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

/*
 * Copyright (c) 1998-2016 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@
 */
#ifndef _IOBUFFERMEMORYDESCRIPTOR_H
#define _IOBUFFERMEMORYDESCRIPTOR_H

#include <IOKit/IOMemoryDescriptor.h>

enum {
    kIOMemoryPhysicallyContiguous	= 0x00000010,
    kIOMemoryPageable	      		= 0x00000020,
    kIOMemoryPurgeable	      		= 0x00000040,
    kIOMemoryHostPhysicallyContiguous  	= 0x00000080,
    kIOMemorySharingTypeMask		= 0x000f0000,
    kIOMemoryUnshared			= 0x00000000,
    kIOMemoryKernelUserShared		= 0x00010000,
    // shared IOMemoryDescriptor options for IOBufferMemoryDescriptor:
    kIOBufferDescriptorMemoryFlags	= kIOMemoryDirectionMask 
#ifdef XNU_KERNEL_PRIVATE
					| kIOMemoryAutoPrepare
#endif
					| kIOMemoryThreadSafe
					| kIOMemoryClearEncrypt
					| kIOMemoryMapperNone
					| kIOMemoryUseReserve
};

#define _IOBUFFERMEMORYDESCRIPTOR_INTASKWITHOPTIONS_		1
#define _IOBUFFERMEMORYDESCRIPTOR_HOSTPHYSICALLYCONTIGUOUS_	1
/*!
    @class IOBufferMemoryDescriptor
    @abstract Provides a simple memory descriptor that allocates its own buffer memory.
*/

class IOBufferMemoryDescriptor : public IOGeneralMemoryDescriptor
{
    OSDeclareDefaultStructors(IOBufferMemoryDescriptor);

private:
/*! @struct ExpansionData
    @discussion This structure will be used to expand the capablilties of this class in the future.
    */    
    struct ExpansionData {
	IOMemoryMap *   map;
    };

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

protected:
    void *               _buffer;
    vm_size_t            _capacity;
    vm_offset_t		 _alignment;
    IOOptionBits	 _options;
private:
    uintptr_t		 _internalReserved;
    unsigned             _internalFlags;

private:
#ifndef __LP64__
    virtual bool initWithOptions(
                               IOOptionBits options,
                               vm_size_t    capacity,
                               vm_offset_t  alignment,
			       task_t	    inTask) APPLE_KEXT_DEPRECATED; /* use withOptions() instead */
#endif /* !__LP64__ */

public:
    virtual bool initWithPhysicalMask(
				task_t		  inTask,
				IOOptionBits      options,
				mach_vm_size_t    capacity,
				mach_vm_address_t alignment,
				mach_vm_address_t physicalMask);

#ifdef __LP64__
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 0);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 1);
#else /* !__LP64__ */
    OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 0);
    OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 1);
#endif /* !__LP64__ */
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 2);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 3);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 4);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 5);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 6);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 7);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 8);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 9);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 10);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 11);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 12);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 13);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 14);
    OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 15);

protected:
    virtual void free() APPLE_KEXT_OVERRIDE;

public:

    /*
     * withOptions:
     *
     * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
     * hold capacity bytes.  The descriptor's length is initially set to the
     * capacity.
     */
#ifndef __LP64__
    virtual bool initWithOptions(   IOOptionBits options,
                                    vm_size_t    capacity,
                                    vm_offset_t  alignment) APPLE_KEXT_DEPRECATED; /* use withOptions() instead */
#endif /* !__LP64__ */

    static IOBufferMemoryDescriptor * withOptions(  IOOptionBits options,
                                                    vm_size_t    capacity,
                                                    vm_offset_t  alignment = 1);

