183 uint32_t edge, pincaps;
186 sc = device_get_softc(dev);
189 mtx_init(&sc->pps_mtx, device_get_nameunit(dev), NULL, MTX_DEF);
191 /* Initialize the pps_state struct. */
192 sc->pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
193 sc->pps_state.driver_abi = PPS_ABI_VERSION;
194 sc->pps_state.driver_mtx = &sc->pps_mtx;
195 pps_init_abi(&sc->pps_state);
197 /* Check which edge we're configured to capture (default is rising). */
198 if (ofw_bus_has_prop(dev, "assert-falling-edge"))
199 edge = GPIO_INTR_EDGE_FALLING;
201 edge = GPIO_INTR_EDGE_RISING;
204 * Look up the configured gpio pin and ensure it can be configured for
205 * the interrupt mode we need.
207 node = ofw_bus_get_node(dev);
208 if ((err = gpio_pin_get_by_ofw_idx(dev, node, 0, &sc->gpin)) != 0) {
209 device_printf(dev, "Cannot obtain gpio pin\n");
212 device_printf(dev, "PPS input on %s pin %u\n",
213 device_get_nameunit(sc->gpin->dev), sc->gpin->pin);
215 if ((err = gpio_pin_getcaps(sc->gpin, &pincaps)) != 0) {
216 device_printf(dev, "Cannot query capabilities of gpio pin\n");
220 if ((pincaps & edge) == 0) {
221 device_printf(dev, "Pin cannot be configured for the requested signal edge\n");
227 * Transform our 'gpios' property into an interrupt resource and set up
230 if ((sc->ires = gpio_alloc_intr_resource(dev, &sc->irid, RF_ACTIVE,
231 sc->gpin, edge)) == NULL) {
232 device_printf(dev, "Cannot allocate an IRQ for the GPIO\n");
237 err = bus_setup_intr(dev, sc->ires, INTR_TYPE_CLK | INTR_MPSAFE,
238 gpiopps_ifltr, gpiopps_ithrd, sc, &sc->ihandler);
240 device_printf(dev, "Unable to setup pps irq handler\n");
245 /* Create the RFC 2783 pps-api cdev. */
246 make_dev_args_init(&devargs);
247 devargs.mda_devsw = &pps_cdevsw;
248 devargs.mda_uid = UID_ROOT;
249 devargs.mda_gid = GID_WHEEL;
250 devargs.mda_mode = 0660;
251 devargs.mda_si_drv1 = sc;
252 err = make_dev_s(&devargs, &sc->pps_cdev, PPS_CDEV_NAME "%d",
253 device_get_unit(dev));
255 device_printf(dev, "Unable to create pps cdev\n");
264 gpiopps_fdt_probe(device_t dev)
267 if (!ofw_bus_status_okay(dev))
270 if (ofw_bus_search_compatible(dev, compat_data)->ocd_data != 0) {
271 device_set_desc(dev, "GPIO PPS");
272 return (BUS_PROBE_DEFAULT);
278 static device_method_t pps_fdt_methods[] = {
279 DEVMETHOD(device_probe, gpiopps_fdt_probe),
280 DEVMETHOD(device_attach, gpiopps_fdt_attach),
281 DEVMETHOD(device_detach, gpiopps_detach),
286 static driver_t pps_fdt_driver = {
289 sizeof(struct pps_softc),
292 DRIVER_MODULE(gpiopps, simplebus, pps_fdt_driver, pps_devclass, 0, 0);