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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) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* $Id$
*/
#include <stdlib.h> /* for atexit() */
#include <bsp.h>
#include <rtems/libio.h>
#include "m68302.h"
#define CLOCK_VECTOR 137
#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;
void Clock_exit( void );
/*
* These are set by clock driver during its init
*/
rtems_device_major_number rtems_clock_major = ~0;
rtems_device_minor_number rtems_clock_minor;
/*
* ISR Handler
*/
rtems_isr Clock_isr(
rtems_vector_number vector
)
{
Clock_driver_ticks += 1;
m302.reg.isr = RBIT_ISR_TIMER1; /* clear in-service bit */
m302.reg.ter1 = (RBIT_TER_REF | RBIT_TER_CAP); /* clear timer intr request */
if ( Clock_isrs == 1 ) {
rtems_clock_tick();
Clock_isrs = BSP_Configuration.microseconds_per_tick / 1000;
}
else
Clock_isrs -= 1;
}
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, CLOCK_VECTOR, 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 */
}
}
rtems_device_driver Clock_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
Install_clock( Clock_isr );
/*
* make major/minor avail to others such as shared memory driver
*/
rtems_clock_major = major;
rtems_clock_minor = minor;
return RTEMS_SUCCESSFUL;
}
rtems_device_driver Clock_control(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
rtems_unsigned32 isrlevel;
rtems_libio_ioctl_args_t *args = pargp;
if (args == 0)
goto done;
/*
* This is hokey, but until we get a defined interface
* to do this, it will just be this simple...
*/
if (args->command == rtems_build_name('I', 'S', 'R', ' '))
{
Clock_isr( CLOCK_VECTOR);
}
else if (args->command == rtems_build_name('N', 'E', 'W', ' '))
{
rtems_interrupt_disable( isrlevel );
(void) set_vector( args->buffer, CLOCK_VECTOR, 1 );
rtems_interrupt_enable( isrlevel );
}
done:
return RTEMS_SUCCESSFUL;
}
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