ambatimer.c

Vxworks下的时钟驱动源程序

* currently enabled, the clock is disabled and then re-enabled with the new
* rate.  Normally it is called by usrRoot() in usrConfig.c.
*
* RETURNS:
* OK, or ERROR if the tick rate is invalid or the timer cannot be set.
*
* SEE ALSO: sysClkRateGet(), sysClkEnable()
*/

STATUS sysClkRateSet
    (
    int ticksPerSecond	    /* number of clock interrupts per second */
    )
    {
    if (ticksPerSecond < SYS_CLK_RATE_MIN || ticksPerSecond > SYS_CLK_RATE_MAX)
	return ERROR;

    sysClkTicksPerSecond = ticksPerSecond;

    if (sysClkRunning)
	{
	sysClkDisable ();
	sysClkEnable ();
	}

    return OK;
    }

/*******************************************************************************
*
* sysAuxClkInt - handle an auxiliary clock interrupt
*
* This routine handles an auxiliary clock interrupt.  It acknowledges the
* interrupt and calls the routine installed by sysAuxClkConnect().
*
* RETURNS: N/A
*/

LOCAL void sysAuxClkInt (void)
    {
    /* Acknowledge interrupt: any write to Clear Register clears interrupt */

    AMBA_TIMER_WRITE (AUX_TIMER_CLEAR (AMBA_TIMER_BASE), 0);


    /* If any routine attached via sysAuxClkConnect(), call it */

    if (sysAuxClkRoutine != NULL)
	(*sysAuxClkRoutine) (sysAuxClkArg);
    }

/*******************************************************************************
*
* sysAuxClkConnect - connect a routine to the auxiliary clock interrupt
*
* This routine specifies the interrupt service routine to be called at each
* auxiliary clock interrupt.  It also connects the clock error interrupt
* service routine.
*
* RETURNS: OK, or ERROR if the routine cannot be connected to the interrupt.
*
* SEE ALSO: intConnect(), sysAuxClkEnable()
*/

STATUS sysAuxClkConnect
    (
    FUNCPTR routine,    /* routine called at each aux clock interrupt */
    int arg             /* argument with which to call routine        */
    )
    {
    sysAuxClkRoutine = NULL;	/* ensure routine not called with wrong arg */
    sysAuxClkArg	= arg;

    if (routine == NULL)
	return OK;

#if ((CPU_FAMILY == ARM) && ARM_THUMB)
    /* set b0 so that sysAuxClkConnect() can be used from shell */

    sysAuxClkRoutine = (FUNCPTR)((UINT32)routine | 1);
#else
    sysAuxClkRoutine	= routine;
#endif /* CPU_FAMILY == ARM */

    return OK;
    }

/*******************************************************************************
*
* sysAuxClkDisable - turn off auxiliary clock interrupts
*
* This routine disables auxiliary clock interrupts.
*
* RETURNS: N/A
*
* SEE ALSO: sysAuxClkEnable()
*/

void sysAuxClkDisable (void)
    {
    if (sysAuxClkRunning)
        {
	/*
	 * Disable timer itself. Might as well leave it configured for
	 * Periodic mode, divided by 16.
	 */

	AMBA_TIMER_WRITE(
		   AUX_TIMER_CTRL (AMBA_TIMER_BASE), AMBA_TIMER_AUX_TC_DISABLE);


	/* Disable the timer interrupt in the Interrupt Controller */

	AMBA_TIMER_INT_DISABLE (AUX_TIMER_INT_LVL);

	sysAuxClkRunning = FALSE;
        }
    }

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

void sysAuxClkEnable (void)
    {
    UINT32 tc;

    if (!sysAuxClkRunning)
	{
	/* Set up in periodic mode, divide clock input by 16, enable timer */

	AMBA_TIMER_WRITE(
		    AUX_TIMER_CTRL (AMBA_TIMER_BASE), AMBA_TIMER_AUX_TC_ENABLE);
	

	/*
	 * Calculate the timer value
	 * Note that it may take some ticks to reload the counter
	 * so counter value = (clock rate / sysAuxClkTicksPerSecond) - num_ticks
	 */

	tc = (AUX_TIMER_CLK / sysAuxClkTicksPerSecond) - AMBA_RELOAD_TICKS;


