1 /* 2 * (C) Copyright 2001 3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4 * 5 * See file CREDITS for list of people who contributed to this 6 * project. 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License as 10 * published by the Free Software Foundation; either version 2 of 11 * the License, or (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 21 * MA 02111-1307 USA 22 */ 23 24 /* 25 * Date & Time support for Philips PCF8563 RTC 26 */ 27 28 #include <common.h> 29 #include <command.h> 30 #include <rtc.h> 31 32 #if defined(CONFIG_CMD_DATE) || defined(CONFIG_TIMESTAMP) 33 34 #define FEBRUARY 2 35 #define STARTOFTIME 1970 36 #define SECDAY 86400L 37 #define SECYR (SECDAY * 365) 38 #define leapyear(year) ((year) % 4 == 0) 39 #define days_in_year(a) (leapyear(a) ? 366 : 365) 40 #define days_in_month(a) (month_days[(a) - 1]) 41 42 static int month_days[12] = { 43 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 44 }; 45 46 /* 47 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) 48 */ 49 void GregorianDay(struct rtc_time * tm) 50 { 51 int leapsToDate; 52 int lastYear; 53 int day; 54 int MonthOffset[] = { 0,31,59,90,120,151,181,212,243,273,304,334 }; 55 56 lastYear=tm->tm_year-1; 57 58 /* 59 * Number of leap corrections to apply up to end of last year 60 */ 61 leapsToDate = lastYear/4 - lastYear/100 + lastYear/400; 62 63 /* 64 * This year is a leap year if it is divisible by 4 except when it is 65 * divisible by 100 unless it is divisible by 400 66 * 67 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 will be 68 */ 69 if((tm->tm_year%4==0) && 70 ((tm->tm_year%100!=0) || (tm->tm_year%400==0)) && 71 (tm->tm_mon>2)) { 72 /* 73 * We are past Feb. 29 in a leap year 74 */ 75 day=1; 76 } else { 77 day=0; 78 } 79 80 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + tm->tm_mday; 81 82 tm->tm_wday=day%7; 83 } 84 85 void to_tm(int tim, struct rtc_time * tm) 86 { 87 register int i; 88 register long hms, day; 89 90 day = tim / SECDAY; 91 hms = tim % SECDAY; 92 93 /* Hours, minutes, seconds are easy */ 94 tm->tm_hour = hms / 3600; 95 tm->tm_min = (hms % 3600) / 60; 96 tm->tm_sec = (hms % 3600) % 60; 97 98 /* Number of years in days */ 99 for (i = STARTOFTIME; day >= days_in_year(i); i++) { 100 day -= days_in_year(i); 101 } 102 tm->tm_year = i; 103 104 /* Number of months in days left */ 105 if (leapyear(tm->tm_year)) { 106 days_in_month(FEBRUARY) = 29; 107 } 108 for (i = 1; day >= days_in_month(i); i++) { 109 day -= days_in_month(i); 110 } 111 days_in_month(FEBRUARY) = 28; 112 tm->tm_mon = i; 113 114 /* Days are what is left over (+1) from all that. */ 115 tm->tm_mday = day + 1; 116 117 /* 118 * Determine the day of week 119 */ 120 GregorianDay(tm); 121 } 122 123 /* Converts Gregorian date to seconds since 1970-01-01 00:00:00. 124 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 125 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. 126 * 127 * [For the Julian calendar (which was used in Russia before 1917, 128 * Britain & colonies before 1752, anywhere else before 1582, 129 * and is still in use by some communities) leave out the 130 * -year/100+year/400 terms, and add 10.] 131 * 132 * This algorithm was first published by Gauss (I think). 133 * 134 * WARNING: this function will overflow on 2106-02-07 06:28:16 on 135 * machines were long is 32-bit! (However, as time_t is signed, we 136 * will already get problems at other places on 2038-01-19 03:14:08) 137 */ 138 unsigned long 139 mktime (unsigned int year, unsigned int mon, 140 unsigned int day, unsigned int hour, 141 unsigned int min, unsigned int sec) 142 { 143 if (0 >= (int) (mon -= 2)) { /* 1..12 -> 11,12,1..10 */ 144 mon += 12; /* Puts Feb last since it has leap day */ 145 year -= 1; 146 } 147 148 return ((( 149 (unsigned long) (year/4 - year/100 + year/400 + 367*mon/12 + day) + 150 year*365 - 719499 151 )*24 + hour /* now have hours */ 152 )*60 + min /* now have minutes */ 153 )*60 + sec; /* finally seconds */ 154 } 155 156 #endif 157