source: rtems/c/src/lib/libbsp/sparc/erc32/timer/timer.c @ 1be1e913

4.104.114.84.95
Last change on this file since 1be1e913 was 1be1e913, checked in by Ralf Corsepius <ralf.corsepius@…>, on Mar 31, 2004 at 5:17:45 AM

2004-03-31 Ralf Corsepius <ralf_corsepius@…>

  • clock/ckinit.c, console/console.c, console/debugputs.c, erc32sonic/erc32sonic.c, include/bsp.h, include/erc32.h, startup/setvec.c, startup/spurious.c, timer/timer.c: Convert to using c99 fixed size types.
  • Property mode set to 100644
File size: 2.1 KB
Line 
1/*  timer.c
2 *
3 *  This file implements a benchmark timer using the General Purpose Timer on
4 *  the MEC.
5 *
6 *  COPYRIGHT (c) 1989-1999.
7 *  On-Line Applications Research Corporation (OAR).
8 *
9 *  The license and distribution terms for this file may be
10 *  found in the file LICENSE in this distribution or at
11 *  http://www.rtems.com/license/LICENSE.
12 *
13 *  Ported to ERC32 implementation of the SPARC by On-Line Applications
14 *  Research Corporation (OAR) under contract to the European Space
15 *  Agency (ESA).
16 *
17 *  ERC32 modifications of respective RTEMS file: COPYRIGHT (c) 1995.
18 *  European Space Agency.
19 *
20 *  $Id$
21 */
22
23
24#include <bsp.h>
25
26rtems_boolean Timer_driver_Find_average_overhead;
27
28rtems_boolean Timer_driver_Is_initialized = FALSE;
29
30void Timer_initialize()
31{
32  /*
33   *  Timer runs long and accurate enough not to require an interrupt.
34   */
35
36  if ( Timer_driver_Is_initialized == FALSE ) {
37
38    /* approximately 1 us per countdown */
39    ERC32_MEC.General_Purpose_Timer_Scalar  = CLOCK_SPEED - 1;
40    ERC32_MEC.General_Purpose_Timer_Counter = 0xffffffff;
41
42  } else {
43    Timer_driver_Is_initialized = TRUE;
44  }
45
46  ERC32_MEC_Set_General_Purpose_Timer_Control( 
47    ERC32_MEC_TIMER_COUNTER_ENABLE_COUNTING | 
48      ERC32_MEC_TIMER_COUNTER_LOAD_COUNTER
49  );
50
51  ERC32_MEC_Set_General_Purpose_Timer_Control( 
52    ERC32_MEC_TIMER_COUNTER_ENABLE_COUNTING
53  );
54
55}
56
57#define AVG_OVERHEAD      3  /* It typically takes 3.0 microseconds */
58                             /*     to start/stop the timer. */
59#define LEAST_VALID       2  /* Don't trust a value lower than this */
60
61int Read_timer()
62{
63  uint32_t          total;
64
65  total = ERC32_MEC.General_Purpose_Timer_Counter;
66
67  total = 0xffffffff - total;
68
69  if ( Timer_driver_Find_average_overhead == 1 )
70    return total;          /* in one microsecond units */
71
72  if ( total < LEAST_VALID )
73    return 0;            /* below timer resolution */
74
75  return total - AVG_OVERHEAD;
76}
77
78rtems_status_code Empty_function( void )
79{
80  return RTEMS_SUCCESSFUL;
81}
82
83void Set_find_average_overhead(
84  rtems_boolean find_flag
85)
86{
87  Timer_driver_Find_average_overhead = find_flag;
88}
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