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/* Clock_init()
*
* This routine initializes Timer 1 for an MC68302.
* The tick frequency is 1 millisecond.
*
* Input parameters: NONE
*
* Output parameters: NONE
*
* COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.
* On-Line Applications Research Corporation (OAR).
* All rights assigned to U.S. Government, 1994.
*
* This material may be reproduced by or for the U.S. Government pursuant
* to the copyright license under the clause at DFARS 252.227-7013. This
* notice must appear in all copies of this file and its derivatives.
*
* $Id$
*/
#include <stdlib.h> /* for atexit() */
#include <rtems.h>
#include <bsp.h>
#include <clockdrv.h>
#include "m68302.h"
#define TMR1_VAL ( RBIT_TMR_RST /* software reset the timer */\
| RBIT_TMR_ICLK_MASTER16 /* master clock divided by 16 */\
| RBIT_TMR_FRR /* restart timer after ref reached */\
| RBIT_TMR_ORI) /* enable interrupt when ref reached */
#define TRR1_VAL 1000 /* 1000 ticks @ 16MHz/16
* = 1 millisecond tick.
*/
/*
* Clock_driver_ticks is a monotonically increasing counter of the
* number of clock ticks since the driver was initialized.
*/
volatile rtems_unsigned32 Clock_driver_ticks;
/*
* Clock_isrs is the number of clock ISRs until the next invocation of
* the RTEMS clock tick routine. The clock tick device driver
* gets an interrupt once a millisecond and counts down until the
* length of time between the user configured microseconds per tick
* has passed.
*/
rtems_unsigned32 Clock_isrs;
rtems_device_driver Clock_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp,
rtems_id tid,
rtems_unsigned32 *rval
)
{
Install_clock( Clock_isr );
}
void Install_clock(
rtems_isr_entry clock_isr
)
{
Clock_driver_ticks = 0;
Clock_isrs = BSP_Configuration.microseconds_per_tick / 1000;
if ( BSP_Configuration.ticks_per_timeslice ) {
/* set_vector( clock_isr, 137, 1 );*/
m302.reg.trr1 = TRR1_VAL; /* set timer reference register */
m302.reg.tmr1 = TMR1_VAL; /* set timer mode register & enable */
/*
* Enable TIMER1 interrupts only.
*/
m302.reg.imr = RBIT_IMR_TIMER1; /* set 68302 int-mask to allow ints */
atexit( Clock_exit );
}
}
void Clock_exit( void )
{
if ( BSP_Configuration.ticks_per_timeslice ) {
/* TODO: figure out what to do here */
/* do not restore old vector */
}
}
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