forked from Imagelibrary/rtems
25c62b02bc
* timer/timer.c: Eliminate empty function from every benchmark timer driver. Fix spelling.
69 lines
2.2 KiB
C
69 lines
2.2 KiB
C
/*
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* This file implements a benchmark timer using a TX39 timer.
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*
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* NOTE: On the simulator, the count directly reflects instructions.
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*
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* COPYRIGHT (c) 1989-2000.
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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 benchmark_timer_find_average_overhead;
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void benchmark_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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TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_TCR, 0x20 );
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TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_CCDR, 0x3 );
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TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_TRR, 0x0 );
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TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_CPRA, 0xFFFFFFFF );
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TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_TISR, 0x00 );
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TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_ITMR, 0x0001 );
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TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_TCR, 0xe0 );
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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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/* tx39 simulator can count instructions. :) */
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int benchmark_timer_read(void)
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{
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uint32_t total;
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total = TX3904_TIMER_READ( TX3904_TIMER1_BASE, TX3904_TIMER_TRR );
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if ( benchmark_timer_find_average_overhead == 1 )
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return total; /* in one microsecond 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;
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}
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void benchmark_timer_disable_subtracting_average_overhead(
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rtems_boolean find_flag
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)
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{
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benchmark_timer_find_average_overhead = find_flag;
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}
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