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