/*! @function inTaskWithOptions
    @abstract Creates a memory buffer with memory descriptor for that buffer. 
    @discussion Added in Mac OS X 10.2, this method allocates a memory buffer with a given size and alignment in the task's address space specified, and returns a memory descriptor instance representing the memory. It is recommended that memory allocated for I/O or sharing via mapping be created via IOBufferMemoryDescriptor. Options passed with the request specify the kind of memory to be allocated - pageablity and sharing are specified with option bits. This function may block and so should not be called from interrupt level or while a simple lock is held.
    @param inTask The task the buffer will be allocated in.
    @param options Options for the allocation:<br>
    kIODirectionOut, kIODirectionIn - set the direction of the I/O transfer.<br>
    kIOMemoryPhysicallyContiguous - pass to request memory be physically contiguous. This option is heavily discouraged. The request may fail if memory is fragmented, may cause large amounts of paging activity, and may take a very long time to execute.<br>
    kIOMemoryPageable - pass to request memory be non-wired - the default for kernel allocated memory is wired.<br>
    kIOMemoryPurgeable - pass to request memory that may later have its purgeable state set with IOMemoryDescriptor::setPurgeable. Only supported for kIOMemoryPageable allocations.<br>
    kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.<br>
    kIOMapInhibitCache - allocate memory with inhibited cache setting. <br>		
    kIOMapWriteThruCache - allocate memory with writethru cache setting. <br>		
    kIOMapCopybackCache - allocate memory with copyback cache setting. <br>		
    kIOMapWriteCombineCache - allocate memory with writecombined cache setting.
    @param capacity The number of bytes to allocate.
    @param alignment The minimum required alignment of the buffer in bytes - 1 is the default for no required alignment. For example, pass 256 to get memory allocated at an address with bits 0-7 zero.
    @result Returns an instance of class IOBufferMemoryDescriptor to be released by the caller, which will free the memory desriptor and associated buffer. */

    static IOBufferMemoryDescriptor * inTaskWithOptions(
					    task_t       inTask,
                                            IOOptionBits options,
                                            vm_size_t    capacity,
                                            vm_offset_t  alignment = 1);

/*! @function inTaskWithPhysicalMask
    @abstract Creates a memory buffer with memory descriptor for that buffer. 
    @discussion Added in Mac OS X 10.5, this method allocates a memory buffer with a given size and alignment in the task's address space specified, and returns a memory descriptor instance representing the memory. It is recommended that memory allocated for I/O or sharing via mapping be created via IOBufferMemoryDescriptor. Options passed with the request specify the kind of memory to be allocated - pageablity and sharing are specified with option bits. This function may block and so should not be called from interrupt level or while a simple lock is held.
    @param inTask The task the buffer will be mapped in. Pass NULL to create memory unmapped in any task (eg. for use as a DMA buffer).
    @param options Options for the allocation:<br>
    kIODirectionOut, kIODirectionIn - set the direction of the I/O transfer.<br>
    kIOMemoryPhysicallyContiguous - pass to request memory be physically contiguous. This option is heavily discouraged. The request may fail if memory is fragmented, may cause large amounts of paging activity, and may take a very long time to execute.<br>
    kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.<br>
    kIOMapInhibitCache - allocate memory with inhibited cache setting. <br>		
    kIOMapWriteThruCache - allocate memory with writethru cache setting. <br>		
    kIOMapCopybackCache - allocate memory with copyback cache setting. <br>		
    kIOMapWriteCombineCache - allocate memory with writecombined cache setting.
    @param capacity The number of bytes to allocate.
    @param physicalMask The buffer will be allocated with pages such that physical addresses will only have bits set present in physicalMask. For example, pass 0x00000000FFFFFFFFULL for a buffer to be accessed by hardware that has 32 address bits.
    @result Returns an instance of class IOBufferMemoryDescriptor to be released by the caller, which will free the memory desriptor and associated buffer. */

    static IOBufferMemoryDescriptor * inTaskWithPhysicalMask(
					    task_t	      inTask,
                                            IOOptionBits      options,
                                            mach_vm_size_t    capacity,
                                            mach_vm_address_t physicalMask);

    /*
     * withCapacity:
     *
     * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
     * hold capacity bytes.  The descriptor's length is initially set to the
     * capacity.
     */
    static IOBufferMemoryDescriptor * withCapacity(
                                     vm_size_t    capacity,
                                     IODirection  withDirection,
                                     bool         withContiguousMemory = false);
#ifndef __LP64__
    virtual bool initWithBytes(const void * bytes,
                               vm_size_t    withLength,
                               IODirection  withDirection,
                               bool         withContiguousMemory = false) APPLE_KEXT_DEPRECATED; /* use withBytes() instead */
#endif /* !__LP64__ */

