ppc860timer.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)
    {
    UINT32  tempDiv = SYS_CPU_FREQ / (sysAuxClkTicksPerSecond << 8);

    if ((!sysAuxClkRunning) && (tempDiv <= USHRT_MAX * 16))
	{
        /* start, reset, but disable timer2 */
        
        *TGCR(CPM_MEM_BASE) &= ~(TGCR_RST2 | TGCR_STP2);
        *TCN2(CPM_MEM_BASE) = 0x0;

	if (tempDiv <= USHRT_MAX)
	    {
            *TRR2(CPM_MEM_BASE) = (UINT16) tempDiv;
            *TMR2(CPM_MEM_BASE) = (TMR_ICLK_IN_GEN | TMR_ORI |
                                   TMR_FRR | (TMR_PS_MSK & 0xff00));
	    }
	else
	    {
            *TRR2(CPM_MEM_BASE) = (UINT16) (tempDiv / 16);
            *TMR2(CPM_MEM_BASE) = (TMR_ICLK_IN_GEN_DIV16 | TMR_ORI |
                                   TMR_FRR | (TMR_PS_MSK & 0xff00));
	    }
 
        *TER2(CPM_MEM_BASE) = 0xffff;		/* clear event */
        *CIMR(CPM_MEM_BASE) |= CISR_TIMER2;	/* unmask interupt */

        if (! sysAuxClkIntConnected)
            {
            (void) intConnect (IV_TIMER2, (VOIDFUNCPTR) sysAuxClkInt, 0);
            sysAuxClkIntConnected = TRUE;
            }
        
        *TGCR(CPM_MEM_BASE) |= TGCR_RST2;	/* enable timer2 */

	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.
*
* 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 (ticksPerSecond < AUX_CLK_RATE_MIN || ticksPerSecond > AUX_CLK_RATE_MAX)
	return (ERROR);

    sysAuxClkTicksPerSecond = ticksPerSecond;

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

    return (OK);
    }



#ifdef  INCLUDE_TIMESTAMP

/*******************************************************************************
*
* sysTimestampInt - timestamp timer interrupt handler
*
* This rountine handles the timestamp timer interrupt.  A user routine is
* called, if one was connected by sysTimestampConnect().
*
* RETURNS: N/A
*
* SEE ALSO: sysTimestampConnect()
*/

LOCAL void sysTimestampInt (void)
    {
    *TER4(CPM_MEM_BASE) |= TER_REF;	/* clear TMR4 reference bit */
    *CISR(CPM_MEM_BASE) = CISR_TIMER4;	/* clear TMR4 interrupt 
								register bit */
    if (sysTimestampRoutine != NULL)    /* call user routine */
        (*sysTimestampRoutine) (sysTimestampArg);
    }

/*******************************************************************************
*
* 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 */
    )
    {
    sysTimestampRoutine = routine;
    sysTimestampArg = arg;

    return (OK);
    }

/*******************************************************************************
*
* sysTimestampEnable - initialize and enable the timestamp timer
*
* This routine connects interrupts, and enables the timer device
*
* RETURNS: TRUE always
*/
STATUS sysTimestampEnable (void)
    {
    if (sysTimestampRunning)
        {
        *TCN3(CPM_MEM_BASE) = (UINT32) 0;	/* clear the counter */
        return (OK);
        }

    if (! sysTimestampIntConnected)
        {
        (void) intConnect (IV_TIMER4, (VOIDFUNCPTR) sysTimestampInt, 0);
        sysTimestampIntConnected = FALSE;
        }

    sysTimestampRunning = TRUE;

    /* cascade timer 3 and 4 in order to get a 32 bit timer */

    *TGCR(CPM_MEM_BASE) |= TGCR_CAS4;

    /* start, reset, but disable timers 3 and 4 */
    
    *TGCR(CPM_MEM_BASE) &= ~(TGCR_RST4 | TGCR_RST3 | TGCR_STP4 | TGCR_STP3 );

    /*
     * When timers 3 and 4 are cascaded, TMR4 is the mode register, while
     * TMR3 is ignored.
     * Set prescaler to 0, to divide the clock (SYS_CPU_FREQ) by 1.
     */

    *TMR4(CPM_MEM_BASE) = 0x0000 | TMR_ICLK_IN_GEN | TMR_ORI | TMR_FRR;
    *TMR3(CPM_MEM_BASE) = TMR_ICLK_IN_CAS;

    *((UINT32 *)TRR3(CPM_MEM_BASE)) = (UINT32) sysTimestampPeriod ();
    *((UINT32 *)TCN3(CPM_MEM_BASE)) = (UINT32) 0;
    *TER4(CPM_MEM_BASE) = (UINT16) 0xffff;
    *CIMR(CPM_MEM_BASE) |= CISR_TIMER4;
    *TGCR(CPM_MEM_BASE) |= TGCR_RST4 | TGCR_RST3;	/* enable */

    return (OK);
    }

/*******************************************************************************
*
* sysTimestampDisable - turn off auxiliary clock interrupts
*
* This routine disables auxiliary clock interrupts.
*
* RETURNS: OK, always
*
* SEE ALSO: sysTimestampEnable()
*/

STATUS sysTimestampDisable (void)
    {
    if (sysTimestampRunning)
        {
        *CIMR(CPM_MEM_BASE) &= ~CISR_TIMER4;	/* disable interrupt */
        *CIMR(CPM_MEM_BASE) &= ~CISR_TIMER3;	/* disable interrupt */
        *TGCR(CPM_MEM_BASE) |= TGCR_STP4;	/* stop timer */
        *TGCR(CPM_MEM_BASE) |= TGCR_STP3;	/* stop timer */

        sysTimestampRunning = FALSE;            /* clock is no longer running */
        }

    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 on-chip
     * timer (ie the Decrementer reload value).
     */
    
    return (0xffffffff);	/* highest period -> freerunning */
    }

/*******************************************************************************
*
* 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 PowerPC decrementer clock serves as the timestamp timer,
* the decrementer clock frequency is also the timestamp timer frequency.
*
* RETURNS: The timestamp timer clock frequency, in ticks per second.
*/

UINT32 sysTimestampFreq (void)
    {
    /* Get the prescaler value from TMR4. TMR3 is ignored in cascade mode. */

    return (SYS_CPU_FREQ / ((*TMR4(CPM_MEM_BASE) >> 8) + 1));
    }

/*******************************************************************************
*
* 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)
    {
    return (*((UINT32 *) TCN3(CPM_MEM_BASE)));
    }

/*******************************************************************************
*
* 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)
    {
    return (*((UINT32 *) TCN3(CPM_MEM_BASE)));
    }

#endif  /* INCLUDE_TIMESTAMP */