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Tom Rini83d290c2018-05-06 17:58:06 -04001// SPDX-License-Identifier: GPL-2.0+
wdenk0587dd12002-10-26 17:33:42 +00002/*
3 * (C) Copyright 2001
4 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
wdenk0587dd12002-10-26 17:33:42 +00005 */
6
wdenk0587dd12002-10-26 17:33:42 +00007#include <common.h>
8#include <command.h>
Simon Glass199e87c2015-04-20 12:37:17 -06009#include <errno.h>
wdenk0587dd12002-10-26 17:33:42 +000010#include <rtc.h>
11
AKASHI Takahiro05429b62019-11-13 09:44:49 +090012#if defined(CONFIG_LIB_DATE) || defined(CONFIG_TIMESTAMP)
wdenk0587dd12002-10-26 17:33:42 +000013
14#define FEBRUARY 2
15#define STARTOFTIME 1970
16#define SECDAY 86400L
17#define SECYR (SECDAY * 365)
18#define leapyear(year) ((year) % 4 == 0)
Wolfgang Denk53677ef2008-05-20 16:00:29 +020019#define days_in_year(a) (leapyear(a) ? 366 : 365)
20#define days_in_month(a) (month_days[(a) - 1])
wdenk0587dd12002-10-26 17:33:42 +000021
Simon Glass36b898b2016-06-19 19:51:00 -060022static int month_offset[] = {
23 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
24};
25
wdenk0587dd12002-10-26 17:33:42 +000026/*
27 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
28 */
Simon Glass199e87c2015-04-20 12:37:17 -060029int rtc_calc_weekday(struct rtc_time *tm)
wdenk0587dd12002-10-26 17:33:42 +000030{
Simon Glass36b898b2016-06-19 19:51:00 -060031 int leaps_to_date;
32 int last_year;
wdenk0587dd12002-10-26 17:33:42 +000033 int day;
wdenk0587dd12002-10-26 17:33:42 +000034
Simon Glass199e87c2015-04-20 12:37:17 -060035 if (tm->tm_year < 1753)
Simon Glass36b898b2016-06-19 19:51:00 -060036 return -1;
37 last_year = tm->tm_year - 1;
wdenk0587dd12002-10-26 17:33:42 +000038
Simon Glass36b898b2016-06-19 19:51:00 -060039 /* Number of leap corrections to apply up to end of last year */
40 leaps_to_date = last_year / 4 - last_year / 100 + last_year / 400;
wdenk0587dd12002-10-26 17:33:42 +000041
42 /*
43 * This year is a leap year if it is divisible by 4 except when it is
44 * divisible by 100 unless it is divisible by 400
45 *
Simon Glass36b898b2016-06-19 19:51:00 -060046 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 is.
wdenk0587dd12002-10-26 17:33:42 +000047 */
Simon Glass36b898b2016-06-19 19:51:00 -060048 if (tm->tm_year % 4 == 0 &&
49 ((tm->tm_year % 100 != 0) || (tm->tm_year % 400 == 0)) &&
50 tm->tm_mon > 2) {
51 /* We are past Feb. 29 in a leap year */
52 day = 1;
wdenk0587dd12002-10-26 17:33:42 +000053 } else {
Simon Glass36b898b2016-06-19 19:51:00 -060054 day = 0;
wdenk0587dd12002-10-26 17:33:42 +000055 }
56
Simon Glass36b898b2016-06-19 19:51:00 -060057 day += last_year * 365 + leaps_to_date + month_offset[tm->tm_mon - 1] +
58 tm->tm_mday;
59 tm->tm_wday = day % 7;
Simon Glass199e87c2015-04-20 12:37:17 -060060
61 return 0;
wdenk0587dd12002-10-26 17:33:42 +000062}
63
Simon Glass36b898b2016-06-19 19:51:00 -060064/*
65 * Converts Gregorian date to seconds since 1970-01-01 00:00:00.
wdenk0587dd12002-10-26 17:33:42 +000066 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
67 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
68 *
69 * [For the Julian calendar (which was used in Russia before 1917,
70 * Britain & colonies before 1752, anywhere else before 1582,
71 * and is still in use by some communities) leave out the
Simon Glass36b898b2016-06-19 19:51:00 -060072 * -year / 100 + year / 400 terms, and add 10.]
wdenk0587dd12002-10-26 17:33:42 +000073 *
74 * This algorithm was first published by Gauss (I think).
75 *
76 * WARNING: this function will overflow on 2106-02-07 06:28:16 on
Simon Glass36b898b2016-06-19 19:51:00 -060077 * machines where long is 32-bit! (However, as time_t is signed, we
wdenk0587dd12002-10-26 17:33:42 +000078 * will already get problems at other places on 2038-01-19 03:14:08)
79 */
Simon Glass71420982015-04-20 12:37:19 -060080unsigned long rtc_mktime(const struct rtc_time *tm)
wdenk0587dd12002-10-26 17:33:42 +000081{
Simon Glass71420982015-04-20 12:37:19 -060082 int mon = tm->tm_mon;
83 int year = tm->tm_year;
84 int days, hours;
85
86 mon -= 2;
Simon Glass36b898b2016-06-19 19:51:00 -060087 if (0 >= (int)mon) { /* 1..12 -> 11, 12, 1..10 */
88 mon += 12; /* Puts Feb last since it has leap day */
wdenk0587dd12002-10-26 17:33:42 +000089 year -= 1;
90 }
91
Simon Glass71420982015-04-20 12:37:19 -060092 days = (unsigned long)(year / 4 - year / 100 + year / 400 +
93 367 * mon / 12 + tm->tm_mday) +
94 year * 365 - 719499;
95 hours = days * 24 + tm->tm_hour;
96 return (hours * 60 + tm->tm_min) * 60 + tm->tm_sec;
wdenk0587dd12002-10-26 17:33:42 +000097}
98
AKASHI Takahiro05429b62019-11-13 09:44:49 +090099#endif /* CONFIG_LIB_DATE || CONFIG_TIMESTAMP */