iokit/Kernel/IOPMchangeNoteList.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, 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
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  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,
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  23  * Please see the License for the specific language governing rights and
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  27  */
  28 #include <IOKit/pwr_mgt/IOPM.h>
  29 #include <IOKit/pwr_mgt/IOPMchangeNoteList.h>
  30 #include <IOKit/pwr_mgt/IOPowerConnection.h>
  31
  32 #define super OSObject
  33 OSDefineMetaClassAndStructors(IOPMchangeNoteList,OSObject)
  34
  35 //*********************************************************************************
  36 // init
  37 //
  38 //*********************************************************************************
  39 void IOPMchangeNoteList::initialize ( void )
  40 {
  41     long i;
  42
  43     firstInList = 0;
  44     firstUnused = 0;
  45     for ( i = 0; i < IOPMMaxChangeNotes; i++ ) {
  46         changeNote[i].flags = IOPMNotInUse;
  47     }
  48 }
  49
  50 //*********************************************************************************
  51 // createChangeNote
  52 //
  53 //*********************************************************************************
  54
  55 long IOPMchangeNoteList::createChangeNote ( void )
  56 {
  57     unsigned long i, j;
  58
  59     i = increment(firstUnused);
  60     if ( firstInList == i ) {
  61         return -1;
  62     }
  63     j = firstUnused;
  64     firstUnused = i;
  65
  66     return j;
  67 }
  68
  69 //*********************************************************************************
  70 // currentChange
  71 //
  72 // Return the ordinal of the first change note in the list.
  73 // If the list is empty, return -1.
  74 //*********************************************************************************
  75
  76 long IOPMchangeNoteList::currentChange ( void )
  77 {
  78     if ( firstUnused == firstInList ) {
  79         return -1;
  80     }
  81     else {
  82         return firstInList;
  83     }
  84 }
  85
  86 //*********************************************************************************
  87 // latestChange
  88 //
  89 // Return the ordinal of the last change note in the list.
  90 // If the list is empty, return -1.
  91 //*********************************************************************************
  92
  93 long IOPMchangeNoteList::latestChange ( void )
  94 {
  95     if ( firstUnused == firstInList ) {
  96         return -1;
  97     }
  98     else {
  99         return decrement(firstUnused);
 100     }
 101 }
 102
 103 //*********************************************************************************
 104 // releaseHeadChangeNote
 105 //
 106 // Mark the head node unused.
 107 // This happens when the first change in the list is completely processed.
 108 // That is, all interested parties have acknowledged it, and power is settled
 109 // at the new level.
 110 //*********************************************************************************
 111
 112 IOReturn IOPMchangeNoteList::releaseHeadChangeNote ( void )
 113 {
 114     IOPowerConnection *tmp;
 115
 116     if((tmp = changeNote[firstInList].parent)) {
 117        changeNote[firstInList].parent = 0;
 118        tmp->release();
 119     }
 120
 121     changeNote[firstInList].flags = IOPMNotInUse;
 122     firstInList = increment(firstInList);
 123     return IOPMNoErr;
 124 }
 125
 126 //*********************************************************************************
 127 // releaseTailChangeNote
 128 //
 129 // Mark the tail node unused.
 130 // This happens when a power change is queued up after another which has
 131 // not yet been started, and the second one supercedes the first.  The data in
 132 // the second is copied into the first and the the second is released.  This
 133 // collapses the first change out of the list.
 134 //*********************************************************************************
 135
 136 IOReturn IOPMchangeNoteList::releaseTailChangeNote ( void )
 137 {
 138     IOPowerConnection *tmp;
 139
 140     if((tmp = changeNote[firstInList].parent)) {
 141        changeNote[firstInList].parent = 0;
 142        tmp->release();
 143     }
 144
 145     firstUnused = decrement(firstUnused);
 146     changeNote[firstUnused].flags = IOPMNotInUse;
 147     return IOPMNoErr;
 148 }
 149
 150 //*********************************************************************************
 151 // changeNoteInUse
 152 //
 153 //*********************************************************************************
 154
 155 bool IOPMchangeNoteList::changeNoteInUse ( unsigned long ordinal )
 156 {
 157     if ( changeNote[ordinal].flags == IOPMNotInUse ) {
 158         return false;
 159     }
 160     else {
 161         return true;
 162     }
 163 }
 164
 165 //*********************************************************************************
 166 // nextChangeNote
 167 //
 168 // If the parameter corresponds to the most recent power change notification
 169 // passed to drivers and children, return -1.  Otherwise, return the array
 170 // position of the next notification in the circular list.
 171 //*********************************************************************************
 172
 173 long IOPMchangeNoteList::nextChangeNote ( unsigned long ordinal )
 174 {
 175     unsigned long i;
 176
 177     i = increment(ordinal);
 178     if ( i == firstUnused)  {
 179         return -1;
 180     }
 181     return ( i );
 182 }
 183
 184 //*********************************************************************************
 185 // increment
 186 //
 187 // Increment the parameter mod the circular list size and return it.
 188 //*********************************************************************************
 189
 190 unsigned long IOPMchangeNoteList::increment ( unsigned long ordinal )
 191 {
 192     if ( ordinal == (IOPMMaxChangeNotes - 1) ) {
 193         return 0;
 194     }
 195     else {
 196         return ordinal + 1;
 197     }
 198 }
 199
 200 //*********************************************************************************
 201 // decrement
 202 //
 203 // Decrement the parameter mod the circular list size and return it.
 204 //*********************************************************************************
 205
 206 unsigned long IOPMchangeNoteList::decrement ( unsigned long  ordinal )
 207 {
 208     if ( ordinal == 0 ) {
 209         return IOPMMaxChangeNotes - 1;
 210     }
 211     else {
 212         return ordinal - 1;
 213     }
 214 }
 215
 216 //*********************************************************************************
 217 // previousChangeNote
 218 //
 219 // If the parameter corresponds to the oldest power change notification
 220 // passed to drivers and children, return -1.  Otherwise, return the array
 221 // position of the previous notification in the circular list.
 222 //*********************************************************************************
 223
 224 long IOPMchangeNoteList::previousChangeNote ( unsigned long ordinal )
 225 {
 226     if ( ordinal == firstInList )  {
 227         return -1;
 228     }
 229     return decrement(ordinal);
 230 }
 231
 232 //*********************************************************************************
 233 // listEmpty
 234 //
 235 //*********************************************************************************
 236
 237 bool IOPMchangeNoteList::listEmpty ( void )
 238 {
 239     return ( firstInList == firstUnused ) ;
 240 }