xref: /src/sys/dev/goldfish/gfrtc.c

/*	$NetBSD: gfrtc.c,v 1.1 2023/12/29 23:31:44 thorpej Exp $	*/

/*-
 * Copyright (c) 2023 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Nick Hudson.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: gfrtc.c,v 1.1 2023/12/29 23:31:44 thorpej Exp $");

#include <sys/param.h>

#include <sys/bus.h>
#include <sys/device.h>

#include <dev/goldfish/gfrtcvar.h>

/*
 * https://android.googlesource.com/platform/external/qemu/+/master/docs/GOLDFISH-VIRTUAL-HARDWARE.TXT
 */

#define	GOLDFISH_RTC_READ(sc, reg) \
	bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (reg))
#define	GOLDFISH_RTC_WRITE(sc, reg, val) \
	bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (reg), (val))


#define	GOLDFISH_RTC_TIME_LOW	0x00
#define	GOLDFISH_RTC_TIME_HIGH	0x04


static int
gfrtc_gettime(struct todr_chip_handle *ch, struct timeval *tv)
{
	struct gfrtc_softc *sc = ch->cookie;
	const uint64_t lo = GOLDFISH_RTC_READ(sc, GOLDFISH_RTC_TIME_LOW);
	const uint64_t hi = GOLDFISH_RTC_READ(sc, GOLDFISH_RTC_TIME_HIGH);

	uint64_t nsec = (hi << 32) | lo;

	tv->tv_sec = nsec / 1000000000;
	tv->tv_usec = (nsec - tv->tv_sec) / 1000;	// Always 0?

	return 0;
}

static int
gfrtc_settime(struct todr_chip_handle *ch, struct timeval *tv)
{
	struct gfrtc_softc *sc = ch->cookie;

	uint64_t nsec = (tv->tv_sec * 1000000 + tv->tv_usec) * 1000;
	uint32_t hi = nsec >> 32;
	uint32_t lo = nsec;

	GOLDFISH_RTC_WRITE(sc, GOLDFISH_RTC_TIME_HIGH, hi);
	GOLDFISH_RTC_WRITE(sc, GOLDFISH_RTC_TIME_HIGH, lo);

	return 0;
}


void
gfrtc_attach(struct gfrtc_softc * const sc)
{
	sc->sc_todr.cookie = sc;
	sc->sc_todr.todr_gettime = gfrtc_gettime;
	sc->sc_todr.todr_settime = gfrtc_settime;
	sc->sc_todr.todr_setwen = NULL;

	todr_attach(&sc->sc_todr);
}