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/*
* 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.
*
* $Id$
*/
#include <rtems.h>
#include <bsp.h>
#include <stdlib.h>
int Ttimer_val;
bool benchmark_timer_find_average_overhead;
extern void timerisr(void);
extern int ClockIsOn(const rtems_raw_irq_connect_data*);
#define TMR0 0xF040
#define TMR1 0xF041
#define TMR2 0xF042
#define TMRCON 0xF043
#define TMRCFG 0xF834
void TimerOn(const rtems_raw_irq_connect_data* used)
{
Ttimer_val = 0; /* clear timer ISR count */
outport_byte ( TMRCON , 0xb0 ); /* select tmr2, stay in mode 0 */
outport_byte ( TMR1 , 0xfa ); /* set to 250 usec interval */
outport_byte ( TMR1 , 0x00 );
outport_byte ( TMRCON , 0x64 ); /* change to mode 2 ( starts timer ) */
/* interrupts ARE enabled */
/* outport_byte( IERA, 0x41 ); enable interrupt */
/*
* enable interrrupt at i8259 level
*/
BSP_irq_enable_at_i8259s(used->idtIndex - BSP_IRQ_VECTOR_BASE);
}
void TimerOff(const rtems_raw_irq_connect_data* used)
{
/*
* disable interrrupt at i8259 level
*/
BSP_irq_disable_at_i8259s(used->idtIndex - BSP_IRQ_VECTOR_BASE);
/* reset timer mode to standard (DOS) value */
}
static rtems_raw_irq_connect_data timer_raw_irq_data = {
BSP_RT_TIMER3 + BSP_IRQ_VECTOR_BASE,
timerisr,
TimerOn,
TimerOff,
ClockIsOn
};
void Timer_exit(void)
{
if (!i386_delete_idt_entry(&timer_raw_irq_data)) {
printk("Timer_exit:Timer raw handler removal failed\n");
rtems_fatal_error_occurred(1);
}
}
void benchmark_timer_initialize(void)
{
static bool First = true;
if (First)
{
First = false;
atexit(Timer_exit); /* Try not to hose the system at exit. */
if (!i386_set_idt_entry (&timer_raw_irq_data)) {
printk("benchmark_timer_initialize: raw handler installation failed\n");
rtems_fatal_error_occurred(1);
}
}
/* wait for ISR to be called at least once */
Ttimer_val = 0;
while (Ttimer_val == 0)
continue;
Ttimer_val = 0;
}
#define AVG_OVERHEAD 3 /* It typically takes 3.0 microseconds */
/* (3 ticks) to start/stop the timer. */
#define LEAST_VALID 4 /* Don't trust a value lower than this */
int benchmark_timer_read(void)
{
register uint32_t clicks;
register uint32_t total;
/* outport_byte( TBCR, 0x00 ); stop the timer -- not needed on intel */
outport_byte ( TMRCON, 0x40 ); /* latch the count */
inport_byte ( TMR1, clicks ); /* read the count */
total = Ttimer_val + 250 - clicks;
/* outport_byte( TBCR, 0x00 ); initial value */
/* outport_byte( IERA, 0x40 ); disable interrupt */
/* ??? Is "do not restore old vector" causing problems? */
if ( benchmark_timer_find_average_overhead == true )
return total; /* in one microsecond units */
else {
if ( total < LEAST_VALID )
return 0; /* below timer resolution */
return (total - AVG_OVERHEAD);
}
}
void benchmark_timer_disable_subtracting_average_overhead(
bool find_flag
)
{
benchmark_timer_find_average_overhead = find_flag;
}
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