Simon Glass | 2cf99e1 | 2016-06-10 20:58:24 -0600 | [diff] [blame] | 1 | /* |
| 2 | * This file is part of the coreboot project. |
| 3 | * |
| 4 | * (C) Copyright 2001 Wolfgang Denk, DENX Software Engineering, wd@denx.de. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; version 2 of the License or (at your |
| 9 | * option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * From U-Boot 2016.05 |
| 17 | */ |
| 18 | |
| 19 | #include <console/console.h> |
| 20 | #include <rtc.h> |
| 21 | |
| 22 | #define FEBRUARY 2 |
| 23 | #define STARTOFTIME 1970 |
| 24 | #define SECDAY 86400L |
| 25 | #define SECYR (SECDAY * 365) |
| 26 | #define LEAP_YEAR(year) ((year) % 4 == 0) |
| 27 | #define DAYS_IN_YEAR(a) (LEAP_YEAR(a) ? 366 : 365) |
| 28 | #define DAYS_IN_MONTH(a) (month_days[(a) - 1]) |
| 29 | |
| 30 | static const int month_offset[] = { |
| 31 | 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 |
| 32 | }; |
| 33 | |
| 34 | static const char * const weekdays[] = { |
| 35 | "Sun", "Mon", "Tues", "Wednes", "Thurs", "Fri", "Satur", |
| 36 | }; |
| 37 | |
| 38 | static int leaps_to_year(int year) |
| 39 | { |
| 40 | return year / 4 - year / 100 + year / 400; |
| 41 | } |
| 42 | |
| 43 | /* This only works for the Gregorian calendar after Jan 1 1971. */ |
| 44 | static int rtc_calc_weekday(struct rtc_time *tm) |
| 45 | { |
| 46 | int leaps_to_date; |
| 47 | int day; |
| 48 | |
| 49 | if (tm->year < 1971) |
| 50 | return -1; |
| 51 | |
| 52 | day = 4; /* Jan 1 1970 was a Thursday. */ |
| 53 | |
| 54 | /* Number of leap corrections to apply up to end of last year */ |
| 55 | leaps_to_date = leaps_to_year(tm->year - 1) - leaps_to_year(1970); |
| 56 | |
| 57 | /* |
| 58 | * This year is a leap year if it is divisible by 4 except when it is |
| 59 | * divisible by 100 unless it is divisible by 400 |
| 60 | * |
| 61 | * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 is. |
| 62 | */ |
| 63 | if ((tm->year % 4) && |
| 64 | ((tm->year % 100 != 0) || (tm->year % 400 == 0)) && |
| 65 | (tm->mon > 2)) { |
| 66 | /* We are past Feb. 29 in a leap year */ |
| 67 | day++; |
| 68 | } |
| 69 | |
| 70 | day += (tm->year - 1970) * 365 + leaps_to_date + |
| 71 | month_offset[tm->mon-1] + tm->mday; |
| 72 | tm->wday = day % 7; |
| 73 | |
| 74 | return 0; |
| 75 | } |
| 76 | |
| 77 | int rtc_to_tm(int tim, struct rtc_time *tm) |
| 78 | { |
| 79 | int month_days[12] = { |
| 80 | 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 |
| 81 | }; |
| 82 | register int i; |
| 83 | register long hms, day; |
| 84 | |
| 85 | day = tim / SECDAY; |
| 86 | hms = tim % SECDAY; |
| 87 | |
| 88 | /* Hours, minutes, seconds are easy */ |
| 89 | tm->hour = hms / 3600; |
| 90 | tm->min = (hms % 3600) / 60; |
| 91 | tm->sec = (hms % 3600) % 60; |
| 92 | |
| 93 | /* Number of years in days */ |
| 94 | for (i = STARTOFTIME; day >= DAYS_IN_YEAR(i); i++) |
| 95 | day -= DAYS_IN_YEAR(i); |
| 96 | tm->year = i; |
| 97 | |
| 98 | /* Number of months in days left */ |
| 99 | if (LEAP_YEAR(tm->year)) |
| 100 | DAYS_IN_MONTH(FEBRUARY) = 29; |
| 101 | for (i = 1; day >= DAYS_IN_MONTH(i); i++) |
| 102 | day -= DAYS_IN_MONTH(i); |
| 103 | DAYS_IN_MONTH(FEBRUARY) = 28; |
| 104 | tm->mon = i; |
| 105 | |
| 106 | /* Days are what is left over (+1) from all that */ |
| 107 | tm->mday = day + 1; |
| 108 | |
| 109 | /* Determine the day of week */ |
| 110 | return rtc_calc_weekday(tm); |
| 111 | } |
| 112 | |
| 113 | /* |
| 114 | * Converts Gregorian date to seconds since 1970-01-01 00:00:00. |
| 115 | * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 |
| 116 | * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. |
| 117 | * |
| 118 | * [For the Julian calendar (which was used in Russia before 1917, |
| 119 | * Britain & colonies before 1752, anywhere else before 1582, |
| 120 | * and is still in use by some communities) leave out the |
| 121 | * -year / 100 + year / 400 terms, and add 10.] |
| 122 | * |
| 123 | * This algorithm was first published by Gauss (I think). |
| 124 | * |
| 125 | * WARNING: this function will overflow on 2106-02-07 06:28:16 on |
| 126 | * machines where long is 32-bit! (However, as time_t is signed, we |
| 127 | * will already get problems at other places on 2038-01-19 03:14:08) |
| 128 | */ |
| 129 | unsigned long rtc_mktime(const struct rtc_time *tm) |
| 130 | { |
| 131 | int mon = tm->mon; |
| 132 | int year = tm->year; |
| 133 | int days, hours; |
| 134 | |
| 135 | mon -= 2; |
| 136 | if (0 >= (int)mon) { /* 1..12 -> 11, 12, 1..10 */ |
| 137 | mon += 12; /* Puts Feb last since it has leap day */ |
| 138 | year -= 1; |
| 139 | } |
| 140 | |
| 141 | days = (unsigned long)(year / 4 - year / 100 + year / 400 + |
| 142 | 367 * mon / 12 + tm->mday) + |
| 143 | year * 365 - 719499; |
| 144 | hours = days * 24 + tm->hour; |
| 145 | return (hours * 60 + tm->min) * 60 + tm->sec; |
| 146 | } |
| 147 | |
| 148 | void rtc_display(const struct rtc_time *tm) |
| 149 | { |
| 150 | printk(BIOS_INFO, "Date: %4d-%02d-%02d (%sday) Time: %2d:%02d:%02d\n", |
| 151 | tm->year, tm->mon, tm->mday, |
| 152 | (tm->wday < 0 || tm->wday > 6) ? "unknown " : weekdays[tm->wday], |
| 153 | tm->hour, tm->min, tm->sec); |
| 154 | } |