1 /*-
2 * Copyright (c) 2016 Ian Lepore <ian@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
13 *
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
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/param.h>
28 #include <sys/gpio.h>
29 #include <sys/kernel.h>
30 #include <sys/lock.h>
31 #include <sys/module.h>
32 #include <sys/bus.h>
33 #include <sys/conf.h>
34 #include <sys/timepps.h>
35
36 #include <dev/gpio/gpiobusvar.h>
37
38 #include "opt_platform.h"
39
40 #ifdef FDT
41 #include <dev/ofw/ofw_bus.h>
42
43 static struct ofw_compat_data compat_data[] = {
44 {"pps-gpio", 1},
45 {NULL, 0}
46 };
47 SIMPLEBUS_PNP_INFO(compat_data);
48 #endif /* FDT */
49
50 struct pps_softc {
51 device_t dev;
52 gpio_pin_t gpin;
53 void *ihandler;
54 struct resource *ires;
55 int irid;
56 struct cdev *pps_cdev;
57 struct pps_state pps_state;
58 struct mtx pps_mtx;
59 bool falling_edge;
60 };
61
62 #define PPS_CDEV_NAME "gpiopps"
63
64 static int
gpiopps_open(struct cdev * dev,int flags,int fmt,struct thread * td)65 gpiopps_open(struct cdev *dev, int flags, int fmt, struct thread *td)
66 {
67 struct pps_softc *sc = dev->si_drv1;
68
69 /* We can't be unloaded while open, so mark ourselves BUSY. */
70 mtx_lock(&sc->pps_mtx);
71 device_busy(sc->dev);
72 mtx_unlock(&sc->pps_mtx);
73
74 return 0;
75 }
76
77 static int
gpiopps_close(struct cdev * dev,int flags,int fmt,struct thread * td)78 gpiopps_close(struct cdev *dev, int flags, int fmt, struct thread *td)
79 {
80 struct pps_softc *sc = dev->si_drv1;
81
82 mtx_lock(&sc->pps_mtx);
83 device_unbusy(sc->dev);
84 mtx_unlock(&sc->pps_mtx);
85
86 return 0;
87 }
88
89 static int
gpiopps_ioctl(struct cdev * dev,u_long cmd,caddr_t data,int flags,struct thread * td)90 gpiopps_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags, struct thread *td)
91 {
92 struct pps_softc *sc = dev->si_drv1;
93 int err;
94
95 /* Let the kernel do the heavy lifting for ioctl. */
96 mtx_lock(&sc->pps_mtx);
97 err = pps_ioctl(cmd, data, &sc->pps_state);
98 mtx_unlock(&sc->pps_mtx);
99
100 return err;
101 }
102
103 static struct cdevsw pps_cdevsw = {
104 .d_version = D_VERSION,
105 .d_flags = D_TRACKCLOSE,
106 .d_open = gpiopps_open,
107 .d_close = gpiopps_close,
108 .d_ioctl = gpiopps_ioctl,
109 .d_name = PPS_CDEV_NAME,
110 };
111
112 static int
gpiopps_ifltr(void * arg)113 gpiopps_ifltr(void *arg)
114 {
115 struct pps_softc *sc = arg;
116
117 /*
118 * There is no locking here by design... The kernel cleverly captures
119 * the current time into an area of the pps_state structure which is
120 * written only by the pps_capture() routine and read only by the
121 * pps_event() routine. We don't need lock-based management of access
122 * to the capture area because we have time-based access management: we
123 * can't be reading and writing concurrently because we can't be running
124 * both the threaded and filter handlers concurrently (because a new
125 * hardware interrupt can't happen until the threaded handler for the
126 * current interrupt exits, after which the system does the EOI that
127 * enables a new hardware interrupt).
128 */
129 pps_capture(&sc->pps_state);
130 return (FILTER_SCHEDULE_THREAD);
131 }
132
133 static void
gpiopps_ithrd(void * arg)134 gpiopps_ithrd(void *arg)
135 {
136 struct pps_softc *sc = arg;
137
138 /*
139 * Go create a pps event from the data captured in the filter handler.
140 *
141 * Note that we DO need locking here, unlike the case with the filter
142 * handler. The pps_event() routine updates the non-capture part of the
143 * pps_state structure, and the ioctl() code could be accessing that
144 * data right now in a non-interrupt context, so we need an interlock.
