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146 lines
3.3 KiB
146 lines
3.3 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* rtc and date/time utility functions |
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* |
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* Copyright (C) 2005-06 Tower Technologies |
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* Author: Alessandro Zummo <[email protected]> |
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* |
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* based on arch/arm/common/rtctime.c and other bits |
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*/ |
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#include <linux/export.h> |
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#include <linux/rtc.h> |
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static const unsigned char rtc_days_in_month[] = { |
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31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 |
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}; |
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static const unsigned short rtc_ydays[2][13] = { |
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/* Normal years */ |
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{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 }, |
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/* Leap years */ |
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{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 } |
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}; |
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#define LEAPS_THRU_END_OF(y) ((y) / 4 - (y) / 100 + (y) / 400) |
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/* |
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* The number of days in the month. |
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*/ |
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int rtc_month_days(unsigned int month, unsigned int year) |
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{ |
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return rtc_days_in_month[month] + (is_leap_year(year) && month == 1); |
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} |
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EXPORT_SYMBOL(rtc_month_days); |
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/* |
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* The number of days since January 1. (0 to 365) |
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*/ |
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int rtc_year_days(unsigned int day, unsigned int month, unsigned int year) |
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{ |
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return rtc_ydays[is_leap_year(year)][month] + day - 1; |
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} |
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EXPORT_SYMBOL(rtc_year_days); |
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/* |
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* rtc_time64_to_tm - Converts time64_t to rtc_time. |
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* Convert seconds since 01-01-1970 00:00:00 to Gregorian date. |
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*/ |
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void rtc_time64_to_tm(time64_t time, struct rtc_time *tm) |
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{ |
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unsigned int month, year, secs; |
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int days; |
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/* time must be positive */ |
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days = div_s64_rem(time, 86400, &secs); |
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/* day of the week, 1970-01-01 was a Thursday */ |
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tm->tm_wday = (days + 4) % 7; |
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year = 1970 + days / 365; |
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days -= (year - 1970) * 365 |
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+ LEAPS_THRU_END_OF(year - 1) |
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- LEAPS_THRU_END_OF(1970 - 1); |
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while (days < 0) { |
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year -= 1; |
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days += 365 + is_leap_year(year); |
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} |
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tm->tm_year = year - 1900; |
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tm->tm_yday = days + 1; |
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for (month = 0; month < 11; month++) { |
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int newdays; |
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newdays = days - rtc_month_days(month, year); |
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if (newdays < 0) |
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break; |
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days = newdays; |
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} |
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tm->tm_mon = month; |
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tm->tm_mday = days + 1; |
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tm->tm_hour = secs / 3600; |
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secs -= tm->tm_hour * 3600; |
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tm->tm_min = secs / 60; |
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tm->tm_sec = secs - tm->tm_min * 60; |
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tm->tm_isdst = 0; |
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} |
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EXPORT_SYMBOL(rtc_time64_to_tm); |
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/* |
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* Does the rtc_time represent a valid date/time? |
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*/ |
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int rtc_valid_tm(struct rtc_time *tm) |
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{ |
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if (tm->tm_year < 70 || |
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tm->tm_year > (INT_MAX - 1900) || |
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((unsigned int)tm->tm_mon) >= 12 || |
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tm->tm_mday < 1 || |
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tm->tm_mday > rtc_month_days(tm->tm_mon, |
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((unsigned int)tm->tm_year + 1900)) || |
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((unsigned int)tm->tm_hour) >= 24 || |
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((unsigned int)tm->tm_min) >= 60 || |
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((unsigned int)tm->tm_sec) >= 60) |
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return -EINVAL; |
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return 0; |
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} |
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EXPORT_SYMBOL(rtc_valid_tm); |
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/* |
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* rtc_tm_to_time64 - Converts rtc_time to time64_t. |
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* Convert Gregorian date to seconds since 01-01-1970 00:00:00. |
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*/ |
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time64_t rtc_tm_to_time64(struct rtc_time *tm) |
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{ |
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return mktime64(((unsigned int)tm->tm_year + 1900), tm->tm_mon + 1, |
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tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec); |
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} |
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EXPORT_SYMBOL(rtc_tm_to_time64); |
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/* |
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* Convert rtc_time to ktime |
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*/ |
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ktime_t rtc_tm_to_ktime(struct rtc_time tm) |
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{ |
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return ktime_set(rtc_tm_to_time64(&tm), 0); |
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} |
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EXPORT_SYMBOL_GPL(rtc_tm_to_ktime); |
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/* |
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* Convert ktime to rtc_time |
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*/ |
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struct rtc_time rtc_ktime_to_tm(ktime_t kt) |
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{ |
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struct timespec64 ts; |
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struct rtc_time ret; |
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ts = ktime_to_timespec64(kt); |
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/* Round up any ns */ |
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if (ts.tv_nsec) |
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ts.tv_sec++; |
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rtc_time64_to_tm(ts.tv_sec, &ret); |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(rtc_ktime_to_tm);
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