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 if (device_get_state(sc->dev) < DS_BUSY) { 77 device_busy(sc->dev); 78 } 79 mtx_unlock(&sc->pps_mtx); 80 81 return 0; 82 } 83 84 static int 85 gpiopps_close(struct cdev *dev, int flags, int fmt, struct thread *td) 86 { 87 struct pps_softc *sc = dev->si_drv1; 88 89 /* 90 * Un-busy on last close. We rely on the vfs counting stuff to only call 91 * this routine on last-close, so we don't need any open-count logic. 92 */ 93 mtx_lock(&sc->pps_mtx); 94 device_unbusy(sc->dev); 95 mtx_unlock(&sc->pps_mtx); 96 97 return 0; 98 } 99 100 static int 101 gpiopps_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags, struct thread *td) 102 { 103 struct pps_softc *sc = dev->si_drv1; 104 int err; 105 106 /* Let the kernel do the heavy lifting for ioctl. */ 107 mtx_lock(&sc->pps_mtx); 108 err = pps_ioctl(cmd, data, &sc->pps_state); 109 mtx_unlock(&sc->pps_mtx); 110 111 return err; 112 } 113 114 static struct cdevsw pps_cdevsw = { 115 .d_version = D_VERSION, 116 .d_open = gpiopps_open, 117 .d_close = gpiopps_close, 118 .d_ioctl = gpiopps_ioctl, 119 .d_name = PPS_CDEV_NAME, 120 }; 121 122 static int 123 gpiopps_ifltr(void *arg) 124 { 125 struct pps_softc *sc = arg; 126 127 /* 128 * There is no locking here by design... The kernel cleverly captures 129 * the current time into an area of the pps_state structure which is 130 * written only by the pps_capture() routine and read only by the 131 * pps_event() routine. We don't need lock-based management of access 132 * to the capture area because we have time-based access management: we 133 * can't be reading and writing concurently because we can't be running 134 * both the threaded and filter handlers concurrently (because a new 135 * hardware interrupt can't happen until the threaded handler for the 136 * current interrupt exits, after which the system does the EOI that 137 * enables a new hardware interrupt). 138 */ 139 pps_capture(&sc->pps_state); 140 return (FILTER_SCHEDULE_THREAD); 141 } 142 143 static void 144 gpiopps_ithrd(void *arg) 145 { 146 struct pps_softc *sc = arg; 147 148 /* 149 * Go create a pps event from the data captured in the filter handler. 150 * 151 * Note that we DO need locking here, unlike the case with the filter 152 * handler. The pps_event() routine updates the non-capture part of the 153 * pps_state structure, and the ioctl() code could be accessing that 154 * data right now in a non-interrupt context, so we need an interlock. 155 */ 156 mtx_lock(&sc->pps_mtx); 157 pps_event(&sc->pps_state, PPS_CAPTUREASSERT); 158 mtx_unlock(&sc->pps_mtx); 159 } 160 161 static int 162 gpiopps_detach(device_t dev) 163 { 164 struct pps_softc *sc = device_get_softc(dev); 165 166 if (sc->pps_cdev != NULL) 167 destroy_dev(sc->pps_cdev); 168 if (sc->ihandler != NULL) 169 bus_teardown_intr(dev, sc->ires, sc->ihandler); 170 if (sc->ires != NULL) 171 bus_release_resource(dev, SYS_RES_IRQ, sc->irid, sc->ires); 172 if (sc->gpin != NULL) 173 gpiobus_release_pin(GPIO_GET_BUS(sc->gpin->dev), sc->gpin->pin); 174 return (0); 175 } 176 177 #ifdef FDT 178 static int 179 gpiopps_fdt_attach(device_t dev) 180 { 181 struct pps_softc *sc; 182 struct make_dev_args devargs; 183 phandle_t