diff options
Diffstat (limited to 'bsps/m68k/csb360/dev/timer.c')
| -rw-r--r-- | bsps/m68k/csb360/dev/timer.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/bsps/m68k/csb360/dev/timer.c b/bsps/m68k/csb360/dev/timer.c new file mode 100644 index 0000000000..812310fbea --- /dev/null +++ b/bsps/m68k/csb360/dev/timer.c @@ -0,0 +1,159 @@ +/** + * @file + * + * This module initializes TIMER 2 for on the MCF5272 for benchmarks. + */ + +/* + * Copyright (C) 2000 OKTET Ltd., St.-Petersburg, Russia + * Author: Victor V. Vengerov <vvv@oktet.ru> + * + * Based on work: + * Author: + * David Fiddes, D.J@fiddes.surfaid.org + * http://www.calm.hw.ac.uk/davidf/coldfire/ + * + * COPYRIGHT (c) 1989-1998. + * On-Line Applications Research Corporation (OAR). + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.org/license/LICENSE. + */ + +#include <rtems.h> +#include <bsp.h> +#include <mcf5272/mcf5272.h> +#include <rtems/btimer.h> + +#define TRR2_VAL 65530 + +uint32_t Timer_interrupts; + +bool benchmark_timer_find_average_overhead; + +/* External assembler interrupt handler routine */ +extern rtems_isr timerisr(rtems_vector_number vector); + + +/* benchmark_timer_initialize -- + * Initialize timer 2 for accurate time measurement. + * + * PARAMETERS: + * none + * + * RETURNS: + * none + */ +void +benchmark_timer_initialize(void) +{ + uint32_t icr; + /* Catch timer2 interrupts */ + set_vector(timerisr, BSP_INTVEC_TMR2, 0); + + /* Reset Timer */ + g_timer_regs->tmr2 = MCF5272_TMR_RST; + g_timer_regs->tmr2 = MCF5272_TMR_CLK_STOP; + g_timer_regs->tmr2 = MCF5272_TMR_RST; + g_timer_regs->tcn2 = 0; /* reset counter */ + Timer_interrupts = 0; /* Clear timer ISR counter */ + g_timer_regs->ter2 = MCF5272_TER_REF | MCF5272_TER_CAP; + g_timer_regs->trr2 = TRR2_VAL -1 ; + + + /* Set Timer 2 prescaler so that it counts in microseconds */ + g_timer_regs->tmr2 = ( + (((BSP_SYSTEM_FREQUENCY / 1000000) - 1) << MCF5272_TMR_PS_SHIFT) | + MCF5272_TMR_CE_DISABLE | + MCF5272_TMR_ORI | + MCF5272_TMR_FRR | + MCF5272_TMR_CLK_MSTR | + MCF5272_TMR_RST); + + /* Initialize interrupts for timer2 */ + icr = g_intctrl_regs->icr1; + icr = icr & ~(MCF5272_ICR1_TMR2_MASK | MCF5272_ICR1_TMR2_PI); + icr |= (MCF5272_ICR1_TMR2_IPL(BSP_INTLVL_TMR2) | MCF5272_ICR1_TMR2_PI); + g_intctrl_regs->icr1 = icr; + +} + +/* + * The following controls the behavior of benchmark_timer_read(). + * + * FIND_AVG_OVERHEAD * instructs the routine to return the "raw" count. + * + * AVG_OVEREHAD is the overhead for starting and stopping the timer. It + * is usually deducted from the number returned. + * + * LEAST_VALID is the lowest number this routine should trust. Numbers + * below this are "noise" and zero is returned. + */ + +#define AVG_OVERHEAD 0 /* It typically takes 2.0 microseconds */ + /* (Y countdowns) to start/stop the timer. */ + /* This value is in microseconds. */ +#define LEAST_VALID 1 /* Don't trust a clicks value lower than this */ + +/* benchmark_timer_read -- + * Read timer value in microsecond units since timer start. + * + * PARAMETERS: + * none + * + * RETURNS: + * number of microseconds since timer has been started + */ +benchmark_timer_t +benchmark_timer_read( void ) +{ + uint16_t clicks; + uint32_t total; + + /* + * Read the timer and see how many clicks it has been since counter + * rolled over. + */ + clicks = g_timer_regs->tcn2; + + /* Stop Timer... */ + g_timer_regs->tmr2 = MCF5272_TMR_CLK_STOP | MCF5272_TMR_RST; + + /* + * Total is calculated by taking into account the number of timer + * overflow interrupts since the timer was initialized and clicks + * since the last interrupts. + */ + + total = (Timer_interrupts * TRR2_VAL) + clicks; + + if ( benchmark_timer_find_average_overhead == 1 ) + return total; /* in XXX microsecond units */ + + if ( total < LEAST_VALID ) + return 0; /* below timer resolution */ + + /* + * Return the count in microseconds + */ + return (total - AVG_OVERHEAD); +} + +/* benchmark_timer_disable_subtracting_average_overhead -- + * This routine is invoked by the "Check Timer" (tmck) test in the + * RTEMS Timing Test Suite. It makes the benchmark_timer_read routine not + * subtract the overhead required to initialize and read the benchmark + * timer. + * + * PARAMETERS: + * find_flag - bool flag, true if overhead must not be subtracted. + * + * RETURNS: + * none + */ +void +benchmark_timer_disable_subtracting_average_overhead(bool find_flag) +{ + benchmark_timer_find_average_overhead = find_flag; +} |