[apple/xnu.git] / iokit / IOKit / IOEventSource.h

/*
 * Copyright (c) 1998-2000, 2009 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
Copyright (c) 1998 Apple Computer, Inc.	 All rights reserved.
HISTORY
    1998-7-13	Godfrey van der Linden(gvdl)
	Created.
    1998-10-30	Godfrey van der Linden(gvdl)
	Converted to C++
*/
#ifndef _IOKIT_IOEVENTSOURCE_H
#define _IOKIT_IOEVENTSOURCE_H

#include <sys/cdefs.h>

#include <libkern/c++/OSObject.h>

#include <IOKit/IOLib.h>
#include <IOKit/system.h>
#include <IOKit/IOWorkLoop.h>

#if IOKITSTATS
#include <IOKit/IOStatisticsPrivate.h>
#endif

__BEGIN_DECLS
#include <mach/clock_types.h>
#include <kern/clock.h>
__END_DECLS

/*!
    @class IOEventSource : public OSObject
    @abstract Abstract class for all work-loop event sources.
    @discussion The IOEventSource declares the abstract super class that all
event sources must inherit from if an IOWorkLoop is to receive events from them.
<br><br>
	An event source can represent any event that should cause the work-loop of a
device to wake up and perform work.  Two examples of event sources are the
IOInterruptEventSource which delivers interrupt notifications and IOCommandGate
which delivers command requests.
<br><br>
	A kernel module can always use the work-loop model for serialising access to
anything at all.  The IOEventSource is used for communicating events to the
work-loop, and the chain of event sources should be used to walk the possible
event sources and demultipex them.  Note a particular instance of an event
source may only be a member of 1 linked list chain.  If you need to move it
between chains than make sure it is removed from the original chain before
attempting to move it.
<br><br>
	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.
<br><br>
	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.

<br><br>
	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.
<br><br>
	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.
*/
class IOEventSource : public OSObject
{
    OSDeclareAbstractStructors(IOEventSource)
    friend class IOWorkLoop;
#if IOKITSTATS
    friend class IOStatistics;
#endif

public:
/*!
    @typedef Action
    @discussion Placeholder type for C++ function overloading discrimination.
As the all event sources require an action and it has to be stored somewhere
and be of some type, this is that type.
    @param owner
	Target of the function, can be used as a refcon.  The owner is set
during initialisation.	 Note if a C++ function was specified this parameter
is implicitly the first paramter in the target member function's parameter list.
*/
    typedef void (*Action)(OSObject *owner, ...);

/*! @defined IOEventSourceAction
    @discussion Backward compatibilty define for the old non-class scoped type definition.  See $link IOEventSource::Action */
 #define IOEventSourceAction IOEventSource::Action

protected:
/*! @var eventChainNext
	The next event source in the event chain. nil at end of chain. */
    IOEventSource *eventChainNext;

/*! @var owner The owner object called when an event has been delivered. */
    OSObject *owner;

/*! @var action
	The action method called when an event has been delivered */
    Action action;

/*! @var enabled
	Is this event source enabled to deliver requests to the work-loop. */
    bool enabled;

#if XNU_KERNEL_PRIVATE

    enum
    {
        kPassive = 0x0001,
        kActive  = 0x0002,
    };
    uint8_t  eventSourceReserved1[1];
    uint16_t flags;
#if __LP64__
    uint8_t eventSourceReserved2[4];
#endif /* __LP64__ */

#endif /* XNU_KERNEL_PRIVATE */

/*! @var workLoop What is the work-loop for this event source. */
    IOWorkLoop *workLoop;

/*! @var refcon What ever the client wants to do, see $link setRefcon. */
    void *refcon;

/*! @struct ExpansionData
    @discussion This structure will be used to expand the capablilties of the IOEventSource in the future.
    */    
    struct ExpansionData {
#if IOKITSTATS
	    struct IOEventSourceCounter *counter;
#else
	    void *iokitstatsReserved;
#endif
	};

/*! @var reserved
    Reserved for future use.  (Internal use only)  */
    ExpansionData *reserved;

