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 #endif /* FDT */ 51 52 static devclass_t pps_devclass; 53 54 struct pps_softc { 55 device_t dev; 56 gpio_pin_t gpin; 57 void *ihandler; 58 struct resource *ires; 59 int irid; 60 struct cdev *pps_cdev; 61 struct pps_state pps_state; 62 struct mtx pps_mtx; 63 bool falling_edge; 64 }; 65 66 #define PPS_CDEV_NAME "gpiopps" 67 68 static int 69 gpiopps_open(struct cdev *dev, int flags, int fmt, struct thread *td) 70 { 71 struct pps_softc *sc = dev->si_drv1; 72 73 /* We can't be unloaded while open, so mark ourselves BUSY. */ 74 mtx_lock(&sc->pps_mtx); 75 if (device_get_state(sc->dev) < DS_BUSY) { 76 device_busy(sc->dev); 77 } 78 mtx_unlock(&sc->pps_mtx); 79 80 return 0; 81 } 82 83 static int 84 gpiopps_close(struct cdev *dev, int flags, int fmt, struct thread *td) 85 { 86 struct pps_softc *sc = dev->si_drv1; 87 88 /* 89 * Un-busy on last close. We rely on the vfs counting stuff to only call 90 * this routine on last-close, so we don't need any open-count logic. 91 */ 92 mtx_lock(&sc->pps_mtx); 93 device_unbusy(sc->dev); 94 mtx_unlock(&sc->pps_mtx); 95 96 return 0; 97 } 98 99 static int 100 gpiopps_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags, struct thread *td) 101 { 102 struct pps_softc *sc = dev->si_drv1; 103 int err; 104 105 /* Let the kernel do the heavy lifting for ioctl. */ 106 mtx_lock(&sc->pps_mtx); 107 err = pps_ioctl(cmd, data, &sc->pps_state); 108 mtx_unlock(&sc->pps_mtx); 109 110 return err; 111 } 112 113 static struct cdevsw pps_cdevsw = { 114 .d_version = D_VERSION, 115 .d_open = gpiopps_open, 116 .d_close = gpiopps_close, 117 .d_ioctl = gpiopps_ioctl, 118 .d_name = PPS_CDEV_NAME, 119 }; 120 121 static int 122 gpiopps_ifltr(void *arg) 123 { 124 struct pps_softc *sc = arg; 125 126 /* 127 * There is no locking here by design... The kernel cleverly captures 128 * the current time into an area of the pps_state structure which is 129 * written only by the pps_capture() routine and read only by the 130 * pps_event() routine. We don't need lock-based management of access 131 * to the capture area because we have time-based access management: we 132 * can't be reading and writing concurently because we can't be running 133 * both the threaded and filter handlers concurrently (because a new 134 * hardware interrupt can't happen until the threaded handler for the 135 * current interrupt exits, after which the system does the EOI that 136 * enables a new hardware interrupt). 137 */ 138 pps_capture(&sc->pps_state); 139 return (FILTER_SCHEDULE_THREAD); 140 } 141 142 static void 143 gpiopps_ithrd(void *arg) 144 { 145 struct pps_softc *sc = arg; 146 147 /* 148 * Go create a pps event from the data captured in the filter handler. 149 * 150 * Note that we DO need locking here, unlike the case with the filter 151 * handler. The pps_event() routine updates the non-capture part of the 152 * pps_state structure, and the ioctl() code could be accessing that 153 * data right now in a non-interrupt context, so we need an interlock. 