iokit/Kernel/IOPMchangeNoteList.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 #include <IOKit/pwr_mgt/IOPM.h>
  31 #include <IOKit/pwr_mgt/IOPMchangeNoteList.h>
  32 #include <IOKit/pwr_mgt/IOPowerConnection.h>
  33
  34 #define super OSObject
  35 OSDefineMetaClassAndStructors(IOPMchangeNoteList,OSObject)
  36
  37 //*********************************************************************************
  38 // init
  39 //
  40 //*********************************************************************************
  41 void IOPMchangeNoteList::initialize ( void )
  42 {
  43     long i;
  44
  45     firstInList = 0;
  46     firstUnused = 0;
  47     for ( i = 0; i < IOPMMaxChangeNotes; i++ ) {
  48         changeNote[i].flags = IOPMNotInUse;
  49     }
  50 }
  51
  52 //*********************************************************************************
  53 // createChangeNote
  54 //
  55 //*********************************************************************************
  56
  57 long IOPMchangeNoteList::createChangeNote ( void )
  58 {
  59     unsigned long i, j;
  60
  61     i = increment(firstUnused);
  62     if ( firstInList == i ) {
  63         return -1;
  64     }
  65     j = firstUnused;
  66     firstUnused = i;
  67
  68     return j;
  69 }
  70
  71 //*********************************************************************************
  72 // currentChange
  73 //
  74 // Return the ordinal of the first change note in the list.
  75 // If the list is empty, return -1.
  76 //*********************************************************************************
  77
  78 long IOPMchangeNoteList::currentChange ( void )
  79 {
  80     if ( firstUnused == firstInList ) {
  81         return -1;
  82     }
  83     else {
  84         return firstInList;
  85     }
  86 }
  87
  88 //*********************************************************************************
  89 // latestChange
  90 //
  91 // Return the ordinal of the last change note in the list.
  92 // If the list is empty, return -1.
  93 //*********************************************************************************
  94
  95 long IOPMchangeNoteList::latestChange ( void )
  96 {
  97     if ( firstUnused == firstInList ) {
  98         return -1;
  99     }
 100     else {
 101         return decrement(firstUnused);
 102     }
 103 }
 104
 105 //*********************************************************************************
 106 // releaseHeadChangeNote
 107 //
 108 // Mark the head node unused.
 109 // This happens when the first change in the list is completely processed.
 110 // That is, all interested parties have acknowledged it, and power is settled
 111 // at the new level.
 112 //*********************************************************************************
 113
 114 IOReturn IOPMchangeNoteList::releaseHeadChangeNote ( void )
 115 {
 116     IOPowerConnection *tmp;
 117
 118     if((tmp = changeNote[firstInList].parent)) {
 119        changeNote[firstInList].parent = 0;
 120        tmp->release();
 121     }
 122
 123     changeNote[firstInList].flags = IOPMNotInUse;
 124     firstInList = increment(firstInList);
 125     return IOPMNoErr;
 126 }
 127
 128 //*********************************************************************************
 129 // releaseTailChangeNote
 130 //
 131 // Mark the tail node unused.
 132 // This happens when a power change is queued up after another which has
 133 // not yet been started, and the second one supercedes the first.  The data in
 134 // the second is copied into the first and the the second is released.  This
 135 // collapses the first change out of the list.
 136 //*********************************************************************************
 137
 138 IOReturn IOPMchangeNoteList::releaseTailChangeNote ( void )
 139 {
 140     IOPowerConnection *tmp;
 141
 142     if((tmp = changeNote[firstInList].parent)) {
 143        changeNote[firstInList].parent = 0;
 144        tmp->release();
 145     }
 146
 147     firstUnused = decrement(firstUnused);
 148     changeNote[firstUnused].flags = IOPMNotInUse;
 149     return IOPMNoErr;
 150 }
 151
 152 //*********************************************************************************
 153 // changeNoteInUse
 154 //
 155 //*********************************************************************************
 156
 157 bool IOPMchangeNoteList::changeNoteInUse ( unsigned long ordinal )
 158 {
 159     if ( changeNote[ordinal].flags == IOPMNotInUse ) {
 160         return false;
 161     }
 162     else {
 163         return true;
 164     }
 165 }
 166
 167 //*********************************************************************************
 168 // nextChangeNote
 169 //
 170 // If the parameter corresponds to the most recent power change notification
 171 // passed to drivers and children, return -1.  Otherwise, return the array
 172 // position of the next notification in the circular list.
 173 //*********************************************************************************
 174
 175 long IOPMchangeNoteList::nextChangeNote ( unsigned long ordinal )
 176 {
 177     unsigned long i;
 178
 179     i = increment(ordinal);
 180     if ( i == firstUnused)  {
 181         return -1;
 182     }
 183     return ( i );
 184 }
 185
 186 //*********************************************************************************
 187 // increment
 188 //
 189 // Increment the parameter mod the circular list size and return it.
 190 //*********************************************************************************
 191
 192 unsigned long IOPMchangeNoteList::increment ( unsigned long ordinal )
 193 {
 194     if ( ordinal == (IOPMMaxChangeNotes - 1) ) {
 195         return 0;
 196     }
 197     else {
 198         return ordinal + 1;
 199     }
 200 }
 201
 202 //*********************************************************************************
 203 // decrement
 204 //
 205 // Decrement the parameter mod the circular list size and return it.
 206 //*********************************************************************************
 207
 208 unsigned long IOPMchangeNoteList::decrement ( unsigned long  ordinal )
 209 {
 210     if ( ordinal == 0 ) {
 211         return IOPMMaxChangeNotes - 1;
 212     }
 213     else {
 214         return ordinal - 1;
 215     }
 216 }
 217
 218 //*********************************************************************************
 219 // previousChangeNote
 220 //
 221 // If the parameter corresponds to the oldest power change notification
 222 // passed to drivers and children, return -1.  Otherwise, return the array
 223 // position of the previous notification in the circular list.
 224 //*********************************************************************************
 225
 226 long IOPMchangeNoteList::previousChangeNote ( unsigned long ordinal )
 227 {
 228     if ( ordinal == firstInList )  {
 229         return -1;
 230     }
 231     return decrement(ordinal);
 232 }
 233
 234 //*********************************************************************************
 235 // listEmpty
 236 //
 237 //*********************************************************************************
 238
 239 bool IOPMchangeNoteList::listEmpty ( void )
 240 {
 241     return ( firstInList == firstUnused ) ;
 242 }