/*! @function init
    @abstract Primary initialiser for the IOEventSource class.
    @param owner
	Owner of this instance of an event source.  Used as the first parameter
of the action callout.	Owner must be an OSObject.
    @param action
	Pointer to C call out function.	 Action is a pointer to a C function
that gets called when this event source has outstanding work.  It will usually
be called by the checkForWork member function.	The first parameter of the
action call out will always be the owner, this allows C++ member functions to
be used as actions.  Defaults to 0.
    @result true if the inherited classes and this instance initialise
successfully.
*/
    virtual bool init(OSObject *owner, IOEventSource::Action action = 0);

    virtual void free( void ) APPLE_KEXT_OVERRIDE;

/*! @function checkForWork
    @abstract Virtual member function used by IOWorkLoop for work
scheduling.
    @discussion This function will be called to request a subclass to check
its internal state for any work to do and then to call out the owner/action.
If this event source never performs any work (e.g. IOCommandGate), this
method should not be overridden. NOTE: This method is no longer declared pure
virtual. A default implementation is provided in IOEventSource.
    @result Return true if this function needs to be called again before all its outstanding events have been processed.
        */
    virtual bool checkForWork();

/*! @function setWorkLoop
    @abstract Set'ter for $link workLoop variable.
    @param workLoop
	Target work-loop of this event source instance.	 A subclass of
IOWorkLoop that at least reacts to signalWorkAvailable() and onThread functions. 
*/
    virtual void setWorkLoop(IOWorkLoop *workLoop);

/*! @function setNext
    @abstract Set'ter for $link eventChainNext variable.
    @param next
	Pointer to another IOEventSource instance.
*/
    virtual void setNext(IOEventSource *next);

/*! @function getNext
    @abstract Get'ter for $link eventChainNext variable.
    @result value of eventChainNext.
*/
    virtual IOEventSource *getNext() const;


protected:
    // Methods to access the IOWorkLoop exported fields
    void signalWorkAvailable();
    void openGate();
    void closeGate();
    bool tryCloseGate();
    int sleepGate(void *event, UInt32 type);
	int sleepGate(void *event, AbsoluteTime deadline, UInt32 type);
    void wakeupGate(void *event, bool oneThread);

public:
/*! @function setAction
    @abstract Set'ter for $link action variable.
    @param action Pointer to a C function of type IOEventSource::Action. */
    virtual void setAction(IOEventSource::Action action);

/*! @function getAction
    @abstract Get'ter for $link action variable.
    @result value of action. */
    virtual IOEventSource::Action getAction() const;

/*! @function enable
    @abstract Enable event source.
    @discussion A subclass implementation is expected to respect the enabled
state when checkForWork is called.  Calling this function will cause the
work-loop to be signalled so that a checkForWork is performed. */
    virtual void enable();

/*! @function disable
    @abstract Disable event source.
    @discussion A subclass implementation is expected to respect the enabled
state when checkForWork is called. */
    virtual void disable();

/*! @function isEnabled
    @abstract Get'ter for $link enable variable.
    @result true if enabled. */
    virtual bool isEnabled() const;

/*! @function getWorkLoop
    @abstract Get'ter for $link workLoop variable.
    @result value of workLoop. */
    virtual IOWorkLoop *getWorkLoop() const;

/*! @function onThread
    @abstract Convenience function for workLoop->onThread.
    @result true if called on the work-loop thread.
*/
    virtual bool onThread() const;

private:
    OSMetaClassDeclareReservedUnused(IOEventSource, 0);
    OSMetaClassDeclareReservedUnused(IOEventSource, 1);
    OSMetaClassDeclareReservedUnused(IOEventSource, 2);
    OSMetaClassDeclareReservedUnused(IOEventSource, 3);
    OSMetaClassDeclareReservedUnused(IOEventSource, 4);
    OSMetaClassDeclareReservedUnused(IOEventSource, 5);
    OSMetaClassDeclareReservedUnused(IOEventSource, 6);
    OSMetaClassDeclareReservedUnused(IOEventSource, 7);
};

