1/* 2 * Copyright (c) 1998-2000, 2009 Apple Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_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 License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 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 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28/* 29Copyright (c) 1998 Apple Computer, Inc. All rights reserved. 30HISTORY 31 1998-7-13 Godfrey van der Linden(gvdl) 32 Created. 33 1998-10-30 Godfrey van der Linden(gvdl) 34 Converted to C++ 35*/ 36#ifndef _IOKIT_IOEVENTSOURCE_H 37#define _IOKIT_IOEVENTSOURCE_H 38 39#include <sys/cdefs.h> 40 41#include <libkern/c++/OSObject.h> 42 43#include <IOKit/IOLib.h> 44#include <IOKit/system.h> 45#include <IOKit/IOWorkLoop.h> 46 47#if IOKITSTATS 48#include <IOKit/IOStatisticsPrivate.h> 49#endif 50 51__BEGIN_DECLS 52#include <mach/clock_types.h> 53#include <kern/clock.h> 54__END_DECLS 55 56/*! 57 @class IOEventSource : public OSObject 58 @abstract Abstract class for all work-loop event sources. 59 @discussion The IOEventSource declares the abstract super class that all 60event sources must inherit from if an IOWorkLoop is to receive events from them. 61<br><br> 62 An event source can represent any event that should cause the work-loop of a 63device to wake up and perform work. Two examples of event sources are the 64IOInterruptEventSource which delivers interrupt notifications and IOCommandGate 65which delivers command requests. 66<br><br> 67 A kernel module can always use the work-loop model for serialising access to 68anything at all. The IOEventSource is used for communicating events to the 69work-loop, and the chain of event sources should be used to walk the possible 70event sources and demultipex them. Note a particular instance of an event 71source may only be a member of 1 linked list chain. If you need to move it 72between chains than make sure it is removed from the original chain before 73attempting to move it. 74<br><br> 75 The IOEventSource makes no attempt to maintain the consistency of its internal data across multi-threading. It is assumed that the user of these basic tools will protect the data that these objects represent in some sort of device wide instance lock. For example the IOWorkLoop maintains the event chain by using an IOCommandGate and thus single threading access to its state. 76<br><br> 77 All subclasses of IOEventSource that wish to perform work on the work-loop thread are expected to implement the checkForWork() member function. As of Mac OS X, 10.7 (Darwin 11), checkForWork is no longer pure virtual, and should not be overridden if there is no work to be done. 78 79<br><br> 80 checkForWork() is the key method in this class. It is called by some work-loop when convienient and is expected to evaluate its internal state and determine if an event has occurred since the last call. In the case of an event having occurred then the instance defined target(owner)/action will be called. The action is stored as an ordinary C function pointer but the first parameter is always the owner. This means that a C++ member function can be used as an action function though this depends on the ABI. 81<br><br> 82 Although the eventChainNext variable contains a reference to the next event source in the chain this reference is not retained. The list 'owner' i.e. the client that creates the event, not the work-loop, is expected to retain the source. 83*/ 84class IOEventSource : public OSObject 85{ 86 OSDeclareAbstractStructors(IOEventSource) 87 friend class IOWorkLoop; 88#if IOKITSTATS 89 friend class IOStatistics; 90#endif 91 92public: 93/*! 94 @typedef Action 95 @discussion Placeholder type for C++ function overloading discrimination. 96As the all event sources require an action and it has to be stored somewhere 97and be of some type, this is that type. 98 @param owner 99 Target of the function, can be used as a refcon. The owner is set 100during initialisation. Note if a C++ function was specified this parameter 101is implicitly the first paramter in the target member function's parameter list. 102*/ 103 typedef void (*Action)(OSObject *owner, ...); 104 105/*! @defined IOEventSourceAction 106 @discussion Backward compatibilty define for the old non-class scoped type definition. See $link IOEventSource::Action */ 107 #define IOEventSourceAction IOEventSource::Action 108 109protected: 110/*! @var eventChainNext 111 The next event source in the event chain. nil at end of chain. */ 112 IOEventSource *eventChainNext; 113 114/*! @var owner The owner object called when an event has been delivered. */ 115 OSObject *owner; 116 117/*! @var action 118 The action method called when an event has been delivered */ 119 Action action; 120 121/*! @var enabled 122 Is this event source enabled to deliver requests to the work-loop. */ 123 bool enabled; 124 125/*! @var workLoop What is the work-loop for this event source. */ 126 IOWorkLoop *workLoop; 127 128/*! @var refcon What ever the client wants to do, see $link setRefcon. */ 129 void *refcon; 130 131/*! @struct ExpansionData 132 @discussion This structure will be used to expand the capablilties of the IOEventSource in the future. 