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e94ef57952
Function rtc_to_tm() is needed for FAT file system support even if we don't have a real time clock. So move it from drivers/ to lib/. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
78 lines
1.8 KiB
C
78 lines
1.8 KiB
C
// 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 <a.zummo@towertech.it>
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*
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* U-Boot rtc_time differs from Linux rtc_time:
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* - The year field takes the actual value, not year - 1900.
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* - January is month 1.
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*/
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#include <common.h>
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#include <rtc.h>
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#include <linux/math64.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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#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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/*
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* rtc_to_tm - Converts u64 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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* This function is copied from rtc_time64_to_tm() in the Linux kernel.
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* But in U-Boot January is month 1 and we do not subtract 1900 from the year.
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*/
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void rtc_to_tm(u64 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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days = div_u64_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; /* Not 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 + 1; /* January = 1 */
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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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/* Zero unused fields */
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tm->tm_isdst = 0;
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}
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