#endif /* !_IOKIT_IOEVENTSOURCE_H */
Commit	Line	Data
1c79356b	1	/*
6d2010ae	2	* Copyright (c) 1998-2000, 2009 Apple Inc. All rights reserved.
1c79356b	3	*
2d21ac55	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
2d21ac55 A	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.
8f6c56a5	14	*
2d21ac55 A	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
8f6c56a5 A	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55 A	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.
8f6c56a5	25	*
2d21ac55	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b A	27	*/
	28	/*
	29	Copyright (c) 1998 Apple Computer, Inc. All rights reserved.
	30	HISTORY
	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
6d2010ae A	47	#if IOKITSTATS
	48	#include <IOKit/IOStatisticsPrivate.h>
	49	#endif
1c79356b A	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
	60	event 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
	63	device to wake up and perform work. Two examples of event sources are the
	64	IOInterruptEventSource which delivers interrupt notifications and IOCommandGate
	65	which delivers command requests.
	66	<br><br>
	67	A kernel module can always use the work-loop model for serialising access to
	68	anything at all. The IOEventSource is used for communicating events to the
	69	work-loop, and the chain of event sources should be used to walk the possible
	70	event sources and demultipex them. Note a particular instance of an event
	71	source may only be a member of 1 linked list chain. If you need to move it
	72	between chains than make sure it is removed from the original chain before
	73	attempting to move it.
	74	<br><br>
6d2010ae	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.
1c79356b	76	<br><br>
6d2010ae	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.
1c79356b A	78
1c79356b A	79	<br><br>
6d2010ae	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.
1c79356b A	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	*/
	84	class IOEventSource : public OSObject
	85	{
	86	OSDeclareAbstractStructors(IOEventSource)
	87	friend class IOWorkLoop;
6d2010ae A	88	#if IOKITSTATS
	89	friend class IOStatistics;
	90	#endif
1c79356b A	91
	92	public:
	93	/*!
	94	@typedef Action
	95	@discussion Placeholder type for C++ function overloading discrimination.
	96	As the all event sources require an action and it has to be stored somewhere
	97	and 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
	100	during initialisation. Note if a C++ function was specified this parameter
	101	is 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
	109	protected:
	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
5ba3f43e A	125	#if XNU_KERNEL_PRIVATE
	126
	127	enum
	128	{
	129	kPassive = 0x0001,
	130	kActive = 0x0002,
	131	};
	132	uint8_t eventSourceReserved1[1];
	133	uint16_t flags;
	134	#if __LP64__
	135	uint8_t eventSourceReserved2[4];
	136	#endif /* __LP64__ */
	137
	138	#endif /* XNU_KERNEL_PRIVATE */
	139
1c79356b A	140	/! @var workLoop What is the work-loop for this event source. /
	141	IOWorkLoop *workLoop;
	142
	143	/! @var refcon What ever the client wants to do, see $link setRefcon. /
	144	void *refcon;
	145
	146	/*! @struct ExpansionData
	147	@discussion This structure will be used to expand the capablilties of the IOEventSource in the future.
	148	*/
6d2010ae A	149	struct ExpansionData {
	150	#if IOKITSTATS
	151	struct IOEventSourceCounter *counter;
	152	#else
	153	void *iokitstatsReserved;
	154	#endif
	155	};
1c79356b A	156
	157	/*! @var reserved
	158	Reserved for future use. (Internal use only) */
	159	ExpansionData *reserved;
	160
	161	/*! @function init
	162	@abstract Primary initialiser for the IOEventSource class.
	163	@param owner
	164	Owner of this instance of an event source. Used as the first parameter
5ba3f43e	165	of the action callout. Owner must be an OSObject.
1c79356b A	166	@param action
	167	Pointer to C call out function. Action is a pointer to a C function
	168	that gets called when this event source has outstanding work. It will usually
	169	be called by the checkForWork member function. The first parameter of the
	170	action call out will always be the owner, this allows C++ member functions to