133 */ 134 struct ExpansionData { 135#if IOKITSTATS 136 struct IOEventSourceCounter *counter; 137#else 138 void *iokitstatsReserved; 139#endif 140 }; 141 142/*! @var reserved 143 Reserved for future use. (Internal use only) */ 144 ExpansionData *reserved; 145 146/*! @function init 147 @abstract Primary initialiser for the IOEventSource class. 148 @param owner 149 Owner of this instance of an event source. Used as the first parameter 150of the action callout. Owner will generally be an OSObject it doesn't have to 151be as no member functions will be called directly in it. It can just be a 152refcon for a client routine. 153 @param action 154 Pointer to C call out function. Action is a pointer to a C function 155that gets called when this event source has outstanding work. It will usually 156be called by the checkForWork member function. The first parameter of the 157action call out will always be the owner, this allows C++ member functions to 158be used as actions. Defaults to 0. 159 @result true if the inherited classes and this instance initialise 160successfully. 161*/ 162 virtual bool init(OSObject *owner, IOEventSource::Action action = 0); 163 164 virtual void free( void ); 165 166/*! @function checkForWork 167 @abstract Virtual member function used by IOWorkLoop for work 168scheduling. 169 @discussion This function will be called to request a subclass to check 170its internal state for any work to do and then to call out the owner/action. 171If this event source never performs any work (e.g. IOCommandGate), this 172method should not be overridden. NOTE: This method is no longer declared pure 173virtual. A default implementation is provided in IOEventSource. 174 @result Return true if this function needs to be called again before all its outstanding events have been processed. 175 */ 176 virtual bool checkForWork(); 177 178/*! @function setWorkLoop 179 @abstract Set'ter for $link workLoop variable. 180 @param workLoop 181 Target work-loop of this event source instance. A subclass of 182IOWorkLoop that at least reacts to signalWorkAvailable() and onThread functions. 183*/ 184 virtual void setWorkLoop(IOWorkLoop *workLoop); 185 186/*! @function setNext 187 @abstract Set'ter for $link eventChainNext variable. 188 @param next 189 Pointer to another IOEventSource instance. 190*/ 191 virtual void setNext(IOEventSource *next); 192 193/*! @function getNext 194 @abstract Get'ter for $link eventChainNext variable. 195 @result value of eventChainNext. 196*/ 197 virtual IOEventSource *getNext() const; 198 199 200protected: 201 // Methods to access the IOWorkLoop exported fields 202 void signalWorkAvailable(); 203 void openGate(); 204 void closeGate(); 205 bool tryCloseGate(); 206 int sleepGate(void *event, UInt32 type); 207 int sleepGate(void *event, AbsoluteTime deadline, UInt32 type); 208 void wakeupGate(void *event, bool oneThread); 209 210public: 211/*! @function setAction 212 @abstract Set'ter for $link action variable. 213 @param action Pointer to a C function of type IOEventSource::Action. */ 214 virtual void setAction(IOEventSource::Action action); 215 216/*! @function getAction 217 @abstract Get'ter for $link action variable. 218 @result value of action. */ 219 virtual IOEventSource::Action getAction() const; 220 221/*! @function enable 222 @abstract Enable event source. 223 @discussion A subclass implementation is expected to respect the enabled 224state when checkForWork is called. Calling this function will cause the 225work-loop to be signalled so that a checkForWork is performed. */ 226 virtual void enable(); 227 228/*! @function disable 229 @abstract Disable event source. 230 @discussion A subclass implementation is expected to respect the enabled 231state when checkForWork is called. */ 232 virtual void disable(); 233 234/*! @function isEnabled 235 @abstract Get'ter for $link enable variable. 236 @result true if enabled. */ 237 virtual bool isEnabled() const; 238 239/*! @function getWorkLoop 240 @abstract Get'ter for $link workLoop variable. 241 @result value of workLoop. */ 242 virtual IOWorkLoop *getWorkLoop() const; 243 244/*! @function onThread 245 @abstract Convenience function for workLoop->onThread. 246 @result true if called on the work-loop thread. 247*/ 248 virtual bool onThread() const; 249 250private: 251 OSMetaClassDeclareReservedUnused(IOEventSource, 0); 252 OSMetaClassDeclareReservedUnused(IOEventSource, 1); 253 OSMetaClassDeclareReservedUnused(IOEventSource, 2); 254 OSMetaClassDeclareReservedUnused(IOEventSource, 3); 255 OSMetaClassDeclareReservedUnused(IOEventSource, 4); 256 OSMetaClassDeclareReservedUnused(IOEventSource, 5); 257 OSMetaClassDeclareReservedUnused(IOEventSource, 6); 258 OSMetaClassDeclareReservedUnused(IOEventSource, 7); 259}; 260 261#endif /* !_IOKIT_IOEVENTSOURCE_H */ 262