blob: d9225a7f605effb4f6b2058178a62987276c17f7 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
/*
* Cogent CSB336 Timer driver
*
* This uses timer 2 for timing measurments.
*
* Copyright (c) 2004 Cogent Computer Systems
* Written by Jay Monkman <jtm@lopingdog.com>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* Notes:
* This file manages the benchmark timer used by the RTEMS Timing Test
* Suite. Each measured time period is demarcated by calls to
* benchmark_timer_initialize() and benchmark_timer_read(). benchmark_timer_read() usually returns
* the number of microseconds since benchmark_timer_initialize() exitted.
*
* It is important that the timer start/stop overhead be determined
* when porting or modifying this code.
*
* $Id$
*/
#include <rtems.h>
#include <bsp.h>
#include <mc9328mxl.h>
uint32_t g_start;
uint32_t g_freq;
bool benchmark_timer_find_average_overhead;
/*
* Set up Timer 1
*/
void benchmark_timer_initialize( void )
{
MC9328MXL_TMR2_TCTL = (MC9328MXL_TMR_TCTL_CLKSRC_PCLK1 |
MC9328MXL_TMR_TCTL_FRR |
MC9328MXL_TMR_TCTL_TEN);
/* set prescaler to 1 (register value + 1) */ \
MC9328MXL_TMR2_TPRER = 0;
/* get freq of counter in KHz */
g_freq = get_perclk1_freq() / 1000;
g_start = MC9328MXL_TMR2_TCN;
}
/*
* The following controls the behavior of benchmark_timer_read().
*
* 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 X.X 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 */
int benchmark_timer_read( void )
{
uint32_t t;
unsigned long long total;
t = MC9328MXL_TMR2_TCN;
/*
* 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 = (t - g_start);
/* convert to nanoseconds */
total = (total * 1000)/ g_freq;
if ( benchmark_timer_find_average_overhead == 1 ) {
return (int) total;
} else if ( total < LEAST_VALID ) {
return 0;
}
/*
* Somehow convert total into microseconds
*/
return (total - AVG_OVERHEAD);
}
void benchmark_timer_disable_subtracting_average_overhead(bool find_flag)
{
benchmark_timer_find_average_overhead = find_flag;
}
|
