/*-
 * Copyright (c) 2017 Andrew Turner
 * All rights reserved.
 *
 * This software was developed by SRI International and the University of
 * Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
 * ("CTSRD"), as part of the DARPA CRASH research programme.
 *
 * 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.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/clock.h>
#include <sys/efi.h>
#include <sys/kernel.h>
#include <sys/module.h>

#include "clock_if.h"

static void
efirtc_identify(driver_t *driver, device_t parent)
{
	struct efi_tm tm;
	int error;

	/*
	 * Check if we can read the time. This will stop us attaching when
	 * there is no EFI Runtime support, or the gettime function is
	 * unimplemented, e.g. on some builds of U-Boot.
	 */
	error = efi_get_time(&tm);
	if (error != 0)
		return;

	if (device_find_child(parent, "efirtc", -1) != NULL)
		return;
	if (BUS_ADD_CHILD(parent, 0, "efirtc", -1) == NULL)
		device_printf(parent, "add child failed\n");
}

static int
efirtc_probe(device_t dev)
{

	device_quiet(dev);
	return (0);
}

static int
efirtc_attach(device_t dev)
{

	clock_register(dev, 1000000);
	return (0);
}

static int
efirtc_detach(device_t dev)
{

	clock_unregister(dev);
	return (0);
}

static int
efirtc_gettime(device_t dev, struct timespec *ts)
{
	struct clocktime ct;
	struct efi_tm tm;
	int error;

	error = efi_get_time(&tm);
	if (error != 0)
		return (error);

	ct.sec = tm.tm_sec;
	ct.min = tm.tm_min;
	ct.hour = tm.tm_hour;
	ct.day = tm.tm_mday;
	ct.mon = tm.tm_mon;
	ct.year = tm.tm_year;
	ct.nsec = tm.tm_nsec;

	return (clock_ct_to_ts(&ct, ts));
}

static int
efirtc_settime(device_t dev, struct timespec *ts)
{
	struct clocktime ct;
	struct efi_tm tm;

	clock_ts_to_ct(ts, &ct);

	bzero(&tm, sizeof(tm));
	tm.tm_sec = ct.sec;
	tm.tm_min = ct.min;
	tm.tm_hour = ct.hour;
	tm.tm_mday = ct.day;
	tm.tm_mon = ct.mon;
	tm.tm_year = ct.year;
	tm.tm_nsec = ct.nsec;

	return (efi_set_time(&tm));
}

static device_method_t efirtc_methods[] = {
	/* Device interface */
	DEVMETHOD(device_identify,	efirtc_identify),
	DEVMETHOD(device_probe,		efirtc_probe),
	DEVMETHOD(device_attach,	efirtc_attach),
	DEVMETHOD(device_detach,	efirtc_detach),

	/* Clock interface */
	DEVMETHOD(clock_gettime,	efirtc_gettime),
	DEVMETHOD(clock_settime,	efirtc_settime),

	DEVMETHOD_END
};

static devclass_t efirtc_devclass;
static driver_t efirtc_driver = {
	"efirtc",
	efirtc_methods,
	0
};

DRIVER_MODULE(efirtc, nexus, efirtc_driver, efirtc_devclass, 0, 0);