forked from Imagelibrary/rtems
160 lines
4.5 KiB
C
160 lines
4.5 KiB
C
/**
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* @file
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*
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* This module initializes TIMER 2 for on the MCF5272 for benchmarks.
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*/
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/*
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* Copyright (C) 2000 OKTET Ltd., St.-Petersburg, Russia
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* Author: Victor V. Vengerov <vvv@oktet.ru>
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*
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* Based on work:
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* Author:
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* David Fiddes, D.J@fiddes.surfaid.org
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* http://www.calm.hw.ac.uk/davidf/coldfire/
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*
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* COPYRIGHT (c) 1989-1998.
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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 the file LICENSE in this distribution or at
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* http://www.rtems.org/license/LICENSE.
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*/
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#include <rtems.h>
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#include <bsp.h>
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#include <mcf5272/mcf5272.h>
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#include <rtems/btimer.h>
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#define TRR2_VAL 65530
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uint32_t Timer_interrupts;
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bool benchmark_timer_find_average_overhead;
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/* External assembler interrupt handler routine */
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extern rtems_isr timerisr(rtems_vector_number vector);
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/* benchmark_timer_initialize --
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* Initialize timer 2 for accurate time measurement.
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*
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* PARAMETERS:
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* none
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*
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* RETURNS:
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* none
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*/
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void
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benchmark_timer_initialize(void)
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{
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uint32_t icr;
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/* Catch timer2 interrupts */
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set_vector(timerisr, BSP_INTVEC_TMR2, 0);
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/* Reset Timer */
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g_timer_regs->tmr2 = MCF5272_TMR_RST;
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g_timer_regs->tmr2 = MCF5272_TMR_CLK_STOP;
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g_timer_regs->tmr2 = MCF5272_TMR_RST;
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g_timer_regs->tcn2 = 0; /* reset counter */
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Timer_interrupts = 0; /* Clear timer ISR counter */
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g_timer_regs->ter2 = MCF5272_TER_REF | MCF5272_TER_CAP;
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g_timer_regs->trr2 = TRR2_VAL -1 ;
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/* Set Timer 2 prescaler so that it counts in microseconds */
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g_timer_regs->tmr2 = (
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(((BSP_SYSTEM_FREQUENCY / 1000000) - 1) << MCF5272_TMR_PS_SHIFT) |
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MCF5272_TMR_CE_DISABLE |
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MCF5272_TMR_ORI |
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MCF5272_TMR_FRR |
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MCF5272_TMR_CLK_MSTR |
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MCF5272_TMR_RST);
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/* Initialize interrupts for timer2 */
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icr = g_intctrl_regs->icr1;
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icr = icr & ~(MCF5272_ICR1_TMR2_MASK | MCF5272_ICR1_TMR2_PI);
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icr |= (MCF5272_ICR1_TMR2_IPL(BSP_INTLVL_TMR2) | MCF5272_ICR1_TMR2_PI);
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g_intctrl_regs->icr1 = icr;
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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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* FIND_AVG_OVERHEAD * instructs the routine to return the "raw" count.
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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 0 /* It typically takes 2.0 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 1 /* Don't trust a clicks value lower than this */
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/* benchmark_timer_read --
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* Read timer value in microsecond units since timer start.
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*
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* PARAMETERS:
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* none
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*
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* RETURNS:
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* number of microseconds since timer has been started
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*/
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benchmark_timer_t
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benchmark_timer_read( void )
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{
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uint16_t clicks;
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uint32_t total;
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/*
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* Read the timer and see how many clicks it has been since counter
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* rolled over.
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*/
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clicks = g_timer_regs->tcn2;
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/* Stop Timer... */
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g_timer_regs->tmr2 = MCF5272_TMR_CLK_STOP | MCF5272_TMR_RST;
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/*
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* Total is calculated by taking into account the number of timer
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* overflow interrupts since the timer was initialized and clicks
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* since the last interrupts.
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*/
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total = (Timer_interrupts * TRR2_VAL) + clicks;
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if ( benchmark_timer_find_average_overhead == 1 )
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return total; /* in XXX microsecond units */
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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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* Return the count in microseconds
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*/
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return (total - AVG_OVERHEAD);
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}
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/* benchmark_timer_disable_subtracting_average_overhead --
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* This routine is invoked by the "Check Timer" (tmck) test in the
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* RTEMS Timing Test Suite. It makes the benchmark_timer_read routine not
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* subtract the overhead required to initialize and read the benchmark
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* timer.
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*
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* PARAMETERS:
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* find_flag - bool flag, true if overhead must not be subtracted.
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*
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* RETURNS:
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* none
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*/
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void
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benchmark_timer_disable_subtracting_average_overhead(bool find_flag)
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{
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benchmark_timer_find_average_overhead = find_flag;
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}
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