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 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 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 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 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 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 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 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 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