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