1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2020 Jessica Clarke <jrtc27@FreeBSD.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 /* 29 * RTC for the goldfish virtual hardware platform implemented in QEMU, 30 * initially for Android but now also used for RISC-V's virt machine. 31 * 32 * https://android.googlesource.com/platform/external/qemu/+/master/docs/GOLDFISH-VIRTUAL-HARDWARE.TXT 33 */ 34 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/bus.h> 41 #include <sys/clock.h> 42 #include <sys/kernel.h> 43 #include <sys/lock.h> 44 #include <sys/module.h> 45 #include <sys/mutex.h> 46 #include <sys/types.h> 47 48 #include <dev/ofw/ofw_bus.h> 49 #include <dev/ofw/ofw_bus_subr.h> 50 51 #include <machine/bus.h> 52 #include <machine/resource.h> 53 #include <sys/rman.h> 54 55 #include "clock_if.h" 56 57 #define GOLDFISH_RTC_TIME_LOW 0x00 58 #define GOLDFISH_RTC_TIME_HIGH 0x04 59 60 struct goldfish_rtc_softc { 61 struct resource *res; 62 int rid; 63 struct mtx mtx; 64 }; 65 66 static int 67 goldfish_rtc_probe(device_t dev) 68 { 69 70 if (!ofw_bus_status_okay(dev)) 71 return (ENXIO); 72 73 if (ofw_bus_is_compatible(dev, "google,goldfish-rtc")) { 74 device_set_desc(dev, "Goldfish RTC"); 75 return (BUS_PROBE_DEFAULT); 76 } 77 78 return (ENXIO); 79 } 80 81 static int 82 goldfish_rtc_attach(device_t dev) 83 { 84 struct goldfish_rtc_softc *sc; 85 86 sc = device_get_softc(dev); 87 88 sc->rid = 0; 89 sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->rid, 90 RF_ACTIVE); 91 if (sc->res == NULL) { 92 device_printf(dev, "could not allocate resource\n"); 93 return (ENXIO); 94 } 95 96 mtx_init(&sc->mtx, device_get_nameunit(dev), NULL, MTX_DEF); 97 98 /* 99 * Register as a system realtime clock with 1 second resolution. 100 */ 101 clock_register_flags(dev, 1000000, CLOCKF_SETTIME_NO_ADJ); 102 clock_schedule(dev, 1); 103 104 return (0); 105 } 106 107 static int 108 goldfish_rtc_detach(device_t dev) 109 { 110 struct goldfish_rtc_softc *sc; 111 112 sc = device_get_softc(dev); 113 114 clock_unregister(dev); 115 mtx_destroy(&sc->mtx); 116 bus_release_resource(dev, SYS_RES_MEMORY, sc->rid, sc->res); 117 118 return (0); 119 } 120 121 static int 122 goldfish_rtc_gettime(device_t dev, struct timespec *ts) 123 { 124 struct goldfish_rtc_softc *sc; 125 uint64_t low, high, nsec; 126 127 sc = device_get_softc(dev); 128 129 /* 130 * Reading TIME_HIGH is defined in the documentation to give the high 131 * 32 bits corresponding to the last TIME_LOW read, so must be done in 132 * that order, but means we have atomicity guaranteed. 133 */ 134 mtx_lock(&sc->mtx); 135 low = bus_read_4(sc->res, GOLDFISH_RTC_TIME_LOW); 136 high = bus_read_4(sc->res, GOLDFISH_RTC_TIME_HIGH); 137 mtx_unlock(&sc->mtx); 138 139 nsec = (high << 32) | low; 140 ts->tv_sec = nsec / 1000000000; 141 ts->tv_nsec = nsec % 1000000000; 142 143 return (0); 144 } 145 146 static int 147 goldfish_rtc_settime(device_t dev, struct timespec *ts) 148 { 149 struct goldfish_rtc_softc *sc; 150 uint64_t nsec; 151 152 sc = device_get_softc(dev); 153 154 /* 155 * We request a timespec with no resolution-adjustment. That also 156 * disables utc adjustment, so apply that ourselves. 157 */ 158 ts->tv_sec -= utc_offset(); 159 nsec = (uint64_t)ts->tv_sec * 1000000000 + ts->tv_nsec; 160 161 mtx_lock(&sc->mtx); 162 bus_write_4(sc->res, GOLDFISH_RTC_TIME_HIGH, nsec >> 32); 163 bus_write_4(sc->res, GOLDFISH_RTC_TIME_LOW, nsec); 164 mtx_unlock(&sc->mtx); 165 166 return (0); 167 } 168 169 static device_method_t goldfish_rtc_methods[] = { 170 /* Device interface */ 171 DEVMETHOD(device_probe, goldfish_rtc_probe), 172 DEVMETHOD(device_attach, goldfish_rtc_attach), 173 DEVMETHOD(device_detach, goldfish_rtc_detach), 174 175 /* Clock interface */ 176 DEVMETHOD(clock_gettime, goldfish_rtc_gettime), 177 DEVMETHOD(clock_settime, goldfish_rtc_settime), 178 179 DEVMETHOD_END, 180 }; 181 182 DEFINE_CLASS_0(goldfish_rtc, goldfish_rtc_driver, goldfish_rtc_methods, 183 sizeof(struct goldfish_rtc_softc)); 184 185 DRIVER_MODULE(goldfish_rtc, simplebus, goldfish_rtc_driver, NULL, NULL); 186