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/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/gpio.h> 32 #include <sys/kernel.h> 33 #include <sys/lock.h> 34 #include <sys/module.h> 35 #include <sys/bus.h> 36 #include <sys/conf.h> 37 #include <sys/timepps.h> 38 39 #include <dev/gpio/gpiobusvar.h> 40 41 #include "opt_platform.h" 42 43 #ifdef FDT 44 #include <dev/ofw/ofw_bus.h> 45 46 static struct ofw_compat_data compat_data[] = { 47 {"pps-gpio", 1}, 48 {NULL, 0} 49 }; 50 SIMPLEBUS_PNP_INFO(compat_data); 51 #endif /* FDT */ 52 53 static devclass_t pps_devclass; 54 55 struct pps_softc { 56 device_t dev; 57 gpio_pin_t gpin; 58 void *ihandler; 59 struct resource *ires; 60 int irid; 61 struct cdev *pps_cdev; 62 struct pps_state pps_state; 63 struct mtx pps_mtx; 64 bool falling_edge; 65 }; 66 67 #define PPS_CDEV_NAME "gpiopps" 68 69 static int 70 gpiopps_open(struct cdev *dev, int flags, int fmt, struct thread *td) 71 { 72 struct pps_softc *sc = dev->si_drv1; 73 74 /* We can't be unloaded while open, so mark ourselves BUSY. */ 75 mtx_lock(&sc->pps_mtx); 76 device_busy(sc->dev); 77 mtx_unlock(&sc->pps_mtx); 78 79 return 0; 80 } 81 82 static int 83 gpiopps_close(struct cdev *dev, int flags, int fmt, struct thread *td) 84 { 85 struct pps_softc *sc = dev->si_drv1; 86 87 mtx_lock(&sc->pps_mtx); 88 device_unbusy(sc->dev); 89 mtx_unlock(&sc->pps_mtx); 90 91 return 0; 92 } 93 94 static int 95 gpiopps_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags, struct thread *td) 96 { 97 struct pps_softc *sc = dev->si_drv1; 98 int err; 99 100 /* Let the kernel do the heavy lifting for ioctl. */ 101 mtx_lock(&sc->pps_mtx); 102 err = pps_ioctl(cmd, data, &sc->pps_state); 103 mtx_unlock(&sc->pps_mtx); 104 105 return err; 106 } 107 108 static struct cdevsw pps_cdevsw = { 109 .d_version = D_VERSION, 110 .d_flags = D_TRACKCLOSE, 111 .d_open = gpiopps_open, 112 .d_close = gpiopps_close, 113 .d_ioctl = gpiopps_ioctl, 114 .d_name = PPS_CDEV_NAME, 115 }; 116 117 static int 118 gpiopps_ifltr(void *arg) 119 { 120 struct pps_softc *sc = arg; 121 122 /* 123 * There is no locking here by design... The kernel cleverly captures 124 * the current time into an area of the pps_state structure which is 125 * written only by the pps_capture() routine and read only by the 126 * pps_event() routine. We don't need lock-based management of access 127 * to the capture area because we have time-based access management: we 128 * can't be reading and writing concurrently because we can't be running 129 * both the threaded and filter handlers concurrently (because a new 130 * hardware interrupt can't happen until the threaded handler for the 131 * current interrupt exits, after which the system does the EOI that 132 * enables a new hardware interrupt). 133 */ 134 pps_capture(&sc->pps_state); 135 return (FILTER_SCHEDULE_THREAD); 136 } 137 138 static void 139 gpiopps_ithrd(void *arg) 140 { 141 struct pps_softc *sc = arg; 142 143 /* 144 * Go create a pps event from the data captured in the filter handler. 145 * 146 * Note that we DO need locking here, unlike the case with the filter 147 * handler. The pps_event() routine updates the non-capture part of the 148 * pps_state structure, and the ioctl() code could be accessing that 149 * data right now in a non-interrupt context, so we need an interlock. 