LXR uboot/lib/date.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * (C) Copyright 2001
   4 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   5 */
   6
   7#include <common.h>
   8#include <command.h>
   9#include <errno.h>
  10#include <rtc.h>
  11#include <linux/time.h>
  12
  13#if defined(CONFIG_LIB_DATE) || defined(CONFIG_TIMESTAMP)
  14
  15#define FEBRUARY                2
  16#define STARTOFTIME             1970
  17#define SECDAY                  86400L
  18#define SECYR                   (SECDAY * 365)
  19#define leapyear(year)          ((year) % 4 == 0)
  20#define days_in_year(a)         (leapyear(a) ? 366 : 365)
  21#define days_in_month(a)        (month_days[(a) - 1])
  22
  23static int month_offset[] = {
  24        0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
  25};
  26
  27/*
  28 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
  29 */
  30int rtc_calc_weekday(struct rtc_time *tm)
  31{
  32        int leaps_to_date;
  33        int last_year;
  34        int day;
  35
  36        if (tm->tm_year < 1753)
  37                return -1;
  38        last_year = tm->tm_year - 1;
  39
  40        /* Number of leap corrections to apply up to end of last year */
  41        leaps_to_date = last_year / 4 - last_year / 100 + last_year / 400;
  42
  43        /*
  44         * This year is a leap year if it is divisible by 4 except when it is
  45         * divisible by 100 unless it is divisible by 400
  46         *
  47         * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 is.
  48         */
  49        if (tm->tm_year % 4 == 0 &&
  50            ((tm->tm_year % 100 != 0) || (tm->tm_year % 400 == 0)) &&
  51            tm->tm_mon > 2) {
  52                /* We are past Feb. 29 in a leap year */
  53                day = 1;
  54        } else {
  55                day = 0;
  56        }
  57
  58        day += last_year * 365 + leaps_to_date + month_offset[tm->tm_mon - 1] +
  59                        tm->tm_mday;
  60        tm->tm_wday = day % 7;
  61
  62        return 0;
  63}
  64
  65/*
  66 * Converts Gregorian date to seconds since 1970-01-01 00:00:00.
  67 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
  68 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
  69 *
  70 * [For the Julian calendar (which was used in Russia before 1917,
  71 * Britain & colonies before 1752, anywhere else before 1582,
  72 * and is still in use by some communities) leave out the
  73 * -year / 100 + year / 400 terms, and add 10.]
  74 *
  75 * This algorithm was first published by Gauss (I think).
  76 *
  77 * WARNING: this function will overflow on 2106-02-07 06:28:16 on
  78 * machines where long is 32-bit! (However, as time_t is signed, we
  79 * will already get problems at other places on 2038-01-19 03:14:08)
  80 */
  81unsigned long rtc_mktime(const struct rtc_time *tm)
  82{
  83        int mon = tm->tm_mon;
  84        int year = tm->tm_year;
  85        int days, hours;
  86
  87        mon -= 2;
  88        if (0 >= (int)mon) {    /* 1..12 -> 11, 12, 1..10 */
  89                mon += 12;      /* Puts Feb last since it has leap day */
  90                year -= 1;
  91        }
  92
  93        days = (unsigned long)(year / 4 - year / 100 + year / 400 +
  94                        367 * mon / 12 + tm->tm_mday) +
  95                        year * 365 - 719499;
  96        hours = days * 24 + tm->tm_hour;
  97        return (hours * 60 + tm->tm_min) * 60 + tm->tm_sec;
  98}
  99
 100#endif /* CONFIG_LIB_DATE || CONFIG_TIMESTAMP */
 101
 102#ifdef CONFIG_LIB_DATE
 103/* for compatibility with linux code */
 104time64_t mktime64(const unsigned int year, const unsigned int mon,
 105                  const unsigned int day, const unsigned int hour,
 106                  const unsigned int min, const unsigned int sec)
 107{
 108        struct rtc_time time;
 109
 110        time.tm_year = year;
 111        time.tm_mon = mon;
 112        time.tm_mday = day;
 113        time.tm_hour = hour;
 114        time.tm_min = min;
 115        time.tm_sec = sec;
 116
 117        return (time64_t)rtc_mktime((const struct rtc_time *)&time);
 118}
 119#endif
 120