source: rtems/c/src/lib/libbsp/i386/go32/clock/rtc.c @ 637df35

/* 
 *  $Id$
 */

#define IO_RTC          0x70    /* RTC */

#define RTC_SEC         0x00    /* seconds */
#define RTC_SECALRM     0x01    /* seconds alarm */
#define RTC_MIN         0x02    /* minutes */
#define RTC_MINALRM     0x03    /* minutes alarm */
#define RTC_HRS         0x04    /* hours */
#define RTC_HRSALRM     0x05    /* hours alarm */
#define RTC_WDAY        0x06    /* week day */
#define RTC_DAY         0x07    /* day of month */
#define RTC_MONTH       0x08    /* month of year */
#define RTC_YEAR        0x09    /* month of year */
#define RTC_STATUSA     0x0a    /* status register A */
#define  RTCSA_TUP       0x80   /* time update, don't look now */

#define RTC_STATUSB     0x0b    /* status register B */

#define RTC_INTR        0x0c    /* status register C (R) interrupt source */
#define  RTCIR_UPDATE    0x10   /* update intr */
#define  RTCIR_ALARM     0x20   /* alarm intr */
#define  RTCIR_PERIOD    0x40   /* periodic intr */
#define  RTCIR_INT       0x80   /* interrupt output signal */

#define RTC_STATUSD     0x0d    /* status register D (R) Lost Power */
#define  RTCSD_PWR       0x80   /* clock lost power */

#define RTC_DIAG        0x0e    /* status register E - bios diagnostic */
#define RTCDG_BITS      "\020\010clock_battery\007ROM_cksum\006config_unit\005memory_size\004fixed_disk\003invalid_time"

#define RTC_CENTURY     0x32    /* current century - increment in Dec99 */



#include <rtems.h>
#include <cpu.h>
#include <memory.h>

void init_rtc( void )
{
    int s;

        /* initialize brain-dead battery powered clock */
        outport_byte( IO_RTC, RTC_STATUSA );
        outport_byte( IO_RTC+1, 0x26 );
        outport_byte( IO_RTC, RTC_STATUSB );
        outport_byte( IO_RTC+1, 2 );

        outport_byte( IO_RTC, RTC_DIAG );
        inport_byte( IO_RTC+1, s );
#if 0
        if (s) printf("RTC BIOS diagnostic error %b\n", s, RTCDG_BITS);
#endif
}


/* convert 2 digit BCD number */
static int bcd( unsigned int i )
{
        return ((i/16)*10 + (i%16));
}

/* convert years to seconds (from 1970) */
static unsigned long ytos( int y )
{
        int i;
        unsigned long ret;

        ret = 0;
        for(i = 1970; i < y; i++) {
                if (i % 4) ret += 365*24*60*60;
                else ret += 366*24*60*60;
        }
        return ret;
}

/* convert months to seconds */
static unsigned long mtos( int m, int leap )
{
        int i;
        unsigned long ret;

        ret = 0;
        for(i=1;i<m;i++) {
                switch(i){
                case 1: case 3: case 5: case 7: case 8: case 10: case 12:
                        ret += 31*24*60*60;
                        break;
                case 4: case 6: case 9: case 11:
                        ret += 30*24*60*60;
                        break;
                case 2:
                        if (leap)
                            ret += 29*24*60*60;
                        else
                            ret += 28*24*60*60;
                }
        }
        return ret;
}


static inline unsigned int rtcin( unsigned int what )
{
    unsigned int r;
    outport_byte( IO_RTC, what );
    inport_byte( IO_RTC+1, r );
    return r;
}


/*
 * Initialize the time of day register, based on the time base which is, e.g.
 * from a filesystem.
 */
long rtc_read( rtems_time_of_day * tod )
{
        int sa;
        unsigned long sec = 0;

        memset( tod, 0, sizeof *tod );

        /* do we have a realtime clock present? (otherwise we loop below) */
        sa = rtcin(RTC_STATUSA);
        if (sa == 0xff || sa == 0)
            return -1;

        /* ready for a read? */
        while ((sa&RTCSA_TUP) == RTCSA_TUP)
            sa = rtcin(RTC_STATUSA);

        tod->year       = bcd(rtcin(RTC_YEAR)) + 1900;  /* year   */
        if (tod->year < 1970)   tod->year += 100;       
        tod->month      = bcd(rtcin(RTC_MONTH));        /* month   */
        tod->day        = bcd(rtcin(RTC_DAY));          /* day     */
        (void)            bcd(rtcin(RTC_WDAY));         /* weekday */
        tod->hour       = bcd(rtcin(RTC_HRS));          /* hour    */
        tod->minute     = bcd(rtcin(RTC_MIN));          /* minutes */
        tod->second     = bcd(rtcin(RTC_SEC));          /* seconds */
        tod->ticks      = 0;
#if 0
        sec = ytos( tod->year );
        sec += mtos( tod->month, tod->year % 4 == 0 );
        sec += tod->day * 24*60*60;
        sec += tod->hour * 60*60;                       /* hour    */
        sec += tod->minute * 60;                        /* minutes */
        sec += tod->second;                             /* seconds */
#else
        sec = 0;
#endif
        return sec;
}



/* from djgpp: include before rtems.h to avoid conflicts */
#undef delay
#include <dos.h>

void rtc_set_dos_date( void )
{
    int s;
    struct date date;
    struct time time;

    /* initialize brain-dead battery powered clock */
    outport_byte( IO_RTC, RTC_STATUSA );
    outport_byte( IO_RTC+1, 0x26 );
    outport_byte( IO_RTC, RTC_STATUSB );
    outport_byte( IO_RTC+1, 2 );

    outport_byte( IO_RTC, RTC_DIAG );
    inport_byte( IO_RTC+1, s );
    if (s)  {
#if 0
        printf("RTC BIOS diagnostic error %b\n", s, RTCDG_BITS);
#else
        return;
#endif
    }

    /* check for presence of clock */
    s = rtcin(RTC_STATUSA);
    if ( s == 0xff  ||  s == 0 )  {
#if 0
        printf( "Real-time clock not found\n" );
#endif
        return;
    }

    /* ready for a read? */
    while ((s & RTCSA_TUP) == RTCSA_TUP)
        s = rtcin(RTC_STATUSA);

    date.da_year        = bcd(rtcin(RTC_YEAR)) + 1900;  /* year   */
    if ( date.da_year < 1970)   date.da_year += 100;
    date.da_year        -= 1980;
    date.da_mon         = bcd(rtcin(RTC_MONTH));        /* month   */
    date.da_day         = bcd(rtcin(RTC_DAY));          /* day     */

    (void)bcd(rtcin(RTC_WDAY));         /* weekday */

    time.ti_hour        = bcd(rtcin(RTC_HRS));          /* hour    */
    time.ti_min         = bcd(rtcin(RTC_MIN));          /* minutes */
    time.ti_sec         = bcd(rtcin(RTC_SEC));          /* seconds */
    time.ti_hund        = 0;

    setdate( & date );
    settime( & time );
}