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

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This 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 OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */

/*
 *
 *	Copyright (c) 2000 Apple Computer, Inc.  All rights reserved.
 *
 *	HISTORY
 *
 *	2001-01-17	gvdl	Re-implement on IOCommandGate::commandSleep
 *	11/13/2000	CJS	Created IOCommandPool class and implementation
 *
 */

/*!
 * @header IOCommandPool
 * @abstract
 * This header contains the IOCommandPool class definition.
 */

#ifndef _IOKIT_IO_COMMAND_POOL_H_
#define _IOKIT_IO_COMMAND_POOL_H_

/*
 * Kernel
 */

#if defined(KERNEL) && defined(__cplusplus)

#include <kern/kern_types.h>
#include <kern/queue.h>
#include <IOKit/IOCommand.h>
#include <IOKit/IOCommandGate.h>
#include <IOKit/IOService.h>
#include <IOKit/IOWorkLoop.h>

/*!
 * @class IOCommandPool
 * @abstract Manipulates a pool of commands which inherit from IOCommand.
 * @discussion
 * The IOCommandPool class is used to manipulate a pool of commands which
 * inherit from IOCommand. It includes a factory method to create a pool
 * of a certain size. Once the factory method is invoked, the semaphore
 * is set to zero. The caller must then put commands in the pool by creating
 * the command (via the controller's factory method or a memory allocation)
 * and calling the returnCommand method with the newly created command as its
 * argument.
 */

class IOCommandPool : public OSObject
{
	
    OSDeclareDefaultStructors(IOCommandPool)
    
    
protected:

    queue_head_t fQueueHead;	/* head of the queue of elements available */
    UInt32 fSleepers;		/* Count of threads sleeping on this pool */
    IOCommandGate *fSerializer;	/* command gate used for serializing pool access */

/*! @struct ExpansionData
    @discussion This structure will be used to expand the capablilties of the IOEventSource in the future.
    */    
    struct ExpansionData { };

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

    /*!
     * @const kIOCommandPoolDefaultSize
     * @abstract The default size of any command pool.
     * @discussion
     * kIOCommandPoolDefaultSize is the default size of any command pool.
     * The default size was determined to be the smallest size for which
     * a pool makes sense.
     */

    static const UInt32 kIOCommandPoolDefaultSize = 2;
    
    /*
     * Free all of this object's outstanding resources.
     */

    virtual void free(void);
    
    
public:

    /*!
     * @function initWithWorkLoop
     * @abstract Primary initializer for an IOCommandPool object.
     * @discussion Primary initializer for an IOCommandPool.
     * Should probably use IOCommandPool::withWorkLoop() as it is easier to use.
     * @param inWorkLoop
     * The workloop that this command pool should synchronize with.
     * @result Returns true if command pool was successfully initialized.
     */
    virtual bool initWithWorkLoop(IOWorkLoop *workLoop);

    /*!
     * @function withWorkLoop
     * @abstract Primary factory method for the IOCommandPool class
     * @discussion
     * The withWorkLoop method is what is known as a factory method. It creates
     * a new instance of an IOCommandPool and returns a pointer to that object.
     * @param inWorkLoop
     * The workloop that this command pool should synchronize with.
     * @result
     * Returns a pointer to an instance of IOCommandPool if successful,
     * otherwise NULL.
     */

    static IOCommandPool *withWorkLoop(IOWorkLoop *inWorkLoop);

    /*!
     * @function init
     * @abstract Should never be used, obsolete. See initWithWorkLoop.
     */
    virtual bool init(IOService *inOwner,
                      IOWorkLoop *inWorkLoop,
                      UInt32 inSize = kIOCommandPoolDefaultSize);

    /*!
     * @function withWorkLoop
     * @abstract Should never be used, obsolete. See IOCommandPool::withWorkLoop.
     */
    static IOCommandPool *commandPool(IOService *inOwner,
                                        IOWorkLoop *inWorkLoop,
                                        UInt32 inSize = kIOCommandPoolDefaultSize);
    
    
    /*!
     * @function getCommand
     * @discussion The getCommand method is used to get a pointer to an object of type IOCommand from the pool.
     * @param blockForCommand
     * If the caller would like to have its thread slept until a command is
     * available, it should pass true, else false.
     * @result
     * If the caller passes true in blockForCommand, getCommand guarantees that
     * the result will be a pointer to an IOCommand object from the pool. If
     * the caller passes false, s/he is responsible for checking whether a non-NULL
     * pointer was returned.
     */

    virtual IOCommand *getCommand(bool blockForCommand = true);
    
    /*!
     * @function returnCommand
     * @discussion
     * The returnCommand method is used to place an object of type IOCommand
     * into the pool, whether it be the first time, or the 1000th time.
     * @param commmand
     * The command to place in the pool.
     */
    
    virtual void returnCommand(IOCommand *command);
    
protected:
    
