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Diffstat (limited to 'fs/exfat/exfat_oal.c')
| -rw-r--r-- | fs/exfat/exfat_oal.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/fs/exfat/exfat_oal.c b/fs/exfat/exfat_oal.c new file mode 100644 index 000000000..9b3399826 --- /dev/null +++ b/fs/exfat/exfat_oal.c @@ -0,0 +1,190 @@ +/* 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 = CURRENT_TIME_SEC; + time_t second = ts.tv_sec; + time_t day, leap_day, month, year; + + 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 */ |