source: rtems/c/src/lib/libcpu/m68k/mcf5206/timer/timer.c @ 8fbe2e6

4.11
Last change on this file since 8fbe2e6 was 8fbe2e6, checked in by Joel Sherrill <joel.sherrill@…>, on Sep 4, 2014 at 1:59:49 PM

Use correct prototype of benchmark_timer_read()

This change starts with removing the effectively empty file
timerdrv.h. The prototypes for benchmark_timer_XXX() were in
btimer.h which was not universally used. Thus every use of
timerdrv.h had to be changed to btimer.h. Then the prototypes
for benchmark_timer_read() had to be adjusted to return
benchmark_timer_t rather than int or uint32_t.

I took this opportunity to also correct the file headers to
separate the copyright from the file description comments which
is needed to ensure the copyright isn't propagated into Doxygen
output.

  • Property mode set to 100644
File size: 4.5 KB
Line 
1/**
2 *  @file
3 *  @brief Timer Init
4 *
5 *  This module initializes TIMER 2 for on the MCF5206E for benchmarks.
6 */
7
8/*
9 *  Copyright (C) 2000 OKTET Ltd., St.-Petersburg, Russia
10 *  Author: Victor V. Vengerov <vvv@oktet.ru>
11 *
12 *  Based on work:
13 *  Author:
14 *    David Fiddes, D.J@fiddes.surfaid.org
15 *    http://www.calm.hw.ac.uk/davidf/coldfire/
16 *
17 *  COPYRIGHT (c) 1989-1998.
18 *  On-Line Applications Research Corporation (OAR).
19 *
20 *  The license and distribution terms for this file may be
21 *  found in the file LICENSE in this distribution or at
22 *  http://www.rtems.org/license/LICENSE.
23 */
24
25#include <rtems.h>
26#include <bsp.h>
27#include <rtems/btimer.h>
28#include "mcf5206/mcf5206e.h"
29
30#define TRR2_VAL 65530
31
32uint32_t   Timer_interrupts;
33
34bool benchmark_timer_find_average_overhead;
35
36/* External assembler interrupt handler routine */
37extern rtems_isr timerisr(rtems_vector_number vector);
38
39
40/* benchmark_timer_initialize --
41 *     Initialize timer 2 for accurate time measurement.
42 *
43 * PARAMETERS:
44 *     none
45 *
46 * RETURNS:
47 *     none
48 */
49void
50benchmark_timer_initialize(void)
51{
52    /* Catch timer2 interrupts */
53    set_vector(timerisr, BSP_INTVEC_TIMER2, 0);
54
55    /* Initialize interrupts for timer2 */
56    *MCF5206E_ICR(MBAR, MCF5206E_INTR_TIMER_2) =
57        MCF5206E_ICR_AVEC |
58        ((BSP_INTLVL_TIMER2 << MCF5206E_ICR_IL_S) & MCF5206E_ICR_IL) |
59        ((BSP_INTPRIO_TIMER2 << MCF5206E_ICR_IP_S) & MCF5206E_ICR_IP);
60
61    /* Enable interrupts from timer2 */
62    *MCF5206E_IMR(MBAR) &= ~MCF5206E_INTR_BIT(MCF5206E_INTR_TIMER_2);
63
64    /* Reset Timer */
65    *MCF5206E_TMR(MBAR, 2) = MCF5206E_TMR_RST;
66    *MCF5206E_TMR(MBAR, 2) = MCF5206E_TMR_ICLK_STOP;
67    *MCF5206E_TMR(MBAR, 2) = MCF5206E_TMR_RST;
68    *MCF5206E_TCN(MBAR, 2) = 0; /* Zero timer counter */
69    Timer_interrupts = 0; /* Clear timer ISR counter */
70    *MCF5206E_TER(MBAR, 2) = MCF5206E_TER_REF | MCF5206E_TER_CAP; /*clr pend*/
71    *MCF5206E_TRR(MBAR, 2) = TRR2_VAL - 1;
72    *MCF5206E_TMR(MBAR, 2) =
73        (((BSP_SYSTEM_FREQUENCY / 1000000) << MCF5206E_TMR_PS_S) &
74          MCF5206E_TMR_PS) |
75        MCF5206E_TMR_CE_NONE | MCF5206E_TMR_ORI | MCF5206E_TMR_FRR |
76        MCF5206E_TMR_RST;
77    *MCF5206E_TMR(MBAR, 2) |= MCF5206E_TMR_ICLK_MSCLK;
78}
79
80/*
81 *  The following controls the behavior of benchmark_timer_read().
82 *
83 *  FIND_AVG_OVERHEAD *  instructs the routine to return the "raw" count.
84 *
85 *  AVG_OVEREHAD is the overhead for starting and stopping the timer.  It
86 *  is usually deducted from the number returned.
87 *
88 *  LEAST_VALID is the lowest number this routine should trust.  Numbers
89 *  below this are "noise" and zero is returned.
90 */
91
92#define AVG_OVERHEAD      0  /* It typically takes 2.0 microseconds */
93                             /* (Y countdowns) to start/stop the timer. */
94                             /* This value is in microseconds. */
95#define LEAST_VALID       1  /* Don't trust a clicks value lower than this */
96
97/* benchmark_timer_read --
98 *     Read timer value in microsecond units since timer start.
99 *
100 * PARAMETERS:
101 *     none
102 *
103 * RETURNS:
104 *     number of microseconds since timer has been started
105 */
106benchmark_timer_t
107benchmark_timer_read( void )
108{
109    uint16_t   clicks;
110    uint32_t   total;
111
112    /*
113     *  Read the timer and see how many clicks it has been since counter
114     *  rolled over.
115     */
116    clicks = *MCF5206E_TCN(MBAR, 2);
117
118    /* Stop Timer... */
119    *MCF5206E_TMR(MBAR, 2) = MCF5206E_TMR_ICLK_STOP |
120                             MCF5206E_TMR_RST;
121
122    /*
123     *  Total is calculated by taking into account the number of timer
124     *  overflow interrupts since the timer was initialized and clicks
125     *  since the last interrupts.
126     */
127
128    total = (Timer_interrupts * TRR2_VAL) + clicks;
129
130    if ( benchmark_timer_find_average_overhead == 1 )
131        return total;          /* in XXX microsecond units */
132
133    if ( total < LEAST_VALID )
134        return 0;            /* below timer resolution */
135
136    /*
137     *  Return the count in microseconds
138     */
139    return (total - AVG_OVERHEAD);
140}
141
142/* benchmark_timer_disable_subtracting_average_overhead --
143 *     This routine is invoked by the "Check Timer" (tmck) test in the
144 *     RTEMS Timing Test Suite. It makes the benchmark_timer_read routine not
145 *     subtract the overhead required to initialize and read the benchmark
146 *     timer.
147 *
148 * PARAMETERS:
149 *     find_flag - boolean flag, true if overhead must not be subtracted.
150 *
151 * RETURNS:
152 *     none
153 */
154void
155benchmark_timer_disable_subtracting_average_overhead(bool find_flag)
156{
157  benchmark_timer_find_average_overhead = find_flag;
158}
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