iokit/Kernel/IOPMchangeNoteList.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 #include <IOKit/pwr_mgt/IOPM.h>
  24 #include <IOKit/pwr_mgt/IOPMchangeNoteList.h>
  25 #include <IOKit/pwr_mgt/IOPowerConnection.h>
  26
  27 #define super OSObject
  28 OSDefineMetaClassAndStructors(IOPMchangeNoteList,OSObject)
  29
  30 //*********************************************************************************
  31 // init
  32 //
  33 //*********************************************************************************
  34 void IOPMchangeNoteList::initialize ( void )
  35 {
  36     long i;
  37
  38     firstInList = 0;
  39     firstUnused = 0;
  40     for ( i = 0; i < IOPMMaxChangeNotes; i++ ) {
  41         changeNote[i].flags = IOPMNotInUse;
  42     }
  43 }
  44
  45 //*********************************************************************************
  46 // createChangeNote
  47 //
  48 //*********************************************************************************
  49
  50 long IOPMchangeNoteList::createChangeNote ( void )
  51 {
  52     unsigned long i, j;
  53
  54     i = increment(firstUnused);
  55     if ( firstInList == i ) {
  56         return -1;
  57     }
  58     j = firstUnused;
  59     firstUnused = i;
  60
  61     return j;
  62 }
  63
  64 //*********************************************************************************
  65 // currentChange
  66 //
  67 // Return the ordinal of the first change note in the list.
  68 // If the list is empty, return -1.
  69 //*********************************************************************************
  70
  71 long IOPMchangeNoteList::currentChange ( void )
  72 {
  73     if ( firstUnused == firstInList ) {
  74         return -1;
  75     }
  76     else {
  77         return firstInList;
  78     }
  79 }
  80
  81 //*********************************************************************************
  82 // latestChange
  83 //
  84 // Return the ordinal of the last change note in the list.
  85 // If the list is empty, return -1.
  86 //*********************************************************************************
  87
  88 long IOPMchangeNoteList::latestChange ( void )
  89 {
  90     if ( firstUnused == firstInList ) {
  91         return -1;
  92     }
  93     else {
  94         return decrement(firstUnused);
  95     }
  96 }
  97
  98 //*********************************************************************************
  99 // releaseHeadChangeNote
 100 //
 101 // Mark the head node unused.
 102 // This happens when the first change in the list is completely processed.
 103 // That is, all interested parties have acknowledged it, and power is settled
 104 // at the new level.
 105 //*********************************************************************************
 106
 107 IOReturn IOPMchangeNoteList::releaseHeadChangeNote ( void )
 108 {
 109     IOPowerConnection *tmp;
 110
 111     if((tmp = changeNote[firstInList].parent)) {
 112        changeNote[firstInList].parent = 0;
 113        tmp->release();
 114     }
 115
 116     changeNote[firstInList].flags = IOPMNotInUse;
 117     firstInList = increment(firstInList);
 118     return IOPMNoErr;
 119 }
 120
 121 //*********************************************************************************
 122 // releaseTailChangeNote
 123 //
 124 // Mark the tail node unused.
 125 // This happens when a power change is queued up after another which has
 126 // not yet been started, and the second one supercedes the first.  The data in
 127 // the second is copied into the first and the the second is released.  This
 128 // collapses the first change out of the list.
 129 //*********************************************************************************
 130
 131 IOReturn IOPMchangeNoteList::releaseTailChangeNote ( void )
 132 {
 133     IOPowerConnection *tmp;
 134
 135     if((tmp = changeNote[firstInList].parent)) {
 136        changeNote[firstInList].parent = 0;
 137        tmp->release();
 138     }
 139
 140     firstUnused = decrement(firstUnused);
 141     changeNote[firstUnused].flags = IOPMNotInUse;
 142     return IOPMNoErr;
 143 }
 144
 145 //*********************************************************************************
 146 // changeNoteInUse
 147 //
 148 //*********************************************************************************
 149
 150 bool IOPMchangeNoteList::changeNoteInUse ( unsigned long ordinal )
 151 {
 152     if ( changeNote[ordinal].flags == IOPMNotInUse ) {
 153         return false;
 154     }
 155     else {
 156         return true;
 157     }
 158 }
 159
 160 //*********************************************************************************
 161 // nextChangeNote
 162 //
 163 // If the parameter corresponds to the most recent power change notification
 164 // passed to drivers and children, return -1.  Otherwise, return the array
 165 // position of the next notification in the circular list.
 166 //*********************************************************************************
 167
 168 long IOPMchangeNoteList::nextChangeNote ( unsigned long ordinal )
 169 {
 170     unsigned long i;
 171
 172     i = increment(ordinal);
 173     if ( i == firstUnused)  {
 174         return -1;
 175     }
 176     return ( i );
 177 }
 178
 179 //*********************************************************************************
 180 // increment
 181 //
 182 // Increment the parameter mod the circular list size and return it.
 183 //*********************************************************************************
 184
 185 unsigned long IOPMchangeNoteList::increment ( unsigned long ordinal )
 186 {
 187     if ( ordinal == (IOPMMaxChangeNotes - 1) ) {
 188         return 0;
 189     }
 190     else {
 191         return ordinal + 1;
 192     }
 193 }
 194
 195 //*********************************************************************************
 196 // decrement
 197 //
 198 // Decrement the parameter mod the circular list size and return it.
 199 //*********************************************************************************
 200
 201 unsigned long IOPMchangeNoteList::decrement ( unsigned long  ordinal )
 202 {
 203     if ( ordinal == 0 ) {
 204         return IOPMMaxChangeNotes - 1;
 205     }
 206     else {
 207         return ordinal - 1;
 208     }
 209 }
 210
 211 //*********************************************************************************
 212 // previousChangeNote
 213 //
 214 // If the parameter corresponds to the oldest power change notification
 215 // passed to drivers and children, return -1.  Otherwise, return the array
 216 // position of the previous notification in the circular list.
 217 //*********************************************************************************
 218
 219 long IOPMchangeNoteList::previousChangeNote ( unsigned long ordinal )
 220 {
 221     if ( ordinal == firstInList )  {
 222         return -1;
 223     }
 224     return decrement(ordinal);
 225 }
 226
 227 //*********************************************************************************
 228 // listEmpty
 229 //
 230 //*********************************************************************************
 231
 232 bool IOPMchangeNoteList::listEmpty ( void )
 233 {
 234     return ( firstInList == firstUnused ) ;
 235 }