osfmk/kern/timer.h

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