iokit/Kernel/IOPMinformeeList.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
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   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 License
  10  * may not be used to create, or enable the creation or redistribution of,
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  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
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  23  * Please see the License for the specific language governing rights and
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  27  */
  28 #include <IOKit/pwr_mgt/IOPM.h>
  29 #include <IOKit/pwr_mgt/IOPMinformeeList.h>
  30 #include <IOKit/pwr_mgt/IOPMinformee.h>
  31
  32 #define super OSObject
  33 OSDefineMetaClassAndStructors(IOPMinformeeList,OSObject)
  34
  35 //*********************************************************************************
  36 // init
  37 //
  38 //*********************************************************************************
  39 void IOPMinformeeList::initialize ( void )
  40 {
  41     firstItem = NULL;
  42     length = 0;
  43 }
  44
  45 //******************************************************************************
  46 // getSharedRecursiveLock
  47 //
  48 //******************************************************************************
  49 IORecursiveLock *IOPMinformeeList::getSharedRecursiveLock( void )
  50 {
  51     static IORecursiveLock *sharedListLock = NULL;
  52
  53     /* A running system could have 50-60+ instances of IOPMInformeeList.
  54      * They'll share this lock, since list insertion and removal is relatively
  55      * rare, and generally tied to major events like device discovery.
  56      *
  57      * getSharedRecursiveLock() is called from IOStartIOKit to initialize
  58      * the sharedListLock before any IOPMinformeeLists are instantiated.
  59      *
  60      * The IOPMinformeeList class will be around for the lifetime of the system,
  61      * we don't worry about freeing this lock.
  62      */
  63
  64     if ( NULL == sharedListLock )
  65     {
  66         sharedListLock = IORecursiveLockAlloc();
  67     }
  68     return sharedListLock;
  69 }
  70
  71 //*********************************************************************************
  72 // addToList
  73 //
  74 //*********************************************************************************
  75
  76 IOReturn IOPMinformeeList::addToList ( IOPMinformee * newInformee )
  77 {
  78     IOPMinformee * nextInformee;
  79     IORecursiveLock    *listLock = getSharedRecursiveLock();
  80
  81     if(!listLock)
  82         return kIOReturnError;
  83
  84     IORecursiveLockLock(listLock);
  85     nextInformee = firstItem;
  86
  87     // Is new object already in the list?
  88     while (  nextInformee != NULL )
  89     {
  90         if ( nextInformee->whatObject == newInformee->whatObject )
  91         {
  92             // object is present; just exit
  93             goto unlock_and_exit;
  94         }
  95         nextInformee = nextInList(nextInformee);
  96     }
  97
  98     // add it to the front of the list
  99     newInformee->nextInList = firstItem;
 100     firstItem = newInformee;
 101     length++;
 102
 103 unlock_and_exit:
 104     IORecursiveLockUnlock(listLock);
 105     return IOPMNoErr;
 106 }
 107
 108
 109 //*********************************************************************************
 110 // removeFromList
 111 //
 112 // Find the item in the list, unlink it, and free it.
 113 //*********************************************************************************
 114
 115 IOReturn IOPMinformeeList::removeFromList ( IOService * theItem )
 116 {
 117     IOPMinformee * item = firstItem;
 118     IOPMinformee * temp;
 119     IORecursiveLock    *listLock = getSharedRecursiveLock();
 120
 121     if ( NULL == item )
 122         return IOPMNoErr;
 123     if(!listLock)
 124         return kIOReturnError;
 125
 126     IORecursiveLockLock( listLock );
 127
 128     if ( item->whatObject == theItem )
 129     {
 130         firstItem = item->nextInList;
 131         length--;
 132         item->release();
 133         goto unlock_and_exit;
 134     }
 135
 136     while ( item->nextInList != NULL )
 137     {
 138         if ( item->nextInList->whatObject == theItem )
 139         {
 140             temp = item->nextInList;
 141             item->nextInList = temp->nextInList;
 142             length--;
 143             temp->release();
 144             goto unlock_and_exit;
 145         }
 146         item = item->nextInList;
 147     }
 148
 149 unlock_and_exit:
 150     IORecursiveLockUnlock(listLock);
 151     return IOPMNoErr;
 152 }
 153
 154
 155 //*********************************************************************************
 156 // firstInList
 157 //
 158 //*********************************************************************************
 159
 160 IOPMinformee * IOPMinformeeList::firstInList ( void )
 161 {
 162     return firstItem;
 163 }
 164
 165 //*********************************************************************************
 166 // nextInList
 167 //
 168 //*********************************************************************************
 169
 170 IOPMinformee * IOPMinformeeList::nextInList ( IOPMinformee * currentItem )
 171 {
 172     if ( currentItem != NULL ) {
 173        return (currentItem->nextInList);
 174     }
 175     return NULL;
 176 }
 177
 178 //*********************************************************************************
 179 // numberOfItems
 180 //
 181 //*********************************************************************************
 182
 183 unsigned long IOPMinformeeList::numberOfItems ( void )
 184 {
 185     return length;
 186 }
 187
 188 //*********************************************************************************
 189 // findItem
 190 //
 191 // Look through the list for the one which points to the object identified
 192 // by the parameter.  Return a pointer to the list item or NULL.
 193 //*********************************************************************************
 194
 195 IOPMinformee * IOPMinformeeList::findItem ( IOService * driverOrChild )
 196 {
 197     IOPMinformee * nextObject;
 198
 199     nextObject = firstInList();
 200     while (  nextObject != NULL ) {
 201         if ( nextObject->whatObject == driverOrChild ) {
 202             return nextObject;
 203         }
 204         nextObject = nextInList(nextObject);
 205     }
 206     return NULL;
 207 }
 208
 209
 210
 211 //*********************************************************************************
 212 // free
 213 //
 214 // Free all items in the list, and then free the list itself
 215 //*********************************************************************************
 216
 217 void IOPMinformeeList::free (void )
 218 {
 219     IOPMinformee * next = firstItem;
 220
 221     while ( next != NULL ) {
 222         firstItem = next->nextInList;
 223         length--;
 224         next->release();
 225         next = firstItem;
 226     }
 227 super::free();
 228 }
 229