pcctimer.c

IXP425的BSP代码

        }
    }

/*******************************************************************************
*
* sysAuxClkEnable - turn on auxiliary clock interrupts
*
* This routine enables auxiliary clock interrupts.
*
* RETURNS: N/A
*
* SEE ALSO: sysAuxClkConnect(), sysAuxClkDisable(), sysAuxClkRateSet()
*/

void sysAuxClkEnable (void)

    {
    if ((!sysAuxClkRunning) && (!sysTimestampRunning))
        {
        /* preload the preload register */
        *TIC_2_PRELOAD = (short) (65536 - (TICK_FREQ / auxClkTicksPerSecond));

        /* enable the clock interrupt */

        *TIC_2_CSR     = TIC_2_CSR_STOP; /* load counter from preload reg */

        /* clear overflow counter, enable & start counter */
        *TIC_2_CSR     = TIC_2_CSR_CLR_OVF |
                         TIC_2_CSR_ENABLE;

        *TIC_2_INT_CTL = TIC_2_INT_CTL_CLEAR  |
                         TIC_2_INT_CTL_ENABLE |
                         INT_LVL_TIC_2;   /* reset&enable int, set level */

        sysAuxClkRunning = TRUE;
        }
    }

/*******************************************************************************
*
* 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
    (
    int ticksPerSecond     /* number of clock interrupts per second */
    )
    {
    if (sysTimestampRunning)
	return (ERROR);

    if (ticksPerSecond < AUX_CLK_RATE_MIN || ticksPerSecond > AUX_CLK_RATE_MAX)
        return (ERROR);

    auxClkTicksPerSecond = ticksPerSecond;

    if (sysAuxClkRunning)
        {
        sysAuxClkDisable ();
        sysAuxClkEnable ();
        }

    return (OK);
    }

#ifdef	INCLUDE_TIMESTAMP

/*******************************************************************************
*
* sysTimestampConnect - connect a user routine to the timestamp timer interrupt
*
* This routine usually specifies the user interrupt routine to be called at
* each timestamp timer interrupt.  In this case, however, the timestamp timer
* interrupt is not used since the timer is reset by the system clock before
* an interrupt can be generated.
*
* 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 disables 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)
    {
    if (sysTimestampRunning)
        {
        *TIC_2_CSR = TIC_2_CSR_STOP;		/* clear the counter */
        *TIC_2_CSR = TIC_2_CSR_ENABLE;		/* enable the timer */
        return (OK);
        }

    if ((sysAuxClkRunning) || (!sysClkRunning))
	return (ERROR);

    sysTimestampRunning = TRUE;

    /*
     * Disable the timer interrupt.  The timestamp timer is reset by the
     * system clock before rollover occurs.
     */

    *TIC_2_INT_CTL = TIC_2_INT_CTL_DISABLE;

    *TIC_2_PRELOAD = 0x0;		/* highest period -> freerunning */

    *TIC_2_CSR = TIC_2_CSR_STOP;	/* clear the counter */
    *TIC_2_CSR = TIC_2_CSR_ENABLE;	/* enable the timer */

    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 (sysAuxClkRunning)
        return (ERROR);

    if (sysTimestampRunning)
	{
        sysTimestampRunning = FALSE;

        *TIC_2_CSR = TIC_2_CSR_DISABLE;		/* disable the timer */
        }

    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)
    {
    return (TICK_FREQ / sysClkTicksPerSecond);
    }

/*******************************************************************************
*
* 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)
    {
    UINT32 timerFreq;

    timerFreq = TICK_FREQ;

    return (timerFreq);
    }

/*******************************************************************************
*
* 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)
    {
    UINT32 tick = 0;
    register short * pCounter;

    if (sysTimestampRunning)
	{
	pCounter = TIC_2_COUNTER;

        *TIC_2_CSR = TIC_2_CSR_DISABLE;		/* disable the timer */

        tick = *pCounter;			/* read tick counter value */

        *TIC_2_CSR = TIC_2_CSR_ENABLE;		/* enable the timer */

	tick &= 0x0000ffff;
	}

    return (tick);
    }

/*******************************************************************************
*
* 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)
    {
    UINT32 tick = 0;
    register short * pCounter;
    int lockKey;

    if (sysTimestampRunning)
	{
	pCounter = TIC_2_COUNTER;

        lockKey = intLock ();			/* LOCK INTERRUPTS */

        *TIC_2_CSR = TIC_2_CSR_DISABLE;		/* disable the timer */

        tick = *pCounter;			/* read tick counter value */

        *TIC_2_CSR = TIC_2_CSR_ENABLE;		/* enable the timer */

        intUnlock (lockKey);			/* UNLOCK INTERRUPTS */

	tick &= 0x0000ffff;
	}

    return (tick);
    }

#endif	/* INCLUDE_TIMESTAMP */