u-boot/lib/rtc-lib.c
Tom Rini 467382ca03 lib: Remove <common.h> inclusion from these files
After some header file cleanups to add missing include files, remove
common.h from all files in the lib directory. This primarily means just
dropping the line but in a few cases we need to add in other header
files now.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
2023-12-21 08:54:37 -05:00

76 lines
1.8 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* rtc and date/time utility functions
*
* Copyright (C) 2005-06 Tower Technologies
* Author: Alessandro Zummo <a.zummo@towertech.it>
*
* U-Boot rtc_time differs from Linux rtc_time:
* - The year field takes the actual value, not year - 1900.
* - January is month 1.
*/
#include <rtc.h>
#include <linux/math64.h>
static const unsigned char rtc_days_in_month[] = {
31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
#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);
}
/*
* rtc_to_tm - Converts u64 to rtc_time.
* Convert seconds since 01-01-1970 00:00:00 to Gregorian date.
*
* This function is copied from rtc_time64_to_tm() in the Linux kernel.
* But in U-Boot January is month 1 and we do not subtract 1900 from the year.
*/
void rtc_to_tm(u64 time, struct rtc_time *tm)
{
unsigned int month, year, secs;
int days;
days = div_u64_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; /* Not 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 + 1; /* January = 1 */
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;
/* Zero unused fields */
tm->tm_isdst = 0;
}