m68332timer.c

IXP425的BSP代码

/* m68332Timer.c - MC68332 timer library */

/* Copyright 1984-1992 Wind River Systems, Inc. */
#include "copyright_wrs.h"

/*
modification history
--------------------
01a,13aug92,caf  moved clock routines from ver 01g of evs332/sysLib.c, ansified.
*/

/*
DESCRIPTION
This library contains routines to manipulate the timer functions on the
Motorola MC68302.  This library handles both the system clock and the auxiliary
clock functions.  However, the auxiliary clock functions have no effect.

The macros SYS_CLK_RATE_MIN, SYS_CLK_RATE_MAX, AUX_CLK_RATE_MIN, and
AUX_CLK_RATE_MAX must be defined to provide parameter checking for the
sys[Aux]ClkRateSet() routines.
*/

/* locals */

LOCAL FUNCPTR sysClkRoutine	= NULL; /* routine to call on clock interrupt */
LOCAL int sysClkArg		= NULL; /* its argument */
LOCAL int sysClkRunning		= FALSE;
LOCAL int sysClkConnected	= FALSE;
LOCAL int sysClkTicksPerSecond	= 60;
LOCAL int sysClkPITR		= 0x182;/* 512 prescale... 60.09 Hz */

LOCAL int auxClkTicksPerSecond	= 60;

/*******************************************************************************
*
* sysClkInt - handle system clock interrupts
*
* This routine handles system clock interrupts.
*
* RETURNS: N/A
*/

LOCAL void sysClkInt (void)
    {
    if (sysClkRoutine != NULL)
        (*sysClkRoutine) (sysClkArg);
    }

/*******************************************************************************
*
* sysClkConnect - connect a routine to the system clock interrupt
*
* This routine specifies the interrupt service routine to be called at each
* clock interrupt.  It does not enable system clock interrupts.  Normally,
* it is called from usrRoot() in usrConfig.c to connect usrClock() to the
* system clock interrupt.
*
* RETURNS: OK, or ERROR if the routine cannot be connected to the interrupt.
*
* SEE ALSO: intConnect(), usrClock(), sysClkEnable()
*/

STATUS sysClkConnect
    (
    FUNCPTR routine,	/* routine to be called at each clock interrupt */
    int     arg		/* argument with which to call routine          */
    )
    {
    sysHwInit2 ();	/* XXX for now -- needs to be in usrConfig.c */

    sysClkRoutine   = routine;
    sysClkArg       = arg;
    sysClkConnected = TRUE;

    return (OK);
    }

/*******************************************************************************
*
* sysClkDisable - turn off system clock interrupts
*
* This routine disables system clock interrupts.
*
* RETURNS: N/A
*
* SEE ALSO: sysClkEnable()
*/

void sysClkDisable (void)
    {
    if (sysClkRunning)
	{
	*M332_SIM_PICR &= ~(SIM_PICR_PIRQL_MASK);	/* disable interrupts */
	sysClkRunning	= FALSE;			/* clock is stopped */
	}
    }

/*******************************************************************************
*
* sysClkEnable - turn on system clock interrupts
*
* This routine enables system clock interrupts.
*
* RETURNS: N/A
*
* SEE ALSO: sysClkConnect(), sysClkDisable(), sysClkRateSet()
*/

void sysClkEnable (void)
    {
    if (!sysClkRunning)
	{
	*M332_SIM_PITR	= sysClkPITR;			/* set clock rate */
	*M332_SIM_PICR |= INT_LVL_SIM << 8;		/* enable interrupts */
	sysClkRunning	= TRUE;
	}
    }

/*******************************************************************************
*
* sysClkRateGet - get the system clock rate
*
* This routine returns the interrupt rate of the system clock.
*
* RETURNS: The number of ticks per second of the system clock.
*
* SEE ALSO: sysClkEnable(), sysClkRateSet()
*/

int sysClkRateGet (void)
    {
    return (sysClkTicksPerSecond);
    }

/*******************************************************************************
*
* sysClkRateSet - set the system clock rate
*
* This routine sets the interrupt rate of the system clock.  It does not
* enable system clock interrupts.  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: sysClkEnable(), sysClkRateGet()
*/

STATUS sysClkRateSet
    (
    int ticksPerSecond	/* number of clock interrupts per second */
    )
    {
    FAST int count;

    if (ticksPerSecond < SYS_CLK_RATE_MIN || ticksPerSecond > SYS_CLK_RATE_MAX)
        return (ERROR);

    /* round to best PITR count value using integer arithmetic */

    count = ((((10 * SYS_EXTAL_FREQ) / (4 * ticksPerSecond)) + 5) / 10);

    if (count < 256)
        sysClkPITR = count;
    else
	{
	count = ((((10 * SYS_EXTAL_FREQ) / (2048 * ticksPerSecond)) + 5) / 10);
        sysClkPITR = SIM_PITR_PTP | count;
	}

    sysClkTicksPerSecond = ticksPerSecond;

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

    return (OK);
    }

/*******************************************************************************
*
* 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 does not enable auxiliary clock
* interrupts.
*
* NOTE
* This routine has no effect, since there is no auxiliary clock.
*
* RETURNS: ERROR, since there is no auxiliary clock.
*
* SEE ALSO: intConnect(), sysAuxClkEnable()
*/

STATUS sysAuxClkConnect
    (
    FUNCPTR routine,	/* routine called at each aux. clock interrupt */
    int     arg		/* argument with which to call routine         */
    )
    {
    return (ERROR);
    }

/*******************************************************************************
*
* sysAuxClkDisable - turn off auxiliary clock interrupts
*
* This routine disables auxiliary clock interrupts.
*
* NOTE:
* This routine has no effect, since there is no auxiliary clock.
*
* RETURNS: N/A
*
* SEE ALSO: sysAuxClkEnable()
*/

void sysAuxClkDisable (void)
    {
    }

/*******************************************************************************
*
* sysAuxClkEnable - turn on auxiliary clock interrupts
*
* This routine enables auxiliary clock interrupts.
*
* NOTE:
* This routine has no effect, since there is no auxiliary clock.
*
* RETURNS: N/A
*
* SEE ALSO: sysAuxClkConnect(), sysAuxClkDisable(), sysAuxClkRateSet()
*/

void sysAuxClkEnable (void)
    {
    }

/*******************************************************************************
*
* sysAuxClkRateGet - get the auxiliary clock rate
*
* This routine returns the interrupt rate of the auxiliary clock.
*
* NOTE:
* This routine has no effect, since there is no auxiliary clock.
* It does not verify the existence 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.
*
* NOTE:
* This routine has no effect, since there is no auxiliary clock.
*
* RETURNS: ERROR, since there is no auxiliary clock.
*
* SEE ALSO: sysAuxClkEnable(), sysAuxClkRateGet()
*/

STATUS sysAuxClkRateSet
    (
    int ticksPerSecond	    /* number of clock interrupts per second */
    )
    {
    return (ERROR);
    }