blob: bfa2e1378e22467cbe9c9049a868f7567ef46eee [file] [log] [blame]
wdenk0587dd12002-10-26 17:33:42 +00001/*
2 * (C) Copyright 2001
3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4 *
Wolfgang Denk1a459662013-07-08 09:37:19 +02005 * SPDX-License-Identifier: GPL-2.0+
wdenk0587dd12002-10-26 17:33:42 +00006 */
7
wdenk0587dd12002-10-26 17:33:42 +00008#include <common.h>
9#include <command.h>
Simon Glass199e87c2015-04-20 12:37:17 -060010#include <errno.h>
wdenk0587dd12002-10-26 17:33:42 +000011#include <rtc.h>
12
Jon Loeligera5938142007-07-09 18:10:50 -050013#if defined(CONFIG_CMD_DATE) || defined(CONFIG_TIMESTAMP)
wdenk0587dd12002-10-26 17:33:42 +000014
15#define FEBRUARY 2
16#define STARTOFTIME 1970
17#define SECDAY 86400L
18#define SECYR (SECDAY * 365)
19#define leapyear(year) ((year) % 4 == 0)
Wolfgang Denk53677ef2008-05-20 16:00:29 +020020#define days_in_year(a) (leapyear(a) ? 366 : 365)
21#define days_in_month(a) (month_days[(a) - 1])
wdenk0587dd12002-10-26 17:33:42 +000022
23static int month_days[12] = {
24 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
25};
26
Simon Glass36b898b2016-06-19 19:51:00 -060027static int month_offset[] = {
28 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
29};
30
wdenk0587dd12002-10-26 17:33:42 +000031/*
32 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
33 */
Simon Glass199e87c2015-04-20 12:37:17 -060034int rtc_calc_weekday(struct rtc_time *tm)
wdenk0587dd12002-10-26 17:33:42 +000035{
Simon Glass36b898b2016-06-19 19:51:00 -060036 int leaps_to_date;
37 int last_year;
wdenk0587dd12002-10-26 17:33:42 +000038 int day;
wdenk0587dd12002-10-26 17:33:42 +000039
Simon Glass199e87c2015-04-20 12:37:17 -060040 if (tm->tm_year < 1753)
Simon Glass36b898b2016-06-19 19:51:00 -060041 return -1;
42 last_year = tm->tm_year - 1;
wdenk0587dd12002-10-26 17:33:42 +000043
Simon Glass36b898b2016-06-19 19:51:00 -060044 /* Number of leap corrections to apply up to end of last year */
45 leaps_to_date = last_year / 4 - last_year / 100 + last_year / 400;
wdenk0587dd12002-10-26 17:33:42 +000046
47 /*
48 * This year is a leap year if it is divisible by 4 except when it is
49 * divisible by 100 unless it is divisible by 400
50 *
Simon Glass36b898b2016-06-19 19:51:00 -060051 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 is.
wdenk0587dd12002-10-26 17:33:42 +000052 */
Simon Glass36b898b2016-06-19 19:51:00 -060053 if (tm->tm_year % 4 == 0 &&
54 ((tm->tm_year % 100 != 0) || (tm->tm_year % 400 == 0)) &&
55 tm->tm_mon > 2) {
56 /* We are past Feb. 29 in a leap year */
57 day = 1;
wdenk0587dd12002-10-26 17:33:42 +000058 } else {
Simon Glass36b898b2016-06-19 19:51:00 -060059 day = 0;
wdenk0587dd12002-10-26 17:33:42 +000060 }
61
Simon Glass36b898b2016-06-19 19:51:00 -060062 day += last_year * 365 + leaps_to_date + month_offset[tm->tm_mon - 1] +
63 tm->tm_mday;
64 tm->tm_wday = day % 7;
Simon Glass199e87c2015-04-20 12:37:17 -060065
66 return 0;
wdenk0587dd12002-10-26 17:33:42 +000067}
68
Simon Glass9f9276c2015-04-20 12:37:18 -060069int rtc_to_tm(int tim, struct rtc_time *tm)
wdenk0587dd12002-10-26 17:33:42 +000070{
Simon Glass36b898b2016-06-19 19:51:00 -060071 register int i;
72 register long hms, day;
wdenk0587dd12002-10-26 17:33:42 +000073