	/* Load Timer Reload value into Timer registers */

	AMBA_TIMER_WRITE (AUX_TIMER_LOAD (AMBA_TIMER_BASE), tc);


	/* enable clock interrupt in interrupt controller */

	AMBA_TIMER_INT_ENABLE (AUX_TIMER_INT_LVL);
	
	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 sysAuxClkTicksPerSecond;
    }

/*******************************************************************************
*
* sysAuxClkRateSet - set the auxiliary clock rate
*
* This routine sets the interrupt rate of the auxiliary clock.  It does
* not enable auxiliary clock interrupts unilaterally, but if the
* auxiliary clock is currently enabled, the clock is disabled and then
* re-enabled with the new rate.
*
* RETURNS: OK or ERROR.
*
* SEE ALSO: sysAuxClkEnable(), sysAuxClkRateGet()
*/

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

    sysAuxClkTicksPerSecond = ticksPerSecond;

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

    return OK;
    }

#ifdef	INCLUDE_TIMESTAMP

/*******************************************************************************
*
* sysTimestampConnect - connect a user routine to a timestamp timer interrupt
*
* This routine specifies the user interrupt routine to be called at each
* timestamp timer interrupt.
*
* RETURNS: ERROR, always.
*/

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

/*******************************************************************************
*
* sysTimestampEnable - enable a timestamp timer interrupt
*
* This routine enables timestamp timer interrupts and resets the counter.
*
* RETURNS: OK, always.
*
* SEE ALSO: sysTimestampDisable()
*/

STATUS sysTimestampEnable (void)
   {
   if (sysTimestampRunning)
      {
      return OK;
      }

   if (!sysClkRunning)          /* timestamp timer is derived from the sysClk */
      return ERROR;

   sysTimestampRunning = TRUE;

   return OK;
   }

/*******************************************************************************
*
* sysTimestampDisable - disable a timestamp timer interrupt
*
* This routine disables timestamp timer interrupts.
*
* RETURNS: OK, always.
*
* SEE ALSO: sysTimestampEnable()
*/

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

    return OK;
    }

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

UINT32 sysTimestampPeriod (void)
    {
    /*
     * The period of the timestamp depends on the clock rate of the system
     * clock.
     */

    return ((UINT32)(SYS_TIMER_CLK / sysClkTicksPerSecond));
    }

/*******************************************************************************
*
* sysTimestampFreq - get a timestamp timer clock frequency
*
* This routine gets the frequency of the timer clock, in ticks per
* second.  The rate of the timestamp timer is set explicitly by the
* hardware and typically cannot be altered.
*
* NOTE: Because the system clock serves as the timestamp timer,
* the system clock frequency is also the timestamp timer frequency.
*
* RETURNS: The timestamp timer clock frequency, in ticks per second.
*/

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

/*******************************************************************************
*
* sysTimestamp - get a 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 it by the return of
* sysTimestampFreq().
*
* This routine should be called with interrupts locked.  If interrupts are
* not locked, sysTimestampLock() should be used instead.
*
* RETURNS: The current timestamp timer tick count.
*
* SEE ALSO: sysTimestampFreq(), sysTimestampLock()
*/

UINT32 sysTimestamp (void)
    {
    UINT32 t;

    AMBA_TIMER_READ (SYS_TIMER_VALUE (AMBA_TIMER_BASE), t);

#if defined (AMBA_TIMER_VALUE_MASK)
    t &= AMBA_TIMER_VALUE_MASK;
#endif

    return (sysTimestampPeriod() - t);
    }

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

UINT32 sysTimestampLock (void)
    {
    UINT32 t;

    AMBA_TIMER_READ (SYS_TIMER_VALUE (AMBA_TIMER_BASE), t);

#if defined (AMBA_TIMER_VALUE_MASK)
    t &= AMBA_TIMER_VALUE_MASK;
#endif

    return (sysTimestampPeriod() - t);
    }

#endif  /* INCLUDE_TIMESTAMP */