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/* Clock_initialize
*
* This routine initializes the Timer/Counter on the Intel
* 386ex evaluation 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.
*
* $Id$
*/
#define TMR0 0xF040
#define TMR1 0xF041
#define TMR2 0xF042
#define TMRCON 0xF043
#define TMRCFG 0xF834
#include <bsp.h>
#include <bsp/irq.h>
#include <rtems/libio.h>
#include <stdlib.h>
uint32_t Clock_isrs; /* ISRs until next tick */
static uint32_t Clock_initial_isr_value;
volatile uint32_t Clock_driver_ticks;
void Clock_exit( void );
/*
* These are set by clock driver during its init
*/
rtems_device_major_number rtems_clock_major = ~0;
rtems_device_major_number rtems_clock_minor = 0;
/*
* This is the ISR handler.
*/
void Clock_isr()
{
/* enable_tracing(); */
Clock_driver_ticks += 1;
if ( Clock_isrs == 1 ) {
rtems_clock_tick();
Clock_isrs = Clock_initial_isr_value; /* rtems_configuration_get_microseconds_per_tick() / 1000;*/
}
else
Clock_isrs -= 1;
}
void ClockOff(const rtems_irq_connect_data* unused)
{
outport_byte ( TMRCFG , 0x80 ); /* disable the counter timer */
}
void ClockOn(const rtems_irq_connect_data* unused)
{
outport_byte ( TMRCFG , 0x00 ); /* enable the counter timer */
}
int ClockIsOn(const rtems_irq_connect_data* unused)
{
return ((i8259s_cache & 0x1) == 0);
}
static rtems_irq_connect_data clockIrqData = {BSP_PERIODIC_TIMER,
Clock_isr,
0,
ClockOn,
ClockOff,
ClockIsOn};
rtems_device_driver Clock_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
unsigned timer_counter_init_value;
unsigned char clock_lsb, clock_msb;
Clock_driver_ticks = 0;
Clock_isrs =
Clock_initial_isr_value =
rtems_configuration_get_microseconds_per_tick() / 1000; /* ticks per clock_isr */
/*
* configure the counter timer ( should be based on microsecs/tick )
* NB. The divisor(Clock_isrs) resolves the is the same number that appears in confdefs.h
* when setting the microseconds_per_tick value.
*/
ClockOff ( &clockIrqData );
timer_counter_init_value = rtems_configuration_get_microseconds_per_tick() / Clock_isrs;
clock_lsb = (unsigned char)timer_counter_init_value;
clock_msb = timer_counter_init_value >> 8;
outport_byte ( TMRCON , 0x34 );
outport_byte ( TMR0 , clock_lsb ); /* load LSB first */
outport_byte ( TMR0 , clock_msb ); /* then MSB */
if (!BSP_install_rtems_irq_handler (&clockIrqData)) {
printk("Unable to initialize system clock\n");
rtems_fatal_error_occurred(1);
}
/*
* make major/minor avail to others such as shared memory driver
*/
rtems_clock_major = major;
rtems_clock_minor = minor;
return RTEMS_SUCCESSFUL;
}
void Clock_exit()
{
ClockOff(&clockIrqData);
BSP_remove_rtems_irq_handler (&clockIrqData);
}
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