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         uint32_t        low_bits;
  76         uint32_t        high_bits;
  77         uint32_t        high_bits_check;
  78 };
  79
  80 typedef struct timer    timer_data_t, *timer_t;
  81
  82 /*
  83  *      Exported kernel interface to timers
  84  */
  85
  86 #if     STAT_TIME
  87
  88 #include <kern/macro_help.h>
  89
  90 /* Advance a timer by a 32 bit value */
  91 #define TIMER_BUMP(timer, ticks)                                                                \
  92 MACRO_BEGIN                                                                                                             \
  93         uint32_t        old_low, low;                                                                   \
  94                                                                                                                                 \
  95         old_low = (timer)->low_bits;                                                            \
  96         low = old_low + (ticks);                                                                        \
  97         if (low < old_low)                                                                                      \
  98                 timer_update((timer), (timer)->high_bits + 1, low);             \
  99         else                                                                                                            \
 100                 (timer)->low_bits = low;                                                                \
 101 MACRO_END
 102
 103 #define timer_start(timer, tstamp)
 104 #define timer_stop(timer, tstamp)
 105 #define timer_switch(timer, tstamp, new_timer)
 106 #define thread_timer_event(tstamp, new_timer)
 107
 108 #else   /* STAT_TIME */
 109
 110 #define TIMER_BUMP(timer, ticks)
 111
 112 /* Start a timer by setting the timestamp */
 113 extern void             timer_start(
 114                                         timer_t         timer,
 115                                         uint64_t        tstamp);
 116
 117 /* Stop a timer by updating from the timestamp */
 118 extern void             timer_stop(
 119                                         timer_t         timer,
 120                                         uint64_t        tstamp);
 121
 122 /* Update the timer and start a new one */
 123 extern void             timer_switch(
 124                                         timer_t         timer,
 125                                         uint64_t        tstamp,
 126                                         timer_t         new_timer);
 127
 128 /* Update the thread timer at an event */
 129 extern void             thread_timer_event(
 130                                         uint64_t        tstamp,
 131                                         timer_t         new_timer);
 132
 133 #endif  /* STAT_TIME */
 134
 135 /* Initialize a timer */
 136 extern void             timer_init(
 137                                         timer_t         timer);
 138
 139 /* Update a saved timer value and return delta to current value */
 140 extern uint64_t timer_delta(
 141                                         timer_t         timer,
 142                                         uint64_t        *save);
 143
 144 /* Advance a timer by a 64 bit value */
 145 extern void             timer_advance(
 146                                         timer_t         timer,
 147                                         uint64_t        delta);
 148
 149 /*
 150  *      Exported hardware interface to timers
 151  */
 152
 153 /* Read timer value */
 154 extern uint64_t timer_grab(
 155                                         timer_t         timer);
 156
 157 /* Update timer value */
 158 extern void             timer_update(
 159                                         timer_t         timer,
 160                                         uint32_t        new_high,
 161                                         uint32_t        new_low);
 162
 163 #endif  /* _KERN_TIMER_H_ */