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time.h

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/*!     \file include/kernel/time.h
 *      \brief Real time clock driver header.
 *      \author Andrea Righi <drizzt@inwind.it>
 *      \date Last update: 2003-08-27
 *      \note Copyright (&copy;) 2003 Andrea Righi
 */

#ifndef TIME_H
#define TIME_H

//! Time variable type.
typedef unsigned long           time_t;

//! The base epoch year.
#define RTC_EPOCH_YEAR          1970
//! The base epoch day (Jan 1).
#define EPOCH_DAY               0

//! RTC port for seconds.
#define RTC_SECONDS             0
//! RTC port for minutes.
#define RTC_MINUTES             2
//! RTC port for hours.
#define RTC_HOURS               4

//! RTC port for the day of the week.
#define RTC_DAY_OF_WEEK         6
//! RTC port for the month.
#define RTC_DAY_OF_MONTH        7
//! RTC port for month.
#define RTC_MONTH               8
//! RTC port for year.
#define RTC_YEAR                9

//! RTC control register A.
#define RTC_REG_A               10
//! RTC control register B.
#define RTC_REG_B               11
//! RTC control register C.
#define RTC_REG_C               12
//! RTC control register D.
#define RTC_REG_D               13

//! Macro to convert from BCD to binary format.
#define BCD2BIN(n) ( ((n) >> 4) * 10 + ((n) & 0x0F) )
//! Macro to convert from binary to BCD format.
#define BIN2BCD(n) ( (((n) / 10) << 4) + ((n) % 10) )

//! CMOS control register.
#define CMOS_CTRL               0x70
//! CMOS data register.
#define CMOS_DATA               0x71

//! \brief Read a value from the CMOS.
//! \param port The port to read from.
//! \return The value read from the CMOS \a port.
#define CMOS_READ(port) ( \
                { \
                        out( CMOS_CTRL, (port) ); \
                        in( CMOS_DATA ); \
                })

//! \brief Write a value to the CMOS.
//! \param port The port to write to.
//! \param val The value to write.
#define CMOS_WRITE(port, val) ( \
                { \
                        out( CMOS_CTRL, (port) ); \
                        out( CMOS_DATA, (val) ); \
                })

// --- Register Details ----------------------------------------------- //
// ******************************************************************** //
//! RTC update frequency register.
#define RTC_FREQ_SELECT         RTC_REG_A

//! Update-in-progress - set to "1" 244 microsecs before RTC goes off
//! the bus, reset after update (may take 1.984ms @ 32768Hz RefClock)
//! is complete, totalling to a max high interval of 2.228 ms.
        #define RTC_UIP         0x80
   /* 2 values for divider stage reset, others for "testing purposes only" */
#define RTC_DIV_RESET1  0x60
#define RTC_DIV_RESET2  0x70

// ******************************************************************** //
//! RTC status register.
#define RTC_CONTROL             RTC_REG_B

//! Disable updates for clock setting.
        #define RTC_SET         0x80
//! RTC binary date; all time/date values are BCD if clear.
        #define RTC_DM_BINARY   0x04
// 24 hour mode - else hours bit 7 means pm.
        #define RTC_24H         0x02

// ******************************************************************** //

/** \ingroup Drivers
 *  \defgroup RTCDriver Real-Time Clock
 *  The real-time clock driver.
 *  @{
 */

// --- Time procedures ------------------------------------------------ //

//! \brief Converts Gregorian date to seconds since 1970-01-01 00:00:00.
//! \param year The year value.
//! \param mon The month value.
//! \param day The day of the month value.
//! \param hour The hours value.
//! \param min The minutes value.
//! \param sec The seconds value.
//! \return
//!     Seconds since 1970-01-01 00:00:00 (UNIX timestamp).
/**
 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
 *
 * [For the Julian calendar (which was used in Russia before 1917,
 * Britain & colonies before 1752, anywhere else before 1582,
 * and is still in use by some communities) leave out the
 * -year/100+year/400 terms, and add 10.]
 *
 * This algorithm was first published by Gauss (I think).
 *
 * WARNING: this function will overflow on 2106-02-07 06:28:16 on
 * machines were long is 32-bit! (However, as time_t is signed, we
 * will already get problems at other places on 2038-01-19 03:14:08)
 * \n\n Thanks to Linux... (Andrea Righi).
 */
static __inline__ unsigned long
mktime (unsigned int year, unsigned int mon,
        unsigned int day, unsigned int hour,
        unsigned int min, unsigned int sec)
{
        if (0 >= (int) (mon -= 2)) {    /* 1..12 -> 11,12,1..10 */
                mon += 12;              /* Puts Feb last since it has leap day */
                year -= 1;
        }

        return (((
                (unsigned long) (year/4 - year/100 + year/400 + 367*mon/12 + day) +
                        year*365 - 719499
            )*24 + hour /* now have hours */
          )*60 + min /* now have minutes */
        )*60 + sec; /* finally seconds */
}

// --- Prototypes ----------------------------------------------------- //

void time_init();
time_t time_read();

/** @} */ // end of RTCDriver

#endif

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