ppc555timer.c

IXP425的BSP代码

/* templateTimer.c - template timer library */

/* Copyright 1984-2001 Wind River Systems, Inc. */

/*
modification history
--------------------
01d,15sep01,dat  removed inline assembly, used vxDecReload()
01c,08sep99,cmc  test
01b,15apr99,cmc  Fixed a bug in sysAuxClkRateSet
01a,15apr99,cmc   ppc555Timer.c created 
*/

/*
DESCRIPTION
This library provides PowerPC/555 system clock, auxiliary clock, and timestamp
support.

The PPC555 Decrementer Timer is used to implement the system clock and timestamp.
The PPC555 PIT (Periodic Interrupt Timer) is used to implement the auxiliary clock.

The macro DEC_CLOCK_FREQ (frequency of the decrementer input clock) should be
defined before using this module. The macro DEC_CLK_TO_INC (ratio between the
number of decrementer input clock cycles and one counter increment) can be 
redefined prior to #including this file into sysLib.c.
The macros SYS_CLK_RATE_MIN and SYS_CLK_RATE_MAX must be defined to provide
parameter checking for sysClkRateSet().

To include the timestamp timer facility, the macro INCLUDE_TIMESTAMP must be
defined. Note that changing the system clock rate will affect the timestamp
timer period, which can be read by calling sysTimestampPeriod().

If dynamic bus clock speed calculation is needed, the BSP can define the
macro PPC_TMR_RATE_SET_ADJUST to be a call to the needed routine.
This macro, if defined, will be executed during each call to sysClkRateSet().
PPC_TMR_RATE_SET_ADJUST is usually not defined.

    e.g. Assuming sysClkRateAdjust can compute a correct value
    for sysDecClkFrequency.

    #define PPC_TMR_RATE_SET_ADJUST \
	sysClkRateAdjust (&sysDecClkFrequency)

INCLUDE FILES: ppc555Timer.h
   
SEE ALSO:
.pG "Configuration"
*/

/* includes */

#include "vxWorks.h"
#include "config.h"
#include "arch/ppc/vxPpcLib.h"
#include "drv/timer/timerDev.h"
#include "drv/timer/timestampDev.h"

/* local defines */

#ifndef	DEC_CLK_TO_INC
#define	DEC_CLK_TO_INC		1		/* # bus clks per increment */
#endif

#define DEFAULT_DEC_CLK_FREQ	33333333	/* 33.33 Mhz default */

#define	DEC_SHIFT 0

#ifndef CPU_INT_UNLOCK
#    define  CPU_INT_UNLOCK(x) (intUnlock(x))
#endif

#ifndef CPU_INT_LOCK
#    define  CPU_INT_LOCK(x) (*x = intLock())
#endif

/* extern declarations */
IMPORT STATUS excIntConnect (VOIDFUNCPTR *, VOIDFUNCPTR);
IMPORT UINT32 vxImemBaseGet();

/* Locals */
LOCAL int 	sysClkTicksPerSecond 	= 60;	  /* default 60 ticks/second */
LOCAL FUNCPTR	sysClkRoutine		= NULL;
LOCAL int	sysClkArg		= NULL;
LOCAL BOOL	sysClkConnectFirstTime	= TRUE;
LOCAL int	decCountVal		= 10000000;	/* default dec value */
LOCAL BOOL	sysClkRunning 		= FALSE;
LOCAL int 	sysDecClkFrequency	= DEFAULT_DEC_CLK_FREQ/DEC_CLK_TO_INC;

LOCAL FUNCPTR sysAuxClkRoutine	= NULL;
LOCAL int sysAuxClkArg		= NULL;
LOCAL BOOL sysAuxClkRunning	= FALSE;
LOCAL BOOL sysAuxClkIntConnected	= FALSE;
LOCAL int sysAuxClkTicksPerSecond = 60;

#ifdef	INCLUDE_TIMESTAMP
LOCAL BOOL	sysTimestampRunning  	= FALSE;   /* timestamp running flag */
#endif	/* INCLUDE_TIMESTAMP */

/*******************************************************************************
*
* sysClkInt - clock interrupt handler
*
* This routine handles the clock interrupt on the PowerPC architecture. It is
* attached to the decrementer vector by the routine sysClkConnect().
*
* RETURNS : N/A
*/

LOCAL void sysClkInt (void)
    {
    vxDecReload (decCountVal); /* reload decrementer */

    /* Unlock interrupts during decrementer processing */

    CPU_INT_UNLOCK (_PPC_MSR_EE);

    /* execute the system clock routine */

    if (sysClkRunning && (sysClkRoutine != NULL))
	(*(FUNCPTR) 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.  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 connect */
    int 	arg		/* argument for the routine */
    )
    {

    if (sysClkConnectFirstTime)
	{
	sysHwInit2();
	sysClkConnectFirstTime = FALSE;
	}

#ifdef	DEC_CLOCK_FREQ 
    sysDecClkFrequency = DEC_CLOCK_FREQ / DEC_CLK_TO_INC;
#endif	/* DEC_CLOCK_FREQ */

    /* connect the routine to the decrementer exception */

    excIntConnect ((VOIDFUNCPTR *) _EXC_OFF_DECR, (VOIDFUNCPTR) sysClkInt);
    
    sysClkRoutine	= routine;
    sysClkArg		= arg;

    return (OK);
    }

/******************************************************************************
*
* 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)
	{
	sysClkRunning = TRUE;
	vxDecSet (decCountVal);
	}
    }

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

void sysClkDisable (void)
    {
    if (sysClkRunning)
	sysClkRunning = FALSE;
    }

/******************************************************************************
*
* sysClkRateGet - get the system clock rate
*
* This routine returns the system clock rate.
*
* 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 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 */
    )
    {
    if (ticksPerSecond < SYS_CLK_RATE_MIN || ticksPerSecond > SYS_CLK_RATE_MAX)
        return (ERROR);

    /* save the clock speed */

    sysClkTicksPerSecond = ticksPerSecond;

    /* Calibrate the clock, if needed. */

#ifdef PPC_TMR_RATE_SET_ADJUST
    PPC_TMR_RATE_SET_ADJUST;
#endif

    /* 
     * compute the value to load in the decrementer. The new value will be
     * load in the decrementer after the end of the current period
     */

    decCountVal = sysDecClkFrequency / ticksPerSecond;

    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.  
*
* NOTE: This routine has no effect, since the CPU decrementer has no
* 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.
*
* NOTE: This routine has no effect, since the CPU decrementer has no
* timestamp timer interrupt.
*
* RETURNS: OK, always.
*
* SEE ALSO: sysTimestampDisable()
*/

STATUS sysTimestampEnable (void)
   {
   if (sysTimestampRunning)
      {