145 */
146 mtx_lock(&sc->pps_mtx);
147 pps_event(&sc->pps_state, PPS_CAPTUREASSERT);
148 mtx_unlock(&sc->pps_mtx);
149 }
150
151 static int
gpiopps_detach(device_t dev)152 gpiopps_detach(device_t dev)
153 {
154 struct pps_softc *sc = device_get_softc(dev);
155
156 if (sc->pps_cdev != NULL)
157 destroy_dev(sc->pps_cdev);
158 if (sc->ihandler != NULL)
159 bus_teardown_intr(dev, sc->ires, sc->ihandler);
160 if (sc->ires != NULL)
161 bus_release_resource(dev, SYS_RES_IRQ, sc->irid, sc->ires);
162 if (sc->gpin != NULL)
163 gpiobus_release_pin(GPIO_GET_BUS(sc->gpin->dev), sc->gpin->pin);
164 return (0);
165 }
166
167 #ifdef FDT
168 static int
gpiopps_fdt_attach(device_t dev)169 gpiopps_fdt_attach(device_t dev)
170 {
171 struct pps_softc *sc;
172 struct make_dev_args devargs;
173 phandle_t node;
174 uint32_t edge, pincaps;
175 int err;
176
177 sc = device_get_softc(dev);
178 sc->dev = dev;
179
180 mtx_init(&sc->pps_mtx, device_get_nameunit(dev), NULL, MTX_DEF);
181
182 /* Initialize the pps_state struct. */
183 sc->pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
184 sc->pps_state.driver_abi = PPS_ABI_VERSION;
185 sc->pps_state.driver_mtx = &sc->pps_mtx;
186 pps_init_abi(&sc->pps_state);
187
188 /* Check which edge we're configured to capture (default is rising). */
189 if (ofw_bus_has_prop(dev, "assert-falling-edge"))
190 edge = GPIO_INTR_EDGE_FALLING;
191 else
192 edge = GPIO_INTR_EDGE_RISING;
193
194 /*
195 * Look up the configured gpio pin and ensure it can be configured for
196 * the interrupt mode we need.
197 */
198 node = ofw_bus_get_node(dev);
199 if ((err = gpio_pin_get_by_ofw_idx(dev, node, 0, &sc->gpin)) != 0) {
200 device_printf(dev, "Cannot obtain gpio pin\n");
201 return (err);
202 }
203 device_printf(dev, "PPS input on %s pin %u\n",
204 device_get_nameunit(sc->gpin->dev), sc->gpin->pin);
205
206 if ((err = gpio_pin_getcaps(sc->gpin, &pincaps)) != 0) {
207 device_printf(dev, "Cannot query capabilities of gpio pin\n");
208 gpiopps_detach(dev);
209 return (err);
210 }
211 if ((pincaps & edge) == 0) {
212 device_printf(dev, "Pin cannot be configured for the requested signal edge\n");
213 gpiopps_detach(dev);
214 return (ENOTSUP);
215 }
216
217 /*
218 * Transform our 'gpios' property into an interrupt resource and set up
219 * the interrupt.
220 */
221 if ((sc->ires = gpio_alloc_intr_resource(dev, &sc->irid, RF_ACTIVE,
222 sc->gpin, edge)) == NULL) {
223 device_printf(dev, "Cannot allocate an IRQ for the GPIO\n");
224 gpiopps_detach(dev);
225 return (err);
226 }
227
228 err = bus_setup_intr(dev, sc->ires, INTR_TYPE_CLK | INTR_MPSAFE,
229 gpiopps_ifltr, gpiopps_ithrd, sc, &sc->ihandler);
230 if (err != 0) {
231 device_printf(dev, "Unable to setup pps irq handler\n");
232 gpiopps_detach(dev);
233 return (err);
234 }
235
236 /* Create the RFC 2783 pps-api cdev. */
237 make_dev_args_init(&devargs);
238 devargs.mda_devsw = &pps_cdevsw;
239 devargs.mda_uid = UID_ROOT;
240 devargs.mda_gid = GID_WHEEL;
241 devargs.mda_mode = 0660;
242 devargs.mda_si_drv1 = sc;
243 err = make_dev_s(&devargs, &sc->pps_cdev, PPS_CDEV_NAME "%d",
244 device_get_unit(dev));
245 if (err != 0) {
246 device_printf(dev, "Unable to create pps cdev\n");
247 gpiopps_detach(dev);
248 return (err);
249 }
250
251 return (0);
252 }
253
254 static int
gpiopps_fdt_probe(device_t dev)255 gpiopps_fdt_probe(device_t dev)
256 {
257
258 if (!ofw_bus_status_okay(dev))
259 return (ENXIO);
260
261 if (ofw_bus_search_compatible(dev, compat_data)->ocd_data != 0) {
262 device_set_desc(dev, "GPIO PPS");
263 return (BUS_PROBE_DEFAULT);
264 }
265
266 return (ENXIO);
267 }
268
269 static device_method_t pps_fdt_methods[] = {
270 DEVMETHOD(device_probe, gpiopps_fdt_probe),
271 DEVMETHOD(device_attach, gpiopps_fdt_attach),
272 DEVMETHOD(device_detach, gpiopps_detach),
273
274 DEVMETHOD_END
275 };
276
277 static driver_t pps_fdt_driver = {
278 "gpiopps",
279 pps_fdt_methods,
280 sizeof(struct pps_softc),
281 };
282
283 DRIVER_MODULE(gpiopps, simplebus, pps_fdt_driver, 0, 0);
284
285 #endif /* FDT */
286