osfmk/kern/timer.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  */
  25 /*
  26  * Mach Operating System
  27  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  28  * All Rights Reserved.
  29  *
  30  * Permission to use, copy, modify and distribute this software and its
  31  * documentation is hereby granted, provided that both the copyright
  32  * notice and this permission notice appear in all copies of the
  33  * software, derivative works or modified versions, and any portions
  34  * thereof, and that both notices appear in supporting documentation.
  35  *
  36  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  37  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  38  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  39  *
  40  * Carnegie Mellon requests users of this software to return to
  41  *
  42  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  43  *  School of Computer Science
  44  *  Carnegie Mellon University
  45  *  Pittsburgh PA 15213-3890
  46  *
  47  * any improvements or extensions that they make and grant Carnegie Mellon
  48  * the rights to redistribute these changes.
  49  */
  50 /*
  51  */
  52
  53 #ifndef _KERN_TIMER_H_
  54 #define _KERN_TIMER_H_
  55
  56 #include <stat_time.h>
  57
  58 #include <kern/kern_types.h>
  59
  60 /*
  61  *      Definitions for high resolution timers.  A check
  62  *      word on the high portion allows atomic updates.
  63  */
  64
  65 struct timer {
  66         uint32_t        low_bits;
  67         uint32_t        high_bits;
  68         uint32_t        high_bits_check;
  69 #if     !STAT_TIME
  70         uint32_t        tstamp;
  71 #endif  /* STAT_TIME */
  72 };
  73
  74 typedef struct timer    timer_data_t, *timer_t;
  75
  76 /*
  77  *      Exported kernel interface to timers
  78  */
  79
  80 #if     STAT_TIME
  81
  82 #include <kern/macro_help.h>
  83
  84 /* Advance a timer by the specified amount */
  85 #define TIMER_BUMP(timer, ticks)                                                                \
  86 MACRO_BEGIN                                                                                                             \
  87         uint32_t        old_low, low;                                                                   \
  88                                                                                                                                 \
  89         old_low = (timer)->low_bits;                                                            \
  90         low = old_low + (ticks);                                                                        \
  91         if (low < old_low)                                                                                      \
  92                 timer_update((timer), (timer)->high_bits + 1, low);             \
  93         else                                                                                                            \
  94                 (timer)->low_bits = low;                                                                \
  95 MACRO_END
  96
  97 #define timer_switch(tstamp, new_timer)
  98 #define timer_event(tstamp, new_timer)
  99
 100 #else   /* STAT_TIME */
 101
 102 /* Update the current timer and start a new one */
 103 extern void             timer_switch(
 104                                         uint32_t        tstamp,
 105                                         timer_t         new_timer);
 106
 107 #define TIMER_BUMP(timer, ticks)
 108
 109 #endif  /* STAT_TIME */
 110
 111 /* Initialize a timer */
 112 extern void             timer_init(
 113                                         timer_t         timer);
 114
 115 /* Update a saved timer value and return delta to current value */
 116 extern uint64_t timer_delta(
 117                                         timer_t         timer,
 118                                         uint64_t        *save);
 119
 120 /*
 121  *      Exported hardware interface to timers
 122  */
 123
 124 /* Read timer value */
 125 extern uint64_t timer_grab(
 126                                         timer_t         timer);
 127
 128 /* Update timer value */
 129 extern void             timer_update(
 130                                         timer_t         timer,
 131                                         uint32_t        new_high,
 132                                         uint32_t        new_low);
 133
 134 #if     !STAT_TIME
 135
 136 /* Update the current timer at an event */
 137 extern void             timer_event(
 138                                         uint32_t        tstamp,
 139                                         timer_t         new_timer);
 140
 141 #endif  /* STAT_TIME */
 142
 143 #endif  /* _KERN_TIMER_H_ */