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/* Clock_init()
*
* This routine initializes the Tick Timer 2 on the MVME162 board.
* 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.rtems.com/license/LICENSE.
*
* Modifications of respective RTEMS file: COPYRIGHT (c) 1994.
* EISCAT Scientific Association. M.Savitski
*
* This material is a part of the MVME162 Board Support Package
* for the RTEMS executive. Its licensing policies are those of the
* RTEMS above.
*/
#include <stdlib.h>
#include <bsp.h>
#define MS_COUNT 1000 /* T2's countdown constant (1 ms) */
#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 );
#define CLOCK_VECTOR (VBR0 * 0x10 + 0x9)
/*
* 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;
lcsr->timer_cnt_2 = 0; /* clear counter */
lcsr->intr_clear |= 0x02000000;
if ( Clock_isrs == 1 ) {
rtems_clock_tick();
Clock_isrs = rtems_configuration_get_microseconds_per_tick() / 1000;
}
else
Clock_isrs -= 1;
}
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, CLOCK_VECTOR, 1 );
lcsr->vector_base |= MASK_INT; /* unmask VMEchip2 interrupts */
lcsr->to_ctl = 0xE7; /* prescaler to 1 MHz (see Appendix A1) */
lcsr->timer_cmp_2 = MS_COUNT;
lcsr->timer_cnt_2 = 0; /* clear counter */
lcsr->board_ctl |= 0x700; /* increment, reset-on-compare, and */
/* clear-overflow-cnt */
lcsr->intr_level[0] |= CLOCK_INT_LEVEL * 0x10; /* set int level */
lcsr->intr_ena |= 0x02000000; /* enable tick timer 2 interrupt */
atexit( Clock_exit );
}
void Clock_exit( void )
{
/* Dummy for now. See other m68k BSP's for code examples */
}
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;
}
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