/*++

Copyright (c) 1991  Microsoft Corporation
Copyright (c) 1992, 1993  Digital Equipment Corporation

Module Name:

    pcrtc.c

Abstract:

    This module implements the HAL set/query realtime clock routines for
    the standard pc-compatible real time clock use on Alpha AXP systems.

Author:

    David N. Cutler (davec) 5-May-1991
    Jeff McLeman (mcleman) 3-Jun-1992

Environment:

    Kernel mode

Revision History:

    13-Jul-1992  Jeff McLeman
     use VTI access routines to access clock

    3-June-1992  Jeff McLeman
     Adapt this module into a Jensen specific module

--*/

#include "halp.h"
#include "pcrtc.h"

//
// Local function prototypes.
//

BOOLEAN
HalQueryRealTimeClock (
    OUT PTIME_FIELDS TimeFields
    );

BOOLEAN
HalSetRealTimeClock (
    IN PTIME_FIELDS TimeFields
    );

UCHAR
HalpReadClockRegister (
    UCHAR Register
    );

VOID
HalpWriteClockRegister (
    UCHAR Register,
    UCHAR Value
    );

#ifdef AXP_FIRMWARE

//
// Put these functions in the discardable text section.
//

#pragma alloc_text(DISTEXT, HalQueryRealTimeClock )
#pragma alloc_text(DISTEXT, HalSetRealTimeClock )
#pragma alloc_text(DISTEXT, HalpReadClockRegister )
#pragma alloc_text(DISTEXT, HalpWriteClockRegister )

#endif // AXP_FIRMWARE

//
// Define globals used to map the realtime clock address and data ports.
//

PVOID HalpRtcAddressPort = NULL;
PVOID HalpRtcDataPort = NULL;


BOOLEAN
HalQueryRealTimeClock (
    OUT PTIME_FIELDS TimeFields
    )

/*++

Routine Description:

    This routine queries the realtime clock.

    N.B. This routine assumes that the caller has provided any required
        synchronization to query the realtime clock information.

Arguments:

    TimeFields - Supplies a pointer to a time structure that receives
        the realtime clock information.

Return Value:

    If the power to the realtime clock has not failed, then the time
    values are read from the realtime clock and a value of TRUE is
    returned. Otherwise, a value of FALSE is returned.

--*/

{

    UCHAR DataByte;
    BOOLEAN Status;
    KIRQL OldIrql;

    KeRaiseIrql(HIGH_LEVEL, &OldIrql);

    //
    // If the realtime clock battery is still functioning, then read
    // the realtime clock values, and return a function value of TRUE.
    // Otherwise, return a function value of FALSE.
    //

    DataByte = HalpReadClockRegister(RTC_CONTROL_REGISTERD);
    if (((PRTC_CONTROL_REGISTER_D)(&DataByte))->ValidTime == 1) {

        //
        // Wait until the realtime clock is not being updated.
        //

        do {
            DataByte = HalpReadClockRegister(RTC_CONTROL_REGISTERA);
        } while (((PRTC_CONTROL_REGISTER_A)(&DataByte))->UpdateInProgress == 1);

        //
        // Read the realtime clock values.
        //

        TimeFields->Year = 1980 + (CSHORT)HalpReadClockRegister(RTC_YEAR);
        TimeFields->Month = (CSHORT)HalpReadClockRegister(RTC_MONTH);
        TimeFields->Day = (CSHORT)HalpReadClockRegister(RTC_DAY_OF_MONTH);
        TimeFields->Weekday  = (CSHORT)HalpReadClockRegister(RTC_DAY_OF_WEEK) - 1;
        TimeFields->Hour = (CSHORT)HalpReadClockRegister(RTC_HOUR);
        TimeFields->Minute = (CSHORT)HalpReadClockRegister(RTC_MINUTE);
        TimeFields->Second = (CSHORT)HalpReadClockRegister(RTC_SECOND);
        TimeFields->Milliseconds = 0;
        Status = TRUE;

    } else {
        Status = FALSE;
    }

    KeLowerIrql(OldIrql);
    return(Status);
}

BOOLEAN
HalSetRealTimeClock (
    IN PTIME_FIELDS TimeFields
    )

/*++

Routine Description:

    This routine sets the realtime clock.

    N.B. This routine is required to provide any synchronization necessary
         to set the realtime clock information.

Arguments:

    TimeFields - Supplies a pointer to a time structure that specifies the
        realtime clock information.

Return Value:

    If the power to the realtime clock has not failed, then the time
    values are written to the realtime clock and a value of TRUE is
    returned. Otherwise, a value of FALSE is returned.

