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