74 day = tim / SECDAY;
75 hms = tim % SECDAY;
76
77 /* Hours, minutes, seconds are easy */
78 tm->tm_hour = hms / 3600;
79 tm->tm_min = (hms % 3600) / 60;
80 tm->tm_sec = (hms % 3600) % 60;
81
82 /* Number of years in days */
Simon Glass36b898b2016-06-19 19:51:00 -060083 for (i = STARTOFTIME; day >= days_in_year(i); i++)
wdenk0587dd12002-10-26 17:33:42 +000084 day -= days_in_year(i);
wdenk0587dd12002-10-26 17:33:42 +000085 tm->tm_year = i;
86
87 /* Number of months in days left */
Simon Glass36b898b2016-06-19 19:51:00 -060088 if (leapyear(tm->tm_year))
wdenk0587dd12002-10-26 17:33:42 +000089 days_in_month(FEBRUARY) = 29;
Simon Glass36b898b2016-06-19 19:51:00 -060090 for (i = 1; day >= days_in_month(i); i++)
wdenk0587dd12002-10-26 17:33:42 +000091 day -= days_in_month(i);
wdenk0587dd12002-10-26 17:33:42 +000092 days_in_month(FEBRUARY) = 28;
93 tm->tm_mon = i;
94
Simon Glass36b898b2016-06-19 19:51:00 -060095 /* Days are what is left over (+1) from all that */
wdenk0587dd12002-10-26 17:33:42 +000096 tm->tm_mday = day + 1;
97
Simon Glass9f9276c2015-04-20 12:37:18 -060098 /* Zero unused fields */
99 tm->tm_yday = 0;
100 tm->tm_isdst = 0;
101
wdenk0587dd12002-10-26 17:33:42 +0000102 /*
103 * Determine the day of week
104 */
Simon Glass9f9276c2015-04-20 12:37:18 -0600105 return rtc_calc_weekday(tm);
wdenk0587dd12002-10-26 17:33:42 +0000106}
107
Simon Glass36b898b2016-06-19 19:51:00 -0600108/*
109 * Converts Gregorian date to seconds since 1970-01-01 00:00:00.
wdenk0587dd12002-10-26 17:33:42 +0000110 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
111 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
112 *
113 * [For the Julian calendar (which was used in Russia before 1917,
114 * Britain & colonies before 1752, anywhere else before 1582,
115 * and is still in use by some communities) leave out the
Simon Glass36b898b2016-06-19 19:51:00 -0600116 * -year / 100 + year / 400 terms, and add 10.]
wdenk0587dd12002-10-26 17:33:42 +0000117 *
118 * This algorithm was first published by Gauss (I think).
119 *
120 * WARNING: this function will overflow on 2106-02-07 06:28:16 on
Simon Glass36b898b2016-06-19 19:51:00 -0600121 * machines where long is 32-bit! (However, as time_t is signed, we
wdenk0587dd12002-10-26 17:33:42 +0000122 * will already get problems at other places on 2038-01-19 03:14:08)
123 */
Simon Glass71420982015-04-20 12:37:19 -0600124unsigned long rtc_mktime(const struct rtc_time *tm)
wdenk0587dd12002-10-26 17:33:42 +0000125{
Simon Glass71420982015-04-20 12:37:19 -0600126 int mon = tm->tm_mon;
127 int year = tm->tm_year;
128 int days, hours;
129
130 mon -= 2;
Simon Glass36b898b2016-06-19 19:51:00 -0600131 if (0 >= (int)mon) { /* 1..12 -> 11, 12, 1..10 */
132 mon += 12; /* Puts Feb last since it has leap day */
wdenk0587dd12002-10-26 17:33:42 +0000133 year -= 1;
134 }
135
Simon Glass71420982015-04-20 12:37:19 -0600136 days = (unsigned long)(year / 4 - year / 100 + year / 400 +
137 367 * mon / 12 + tm->tm_mday) +
138 year * 365 - 719499;
139 hours = days * 24 + tm->tm_hour;
140 return (hours * 60 + tm->tm_min) * 60 + tm->tm_sec;
wdenk0587dd12002-10-26 17:33:42 +0000141}
142
Jon Loeliger068b60a2007-07-10 10:27:39 -0500143#endif