--*/

{
    KIRQL OldIrql;

    UCHAR DataByte;

    //
    // If the realtime clock battery is still functioning, then write
    // the realtime clock values, and return a function value of TRUE.
    // Otherwise, return a function value of FALSE.
    //

    KeRaiseIrql(HIGH_LEVEL, &OldIrql);
    DataByte = HalpReadClockRegister(RTC_CONTROL_REGISTERD);
    if (((PRTC_CONTROL_REGISTER_D)(&DataByte))->ValidTime == 1) {

        //
        // Set the realtime clock control to set the time.
        //

        DataByte = 0;
        ((PRTC_CONTROL_REGISTER_B)(&DataByte))->HoursFormat = 1;
        ((PRTC_CONTROL_REGISTER_B)(&DataByte))->DataMode = 1;
        ((PRTC_CONTROL_REGISTER_B)(&DataByte))->SetTime = 1;

#ifdef RTC_SQE

        //
        // If the platform requires it, make sure that the Square
        // Wave output of the RTC is turned on.
        //

        ((PRTC_CONTROL_REGISTER_B)(&DataByte))->SquareWaveEnable = 1;

#endif //RTC_SQE

        HalpWriteClockRegister(RTC_CONTROL_REGISTERB, DataByte);

        //
        // Write the realtime clock values.
        //

        HalpWriteClockRegister(RTC_YEAR, (UCHAR)(TimeFields->Year - 1980));
        HalpWriteClockRegister(RTC_MONTH, (UCHAR)TimeFields->Month);
        HalpWriteClockRegister(RTC_DAY_OF_MONTH, (UCHAR)TimeFields->Day);
        HalpWriteClockRegister(RTC_DAY_OF_WEEK, (UCHAR)(TimeFields->Weekday + 1));
        HalpWriteClockRegister(RTC_HOUR, (UCHAR)TimeFields->Hour);
        HalpWriteClockRegister(RTC_MINUTE, (UCHAR)TimeFields->Minute);
        HalpWriteClockRegister(RTC_SECOND, (UCHAR)TimeFields->Second);

        //
        // Set the realtime clock control to update the time.
        // (Make sure periodic interrupt is enabled)
        //

        ((PRTC_CONTROL_REGISTER_B)(&DataByte))->SetTime = 0;
        ((PRTC_CONTROL_REGISTER_B)(&DataByte))->TimerInterruptEnable = 1;
        HalpWriteClockRegister(RTC_CONTROL_REGISTERB, DataByte);
        KeLowerIrql(OldIrql);
        return TRUE;

    } else {
        KeLowerIrql(OldIrql);
        return FALSE;
    }
}


UCHAR
HalpReadClockRegister (
    UCHAR Register
    )

/*++

Routine Description:

    This routine reads the specified realtime clock register.

Arguments:

    Register - Supplies the number of the register whose value is read.

Return Value:

    The value of the register is returned as the function value.

--*/

{
    //
    // Read the realtime clock register value.
    //

    WRITE_PORT_UCHAR( HalpRtcAddressPort, Register );

    return READ_PORT_UCHAR( HalpRtcDataPort );
}

VOID
HalpWriteClockRegister (
    UCHAR Register,
    UCHAR Value
    )

/*++

Routine Description:

    This routine writes the specified value to the specified realtime
    clock register.

Arguments:

    Register - Supplies the number of the register whose value is written.

    Value - Supplies the value that is written to the specified register.

Return Value:

    None

--*/

{
    //
    // Write the realtime clock register value.
    //

    WRITE_PORT_UCHAR( HalpRtcAddressPort, Register );

    WRITE_PORT_UCHAR( HalpRtcDataPort, Value );

    return;
}


VOID
HalpProgramIntervalTimer(
    IN ULONG RateSelect
    )

/*++

Routine Description:

    This function is called to program the interval timer.  It is used during
    Phase 1 initialization to start the heartbeat timer.  It also used by
    the clock interrupt interrupt routine to change the hearbeat timer rate
    when a call to HalSetTimeIncrement has been made in the previous time slice.

    On Sable the periodic interrupt comes from the square ware output of
    the Dallas 1489A RTC on the Standard I/O board.  Each processor
    receives this clock phase shifted by at least 90 degrees from all
    other processors.  The periodic interrupt from the RTC is not used and
    thus doesn't need to be enabled or acknowledged.  Each processor has
    its own clock interrupt latch that is cleared locally. This routine is
    not used for Sable platforms.

    Because of the phase shifting among the processors, the clock is
    half the rate given to the RTC.  So, the RTC is programmed twice
    as fast as on a system that takes the RTC periodic interrupt in
    directly.

Arguments:

    RateSelect - Supplies rate select to be placed in the clock.

Return Value:

    None.

--*/

{
    UCHAR DataByte;

    //
    // Set the new rate
    //
    DataByte = 0;
    ((PRTC_CONTROL_REGISTER_A)(&DataByte))->RateSelect = (UCHAR)RateSelect;
    ((PRTC_CONTROL_REGISTER_A)(&DataByte))->TimebaseDivisor = RTC_TIMEBASE_DIVISOR;
    HalpWriteClockRegister( RTC_CONTROL_REGISTERA, DataByte );

    //
    // Set the correct mode
    //
    DataByte = 0;
#if defined(RTC_SQE)
        ((PRTC_CONTROL_REGISTER_B)(&DataByte))->SquareWaveEnable = 1;
#else
        ((PRTC_CONTROL_REGISTER_B)(&DataByte))->TimerInterruptEnable = 1;
#endif

    ((PRTC_CONTROL_REGISTER_B)(&DataByte))->HoursFormat = 1;
    ((PRTC_CONTROL_REGISTER_B)(&DataByte))->DataMode = 1;
    HalpWriteClockRegister( RTC_CONTROL_REGISTERB, DataByte );
}