	171	be used as actions. Defaults to 0.
	172	@result true if the inherited classes and this instance initialise
	173	successfully.
	174	*/
	175	virtual bool init(OSObject *owner, IOEventSource::Action action = 0);
	176
3e170ce0	177	virtual void free( void ) APPLE_KEXT_OVERRIDE;
6d2010ae	178
1c79356b	179	/*! @function checkForWork
6d2010ae	180	@abstract Virtual member function used by IOWorkLoop for work
1c79356b A	181	scheduling.
1c79356b A	182	@discussion This function will be called to request a subclass to check
6d2010ae A	183	its internal state for any work to do and then to call out the owner/action.
	184	If this event source never performs any work (e.g. IOCommandGate), this
	185	method should not be overridden. NOTE: This method is no longer declared pure
	186	virtual. A default implementation is provided in IOEventSource.
1c79356b A	187	@result Return true if this function needs to be called again before all its outstanding events have been processed.
1c79356b A	188	*/
6d2010ae	189	virtual bool checkForWork();
1c79356b A	190
	191	/*! @function setWorkLoop
	192	@abstract Set'ter for $link workLoop variable.
	193	@param workLoop
	194	Target work-loop of this event source instance. A subclass of
	195	IOWorkLoop that at least reacts to signalWorkAvailable() and onThread functions.
	196	*/
	197	virtual void setWorkLoop(IOWorkLoop *workLoop);
	198
	199	/*! @function setNext
	200	@abstract Set'ter for $link eventChainNext variable.
	201	@param next
	202	Pointer to another IOEventSource instance.
	203	*/
	204	virtual void setNext(IOEventSource *next);
	205
	206	/*! @function getNext
	207	@abstract Get'ter for $link eventChainNext variable.
	208	@result value of eventChainNext.
	209	*/
	210	virtual IOEventSource *getNext() const;
	211
	212
	213	protected:
	214	// Methods to access the IOWorkLoop exported fields
b0d623f7 A	215	void signalWorkAvailable();
	216	void openGate();
	217	void closeGate();
	218	bool tryCloseGate();
	219	int sleepGate(void *event, UInt32 type);
	220	int sleepGate(void *event, AbsoluteTime deadline, UInt32 type);
	221	void wakeupGate(void *event, bool oneThread);
1c79356b A	222
	223	public:
	224	/*! @function setAction
	225	@abstract Set'ter for $link action variable.
	226	@param action Pointer to a C function of type IOEventSource::Action. */
	227	virtual void setAction(IOEventSource::Action action);
	228
	229	/*! @function getAction
	230	@abstract Get'ter for $link action variable.
	231	@result value of action. */
	232	virtual IOEventSource::Action getAction() const;
	233
	234	/*! @function enable
	235	@abstract Enable event source.
	236	@discussion A subclass implementation is expected to respect the enabled
	237	state when checkForWork is called. Calling this function will cause the
	238	work-loop to be signalled so that a checkForWork is performed. */
	239	virtual void enable();
	240
	241	/*! @function disable
	242	@abstract Disable event source.
	243	@discussion A subclass implementation is expected to respect the enabled
	244	state when checkForWork is called. */
	245	virtual void disable();
	246
	247	/*! @function isEnabled
	248	@abstract Get'ter for $link enable variable.
	249	@result true if enabled. */
	250	virtual bool isEnabled() const;
	251
	252	/*! @function getWorkLoop
	253	@abstract Get'ter for $link workLoop variable.
	254	@result value of workLoop. */
	255	virtual IOWorkLoop *getWorkLoop() const;
	256
	257	/*! @function onThread
	258	@abstract Convenience function for workLoop->onThread.
	259	@result true if called on the work-loop thread.
	260	*/
	261	virtual bool onThread() const;
	262
	263	private:
	264	OSMetaClassDeclareReservedUnused(IOEventSource, 0);
	265	OSMetaClassDeclareReservedUnused(IOEventSource, 1);
	266	OSMetaClassDeclareReservedUnused(IOEventSource, 2);
	267	OSMetaClassDeclareReservedUnused(IOEventSource, 3);
	268	OSMetaClassDeclareReservedUnused(IOEventSource, 4);
	269	OSMetaClassDeclareReservedUnused(IOEventSource, 5);
	270	OSMetaClassDeclareReservedUnused(IOEventSource, 6);
	271	OSMetaClassDeclareReservedUnused(IOEventSource, 7);
	272	};
	273
	274	#endif /* !_IOKIT_IOEVENTSOURCE_H */