forked from Imagelibrary/rtems
100 lines
2.6 KiB
C
100 lines
2.6 KiB
C
/*
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* This file implements a benchmark timer using a MONGOOSE-V timer.
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*
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* COPYRIGHT (c) 1989-2001.
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* On-Line Applications Research Corporation (OAR).
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*
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* The license and distribution terms for this file may be
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* found in found in the file LICENSE in this distribution or at
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* http://www.rtems.com/license/LICENSE.
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*
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* $Id$
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*/
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#include <assert.h>
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#include <bsp.h>
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rtems_boolean Timer_driver_Find_average_overhead;
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#if defined(USE_TIMER2_FOR_CLOCK)
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#define TIMER_BASE MONGOOSEV_TIMER1_BASE
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#define TIMER_VECTOR MONGOOSEV_IRQ_TIMER1
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#else
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#define TIMER_BASE MONGOOSEV_TIMER2_BASE
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#define TIMER_VECTOR MONGOOSEV_IRQ_TIMER2
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#endif
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void Timer_initialize(void)
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{
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/*
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* Programming the compare register as the maximum value should let
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* it run long enough and accurate enough not to require an interrupt.
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* but if it ever does generate an interrupt, we will simply fault.
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*
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* NOTE: This is similar to the clock driver initialization
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* with the exception that the divider is disabled and
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* the compare register is set to the maximum value.
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*/
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MONGOOSEV_WRITE_REGISTER( TIMER_BASE, MONGOOSEV_TIMER_CONTROL_REGISTER, 0);
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MONGOOSEV_WRITE_REGISTER( TIMER_BASE,
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MONGOOSEV_TIMER_INITIAL_COUNTER_REGISTER,
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0xffffffff );
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MONGOOSEV_WRITE_REGISTER( TIMER_BASE,
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MONGOOSEV_TIMER_CONTROL_REGISTER,
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MONGOOSEV_TIMER_CONTROL_COUNTER_ENABLE );
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}
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#define AVG_OVERHEAD 0 /* It typically takes N instructions */
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/* to start/stop the timer. */
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#define LEAST_VALID 1 /* Don't trust a value lower than this */
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/* mongoose-v can count cycles. :) */
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#include <rtems/bspIo.h>
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int Read_timer(void)
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{
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uint32_t clicks;
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uint32_t total;
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uint32_t tcr;
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clicks = MONGOOSEV_READ_REGISTER( TIMER_BASE,
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MONGOOSEV_TIMER_INITIAL_COUNTER_REGISTER );
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total = 0xffffffff - clicks;
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tcr = MONGOOSEV_READ_REGISTER( TIMER_BASE, MONGOOSEV_TIMER_CONTROL_REGISTER );
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MONGOOSEV_WRITE_REGISTER( TIMER_BASE,
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MONGOOSEV_TIMER_CONTROL_REGISTER,
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0 );
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if ( tcr & MONGOOSEV_TIMER_CONTROL_TIMEOUT )
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printk( "MG5 timer overran\n" );
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if ( Timer_driver_Find_average_overhead == 1 )
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return total; /* in cycle units */
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if ( total < LEAST_VALID )
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return 0; /* below timer resolution */
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return (total - AVG_OVERHEAD) / CPU_CLOCK_RATE_MHZ;
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}
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rtems_status_code Empty_function( void )
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{
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return RTEMS_SUCCESSFUL;
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}
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void Set_find_average_overhead(
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rtems_boolean find_flag
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)
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{
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Timer_driver_Find_average_overhead = find_flag;
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}
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/* eof */
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