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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2020 Jessica Clarke <jrtc27@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* RTC for the goldfish virtual hardware platform implemented in QEMU,
* initially for Android but now also used for RISC-V's virt machine.
*
* https://android.googlesource.com/platform/external/qemu/+/master/docs/GOLDFISH-VIRTUAL-HARDWARE.TXT
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/clock.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/types.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <machine/bus.h>
#include <machine/resource.h>
#include <sys/rman.h>
#include "clock_if.h"
#define GOLDFISH_RTC_TIME_LOW 0x00
#define GOLDFISH_RTC_TIME_HIGH 0x04
struct goldfish_rtc_softc {
struct resource *res;
int rid;
struct mtx mtx;
};
static int
goldfish_rtc_probe(device_t dev)
{
if (!ofw_bus_status_okay(dev))
return (ENXIO);
if (ofw_bus_is_compatible(dev, "google,goldfish-rtc")) {
device_set_desc(dev, "Goldfish RTC");
return (BUS_PROBE_DEFAULT);
}
return (ENXIO);
}
static int
goldfish_rtc_attach(device_t dev)
{
struct goldfish_rtc_softc *sc;
sc = device_get_softc(dev);
sc->rid = 0;
sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->rid,
RF_ACTIVE);
if (sc->res == NULL) {
device_printf(dev, "could not allocate resource\n");
return (ENXIO);
}
mtx_init(&sc->mtx, device_get_nameunit(dev), NULL, MTX_DEF);
/*
* Register as a system realtime clock with 1 second resolution.
*/
clock_register_flags(dev, 1000000, CLOCKF_SETTIME_NO_ADJ);
clock_schedule(dev, 1);
return (0);
}
static int
goldfish_rtc_detach(device_t dev)
{
struct goldfish_rtc_softc *sc;
sc = device_get_softc(dev);
clock_unregister(dev);
mtx_destroy(&sc->mtx);
bus_release_resource(dev, SYS_RES_MEMORY, sc->rid, sc->res);
return (0);
}
static int
goldfish_rtc_gettime(device_t dev, struct timespec *ts)
{
struct goldfish_rtc_softc *sc;
uint64_t low, high, nsec;
sc = device_get_softc(dev);
/*
* Reading TIME_HIGH is defined in the documentation to give the high
* 32 bits corresponding to the last TIME_LOW read, so must be done in
* that order, but means we have atomicity guaranteed.
*/
mtx_lock(&sc->mtx);
low = bus_read_4(sc->res, GOLDFISH_RTC_TIME_LOW);
high = bus_read_4(sc->res, GOLDFISH_RTC_TIME_HIGH);
mtx_unlock(&sc->mtx);
nsec = (high << 32) | low;
ts->tv_sec = nsec / 1000000000;
ts->tv_nsec = nsec % 1000000000;
return (0);
}
static int
goldfish_rtc_settime(device_t dev, struct timespec *ts)
{
struct goldfish_rtc_softc *sc;
uint64_t nsec;
sc = device_get_softc(dev);
nsec = (uint64_t)ts->tv_sec * 1000000000 + ts->tv_nsec;
mtx_lock(&sc->mtx);
bus_write_4(sc->res, GOLDFISH_RTC_TIME_HIGH, nsec >> 32);
bus_write_4(sc->res, GOLDFISH_RTC_TIME_LOW, nsec);
mtx_unlock(&sc->mtx);
return (0);
}
static device_method_t goldfish_rtc_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, goldfish_rtc_probe),
DEVMETHOD(device_attach, goldfish_rtc_attach),
DEVMETHOD(device_detach, goldfish_rtc_detach),
/* Clock interface */
DEVMETHOD(clock_gettime, goldfish_rtc_gettime),
DEVMETHOD(clock_settime, goldfish_rtc_settime),
DEVMETHOD_END,
};
DEFINE_CLASS_0(goldfish_rtc, goldfish_rtc_driver, goldfish_rtc_methods,
sizeof(struct goldfish_rtc_softc));
static devclass_t goldfish_rtc_devclass;
DRIVER_MODULE(goldfish_rtc, simplebus, goldfish_rtc_driver,
goldfish_rtc_devclass, NULL, NULL);
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