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