/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1996 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Gordon W. Ross
 *
 * 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.
 *
 *	$NetBSD: clock_subr.h,v 1.7 2000/10/03 13:41:07 tsutsui Exp $
 *
 *
 * This file is the central clearing-house for calendrical issues.
 *
 * In general the kernel does not know about minutes, hours, days, timezones,
 * daylight savings time, leap-years and such.  All that is theoretically a
 * matter for userland only.
 *
 * Parts of kernel code does however care: badly designed filesystems store
 * timestamps in local time and RTC chips sometimes track time in a local
 * timezone instead of UTC and so on.
 *
 * All that code should go here for service.
 */

#ifndef _SYS_CLOCK_H_
#define _SYS_CLOCK_H_

#ifdef _KERNEL		/* No user serviceable parts */

int utc_offset(void);

/*
 * Structure to hold the values typically reported by time-of-day clocks,
 * expressed as binary integers (see below for a BCD version).  This can be
 * passed to the conversion functions to be converted to/from a struct timespec.
 *
 * On input, the year is interpreted as follows:
 *       0 -   69 = 2000 - 2069
 *      70 -   99 = 1970 - 1999
 *     100 -  199 = 2000 - 2099 (Supports hardware "century bit".)
 *     200 - 1969 = Invalid.
 *    1970 - 9999 = Full 4-digit century+year.
 *
 * The dow field is ignored (not even validated) on input, but is always
 * populated with day-of-week on output.
 *
 * clock_ct_to_ts() returns EINVAL if any values are out of range.  The year
 * field will always be 4-digit on output.
 */
struct clocktime {
	int	year;			/* year (4 digit year) */
	int	mon;			/* month (1 - 12) */
	int	day;			/* day (1 - 31) */
	int	hour;			/* hour (0 - 23) */
	int	min;			/* minute (0 - 59) */
	int	sec;			/* second (0 - 59) */
	int	dow;			/* day of week (0 - 6; 0 = Sunday) */
	long	nsec;			/* nano seconds */
};

int clock_ct_to_ts(const struct clocktime *, struct timespec *);
void clock_ts_to_ct(const struct timespec *, struct clocktime *);

/*
 * Structure to hold the values typically reported by time-of-day clocks,
 * expressed as BCD.  This can be passed to the conversion functions to be
 * converted to/from a struct timespec.
 *
 * The clock_bcd_to_ts() function interprets the values in the year through sec
 * fields as BCD numbers, and returns EINVAL if any BCD values are out of range.
 * After conversion to binary, the values are passed to clock_ct_to_ts() and
 * undergo further validation as described above.  Year may be 2 or 4-digit BCD,
 * interpreted as described above.  The nsec field is binary.  If the ampm arg
 * is true, the incoming hour and ispm values are interpreted as 12-hour am/pm
 * representation of the hour, otherwise hour is interpreted as 24-hour and ispm
 * is ignored.
 *
 * The clock_ts_to_bcd() function converts the timespec to BCD values stored
 * into year through sec.  The value in year will be 4-digit BCD (e.g.,
 * 0x2017). The mon through sec values will be 2-digit BCD.  The nsec field will
 * be binary, and the range of dow makes its binary and BCD values identical.
 * If the ampm arg is true, the hour and ispm fields are set to the 12-hour
 * time plus a pm flag, otherwise the hour is set to 24-hour time and ispm is
 * set to false.
 */
struct bcd_clocktime {
	uint16_t year;			/* year (2 or 4 digit year) */
	uint8_t  mon;			/* month (1 - 12) */
	uint8_t  day;			/* day (1 - 31) */
	uint8_t  hour;			/* hour (0 - 23 or 1 - 12) */
	uint8_t  min;			/* minute (0 - 59) */
	uint8_t  sec;			/* second (0 - 59) */
	uint8_t  dow;			/* day of week (0 - 6; 0 = Sunday) */
	long     nsec;			/* nanoseconds */
	bool     ispm;			/* true if hour represents pm time */
};

int clock_bcd_to_ts(const struct bcd_clocktime *, struct timespec *, bool ampm);
void clock_ts_to_bcd(const struct timespec *, struct bcd_clocktime *, bool ampm);

