iokit/Kernel/IOPMinformeeList.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/IOPMinformeeList.h>
  24 #include <IOKit/pwr_mgt/IOPMinformee.h>
  25
  26 #define super OSObject
  27 OSDefineMetaClassAndStructors(IOPMinformeeList,OSObject)
  28
  29 //*********************************************************************************
  30 // init
  31 //
  32 //*********************************************************************************
  33 void IOPMinformeeList::initialize ( void )
  34 {
  35     firstItem = NULL;
  36     length = 0;
  37 }
  38
  39 //******************************************************************************
  40 // getSharedRecursiveLock
  41 //
  42 //******************************************************************************
  43 IORecursiveLock *IOPMinformeeList::getSharedRecursiveLock( void )
  44 {
  45     static IORecursiveLock *sharedListLock = NULL;
  46
  47     /* A running system could have 50-60+ instances of IOPMInformeeList.
  48      * They'll share this lock, since list insertion and removal is relatively
  49      * rare, and generally tied to major events like device discovery.
  50      *
  51      * getSharedRecursiveLock() is called from IOStartIOKit to initialize
  52      * the sharedListLock before any IOPMinformeeLists are instantiated.
  53      *
  54      * The IOPMinformeeList class will be around for the lifetime of the system,
  55      * we don't worry about freeing this lock.
  56      */
  57
  58     if ( NULL == sharedListLock )
  59     {
  60         sharedListLock = IORecursiveLockAlloc();
  61     }
  62     return sharedListLock;
  63 }
  64
  65 //*********************************************************************************
  66 // addToList
  67 //
  68 //*********************************************************************************
  69
  70 IOReturn IOPMinformeeList::addToList ( IOPMinformee * newInformee )
  71 {
  72     IOPMinformee * nextInformee;
  73     IORecursiveLock    *listLock = getSharedRecursiveLock();
  74
  75     if(!listLock)
  76         return kIOReturnError;
  77
  78     IORecursiveLockLock(listLock);
  79     nextInformee = firstItem;
  80
  81     // Is new object already in the list?
  82     while (  nextInformee != NULL )
  83     {
  84         if ( nextInformee->whatObject == newInformee->whatObject )
  85         {
  86             // object is present; just exit
  87             goto unlock_and_exit;
  88         }
  89         nextInformee = nextInList(nextInformee);
  90     }
  91
  92     // add it to the front of the list
  93     newInformee->nextInList = firstItem;
  94     firstItem = newInformee;
  95     length++;
  96
  97 unlock_and_exit:
  98     IORecursiveLockUnlock(listLock);
  99     return IOPMNoErr;
 100 }
 101
 102
 103 //*********************************************************************************
 104 // removeFromList
 105 //
 106 // Find the item in the list, unlink it, and free it.
 107 //*********************************************************************************
 108
 109 IOReturn IOPMinformeeList::removeFromList ( IOService * theItem )
 110 {
 111     IOPMinformee * item = firstItem;
 112     IOPMinformee * temp;
 113     IORecursiveLock    *listLock = getSharedRecursiveLock();
 114
 115     if ( NULL == item )
 116         return IOPMNoErr;
 117     if(!listLock)
 118         return kIOReturnError;
 119
 120     IORecursiveLockLock( listLock );
 121
 122     if ( item->whatObject == theItem )
 123     {
 124         firstItem = item->nextInList;
 125         length--;
 126         item->release();
 127         goto unlock_and_exit;
 128     }
 129
 130     while ( item->nextInList != NULL )
 131     {
 132         if ( item->nextInList->whatObject == theItem )
 133         {
 134             temp = item->nextInList;
 135             item->nextInList = temp->nextInList;
 136             length--;
 137             temp->release();
 138             goto unlock_and_exit;
 139         }
 140         item = item->nextInList;
 141     }
 142
 143 unlock_and_exit:
 144     IORecursiveLockUnlock(listLock);
 145     return IOPMNoErr;
 146 }
 147
 148
 149 //*********************************************************************************
 150 // firstInList
 151 //
 152 //*********************************************************************************
 153
 154 IOPMinformee * IOPMinformeeList::firstInList ( void )
 155 {
 156     return firstItem;
 157 }
 158
 159 //*********************************************************************************
 160 // nextInList
 161 //
 162 //*********************************************************************************
 163
 164 IOPMinformee * IOPMinformeeList::nextInList ( IOPMinformee * currentItem )
 165 {
 166     if ( currentItem != NULL ) {
 167        return (currentItem->nextInList);
 168     }
 169     return NULL;
 170 }
 171
 172 //*********************************************************************************
 173 // numberOfItems
 174 //
 175 //*********************************************************************************
 176
 177 unsigned long IOPMinformeeList::numberOfItems ( void )
 178 {
 179     return length;
 180 }
 181
 182 //*********************************************************************************
 183 // findItem
 184 //
 185 // Look through the list for the one which points to the object identified
 186 // by the parameter.  Return a pointer to the list item or NULL.
 187 //*********************************************************************************
 188
 189 IOPMinformee * IOPMinformeeList::findItem ( IOService * driverOrChild )
 190 {
 191     IOPMinformee * nextObject;
 192
 193     nextObject = firstInList();
 194     while (  nextObject != NULL ) {
 195         if ( nextObject->whatObject == driverOrChild ) {
 196             return nextObject;
 197         }
 198         nextObject = nextInList(nextObject);
 199     }
 200     return NULL;
 201 }
 202
 203
 204
 205 //*********************************************************************************
 206 // free
 207 //
 208 // Free all items in the list, and then free the list itself
 209 //*********************************************************************************
 210
 211 void IOPMinformeeList::free (void )
 212 {
 213     IOPMinformee * next = firstItem;
 214
 215     while ( next != NULL ) {
 216         firstItem = next->nextInList;
 217         length--;
 218         next->release();
 219         next = firstItem;
 220     }
 221 super::free();
 222 }
 223