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exfat_oal.c
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exfat_oal.c
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/* Some of the source code in this file came from "linux/fs/fat/misc.c". */
/*
* linux/fs/fat/misc.c
*
* Written 1992,1993 by Werner Almesberger
* 22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980
* and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru)
*/
/*
* Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
/************************************************************************/
/* */
/* PROJECT : exFAT & FAT12/16/32 File System */
/* FILE : exfat_oal.c */
/* PURPOSE : exFAT OS Adaptation Layer */
/* (Semaphore Functions & Real-Time Clock Functions) */
/* */
/*----------------------------------------------------------------------*/
/* NOTES */
/* */
/*----------------------------------------------------------------------*/
/* REVISION HISTORY (Ver 0.9) */
/* */
/* - 2010.11.15 [Joosun Hahn] : first writing */
/* */
/************************************************************************/
#include <linux/semaphore.h>
#include <linux/time.h>
#include "exfat_config.h"
#include "exfat_api.h"
#include "exfat_oal.h"
/*======================================================================*/
/* */
/* SEMAPHORE FUNCTIONS */
/* */
/*======================================================================*/
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,36)
DECLARE_MUTEX(z_sem);
#else
DEFINE_SEMAPHORE(z_sem);
#endif
s32 sm_init(struct semaphore *sm)
{
sema_init(sm, 1);
return 0;
} /* end of sm_init */
s32 sm_P(struct semaphore *sm)
{
down(sm);
return 0;
} /* end of sm_P */
void sm_V(struct semaphore *sm)
{
up(sm);
} /* end of sm_V */
/*======================================================================*/
/* */
/* REAL-TIME CLOCK FUNCTIONS */
/* */
/*======================================================================*/
extern struct timezone sys_tz;
/*
* The epoch of FAT timestamp is 1980.
* : bits : value
* date: 0 - 4: day (1 - 31)
* date: 5 - 8: month (1 - 12)
* date: 9 - 15: year (0 - 127) from 1980
* time: 0 - 4: sec (0 - 29) 2sec counts
* time: 5 - 10: min (0 - 59)
* time: 11 - 15: hour (0 - 23)
*/
#define UNIX_SECS_1980 315532800L
#if BITS_PER_LONG == 64
#define UNIX_SECS_2108 4354819200L
#endif
/* days between 1.1.70 and 1.1.80 (2 leap days) */
#define DAYS_DELTA_DECADE (365 * 10 + 2)
/* 120 (2100 - 1980) isn't leap year */
#define NO_LEAP_YEAR_2100 (120)
#define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != NO_LEAP_YEAR_2100)
#define SECS_PER_MIN (60)
#define SECS_PER_HOUR (60 * SECS_PER_MIN)
#define SECS_PER_DAY (24 * SECS_PER_HOUR)
#define MAKE_LEAP_YEAR(leap_year, year) \
do { \
if (unlikely(year > NO_LEAP_YEAR_2100)) \
leap_year = ((year + 3) / 4) - 1; \
else \
leap_year = ((year + 3) / 4); \
} while (0)
/* Linear day numbers of the respective 1sts in non-leap years. */
static time_t accum_days_in_year[] = {
/* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
};
TIMESTAMP_T *tm_current(TIMESTAMP_T *tp)
{
struct timespec ts;
time_t second, day, leap_day, month, year;
#if LINUX_VERSION_CODE < KERNEL_VERSION(4,8,0)
ts = CURRENT_TIME_SEC;
#else
ktime_get_real_ts(&ts);
#endif
second = ts.tv_sec;
second -= sys_tz.tz_minuteswest * SECS_PER_MIN;
/* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
if (second < UNIX_SECS_1980) {
tp->sec = 0;
tp->min = 0;
tp->hour = 0;
tp->day = 1;
tp->mon = 1;
tp->year = 0;
return tp;
}
#if BITS_PER_LONG == 64
if (second >= UNIX_SECS_2108) {
tp->sec = 59;
tp->min = 59;
tp->hour = 23;
tp->day = 31;
tp->mon = 12;
tp->year = 127;
return tp;
}
#endif
day = second / SECS_PER_DAY - DAYS_DELTA_DECADE;
year = day / 365;
MAKE_LEAP_YEAR(leap_day, year);
if (year * 365 + leap_day > day)
year--;
MAKE_LEAP_YEAR(leap_day, year);
day -= year * 365 + leap_day;
if (IS_LEAP_YEAR(year) && day == accum_days_in_year[3]) {
month = 2;
} else {
if (IS_LEAP_YEAR(year) && day > accum_days_in_year[3])
day--;
for (month = 1; month < 12; month++) {
if (accum_days_in_year[month + 1] > day)
break;
}
}
day -= accum_days_in_year[month];
tp->sec = second % SECS_PER_MIN;
tp->min = (second / SECS_PER_MIN) % 60;
tp->hour = (second / SECS_PER_HOUR) % 24;
tp->day = day + 1;
tp->mon = month;
tp->year = year;
return tp;
} /* end of tm_current */