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/*
* This file implements a benchmark timer using a MONGOOSE-V timer.
*
* COPYRIGHT (c) 1989-2001.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* $Id$
*/
#include <assert.h>
#include <bsp.h>
rtems_boolean Timer_driver_Find_average_overhead;
#if defined(USE_TIMER2_FOR_CLOCK)
#define TIMER_BASE MONGOOSEV_TIMER1_BASE
#define TIMER_VECTOR MONGOOSEV_IRQ_TIMER1
#else
#define TIMER_BASE MONGOOSEV_TIMER2_BASE
#define TIMER_VECTOR MONGOOSEV_IRQ_TIMER2
#endif
void Timer_initialize()
{
/*
* Programming the compare register as the maximum value should let
* it run long enough and accurate enough not to require an interrupt.
* but if it ever does generate an interrupt, we will simply fault.
*
* NOTE: This is similar to the clock driver initialization
* with the exception that the divider is disabled and
* the compare register is set to the maximum value.
*/
MONGOOSEV_WRITE_REGISTER( TIMER_BASE, MONGOOSEV_TIMER_CONTROL_REGISTER, 0);
MONGOOSEV_WRITE_REGISTER( TIMER_BASE,
MONGOOSEV_TIMER_INITIAL_COUNTER_REGISTER,
0xffffffff );
MONGOOSEV_WRITE_REGISTER( TIMER_BASE,
MONGOOSEV_TIMER_CONTROL_REGISTER,
MONGOOSEV_TIMER_CONTROL_COUNTER_ENABLE );
}
#define AVG_OVERHEAD 0 /* It typically takes N instructions */
/* to start/stop the timer. */
#define LEAST_VALID 1 /* Don't trust a value lower than this */
/* mongoose-v can count cycles. :) */
#include <bspIo.h>
int Read_timer()
{
rtems_unsigned32 clicks;
rtems_unsigned32 total;
rtems_unsigned32 tcr;
clicks = MONGOOSEV_READ_REGISTER( TIMER_BASE,
MONGOOSEV_TIMER_INITIAL_COUNTER_REGISTER );
total = 0xffffffff - clicks;
tcr = MONGOOSEV_READ_REGISTER( TIMER_BASE, MONGOOSEV_TIMER_CONTROL_REGISTER );
MONGOOSEV_WRITE_REGISTER( TIMER_BASE,
MONGOOSEV_TIMER_CONTROL_REGISTER,
0 );
if ( tcr & MONGOOSEV_TIMER_CONTROL_TIMEOUT )
printk( "MG5 timer overran\n" );
if ( Timer_driver_Find_average_overhead == 1 )
return total; /* in cycle units */
if ( total < LEAST_VALID )
return 0; /* below timer resolution */
return (total - AVG_OVERHEAD) / CPU_CLOCK_RATE_MHZ;
}
rtems_status_code Empty_function( void )
{
return RTEMS_SUCCESSFUL;
}
void Set_find_average_overhead(
rtems_boolean find_flag
)
{
Timer_driver_Find_average_overhead = find_flag;
}
/* eof */
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