    /*
     * withBytes:
     *
     * Returns a new IOBufferMemoryDescriptor preloaded with bytes (copied).
     * The descriptor's length and capacity are set to the input buffer's size.
     */
    static IOBufferMemoryDescriptor * withBytes(
                                     const void * bytes,
                                     vm_size_t    withLength,
                                     IODirection  withDirection,
                                     bool         withContiguousMemory = false);

    /*
     * setLength:
     *
     * Change the buffer length of the memory descriptor.  When a new buffer
     * is created, the initial length of the buffer is set to be the same as
     * the capacity.  The length can be adjusted via setLength for a shorter
     * transfer (there is no need to create more buffer descriptors when you
     * can reuse an existing one, even for different transfer sizes).   Note
     * that the specified length must not exceed the capacity of the buffer.
     */
    virtual void setLength(vm_size_t length);

    /*
     * setDirection:
     *
     * Change the direction of the transfer.  This method allows one to redirect
     * the descriptor's transfer direction.  This eliminates the need to destroy
     * and create new buffers when different transfer directions are needed.
     */
    virtual void setDirection(IODirection direction);

    /*
     * getCapacity:
     *
     * Get the buffer capacity
     */
    virtual vm_size_t getCapacity() const;

    /*
     * getBytesNoCopy:
     *
     * Return the virtual address of the beginning of the buffer
     */
    virtual void *getBytesNoCopy();

    /*
     * getBytesNoCopy:
     *
     * Return the virtual address of an offset from the beginning of the buffer
     */
    virtual void *getBytesNoCopy(vm_size_t start, vm_size_t withLength);

    /*
     * appendBytes:
     *
     * Add some data to the end of the buffer.  This method automatically
     * maintains the memory descriptor buffer length.  Note that appendBytes
     * will not copy past the end of the memory descriptor's current capacity.
     */
    virtual bool appendBytes(const void *bytes, vm_size_t withLength);

#ifndef __LP64__
    virtual void * getVirtualSegment(IOByteCount offset,
					IOByteCount * length) APPLE_KEXT_OVERRIDE APPLE_KEXT_DEPRECATED; /* use getBytesNoCopy() instead */
#endif /* !__LP64__ */
};

