osfmk/kern/timer.h

   1 /*
   2  * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  */
  58
  59 #ifndef _KERN_TIMER_H_
  60 #define _KERN_TIMER_H_
  61
  62 #include <stat_time.h>
  63
  64 #include <kern/kern_types.h>
  65
  66 /*
  67  *      Definitions for high resolution timers.  A check
  68  *      word on the high portion allows atomic updates.
  69  */
  70
  71 struct timer {
  72 #if     !STAT_TIME
  73         uint64_t        tstamp;
  74 #endif  /* STAT_TIME */
  75 #if     defined(__LP64__)
  76         uint64_t        all_bits;
  77 #else
  78         uint32_t        low_bits;
  79         uint32_t        high_bits;
  80         uint32_t        high_bits_check;
  81 #endif
  82 };
  83
  84 typedef struct timer    timer_data_t, *timer_t;
  85
  86 /*
  87  *      Exported kernel interface to timers
  88  */
  89
  90 #if     STAT_TIME
  91
  92 #include <kern/macro_help.h>
  93
  94 /* Advance a timer by a 32 bit value */
  95 #define TIMER_BUMP(timer, ticks)                                                                \
  96 MACRO_BEGIN                                                                                                             \
  97         uint32_t        old_low, low;                                                                   \
  98                                                                                                                                 \
  99         old_low = (timer)->low_bits;                                                            \
 100         low = old_low + (ticks);                                                                        \
 101         if (low < old_low)                                                                                      \
 102                 timer_update((timer), (timer)->high_bits + 1, low);             \
 103         else                                                                                                            \
 104                 (timer)->low_bits = low;                                                                \
 105 MACRO_END
 106
 107 #define timer_start(timer, tstamp)
 108 #define timer_stop(timer, tstamp)
 109 #define timer_switch(timer, tstamp, new_timer)
 110 #define thread_timer_event(tstamp, new_timer)
 111
 112 #else   /* STAT_TIME */
 113
 114 #define TIMER_BUMP(timer, ticks)
 115
 116 /* Start a timer by setting the timestamp */
 117 extern void             timer_start(
 118                                         timer_t         timer,
 119                                         uint64_t        tstamp);
 120
 121 /* Stop a timer by updating from the timestamp */
 122 extern void             timer_stop(
 123                                         timer_t         timer,
 124                                         uint64_t        tstamp);
 125
 126 /* Update the timer and start a new one */
 127 extern void             timer_switch(
 128                                         timer_t         timer,
 129                                         uint64_t        tstamp,
 130                                         timer_t         new_timer);
 131
 132 /* Update the thread timer at an event */
 133 extern void             thread_timer_event(
 134                                         uint64_t        tstamp,
 135                                         timer_t         new_timer);
 136
 137 #endif  /* STAT_TIME */
 138
 139 /* Initialize a timer */
 140 extern void             timer_init(
 141                                         timer_t         timer);
 142
 143 /* Update a saved timer value and return delta to current value */
 144 extern uint64_t timer_delta(
 145                                         timer_t         timer,
 146                                         uint64_t        *save);
 147
 148 /* Advance a timer by a 64 bit value */
 149 extern void             timer_advance(
 150                                         timer_t         timer,
 151                                         uint64_t        delta);
 152
 153 /*
 154  *      Exported hardware interface to timers
 155  */
 156
 157 /* Read timer value */
 158 #if     defined(__LP64__)
 159 static inline uint64_t timer_grab(
 160                                         timer_t         timer)
 161 {
 162         return timer->all_bits;
 163 }
 164 #else
 165 extern uint64_t timer_grab(
 166                                         timer_t         timer);
 167
 168 /* Update timer value */
 169 extern void             timer_update(
 170                                         timer_t         timer,
 171                                         uint32_t        new_high,
 172                                         uint32_t        new_low);
 173 #endif  /* defined(__LP64__) */
 174
 175 #endif  /* _KERN_TIMER_H_ */