[1cfcfd3] | 1 | /* |
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| 2 | * Cogent CSB336 Timer driver |
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| 3 | * |
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| 4 | * This uses timer 2 for timing measurments. |
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| 5 | * |
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| 6 | * Copyright (c) 2004 Cogent Computer Systems |
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| 7 | * Written by Jay Monkman <jtm@lopingdog.com> |
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| 8 | * |
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| 9 | * The license and distribution terms for this file may be |
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| 10 | * found in the file LICENSE in this distribution or at |
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| 11 | * |
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[93f4a906] | 12 | * http://www.rtems.com/license/LICENSE. |
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[1cfcfd3] | 13 | * |
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| 14 | * Notes: |
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| 15 | * This file manages the benchmark timer used by the RTEMS Timing Test |
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| 16 | * Suite. Each measured time period is demarcated by calls to |
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| 17 | * Timer_initialize() and Read_timer(). Read_timer() usually returns |
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| 18 | * the number of microseconds since Timer_initialize() exitted. |
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| 19 | * |
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| 20 | * It is important that the timer start/stop overhead be determined |
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| 21 | * when porting or modifying this code. |
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| 22 | * |
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| 23 | * timer.c,v 1.1 2002/11/13 17:55:09 joel Exp |
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| 24 | */ |
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| 25 | |
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| 26 | #include <rtems.h> |
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| 27 | #include <bsp.h> |
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| 28 | #include <mc9328mxl.h> |
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| 29 | |
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| 30 | uint32_t g_start; |
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| 31 | uint32_t g_freq; |
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| 32 | |
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| 33 | rtems_boolean Timer_driver_Find_average_overhead; |
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| 34 | |
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| 35 | |
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| 36 | /* |
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| 37 | * Set up Timer 1 |
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| 38 | */ |
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| 39 | void Timer_initialize( void ) |
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| 40 | { |
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| 41 | MC9328MXL_TMR2_TCTL = (MC9328MXL_TMR_TCTL_CLKSRC_PCLK1 | |
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| 42 | MC9328MXL_TMR_TCTL_FRR | |
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| 43 | MC9328MXL_TMR_TCTL_TEN); |
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| 44 | /* set prescaler to 1 (register value + 1) */ \ |
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| 45 | MC9328MXL_TMR2_TPRER = 0; |
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| 46 | |
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| 47 | /* get freq of counter in KHz */ |
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| 48 | g_freq = get_perclk1_freq() / 1000; |
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| 49 | |
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| 50 | g_start = MC9328MXL_TMR2_TCN; |
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| 51 | } |
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| 52 | |
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| 53 | /* |
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| 54 | * The following controls the behavior of Read_timer(). |
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| 55 | * |
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| 56 | * AVG_OVEREHAD is the overhead for starting and stopping the timer. It |
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| 57 | * is usually deducted from the number returned. |
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| 58 | * |
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| 59 | * LEAST_VALID is the lowest number this routine should trust. Numbers |
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| 60 | * below this are "noise" and zero is returned. |
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| 61 | */ |
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| 62 | |
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| 63 | #define AVG_OVERHEAD 0 /* It typically takes X.X microseconds */ |
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| 64 | /* (Y countdowns) to start/stop the timer. */ |
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| 65 | /* This value is in microseconds. */ |
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| 66 | #define LEAST_VALID 1 /* Don't trust a clicks value lower than this */ |
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| 67 | |
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| 68 | int Read_timer( void ) |
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| 69 | { |
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[15ebe58b] | 70 | uint32_t t; |
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[1cfcfd3] | 71 | unsigned long long total; |
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| 72 | |
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| 73 | t = MC9328MXL_TMR2_TCN; |
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| 74 | /* |
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| 75 | * Total is calculated by taking into account the number of timer overflow |
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| 76 | * interrupts since the timer was initialized and clicks since the last |
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| 77 | * interrupts. |
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| 78 | */ |
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| 79 | |
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| 80 | total = (t - g_start); |
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| 81 | |
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| 82 | /* convert to nanoseconds */ |
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| 83 | total = (total * 1000)/ g_freq; |
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| 84 | |
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| 85 | if ( Timer_driver_Find_average_overhead == 1 ) { |
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| 86 | return (int) total; |
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| 87 | } else if ( total < LEAST_VALID ) { |
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| 88 | return 0; |
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| 89 | } |
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| 90 | /* |
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| 91 | * Somehow convert total into microseconds |
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| 92 | */ |
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| 93 | |
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| 94 | return (total - AVG_OVERHEAD); |
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| 95 | } |
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| 96 | |
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| 97 | /* |
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| 98 | * Empty function call used in loops to measure basic cost of looping |
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| 99 | * in Timing Test Suite. |
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| 100 | */ |
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| 101 | |
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| 102 | rtems_status_code Empty_function( void ) |
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| 103 | { |
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| 104 | return RTEMS_SUCCESSFUL; |
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| 105 | } |
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| 106 | |
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| 107 | void Set_find_average_overhead( |
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| 108 | rtems_boolean find_flag |
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| 109 | ) |
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| 110 | { |
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| 111 | Timer_driver_Find_average_overhead = find_flag; |
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| 112 | } |
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| 113 | |
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