150 */ 151 mtx_lock(&sc->pps_mtx); 152 pps_event(&sc->pps_state, PPS_CAPTUREASSERT); 153 mtx_unlock(&sc->pps_mtx); 154 } 155 156 static int 157 gpiopps_detach(device_t dev) 158 { 159 struct pps_softc *sc = device_get_softc(dev); 160 161 if (sc->pps_cdev != NULL) 162 destroy_dev(sc->pps_cdev); 163 if (sc->ihandler != NULL) 164 bus_teardown_intr(dev, sc->ires, sc->ihandler); 165 if (sc->ires != NULL) 166 bus_release_resource(dev, SYS_RES_IRQ, sc->irid, sc->ires); 167 if (sc->gpin != NULL) 168 gpiobus_release_pin(GPIO_GET_BUS(sc->gpin->dev), sc->gpin->pin); 169 return (0); 170 } 171 172 #ifdef FDT 173 static int 174 gpiopps_fdt_attach(device_t dev) 175 { 176 struct pps_softc *sc; 177 struct make_dev_args devargs; 178 phandle_t node; 179 uint32_t edge, pincaps; 180 int err; 181 182 sc = device_get_softc(dev); 183 sc->dev = dev; 184 185 mtx_init(&sc->pps_mtx, device_get_nameunit(dev), NULL, MTX_DEF); 186 187 /* Initialize the pps_state struct. */ 188 sc->pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR; 189 sc->pps_state.driver_abi = PPS_ABI_VERSION; 190 sc->pps_state.driver_mtx = &sc->pps_mtx; 191 pps_init_abi(&sc->pps_state); 192 193 /* Check which edge we're configured to capture (default is rising). */ 194 if (ofw_bus_has_prop(dev, "assert-falling-edge")) 195 edge = GPIO_INTR_EDGE_FALLING; 196 else 197 edge = GPIO_INTR_EDGE_RISING; 198 199 /* 200 * Look up the configured gpio pin and ensure it can be configured for 201 * the interrupt mode we need. 202 */ 203 node = ofw_bus_get_node(dev); 204 if ((err = gpio_pin_get_by_ofw_idx(dev, node, 0, &sc->gpin)) != 0) { 205 device_printf(dev, "Cannot obtain gpio pin\n"); 206 return (err); 207 } 208 device_printf(dev, "PPS input on %s pin %u\n", 209 device_get_nameunit(sc->gpin->dev), sc->gpin->pin); 210 211 if ((err = gpio_pin_getcaps(sc->gpin, &pincaps)) != 0) { 212 device_printf(dev, "Cannot query capabilities of gpio pin\n"); 213 gpiopps_detach(dev); 214 return (err); 215 } 216 if ((pincaps & edge) == 0) { 217 device_printf(dev, "Pin cannot be configured for the requested signal edge\n"); 218 gpiopps_detach(dev); 219 return (ENOTSUP); 220 } 221 222 /* 223 * Transform our 'gpios' property into an interrupt resource and set up 224 * the interrupt. 225 */ 226 if ((sc->ires = gpio_alloc_intr_resource(dev, &sc->irid, RF_ACTIVE, 227 sc->gpin, edge)) == NULL) { 228 device_printf(dev, "Cannot allocate an IRQ for the GPIO\n"); 229 gpiopps_detach(dev); 230 return (err); 231 } 232 233 err = bus_setup_intr(dev, sc->ires, INTR_TYPE_CLK | INTR_MPSAFE, 234 gpiopps_ifltr, gpiopps_ithrd, sc, &sc->ihandler); 235 if (err != 0) { 236 device_printf(dev, "Unable to setup pps irq handler\n"); 237 gpiopps_detach(dev); 238 return (err); 239 } 240 241 /* Create the RFC 2783 pps-api cdev. */ 242 make_dev_args_init(&devargs); 243 devargs.mda_devsw = &pps_cdevsw; 244 devargs.mda_uid = UID_ROOT; 245 devargs.mda_gid = GID_WHEEL; 246 devargs.mda_mode = 0660; 247 devargs.mda_si_drv1 = sc; 248 err = make_dev_s(&devargs, &sc->pps_cdev, PPS_CDEV_NAME "%d", 249 device_get_unit(dev)); 250 if (err != 0) { 251 device_printf(dev, "Unable to create pps cdev\n"); 252 gpiopps_detach(dev); 253 return (err); 254 } 255 256 return (0); 257 } 258 259 static int 260 gpiopps_fdt_probe(device_t dev) 261 { 262 263 if (!ofw_bus_status_okay(dev)) 264 return (ENXIO); 265 266 if (ofw_bus_search_compatible(dev, compat_data)->ocd_data != 0) { 267 device_set_desc(dev, "GPIO PPS"); 268 return (BUS_PROBE_DEFAULT); 269 } 270 271 return (ENXIO); 272 } 273 274 static device_method_t pps_fdt_methods[] = { 275 DEVMETHOD(device_probe, gpiopps_fdt_probe), 276 DEVMETHOD(device_attach, gpiopps_fdt_attach), 277 DEVMETHOD(device_detach, gpiopps_detach), 278 279 DEVMETHOD_END 280 }; 281 282 static driver_t pps_fdt_driver = { 283 "gpiopps", 284 pps_fdt_methods, 285 sizeof(struct pps_softc), 286 }; 287 288 DRIVER_MODULE(gpiopps, simplebus, pps_fdt_driver, pps_devclass, 0, 0); 289 290 #endif /* FDT */ 291