forked from Imagelibrary/rtems
131 lines
4.3 KiB
C
131 lines
4.3 KiB
C
/* SPDX-License-Identifier: BSD-2-Clause */
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/* timer.c
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*
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* This file manages the benchmark timer used by the RTEMS Timing
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* Test Suite. Each measured time period is demarcated by calls to
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* benchmark_timer_initialize() and benchmark_timer_read().
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* benchmark_timer_read() usually returns the number of microseconds
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* since benchmark_timer_initialize() exitted.
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*
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* NOTE: It is important that the timer start/stop overhead be
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* determined when porting or modifying this code.
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*
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* COPYRIGHT (c) 1989-1999.
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* On-Line Applications Research Corporation (OAR).
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* Jukka Pietarinen <jukka.pietarinen@mrf.fi>, 2008,
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* Micro-Research Finland Oy
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*/
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#include <rtems.h>
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#include <bsp.h>
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#include <rtems/btimer.h>
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#include <rtems/bspIo.h>
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#include "../include/system_conf.h"
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#include "../../shared/clock/clock.h"
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static inline int timerread(unsigned int reg)
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{
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#if ON_SIMULATOR && defined(TIMER0_BASE_ADDRESS)
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return *((int*)(TIMER0_BASE_ADDRESS + reg));
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#elif defined(TIMER1_BASE_ADDRESS)
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return *((int*)(TIMER1_BASE_ADDRESS + reg));
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#else
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#warning "Benchmarking timer not available!"
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return 0;
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#endif
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}
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static inline void timerwrite(unsigned int reg, int value)
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{
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#if ON_SIMULATOR && defined(TIMER0_BASE_ADDRESS)
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*((int*)(TIMER0_BASE_ADDRESS + reg)) = value;
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#elif defined(TIMER1_BASE_ADDRESS)
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*((int*)(TIMER1_BASE_ADDRESS + reg)) = value;
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#endif
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}
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bool benchmark_timer_find_average_overhead;
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void benchmark_timer_initialize( void )
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{
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/* Set timer period */
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timerwrite(LM32_CLOCK_PERIOD, 0xffffffff);
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/* Stop timer */
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timerwrite(LM32_CLOCK_CR, LM32_CLOCK_CR_STOP);
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/* Clear status register */
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timerwrite(LM32_CLOCK_SR, 0);
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/* Start timer */
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timerwrite(LM32_CLOCK_CR, LM32_CLOCK_CR_START);
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}
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/*
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* The following controls the behavior of benchmark_timer_read().
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*
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* AVG_OVEREHAD is the overhead for starting and stopping the timer. It
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* is usually deducted from the number returned.
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*
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* LEAST_VALID is the lowest number this routine should trust. Numbers
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* below this are "noise" and zero is returned.
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*/
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#define AVG_OVERHEAD 4 /* It typically takes X.X microseconds */
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/* (Y countdowns) to start/stop the timer. */
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/* This value is in microseconds. */
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#define LEAST_VALID 4 /* Don't trust a clicks value lower than this */
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benchmark_timer_t benchmark_timer_read( void )
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{
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uint32_t ticks;
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uint32_t total;
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uint32_t status;
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ticks = 0xffffffff - timerread(LM32_CLOCK_SNAPSHOT);
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status = timerread(LM32_CLOCK_SR);
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if (status & LM32_CLOCK_SR_TO)
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printk("Timer overflow!\n");
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total = ticks / (CPU_FREQUENCY / 1000000);
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if ( benchmark_timer_find_average_overhead == true )
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return total; /* in XXX microsecond units */
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else
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{
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if ( total < LEAST_VALID )
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return 0; /* below timer resolution */
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/*
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* Somehow convert total into microseconds
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*/
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return (total - AVG_OVERHEAD);
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}
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}
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void benchmark_timer_disable_subtracting_average_overhead(
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bool 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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