realtimeclock.c

Cirrus EP9315 wince bsp

//
// Copyright (c) Microsoft Corporation.  All rights reserved.
//
//
// Use of this source code is subject to the terms of the Microsoft end-user
// license agreement (EULA) under which you licensed this SOFTWARE PRODUCT.
// If you did not accept the terms of the EULA, you are not authorized to use
// this source code. For a copy of the EULA, please see the LICENSE.RTF on your
// install media.
//
/* -*-C-*-
 *
 * $Revision: 1.2 $
 *   $Author: rgorsegn $
 *     $Date: 2002/07/08 19:41:00 $
 *
 * Copyright (c) 1999 ARM Limited
 * All Rights Reserved
 *
 * timex20t.c - ARMX20T (X = 7, 9, 10) platform timer routines
 */
#include <windows.h>
#include <nkintr.h>
#include <hwdefs.h>


DWORD dwReschedIncrement;

unsigned __int64 RealTimeBias = 0;  // Number of 100-nanosecond intervals since
                                    // January 1, 1601. 
typedef volatile struct _rtcif_tag 
{
	DWORD	dr;			// data register
	DWORD	mr;			// match register
	union {
		DWORD	stat;		// interrupt status (read only)
		DWORD	eoi;		// interrupt clear (write only)
	};
	DWORD	lr;			// load register
	DWORD	cr;			// control register
} RTCIF, *PRTCIF;


BOOL OEMGetRealTime(LPSYSTEMTIME lpst)
{
    unsigned __int64 realTime;
    FILETIME ft;

    //
    // Implement the realtime clock.
    //
    PRTCIF pRTC = (PRTCIF) RTC_BASE;
    DWORD dwRTCDR = pRTC->dr;

    //
    // read the clock registers
    //
    realTime = (unsigned __int64) dwRTCDR;		// data in seconds
    realTime *= 1000;							// convert to ms
    realTime *= 10000;							// convert to 100ns
    realTime += RealTimeBias;					// convert to "real" time

    //
    // load time/data structure
    //
    ft.dwLowDateTime = (DWORD)realTime;
    ft.dwHighDateTime = (DWORD)(realTime >> 32);

    return KFileTimeToSystemTime( &ft, lpst );
}

BOOL OEMSetRealTime(LPSYSTEMTIME lpst)
{
    unsigned __int64 realTime;
    FILETIME ft;
    BOOL bRet;
    //
    // Impliment battery backed real time clock.
    //
    //
    PRTCIF pRTC = (PRTCIF) RTC_BASE;
    DWORD dwRTCDR = pRTC->dr;
	
    if (bRet = KSystemTimeToFileTime(lpst, &ft))
    {
        // read the clock registers
        realTime = (unsigned __int64) dwRTCDR;		// data in seconds
        realTime *= 1000;							// convert to ms
        realTime *= 10000;							// convert to 100ns
		
        // get the desired "real" time
        RealTimeBias = (unsigned __int64) ft.dwHighDateTime << 32;
        RealTimeBias += ft.dwLowDateTime;
		
		// compensate for the clock time
        RealTimeBias -= realTime;
    }
	
    return bRet;
}

BOOL OEMSetAlarmTime(LPSYSTEMTIME lpst)
{
    FILETIME ft;
    BOOL bRet = FALSE;
    ULARGE_INTEGER alarmTime, currentTime, deltaTime;
    PRTCIF pRTC = (PRTCIF) RTC_BASE;
    DWORD dwRTCDR = pRTC->dr;
	
    // get the desired alarm time
    if (bRet = KSystemTimeToFileTime(lpst, &ft)) {
		alarmTime.LowPart = ft.dwLowDateTime;
		alarmTime.HighPart = ft.dwHighDateTime;
		alarmTime.QuadPart -= RealTimeBias;
		
        // get the current time
        currentTime.QuadPart = (unsigned __int64) dwRTCDR;		// data in seconds
        currentTime.QuadPart *= 1000;							// convert to ms
        currentTime.QuadPart *= 10000;						// convert to 100ns
		
        // make sure the alarm occurs in the future
        if(alarmTime.QuadPart < currentTime.QuadPart) {
			DEBUGMSG(FALSE, (_T("OEMSetAlarmTime: alarm 0x%08x:%08x occurs before 0x%08x:%08x\r\n"),
				alarmTime.HighPart, alarmTime.LowPart, currentTime.HighPart, currentTime.LowPart));
        } else {
			// round up to the nearest number of seconds
			deltaTime.QuadPart = alarmTime.QuadPart - currentTime.QuadPart;
			deltaTime.QuadPart += 9999999;					// msecs, usecs, 100ns
			deltaTime.QuadPart /= 10000000;				// convert to seconds
			
			// do we have enough resolution in our timer to handle the request?
			if(deltaTime.HighPart != 0) {
				DEBUGMSG(FALSE, (_T("OEMSetAlarmTime: alarm 0x%08x:%08x delta with 0x%08x:%08x (0x%08x:%08x) is too large\r\n"),
					alarmTime.HighPart, alarmTime.LowPart, currentTime.HighPart, currentTime.LowPart, deltaTime.HighPart, deltaTime.LowPart));
			} else {
				// clear interrupts, write the comparator, and enable interrupts
				pRTC->eoi = 0;			// any value clears pending interrupts
				pRTC->mr = dwRTCDR + deltaTime.LowPart;
				pRTC->cr = 1;			// enable match interrupt
				OEMInterruptEnable(SYSINTR_RTC_ALARM, NULL, 0);
				bRet = TRUE;
        	}
        }
    }

    // return TRUE if alarm set, FALSE otherwise
    return bRet;
}


/* EOF timex20t.c */