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/*
* This routine initializes the Tick Timer 2 on the MVME147 board.
* The tick frequency is 1 millisecond.
*/
/*
* 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.rtems.org/license/LICENSE.
*
* MVME147 port for TNI - Telecom Bretagne
* by Dominique LE CAMPION (Dominique.LECAMPION@enst-bretagne.fr)
* May 1996
*/
#include <stdlib.h>
#include <bsp.h>
#include <rtems/clockdrv.h>
#define MS_COUNT 65376 /* 1ms */
/* MS_COUNT = 0x10000 - 1e-3/6.25e-6 */
#define CLOCK_INT_LEVEL 6 /* T2's interrupt level */
uint32_t Clock_isrs; /* ISRs until next tick */
volatile uint32_t Clock_driver_ticks; /* ticks since initialization */
rtems_isr_entry Old_ticker;
void Clock_exit( void );
/*
* ISR Handler
*/
static rtems_isr Clock_isr(rtems_vector_number vector)
{
Clock_driver_ticks += 1;
pcc->timer2_int_control |= 0x80; /* Acknowledge interr. */
if (Clock_isrs == 1) {
rtems_clock_tick();
Clock_isrs = rtems_configuration_get_microseconds_per_tick() / 1000;
}
else
Clock_isrs -= 1;
}
static void Install_clock(rtems_isr_entry clock_isr )
{
Clock_driver_ticks = 0;
Clock_isrs = rtems_configuration_get_microseconds_per_tick() / 1000;
Old_ticker = (rtems_isr_entry) set_vector( clock_isr, TIMER_2_VECTOR, 1 );
pcc->timer2_int_control = 0x00; /* Disable T2 Interr. */
pcc->timer2_preload = MS_COUNT;
/* write preload value */
pcc->timer2_control = 0x07; /* clear T2 overflow counter, enable counter */
pcc->timer2_int_control = CLOCK_INT_LEVEL|0x08;
/* Enable Timer 2 and set its int. level */
atexit( Clock_exit );
}
void Clock_exit( void )
{
pcc->timer2_int_control = 0x00; /* Disable T2 Interr. */
}
rtems_device_driver Clock_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
Install_clock( Clock_isr );
return RTEMS_SUCCESSFUL;
}
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