/* Clock_init()
*
* This routine initializes the DP8570A periodic interrupt on the
* efi68k board. 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>
#include <bsp.h>
#include <rtems/libio.h>
#define CLOCK_VECTOR (TCP_ISR_LEVEL+24)
rtems_unsigned32 Clock_isrs; /* ISRs until next tick */
volatile rtems_unsigned32 Clock_driver_ticks;
/* ticks since initialization */
rtems_isr_entry Old_ticker;
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;
void per_interrupt(void)
{
Clock_driver_ticks += 1;
*MSR = PER;
if ( Clock_isrs == 1 ) {
rtems_clock_tick();
Clock_isrs = BSP_Configuration.microseconds_per_tick / 1000;
}
else
Clock_isrs -= 1;
}
rtems_isr Clock_isr(
rtems_vector_number vector
)
{
unsigned char entry_msr, msr;
entry_msr = *MSR;
*MSR = 0;
while ( (msr=*MSR) & INT )
/* test enabled interrupt bits */
if (msr & PER)
per_interrupt();
else if (msr & T0) {
*MSR = T0; /* reset interrupt */
Timer_interrupts++; /* inc wrap around counter */
}
else
/* there has been an error if we reach this point */
/* default action: reset all the interrupts */
*MSR = ( PER | AL | T0 | T1 );
*MSR = entry_msr & (RS | PS);
}
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 ) {
Old_ticker = (rtems_isr_entry) set_vector( clock_isr, CLOCK_VECTOR, 1 );
*MSR = RS; /* enable 1mS interrupts */
*ICR0 |= OME;
atexit( Clock_exit );
}
}
void Clock_exit( void )
{
if ( BSP_Configuration.ticks_per_timeslice ) {
/* shutdown periodic interrupt */
*MSR = RS;
*ICR0 &= 0xc0;
/* 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;
}