154 */ 155 mtx_lock(&sc->pps_mtx); 156 pps_event(&sc->pps_state, PPS_CAPTUREASSERT); 157 mtx_unlock(&sc->pps_mtx); 158 } 159 160 static int 161 gpiopps_detach(device_t dev) 162 { 163 struct pps_softc *sc = device_get_softc(dev); 164 165 if (sc->pps_cdev != NULL) 166 destroy_dev(sc->pps_cdev); 167 if (sc->ihandler != NULL) 168 bus_teardown_intr(dev, sc->ires, sc->ihandler); 169 if (sc->ires != NULL) 170 bus_release_resource(dev, SYS_RES_IRQ, sc->irid, sc->ires); 171 if (sc->gpin != NULL) 172 gpiobus_release_pin(GPIO_GET_BUS(sc->gpin->dev), sc->gpin->pin); 173 return (0); 174 } 175 176 #ifdef FDT 177 static int 178 gpiopps_fdt_attach(device_t dev) 179 { 180 struct pps_softc *sc; 181 struct make_dev_args devargs; 182 phandle_t node; 183 uint32_t edge, pincaps; 184 int err; 185 186 sc = device_get_softc(dev); 187 sc->dev = dev; 188 189 mtx_init(&sc->pps_mtx, device_get_nameunit(dev), NULL, MTX_DEF); 190 191 /* Initialize the pps_state struct. */ 192 sc->pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR; 193 sc->pps_state.driver_abi = PPS_ABI_VERSION; 194 sc->pps_state.driver_mtx = &sc->pps_mtx; 195 pps_init_abi(&sc->pps_state); 196 197 /* Check which edge we're configured to capture (default is rising). */ 198 if (ofw_bus_has_prop(dev, "assert-falling-edge")) 199 edge = GPIO_INTR_EDGE_FALLING; 200 else 201 edge = GPIO_INTR_EDGE_RISING; 202 203 /* 204 * Look up the configured gpio pin and ensure it can be configured for 205 * the interrupt mode we need. 206 */ 207 node = ofw_bus_get_node(dev); 208 if ((err = gpio_pin_get_by_ofw_idx(dev, node, 0, &sc->gpin)) != 0) { 209 device_printf(dev, "Cannot obtain gpio pin\n"); 210 return (err); 211 } 212 device_printf(dev, "PPS input on %s pin %u\n", 213 device_get_nameunit(sc->gpin->dev), sc->gpin->pin); 214 215 if ((err = gpio_pin_getcaps(sc->gpin, &pincaps)) != 0) { 216 device_printf(dev, "Cannot query capabilities of gpio pin\n"); 217 gpiopps_detach(dev); 218 return (err); 219 } 220 if ((pincaps & edge) == 0) { 221 device_printf(dev, "Pin cannot be configured for the requested signal edge\n"); 222 gpiopps_detach(dev); 223 return (ENOTSUP); 224 } 225 226 /* 227 * Transform our 'gpios' property into an interrupt resource and set up 228 * the interrupt. 229 */ 230 if ((sc->ires = gpio_alloc_intr_resource(dev, &sc->irid, RF_ACTIVE, 231 sc->gpin, edge)) == NULL) { 232 device_printf(dev, "Cannot allocate an IRQ for the GPIO\n"); 233 gpiopps_detach(dev); 234 return (err); 235 } 236 237 err = bus_setup_intr(dev, sc->ires, INTR_TYPE_CLK | INTR_MPSAFE, 238 gpiopps_ifltr, gpiopps_ithrd, sc, &sc->ihandler); 239 if (err != 0) { 240 device_printf(dev, "Unable to setup pps irq handler\n"); 241 gpiopps_detach(dev); 242 return (err); 243 } 244 245 /* Create the RFC 2783 pps-api cdev. */ 246 make_dev_args_init(&devargs); 247 devargs.mda_devsw = &pps_cdevsw; 248 devargs.mda_uid = UID_ROOT; 249 devargs.mda_gid = GID_WHEEL; 250 devargs.mda_mode = 0660; 251 devargs.mda_si_drv1 = sc; 252 err = make_dev_s(&devargs, &sc->pps_cdev, PPS_CDEV_NAME "%d", 253 device_get_unit(dev)); 254 if (err != 0) { 255 device_printf(dev, "Unable to create pps cdev\n"); 256 gpiopps_detach(dev); 257 return (err); 258 } 259 260 return (0); 261 } 262 263 static int 264 gpiopps_fdt_probe(device_t dev) 265 { 266 267 if (!ofw_bus_status_okay(dev)) 268 return (ENXIO); 269 270 if (ofw_bus_search_compatible(dev, compat_data)->ocd_data != 0) { 271 device_set_desc(dev, "GPIO PPS"); 272 return (BUS_PROBE_DEFAULT); 273 } 274 275 return (ENXIO); 276 } 277 278 static device_method_t pps_fdt_methods[] = { 279 DEVMETHOD(device_probe, gpiopps_fdt_probe), 280 DEVMETHOD(device_attach, gpiopps_fdt_attach), 281 DEVMETHOD(device_detach, gpiopps_detach), 282 283 DEVMETHOD_END 284 }; 285 286 static driver_t pps_fdt_driver = { 287 "gpiopps", 288 pps_fdt_methods, 289 sizeof(struct pps_softc), 290 }; 291 292 DRIVER_MODULE(gpiopps, simplebus, pps_fdt_driver, pps_devclass, 0, 0); 293 294 #endif /* FDT */ 295