#endif /* !_IOBUFFERMEMORYDESCRIPTOR_H */
Commit	Line	Data
1c79356b	1	/*
39037602	2	* Copyright (c) 1998-2016 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	#ifndef _IOBUFFERMEMORYDESCRIPTOR_H
	29	#define _IOBUFFERMEMORYDESCRIPTOR_H
	30
	31	#include <IOKit/IOMemoryDescriptor.h>
	32
	33	enum {
1c79356b A	34	kIOMemoryPhysicallyContiguous = 0x00000010,
1c79356b A	35	kIOMemoryPageable = 0x00000020,
91447636	36	kIOMemoryPurgeable = 0x00000040,
99c3a104	37	kIOMemoryHostPhysicallyContiguous = 0x00000080,
1c79356b A	38	kIOMemorySharingTypeMask = 0x000f0000,
1c79356b A	39	kIOMemoryUnshared = 0x00000000,
c910b4d9 A	40	kIOMemoryKernelUserShared = 0x00010000,
	41	// shared IOMemoryDescriptor options for IOBufferMemoryDescriptor:
	42	kIOBufferDescriptorMemoryFlags = kIOMemoryDirectionMask
	43	#ifdef XNU_KERNEL_PRIVATE
	44	\| kIOMemoryAutoPrepare
	45	#endif
	46	\| kIOMemoryThreadSafe
0b4c1975	47	\| kIOMemoryClearEncrypt
99c3a104	48	\| kIOMemoryMapperNone
39037602	49	\| kIOMemoryUseReserve
1c79356b A	50	};
1c79356b A	51
99c3a104 A	52	#define _IOBUFFERMEMORYDESCRIPTOR_INTASKWITHOPTIONS_ 1
99c3a104 A	53	#define _IOBUFFERMEMORYDESCRIPTOR_HOSTPHYSICALLYCONTIGUOUS_ 1
91447636 A	54	/*!
	55	@class IOBufferMemoryDescriptor
	56	@abstract Provides a simple memory descriptor that allocates its own buffer memory.
	57	*/
1c79356b A	58
	59	class IOBufferMemoryDescriptor : public IOGeneralMemoryDescriptor
	60	{
	61	OSDeclareDefaultStructors(IOBufferMemoryDescriptor);
	62
2d21ac55	63	private:
1c79356b A	64	/*! @struct ExpansionData
	65	@discussion This structure will be used to expand the capablilties of this class in the future.
	66	*/
9bccf70c	67	struct ExpansionData {
2d21ac55	68	IOMemoryMap * map;
9bccf70c	69	};
1c79356b A	70
	71	/*! @var reserved
	72	Reserved for future use. (Internal use only) */
	73	ExpansionData * reserved;
	74
	75	protected:
	76	void * _buffer;
	77	vm_size_t _capacity;
	78	vm_offset_t _alignment;
	79	IOOptionBits _options;
b0d623f7 A	80	private:
	81	uintptr_t _internalReserved;
	82	unsigned _internalFlags;
1c79356b A	83
1c79356b A	84	private:
b0d623f7	85	#ifndef __LP64__
9bccf70c A	86	virtual bool initWithOptions(
	87	IOOptionBits options,
	88	vm_size_t capacity,
	89	vm_offset_t alignment,
b0d623f7 A	90	task_t inTask) APPLE_KEXT_DEPRECATED; /* use withOptions() instead */
b0d623f7 A	91	#endif /* !__LP64__ */
0c530ab8	92
6d2010ae	93	public:
0c530ab8 A	94	virtual bool initWithPhysicalMask(
	95	task_t inTask,
	96	IOOptionBits options,
	97	mach_vm_size_t capacity,
	98	mach_vm_address_t alignment,
	99	mach_vm_address_t physicalMask);
2d21ac55	100
b0d623f7 A	101	#ifdef __LP64__
	102	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 0);
	103	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 1);
	104	#else /* !__LP64__ */
2d21ac55	105	OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 0);
0c530ab8	106	OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 1);
b0d623f7	107	#endif /* !__LP64__ */
1c79356b A	108	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 2);
	109	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 3);
	110	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 4);
	111	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 5);
	112	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 6);
	113	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 7);
	114	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 8);
	115	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 9);
	116	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 10);
	117	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 11);
	118	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 12);
	119	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 13);
	120	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 14);
	121	OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 15);
	122
	123	protected:
3e170ce0	124	virtual void free() APPLE_KEXT_OVERRIDE;
1c79356b	125
1c79356b A	126	public:
	127
	128	/*
	129	* withOptions:
	130	*
	131	* Returns a new IOBufferMemoryDescriptor with a buffer large enough to
	132	* hold capacity bytes. The descriptor's length is initially set to the
	133	* capacity.
	134	*/
b0d623f7	135	#ifndef __LP64__
1c79356b A	136	virtual bool initWithOptions( IOOptionBits options,
1c79356b A	137	vm_size_t capacity,
b0d623f7 A	138	vm_offset_t alignment) APPLE_KEXT_DEPRECATED; /* use withOptions() instead */
b0d623f7 A	139	#endif /* !__LP64__ */
1c79356b A	140
	141	static IOBufferMemoryDescriptor * withOptions( IOOptionBits options,
	142	vm_size_t capacity,
	143	vm_offset_t alignment = 1);
	144
9bccf70c	145	/*! @function inTaskWithOptions
91447636 A	146	@abstract Creates a memory buffer with memory descriptor for that buffer.
91447636 A	147	@discussion Added in Mac OS X 10.2, this method allocates a memory buffer with a given size and alignment in the task's address space specified, and returns a memory descriptor instance representing the memory. It is recommended that memory allocated for I/O or sharing via mapping be created via IOBufferMemoryDescriptor. Options passed with the request specify the kind of memory to be allocated - pageablity and sharing are specified with option bits. This function may block and so should not be called from interrupt level or while a simple lock is held.