node; 184 uint32_t edge, pincaps; 185 int err; 186 187 sc = device_get_softc(dev); 188 sc->dev = dev; 189 190 mtx_init(&sc->pps_mtx, device_get_nameunit(dev), NULL, MTX_DEF); 191 192 /* Initialize the pps_state struct. */ 193 sc->pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR; 194 sc->pps_state.driver_abi = PPS_ABI_VERSION; 195 sc->pps_state.driver_mtx = &sc->pps_mtx; 196 pps_init_abi(&sc->pps_state); 197 198 /* Check which edge we're configured to capture (default is rising). */ 199 if (ofw_bus_has_prop(dev, "assert-falling-edge")) 200 edge = GPIO_INTR_EDGE_FALLING; 201 else 202 edge = GPIO_INTR_EDGE_RISING; 203 204 /* 205 * Look up the configured gpio pin and ensure it can be configured for 206 * the interrupt mode we need. 207 */ 208 node = ofw_bus_get_node(dev); 209 if ((err = gpio_pin_get_by_ofw_idx(dev, node, 0, &sc->gpin)) != 0) { 210 device_printf(dev, "Cannot obtain gpio pin\n"); 211 return (err); 212 } 213 device_printf(dev, "PPS input on %s pin %u\n", 214 device_get_nameunit(sc->gpin->dev), sc->gpin->pin); 215 216 if ((err = gpio_pin_getcaps(sc->gpin, &pincaps)) != 0) { 217 device_printf(dev, "Cannot query capabilities of gpio pin\n"); 218 gpiopps_detach(dev); 219 return (err); 220 } 221 if ((pincaps & edge) == 0) { 222 device_printf(dev, "Pin cannot be configured for the requested signal edge\n"); 223 gpiopps_detach(dev); 224 return (ENOTSUP); 225 } 226 227 /* 228 * Transform our 'gpios' property into an interrupt resource and set up 229 * the interrupt. 230 */ 231 if ((sc->ires = gpio_alloc_intr_resource(dev, &sc->irid, RF_ACTIVE, 232 sc->gpin, edge)) == NULL) { 233 device_printf(dev, "Cannot allocate an IRQ for the GPIO\n"); 234 gpiopps_detach(dev); 235 return (err); 236 } 237 238 err = bus_setup_intr(dev, sc->ires, INTR_TYPE_CLK | INTR_MPSAFE, 239 gpiopps_ifltr, gpiopps_ithrd, sc, &sc->ihandler); 240 if (err != 0) { 241 device_printf(dev, "Unable to setup pps irq handler\n"); 242 gpiopps_detach(dev); 243 return (err); 244 } 245 246 /* Create the RFC 2783 pps-api cdev. */ 247 make_dev_args_init(&devargs); 248 devargs.mda_devsw = &pps_cdevsw; 249 devargs.mda_uid = UID_ROOT; 250 devargs.mda_gid = GID_WHEEL; 251 devargs.mda_mode = 0660; 252 devargs.mda_si_drv1 = sc; 253 err = make_dev_s(&devargs, &sc->pps_cdev, PPS_CDEV_NAME "%d", 254 device_get_unit(dev)); 255 if (err != 0) { 256 device_printf(dev, "Unable to create pps cdev\n"); 257 gpiopps_detach(dev); 258 return (err); 259 } 260 261 return (0); 262 } 263 264 static int 265 gpiopps_fdt_probe(device_t dev) 266 { 267 268 if (!ofw_bus_status_okay(dev)) 269 return (ENXIO); 270 271 if (ofw_bus_search_compatible(dev, compat_data)->ocd_data != 0) { 272 device_set_desc(dev, "GPIO PPS"); 273 return (BUS_PROBE_DEFAULT); 274 } 275 276 return (ENXIO); 277 } 278 279 static device_method_t pps_fdt_methods[] = { 280 DEVMETHOD(device_probe, gpiopps_fdt_probe), 281 DEVMETHOD(device_attach, gpiopps_fdt_attach), 282 DEVMETHOD(device_detach, gpiopps_detach), 283 284 DEVMETHOD_END 285 }; 286 287 static driver_t pps_fdt_driver = { 288 "gpiopps", 289 pps_fdt_methods, 290 sizeof(struct pps_softc), 291 }; 292 293 DRIVER_MODULE(gpiopps, simplebus, pps_fdt_driver, pps_devclass, 0, 0); 294 295 #endif /* FDT */ 296