iokit/Kernel/IOPMchangeNoteList.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 #include <IOKit/pwr_mgt/IOPM.h>
  23 #include <IOKit/pwr_mgt/IOPMchangeNoteList.h>
  24 #include <IOKit/pwr_mgt/IOPowerConnection.h>
  25
  26 #define super OSObject
  27 OSDefineMetaClassAndStructors(IOPMchangeNoteList,OSObject)
  28
  29 //*********************************************************************************
  30 // init
  31 //
  32 //*********************************************************************************
  33 void IOPMchangeNoteList::initialize ( void )
  34 {
  35     long i;
  36
  37     firstInList = 0;
  38     firstUnused = 0;
  39     for ( i = 0; i < IOPMMaxChangeNotes; i++ ) {
  40         changeNote[i].flags = IOPMNotInUse;
  41     }
  42 }
  43
  44 //*********************************************************************************
  45 // createChangeNote
  46 //
  47 //*********************************************************************************
  48
  49 long IOPMchangeNoteList::createChangeNote ( void )
  50 {
  51     unsigned long i, j;
  52
  53     i = increment(firstUnused);
  54     if ( firstInList == i ) {
  55         return -1;
  56     }
  57     j = firstUnused;
  58     firstUnused = i;
  59
  60     return j;
  61 }
  62
  63 //*********************************************************************************
  64 // currentChange
  65 //
  66 // Return the ordinal of the first change note in the list.
  67 // If the list is empty, return -1.
  68 //*********************************************************************************
  69
  70 long IOPMchangeNoteList::currentChange ( void )
  71 {
  72     if ( firstUnused == firstInList ) {
  73         return -1;
  74     }
  75     else {
  76         return firstInList;
  77     }
  78 }
  79
  80 //*********************************************************************************
  81 // latestChange
  82 //
  83 // Return the ordinal of the last change note in the list.
  84 // If the list is empty, return -1.
  85 //*********************************************************************************
  86
  87 long IOPMchangeNoteList::latestChange ( void )
  88 {
  89     if ( firstUnused == firstInList ) {
  90         return -1;
  91     }
  92     else {
  93         return decrement(firstUnused);
  94     }
  95 }
  96
  97 //*********************************************************************************
  98 // releaseHeadChangeNote
  99 //
 100 // Mark the head node unused.
 101 // This happens when the first change in the list is completely processed.
 102 // That is, all interested parties have acknowledged it, and power is settled
 103 // at the new level.
 104 //*********************************************************************************
 105
 106 IOReturn IOPMchangeNoteList::releaseHeadChangeNote ( void )
 107 {
 108     IOPowerConnection *tmp;
 109
 110     if(tmp = changeNote[firstInList].parent) {
 111        changeNote[firstInList].parent = 0;
 112        tmp->release();
 113     }
 114
 115     changeNote[firstInList].flags = IOPMNotInUse;
 116     firstInList = increment(firstInList);
 117     return IOPMNoErr;
 118 }
 119
 120 //*********************************************************************************
 121 // releaseTailChangeNote
 122 //
 123 // Mark the tail node unused.
 124 // This happens when a power change is queued up after another which has
 125 // not yet been started, and the second one supercedes the first.  The data in
 126 // the second is copied into the first and the the second is released.  This
 127 // collapses the first change out of the list.
 128 //*********************************************************************************
 129
 130 IOReturn IOPMchangeNoteList::releaseTailChangeNote ( void )
 131 {
 132     IOPowerConnection *tmp;
 133
 134     if(tmp = changeNote[firstInList].parent) {
 135        changeNote[firstInList].parent = 0;
 136        tmp->release();
 137     }
 138
 139     firstUnused = decrement(firstUnused);
 140     changeNote[firstUnused].flags = IOPMNotInUse;
 141     return IOPMNoErr;
 142 }
 143
 144 //*********************************************************************************
 145 // changeNoteInUse
 146 //
 147 //*********************************************************************************
 148
 149 bool IOPMchangeNoteList::changeNoteInUse ( unsigned long ordinal )
 150 {
 151     if ( changeNote[ordinal].flags == IOPMNotInUse ) {
 152         return false;
 153     }
 154     else {
 155         return true;
 156     }
 157 }
 158
 159 //*********************************************************************************
 160 // nextChangeNote
 161 //
 162 // If the parameter corresponds to the most recent power change notification
 163 // passed to drivers and children, return -1.  Otherwise, return the array
 164 // position of the next notification in the circular list.
 165 //*********************************************************************************
 166
 167 long IOPMchangeNoteList::nextChangeNote ( unsigned long ordinal )
 168 {
 169     unsigned long i;
 170
 171     i = increment(ordinal);
 172     if ( i == firstUnused)  {
 173         return -1;
 174     }
 175     return ( i );
 176 }
 177
 178 //*********************************************************************************
 179 // increment
 180 //
 181 // Increment the parameter mod the circular list size and return it.
 182 //*********************************************************************************
 183
 184 unsigned long IOPMchangeNoteList::increment ( unsigned long ordinal )
 185 {
 186     if ( ordinal == (IOPMMaxChangeNotes - 1) ) {
 187         return 0;
 188     }
 189     else {
 190         return ordinal + 1;
 191     }
 192 }
 193
 194 //*********************************************************************************
 195 // decrement
 196 //
 197 // Decrement the parameter mod the circular list size and return it.
 198 //*********************************************************************************
 199
 200 unsigned long IOPMchangeNoteList::decrement ( unsigned long  ordinal )
 201 {
 202     if ( ordinal == 0 ) {
 203         return IOPMMaxChangeNotes - 1;
 204     }
 205     else {
 206         return ordinal - 1;
 207     }
 208 }
 209
 210 //*********************************************************************************
 211 // previousChangeNote
 212 //
 213 // If the parameter corresponds to the oldest power change notification
 214 // passed to drivers and children, return -1.  Otherwise, return the array
 215 // position of the previous notification in the circular list.
 216 //*********************************************************************************
 217
 218 long IOPMchangeNoteList::previousChangeNote ( unsigned long ordinal )
 219 {
 220     if ( ordinal == firstInList )  {
 221         return -1;
 222     }
 223     return decrement(ordinal);
 224 }
 225
 226 //*********************************************************************************
 227 // listEmpty
 228 //
 229 //*********************************************************************************
 230
 231 bool IOPMchangeNoteList::listEmpty ( void )
 232 {
 233     return ( firstInList == firstUnused ) ;
 234 }