    /*!
     * @function gatedGetCommand
     * @discussion
     * The gatedGetCommand method is used to serialize the extraction of a 
     * command from the pool behind a command gate, runAction-ed by getCommand.
     * @param vCommand
     * A pointer to a pointer to an IOCommand object where the returned
     * command will be stored.
     * @param vBlock
     * A bool that indicates whether to block the request until a command
     * becomes available.
     * @result
     * Returns kIOReturnNoResources if no command is available and the client
     * doesn't wish to block until one does become available.
     * kIOReturnSuccess if the vCommand argument is valid.
     */
    virtual IOReturn gatedGetCommand(IOCommand **command, bool blockForCommand);
    
    /*!
     * @function gatedReturnCommand
     * @discussion
     * The gatedReturnCommand method is used to serialize the return of a 
     * command to the pool behind a command gate, runAction-ed by returnCommand.
     * @param vCommand
     * A pointer to the IOCommand object to be returned to the pool.
     * @result
     * Always returns kIOReturnSuccess if the vCommand argument is valid.
     */
    virtual IOReturn gatedReturnCommand(IOCommand *command);

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

#endif	/* defined(KERNEL) && defined(__cplusplus) */

#endif	/* _IOKIT_IO_COMMAND_POOL_H_ */
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
e5568f75 A	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.
1c79356b	11	*
e5568f75 A	12	* This Original Code and all software distributed under the License are
e5568f75 A	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
e5568f75 A	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.
1c79356b A	19	*
	20	* @APPLE_LICENSE_HEADER_END@
	21	*/
	22
	23	/*
	24	*
	25	* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
	26	*
	27	* HISTORY
	28	*
	29	* 2001-01-17 gvdl Re-implement on IOCommandGate::commandSleep
	30	* 11/13/2000 CJS Created IOCommandPool class and implementation
	31	*
	32	*/
	33
	34	/*!
	35	* @header IOCommandPool
	36	* @abstract
	37	* This header contains the IOCommandPool class definition.
	38	*/
	39
	40	#ifndef _IOKIT_IO_COMMAND_POOL_H_
	41	#define _IOKIT_IO_COMMAND_POOL_H_
	42
	43	/*
	44	* Kernel
	45	*/
	46
	47	#if defined(KERNEL) && defined(__cplusplus)
	48
	49	#include <kern/kern_types.h>
	50	#include <kern/queue.h>
	51	#include <IOKit/IOCommand.h>
	52	#include <IOKit/IOCommandGate.h>
	53	#include <IOKit/IOService.h>
	54	#include <IOKit/IOWorkLoop.h>
	55
	56	/*!
	57	* @class IOCommandPool
91447636	58	* @abstract Manipulates a pool of commands which inherit from IOCommand.
1c79356b A	59	* @discussion
	60	* The IOCommandPool class is used to manipulate a pool of commands which
	61	* inherit from IOCommand. It includes a factory method to create a pool
	62	* of a certain size. Once the factory method is invoked, the semaphore
	63	* is set to zero. The caller must then put commands in the pool by creating
	64	* the command (via the controller's factory method or a memory allocation)
	65	* and calling the returnCommand method with the newly created command as its
	66	* argument.
	67	*/
	68
	69	class IOCommandPool : public OSObject
	70	{
	71
	72	OSDeclareDefaultStructors(IOCommandPool)
	73
	74
	75	protected:
	76
	77	queue_head_t fQueueHead; /* head of the queue of elements available */
	78	UInt32 fSleepers; /* Count of threads sleeping on this pool */
	79	IOCommandGate fSerializer; / command gate used for serializing pool access */
	80
	81	/*! @struct ExpansionData
	82	@discussion This structure will be used to expand the capablilties of the IOEventSource in the future.
	83	*/
	84	struct ExpansionData { };
	85
	86	/*! @var reserved
	87	Reserved for future use. (Internal use only) */
	88	ExpansionData *reserved;
	89
	90	/*!
91447636 A	91	* @const kIOCommandPoolDefaultSize
91447636 A	92	* @abstract The default size of any command pool.
1c79356b A	93	* @discussion
	94	* kIOCommandPoolDefaultSize is the default size of any command pool.
	95	* The default size was determined to be the smallest size for which
	96	* a pool makes sense.
	97	*/
	98
	99	static const UInt32 kIOCommandPoolDefaultSize = 2;
	100
	101	/*
	102	* Free all of this object's outstanding resources.
	103	*/
	104
	105	virtual void free(void);
	106
	107
	108	public:
	109
	110	/*!
	111	* @function initWithWorkLoop
91447636 A	112	* @abstract Primary initializer for an IOCommandPool object.
91447636 A	113	* @discussion Primary initializer for an IOCommandPool.
