iokit/Kernel/IOPMchangeNoteList.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
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  24  */
  25 #include <IOKit/pwr_mgt/IOPM.h>
  26 #include <IOKit/pwr_mgt/IOPMchangeNoteList.h>
  27
  28 #define super OSObject
  29 OSDefineMetaClassAndStructors(IOPMchangeNoteList,OSObject)
  30
  31 //*********************************************************************************
  32 // init
  33 //
  34 //*********************************************************************************
  35 void IOPMchangeNoteList::initialize ( void )
  36 {
  37     long i;
  38
  39     firstInList = 0;
  40     firstUnused = 0;
  41     for ( i = 0; i < IOPMMaxChangeNotes; i++ ) {
  42         changeNote[i].flags = IOPMNotInUse;
  43     }
  44 }
  45
  46 //*********************************************************************************
  47 // createChangeNote
  48 //
  49 //*********************************************************************************
  50
  51 long IOPMchangeNoteList::createChangeNote ( void )
  52 {
  53     unsigned long i, j;
  54
  55     i = increment(firstUnused);
  56     if ( firstInList == i ) {
  57         return -1;
  58     }
  59     j = firstUnused;
  60     firstUnused = i;
  61
  62     return j;
  63 }
  64
  65 //*********************************************************************************
  66 // currentChange
  67 //
  68 // Return the ordinal of the first change note in the list.
  69 // If the list is empty, return -1.
  70 //*********************************************************************************
  71
  72 long IOPMchangeNoteList::currentChange ( void )
  73 {
  74     if ( firstUnused == firstInList ) {
  75         return -1;
  76     }
  77     else {
  78         return firstInList;
  79     }
  80 }
  81
  82 //*********************************************************************************
  83 // latestChange
  84 //
  85 // Return the ordinal of the last change note in the list.
  86 // If the list is empty, return -1.
  87 //*********************************************************************************
  88
  89 long IOPMchangeNoteList::latestChange ( void )
  90 {
  91     if ( firstUnused == firstInList ) {
  92         return -1;
  93     }
  94     else {
  95         return decrement(firstUnused);
  96     }
  97 }
  98
  99 //*********************************************************************************
 100 // releaseHeadChangeNote
 101 //
 102 // Mark the head node unused.
 103 // This happens when the first change in the list is completely processed.
 104 // That is, all interested parties have acknowledged it, and power is settled
 105 // at the new level.
 106 //*********************************************************************************
 107
 108 IOReturn IOPMchangeNoteList::releaseHeadChangeNote ( void )
 109 {
 110     changeNote[firstInList].flags = IOPMNotInUse;
 111     firstInList = increment(firstInList);
 112     return IOPMNoErr;
 113 }
 114
 115 //*********************************************************************************
 116 // releaseTailChangeNote
 117 //
 118 // Mark the tail node unused.
 119 // This happens when a power change is queued up after another which has
 120 // not yet been started, and the second one supercedes the first.  The data in
 121 // the second is copied into the first and the the second is released.  This
 122 // collapses the first change out of the list.
 123 //*********************************************************************************
 124
 125 IOReturn IOPMchangeNoteList::releaseTailChangeNote ( void )
 126 {
 127     firstUnused = decrement(firstUnused);
 128     changeNote[firstUnused].flags = IOPMNotInUse;
 129     return IOPMNoErr;
 130 }
 131
 132 //*********************************************************************************
 133 // changeNoteInUse
 134 //
 135 //*********************************************************************************
 136
 137 bool IOPMchangeNoteList::changeNoteInUse ( unsigned long ordinal )
 138 {
 139     if ( changeNote[ordinal].flags == IOPMNotInUse ) {
 140         return false;
 141     }
 142     else {
 143         return true;
 144     }
 145 }
 146
 147 //*********************************************************************************
 148 // nextChangeNote
 149 //
 150 // If the parameter corresponds to the most recent power change notification
 151 // passed to drivers and children, return -1.  Otherwise, return the array
 152 // position of the next notification in the circular list.
 153 //*********************************************************************************
 154
 155 long IOPMchangeNoteList::nextChangeNote ( unsigned long ordinal )
 156 {
 157     unsigned long i;
 158
 159     i = increment(ordinal);
 160     if ( i == firstUnused)  {
 161         return -1;
 162     }
 163     return ( i );
 164 }
 165
 166 //*********************************************************************************
 167 // increment
 168 //
 169 // Increment the parameter mod the circular list size and return it.
 170 //*********************************************************************************
 171
 172 unsigned long IOPMchangeNoteList::increment ( unsigned long ordinal )
 173 {
 174     if ( ordinal == (IOPMMaxChangeNotes - 1) ) {
 175         return 0;
 176     }
 177     else {
 178         return ordinal + 1;
 179     }
 180 }
 181
 182 //*********************************************************************************
 183 // decrement
 184 //
 185 // Decrement the parameter mod the circular list size and return it.
 186 //*********************************************************************************
 187
 188 unsigned long IOPMchangeNoteList::decrement ( unsigned long  ordinal )
 189 {
 190     if ( ordinal == 0 ) {
 191         return IOPMMaxChangeNotes - 1;
 192     }
 193     else {
 194         return ordinal - 1;
 195     }
 196 }
 197
 198 //*********************************************************************************
 199 // previousChangeNote
 200 //
 201 // If the parameter corresponds to the oldest power change notification
 202 // passed to drivers and children, return -1.  Otherwise, return the array
 203 // position of the previous notification in the circular list.
 204 //*********************************************************************************
 205
 206 long IOPMchangeNoteList::previousChangeNote ( unsigned long ordinal )
 207 {
 208     if ( ordinal == firstInList )  {
 209         return -1;
 210     }
 211     return decrement(ordinal);
 212 }
 213
 214 //*********************************************************************************
 215 // listEmpty
 216 //
 217 //*********************************************************************************
 218
 219 bool IOPMchangeNoteList::listEmpty ( void )
 220 {
 221     return ( firstInList == firstUnused ) ;
 222 }