i8254timer.c

IXP425的BSP代码

    if (auxClkRunning)
	{
	/* stop timer 1, actually we get one more interrupt after this */
     
        pTimer->cntrl_word = CW_SELECT (1) | CW_BOTHBYTE | 
	    CW_MODE (MD_SWTRIGSB);
        pTimer->counter1 = LSB (0);
        pTimer->counter1 = MSB (0);

#ifdef	SYS_WB_FLUSH
	sysWbFlush ();
#endif	/* SYS_WB_FLUSH */

	auxClkRunning = FALSE;
	}

    intUnlock (statusReg);
    }

/********************************************************************************
* sysAuxClkEnable - turn on auxiliary clock interrupts
*
* This routine enables auxiliary clock interrupts.
*
* RETURNS: N/A
*
* SEE ALSO: sysAuxClkConnect(), sysAuxClkDisable(), susAuxClkRateSet()
*/
 
void sysAuxClkEnable (void)
    {
    FAST volatile TIMER *pTimer = (volatile TIMER *) TIMER_BASE_ADRS;

    if (!auxClkRunning)
	{

        /* Initialize timer 1, aux clock */
        pTimer->cntrl_word = CW_SELECT (1) | CW_BOTHBYTE | CW_MODE (MD_RATEGEN);
        pTimer->counter1 = LSB (PERIOD (auxClkTicksPerSecond));
        pTimer->counter1 = MSB (PERIOD (auxClkTicksPerSecond));

#ifdef	SYS_WB_FLUSH
	sysWbFlush ();
#endif	/* SYS_WB_FLUSH */
 
        auxClkRunning = TRUE;
        intEnable (INT_LVL_TIMER1);	/* turn on timer 1 ints just in case */
	}
    }

/*******************************************************************************
*
* sysAuxClkRateGet - get the auxiliary clock rate
*
* This routine returns the interrupt rate of the auxiliary clock.
*
* RETURNS: The number of ticks per second of the auxiliary clock.
*
* SEE ALSO: sysAuxClkEnable(), sysAuxClkRateSet()
*/

int sysAuxClkRateGet (void)
    {
    return (auxClkTicksPerSecond);
    }

/*******************************************************************************
*
* sysAuxClkRateSet - set the auxiliary clock rate
*
* This routine sets the interrupt rate of the auxiliary clock.
* It does not enable auxiliary clock interrupts.
*
* RETURNS: OK, or ERROR if the tick rate is invalid or the timer cannot be set.
*
* SEE ALSO: sysAuxClkEnable(), sysAuxClkRateGet()
*/

STATUS sysAuxClkRateSet
    (
    FAST int ticksPerSecond	    /* number of clock interrupts per second */
    )
    {
    if (ticksPerSecond < AUX_CLK_RATE_MIN || ticksPerSecond > AUX_CLK_RATE_MAX)
        return (ERROR);

    auxClkTicksPerSecond = ticksPerSecond;
	     
    if (auxClkRunning)
	{
	sysAuxClkDisable ();
	sysAuxClkEnable ();
	}

    return (OK);
    }

#ifdef  INCLUDE_TIMESTAMP

/*******************************************************************************
*
* sysTimestampConnect - connect a user routine to the timestamp timer interrupt
*
* This routine specifies the user interrupt routine to be called at each
* timestamp timer interrupt.  It does not enable the timestamp timer itself.
*
* RETURNS: OK, or ERROR if sysTimestampInt() interrupt handler is not used.
*/

STATUS sysTimestampConnect
    (
    FUNCPTR routine,    /* routine called at each timestamp timer interrupt */
    int arg     /* argument with which to call routine */
    )
    {
	return (ERROR);
    }

/*******************************************************************************
*
* sysTimestampEnable - initialize and enable the timestamp timer
*
* This routine connects the timestamp timer interrupt and initializes the
* counter registers.  If the timestamp timer is already running, this routine
* merely resets the timer counter.
*
* The rate of the timestamp timer should be set explicitly within the BSP,
* in the sysHwInit() routine.  This routine does not intialize the timer
* rate.
*
* RETURNS: OK, or ERROR if the timestamp timer cannot be enabled.
*/