1c79356b A	114	* Should probably use IOCommandPool::withWorkLoop() as it is easier to use.
1c79356b A	115	* @param inWorkLoop
91447636 A	116	* The workloop that this command pool should synchronize with.
91447636 A	117	* @result Returns true if command pool was successfully initialized.
1c79356b A	118	*/
	119	virtual bool initWithWorkLoop(IOWorkLoop *workLoop);
	120
	121	/*!
	122	* @function withWorkLoop
	123	* @abstract Primary factory method for the IOCommandPool class
	124	* @discussion
	125	* The withWorkLoop method is what is known as a factory method. It creates
	126	* a new instance of an IOCommandPool and returns a pointer to that object.
	127	* @param inWorkLoop
91447636	128	* The workloop that this command pool should synchronize with.
1c79356b A	129	* @result
	130	* Returns a pointer to an instance of IOCommandPool if successful,
	131	* otherwise NULL.
	132	*/
	133
	134	static IOCommandPool withWorkLoop(IOWorkLoop inWorkLoop);
	135
	136	/*!
	137	* @function init
91447636	138	* @abstract Should never be used, obsolete. See initWithWorkLoop.
1c79356b A	139	*/
	140	virtual bool init(IOService *inOwner,
	141	IOWorkLoop *inWorkLoop,
	142	UInt32 inSize = kIOCommandPoolDefaultSize);
	143
	144	/*!
	145	* @function withWorkLoop
91447636	146	* @abstract Should never be used, obsolete. See IOCommandPool::withWorkLoop.
1c79356b A	147	*/
	148	static IOCommandPool commandPool(IOService inOwner,
	149	IOWorkLoop *inWorkLoop,
	150	UInt32 inSize = kIOCommandPoolDefaultSize);
	151
	152
	153	/*!
	154	* @function getCommand
91447636	155	* @discussion The getCommand method is used to get a pointer to an object of type IOCommand from the pool.
1c79356b A	156	* @param blockForCommand
1c79356b A	157	* If the caller would like to have its thread slept until a command is
91447636	158	* available, it should pass true, else false.
1c79356b A	159	* @result
	160	* If the caller passes true in blockForCommand, getCommand guarantees that
	161	* the result will be a pointer to an IOCommand object from the pool. If
	162	* the caller passes false, s/he is responsible for checking whether a non-NULL
	163	* pointer was returned.
	164	*/
	165
	166	virtual IOCommand *getCommand(bool blockForCommand = true);
	167
	168	/*!
	169	* @function returnCommand
	170	* @discussion
	171	* The returnCommand method is used to place an object of type IOCommand
	172	* into the pool, whether it be the first time, or the 1000th time.
	173	* @param commmand
	174	* The command to place in the pool.
	175	*/
	176
	177	virtual void returnCommand(IOCommand *command);
	178
	179	protected:
	180
	181	/*!
	182	* @function gatedGetCommand
	183	* @discussion
	184	* The gatedGetCommand method is used to serialize the extraction of a
91447636	185	* command from the pool behind a command gate, runAction-ed by getCommand.
1c79356b A	186	* @param vCommand
1c79356b A	187	* A pointer to a pointer to an IOCommand object where the returned
91447636	188	* command will be stored.
1c79356b A	189	* @param vBlock
	190	* A bool that indicates whether to block the request until a command
	191	* becomes available.
	192	* @result
	193	* Returns kIOReturnNoResources if no command is available and the client
91447636	194	* doesn't wish to block until one does become available.
1c79356b A	195	* kIOReturnSuccess if the vCommand argument is valid.
	196	*/
	197	virtual IOReturn gatedGetCommand(IOCommand **command, bool blockForCommand);
	198
	199	/*!
	200	* @function gatedReturnCommand
	201	* @discussion
	202	* The gatedReturnCommand method is used to serialize the return of a
91447636	203	* command to the pool behind a command gate, runAction-ed by returnCommand.
1c79356b A	204	* @param vCommand
	205	* A pointer to the IOCommand object to be returned to the pool.
	206	* @result
	207	* Always returns kIOReturnSuccess if the vCommand argument is valid.
	208	*/
	209	virtual IOReturn gatedReturnCommand(IOCommand *command);
	210
	211	private:
	212	OSMetaClassDeclareReservedUnused(IOCommandPool, 0);
	213	OSMetaClassDeclareReservedUnused(IOCommandPool, 1);
	214	OSMetaClassDeclareReservedUnused(IOCommandPool, 2);
	215	OSMetaClassDeclareReservedUnused(IOCommandPool, 3);
	216	OSMetaClassDeclareReservedUnused(IOCommandPool, 4);
	217	OSMetaClassDeclareReservedUnused(IOCommandPool, 5);
	218	OSMetaClassDeclareReservedUnused(IOCommandPool, 6);
	219	OSMetaClassDeclareReservedUnused(IOCommandPool, 7);
	220	};
	221
	222	#endif /* defined(KERNEL) && defined(__cplusplus) */
	223
	224	#endif /* _IOKIT_IO_COMMAND_POOL_H_ */