source: rtems/c/src/lib/libcpu/powerpc/mpc5xx/timer/timer.c @ f68401e

4.11
Last change on this file since f68401e was 9b4422a2, checked in by Joel Sherrill <joel.sherrill@…>, on May 3, 2012 at 3:09:24 PM

Remove All CVS Id Strings Possible Using a Script

Script does what is expected and tries to do it as
smartly as possible.

+ remove occurrences of two blank comment lines

next to each other after Id string line removed.

+ remove entire comment blocks which only exited to

contain CVS Ids

+ If the processing left a blank line at the top of

a file, it was removed.

  • Property mode set to 100644
File size: 3.2 KB
Line 
1/*  timer.c
2 *
3 *  This file manages the interval timer on the PowerPC MPC5xx.
4 *  NOTE: This is not the PIT, but rather the RTEMS interval
5 *        timer
6 *  We shall use the bottom 32 bits of the timebase register,
7 *
8 *  The following was in the 403 version of this file. I don't
9 *  know what it means. JTM 5/19/98
10 *  NOTE: It is important that the timer start/stop overhead be
11 *        determined when porting or modifying this code.
12 *
13 *
14 *  MPC5xx port sponsored by Defence Research and Development Canada - Suffield
15 *  Copyright (C) 2004, Real-Time Systems Inc. (querbach@realtime.bc.ca)
16 *
17 *  Derived from c/src/lib/libcpu/powerpc/mpc8xx/timer/timer.c:
18 *
19 *  Author: Jay Monkman (jmonkman@frasca.com)
20 *  Copywright (C) 1998 by Frasca International, Inc.
21 *
22 *  Derived from c/src/lib/libcpu/ppc/ppc403/timer/timer.c:
23 *
24 *  Author:     Andrew Bray <andy@i-cubed.co.uk>
25 *
26 *  COPYRIGHT (c) 1995 by i-cubed ltd.
27 *
28 *  To anyone who acknowledges that this file is provided "AS IS"
29 *  without any express or implied warranty:
30 *      permission to use, copy, modify, and distribute this file
31 *      for any purpose is hereby granted without fee, provided that
32 *      the above copyright notice and this notice appears in all
33 *      copies, and that the name of i-cubed limited not be used in
34 *      advertising or publicity pertaining to distribution of the
35 *      software without specific, written prior permission.
36 *      i-cubed limited makes no representations about the suitability
37 *      of this software for any purpose.
38 *
39 *  Derived from c/src/lib/libcpu/hppa1_1/timer/timer.c:
40 *
41 *  COPYRIGHT (c) 1989-2007.
42 *  On-Line Applications Research Corporation (OAR).
43 *
44 *  The license and distribution terms for this file may be
45 *  found in the file LICENSE in this distribution or at
46 *  http://www.rtems.com/license/LICENSE.
47 */
48
49#include <rtems.h>
50#include <mpc5xx.h>
51
52static volatile uint32_t Timer_starting;
53static bool benchmark_timer_find_average_overhead;
54
55extern uint32_t bsp_timer_least_valid;
56extern uint32_t bsp_timer_average_overhead;
57
58/*
59 *  This is so small that this code will be reproduced where needed.
60 */
61static inline uint32_t get_itimer(void)
62{
63   uint32_t ret;
64
65   __asm__ volatile ("mftb %0" : "=r" ((ret))); /* TBLO */
66
67   return ret;
68}
69
70void benchmark_timer_initialize(void)
71{
72  /* set interrupt level and enable timebase. This should never */
73  /*  generate an interrupt however. */
74  usiu.tbscrk = USIU_UNLOCK_KEY;
75  usiu.tbscr |= USIU_TBSCR_TBIRQ(4)     /* interrupt priority level */
76              | USIU_TBSCR_TBF          /* freeze timebase during debug */
77              | USIU_TBSCR_TBE;         /* enable timebase */
78  usiu.tbscrk = 0;
79
80  Timer_starting = get_itimer();
81}
82
83int benchmark_timer_read(void)
84{
85  uint32_t clicks;
86  uint32_t total;
87
88  clicks = get_itimer();
89
90  total = clicks - Timer_starting;
91
92  if ( benchmark_timer_find_average_overhead == 1 )
93    return total;          /* in XXX microsecond units */
94
95  else {
96    if ( total < bsp_timer_least_valid ) {
97      return 0;            /* below timer resolution */
98    }
99    return (total - bsp_timer_average_overhead);
100  }
101}
102
103void benchmark_timer_disable_subtracting_average_overhead(bool find_flag)
104{
105  benchmark_timer_find_average_overhead = find_flag;
106}
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