STATUS sysTimestampEnable (void)
    {
    sysTimestampPeriodValue = TIMER2_HZ / sysClkTicksPerSecond;

    if (sysTimestampRunning)
    return (OK);

    sysTimestampRunning = TRUE;

    return (OK);
    }

/*******************************************************************************
*
* sysTimestampDisable - disable the timestamp timer
*
* This routine disables the timestamp timer.  Interrupts are not disabled,
* although the tick counter will not increment after the timestamp timer
* is disabled, thus interrupts will no longer be generated.
*
* RETURNS: OK, or ERROR if the timestamp timer cannot be disabled.
*/

STATUS sysTimestampDisable (void)
    {
    if (sysTimestampRunning)
        sysTimestampRunning = FALSE;

    return (OK);
    }

/*******************************************************************************
*
* sysTimestampPeriod - get the timestamp timer period
*
* This routine returns the period of the timestamp timer in ticks.
* The period, or terminal count, is the number of ticks to which the timestamp
* timer will count before rolling over and restarting the counting process.
*
* RETURNS: The period of the timestamp timer in counter ticks.
*/

UINT32 sysTimestampPeriod (void)
    {
    sysTimestampPeriodValue = TIMER2_HZ / sysClkTicksPerSecond;

    return (sysTimestampPeriodValue);
    }

/*******************************************************************************
*
* sysTimestampFreq - get the timestamp timer clock frequency
*
* This routine returns the frequency of the timer clock, in ticks per second.
* The rate of the timestamp timer should be set explicitly within the BSP,
* in the sysHwInit() routine.
*
* RETURNS: The timestamp timer clock frequency, in ticks per second.
*/

UINT32 sysTimestampFreq (void)
    {
    return (TIMER2_HZ);
    }

/*******************************************************************************
*
* sysTimestamp - get the timestamp timer tick count
*
* This routine returns the current value of the timestamp timer tick counter.
* The tick count can be converted to seconds by dividing by the return of
* sysTimestampFreq().
*
* This routine should be called with interrupts locked.  If interrupts are
* not already locked, sysTimestampLock() should be used instead.
*
* RETURNS: The current timestamp timer tick count.
*
* SEE ALSO: sysTimestampLock()
*/

UINT32 sysTimestamp (void)
    {
    unsigned int count;
    FAST volatile TIMER *pTimer = (volatile TIMER *) TIMER_BASE_ADRS;

    /* select timer 0, and latch current count */
    pTimer->cntrl_word = CW_SELECT (0) | CW_COUNTLCH |
	CW_MODE (MD_RATEGEN);
    count = (unsigned int) pTimer->counter0;
    count += (((unsigned int) pTimer->counter0) << 8);

    count = (sysTimestampPeriodValue-1) - count;

    return (count);
    }

/*******************************************************************************
*
* sysTimestampLock - get the timestamp timer tick count
*
* This routine returns the current value of the timestamp timer tick counter.
* The tick count can be converted to seconds by dividing by the return of
* sysTimestampFreq().
*
* This routine locks interrupts for cases where it is necessary to stop the
* tick counter in order to read it, or when two independent counters must
* be read.  If interrupts are already locked, sysTimestamp() should be
* used instead.
*
* RETURNS: The current timestamp timer tick count.
*
* SEE ALSO: sysTimestamp()
*/

UINT32 sysTimestampLock (void)
    {
    FAST ULONG statusReg;
    unsigned int count;
    FAST volatile TIMER *pTimer = (volatile TIMER *) TIMER_BASE_ADRS;

    statusReg = intLock ();	/* turn of timer 1 ints just in case */

    /* select timer 0, and latch current count */
    pTimer->cntrl_word = CW_SELECT (0) | CW_COUNTLCH |
        CW_MODE (MD_RATEGEN);
    count = (unsigned int) pTimer->counter0;
    count += (((unsigned int) pTimer->counter0) << 8);

    intUnlock (statusReg);

    count = (sysTimestampPeriodValue-1) - count;

    return (count);
    }

#endif  /* INCLUDE_TIMESTAMP */