/*
 * Time-of-day clock functions and flags.  These functions might sleep.
 *
 * clock_register and clock_unregister() do what they say.  Upon return from
 * unregister, the clock's methods are not running and will not be called again.
 *
 * clock_schedule() requests that a registered clock's clock_settime() calls
 * happen at the given offset into the second.  The default is 0, meaning no
 * specific scheduling.  To schedule the call as soon after top-of-second as
 * possible, specify 1.  Each clock has its own schedule, but taskqueue_thread
 * is shared by many tasks; the timing of the call is not guaranteed.
 *
 * Flags:
 *
 *  CLOCKF_SETTIME_NO_TS
 *    Do not pass a timespec to clock_settime(), the driver obtains its own time
 *    and applies its own adjustments (this flag implies CLOCKF_SETTIME_NO_ADJ).
 *
 *  CLOCKF_SETTIME_NO_ADJ
 *    Do not apply utc offset and resolution/accuracy adjustments to the value
 *    passed to clock_settime(), the driver applies them itself.
 *
 *  CLOCKF_GETTIME_NO_ADJ
 *    Do not apply utc offset and resolution/accuracy adjustments to the value
 *    returned from clock_gettime(), the driver has already applied them.
 */

#define	CLOCKF_SETTIME_NO_TS	0x00000001
#define	CLOCKF_SETTIME_NO_ADJ	0x00000002
#define	CLOCKF_GETTIME_NO_ADJ	0x00000004

void clock_register(device_t _clockdev, long _resolution_us);
void clock_register_flags(device_t _clockdev, long _resolution_us, int _flags);
void clock_schedule(device_t clockdev, u_int _offsetns);
void clock_unregister(device_t _clockdev);

/*
 * BCD to decimal and decimal to BCD.
 */
#define	FROMBCD(x)	bcd2bin(x)
#define	TOBCD(x)	bin2bcd(x)

/* Some handy constants. */
#define SECDAY		(24 * 60 * 60)
#define SECYR		(SECDAY * 365)

/* Traditional POSIX base year */
#define	POSIX_BASE_YEAR	1970

void timespec2fattime(const struct timespec *tsp, int utc, u_int16_t *ddp,
    u_int16_t *dtp, u_int8_t *dhp);
void fattime2timespec(unsigned dd, unsigned dt, unsigned dh, int utc,
    struct timespec *tsp);

/*
 * Print a [bcd_]clocktime or timespec, optionally with fractional seconds.  The
 * nsdig argument can range from 0-9, and specifies how many decimal digits to
 * display for fractional seconds.
 */
void clock_print_bcd(const struct bcd_clocktime *bct, int nsdig);
void clock_print_ct(const struct clocktime *ct, int nsdig);
void clock_print_ts(const struct timespec  *ts, int nsdig);

/*
 * Debugging helpers for RTC clock drivers.  Print a [bcd_]clocktime or
 * timespec, only if rtc clock debugging has been enabled.  The rw argument is
 * one of CLOCK_DBG_READ or CLOCK_DBG_WRITE.
 */
#define	CLOCK_DBG_READ	0x01
#define	CLOCK_DBG_WRITE	0x02
void clock_dbgprint_bcd(device_t dev, int rw, const struct bcd_clocktime *bct);
void clock_dbgprint_ct(device_t dev, int rw, const struct clocktime *ct);
void clock_dbgprint_err(device_t dev, int rw, int err);
void clock_dbgprint_ts(device_t dev, int rw, const struct timespec *ts);

#endif /* _KERNEL */

#endif /* !_SYS_CLOCK_H_ */