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