9bccf70c	148	@param inTask The task the buffer will be allocated in.
91447636	149	@param options Options for the allocation:<br>
0c530ab8	150	kIODirectionOut, kIODirectionIn - set the direction of the I/O transfer.<br>
91447636 A	151	kIOMemoryPhysicallyContiguous - pass to request memory be physically contiguous. This option is heavily discouraged. The request may fail if memory is fragmented, may cause large amounts of paging activity, and may take a very long time to execute.<br>
	152	kIOMemoryPageable - pass to request memory be non-wired - the default for kernel allocated memory is wired.<br>
	153	kIOMemoryPurgeable - pass to request memory that may later have its purgeable state set with IOMemoryDescriptor::setPurgeable. Only supported for kIOMemoryPageable allocations.<br>
6d2010ae A	154	kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.<br>
	155	kIOMapInhibitCache - allocate memory with inhibited cache setting. <br>
	156	kIOMapWriteThruCache - allocate memory with writethru cache setting. <br>
	157	kIOMapCopybackCache - allocate memory with copyback cache setting. <br>
	158	kIOMapWriteCombineCache - allocate memory with writecombined cache setting.
9bccf70c A	159	@param capacity The number of bytes to allocate.
9bccf70c A	160	@param alignment The minimum required alignment of the buffer in bytes - 1 is the default for no required alignment. For example, pass 256 to get memory allocated at an address with bits 0-7 zero.
91447636	161	@result Returns an instance of class IOBufferMemoryDescriptor to be released by the caller, which will free the memory desriptor and associated buffer. */
9bccf70c A	162
	163	static IOBufferMemoryDescriptor * inTaskWithOptions(
	164	task_t inTask,
	165	IOOptionBits options,
	166	vm_size_t capacity,
	167	vm_offset_t alignment = 1);
	168
0c530ab8 A	169	/*! @function inTaskWithPhysicalMask
	170	@abstract Creates a memory buffer with memory descriptor for that buffer.
	171	@discussion Added in Mac OS X 10.5, this method allocates a memory buffer with a given size and alignment in the task's address space specified, and returns a memory descriptor instance representing the memory. It is recommended that memory allocated for I/O or sharing via mapping be created via IOBufferMemoryDescriptor. Options passed with the request specify the kind of memory to be allocated - pageablity and sharing are specified with option bits. This function may block and so should not be called from interrupt level or while a simple lock is held.
	172	@param inTask The task the buffer will be mapped in. Pass NULL to create memory unmapped in any task (eg. for use as a DMA buffer).
	173	@param options Options for the allocation:<br>
	174	kIODirectionOut, kIODirectionIn - set the direction of the I/O transfer.<br>
	175	kIOMemoryPhysicallyContiguous - pass to request memory be physically contiguous. This option is heavily discouraged. The request may fail if memory is fragmented, may cause large amounts of paging activity, and may take a very long time to execute.<br>
6d2010ae A	176	kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.<br>
	177	kIOMapInhibitCache - allocate memory with inhibited cache setting. <br>
	178	kIOMapWriteThruCache - allocate memory with writethru cache setting. <br>
	179	kIOMapCopybackCache - allocate memory with copyback cache setting. <br>
	180	kIOMapWriteCombineCache - allocate memory with writecombined cache setting.
0c530ab8	181	@param capacity The number of bytes to allocate.
39037602	182	@param physicalMask The buffer will be allocated with pages such that physical addresses will only have bits set present in physicalMask. For example, pass 0x00000000FFFFFFFFULL for a buffer to be accessed by hardware that has 32 address bits.
0c530ab8 A	183	@result Returns an instance of class IOBufferMemoryDescriptor to be released by the caller, which will free the memory desriptor and associated buffer. */
	184
	185	static IOBufferMemoryDescriptor * inTaskWithPhysicalMask(
	186	task_t inTask,
	187	IOOptionBits options,
	188	mach_vm_size_t capacity,
	189	mach_vm_address_t physicalMask);
0c530ab8	190
1c79356b A	191	/*
	192	* withCapacity:
	193	*
	194	* Returns a new IOBufferMemoryDescriptor with a buffer large enough to
	195	* hold capacity bytes. The descriptor's length is initially set to the
	196	* capacity.
	197	*/
	198	static IOBufferMemoryDescriptor * withCapacity(
	199	vm_size_t capacity,
	200	IODirection withDirection,
	201	bool withContiguousMemory = false);
b0d623f7	202	#ifndef __LP64__
1c79356b A	203	virtual bool initWithBytes(const void * bytes,
	204	vm_size_t withLength,
	205	IODirection withDirection,
b0d623f7 A	206	bool withContiguousMemory = false) APPLE_KEXT_DEPRECATED; /* use withBytes() instead */
b0d623f7 A	207	#endif /* !__LP64__ */
1c79356b A	208
	209	/*
	210	* withBytes:
	211	*
	212	* Returns a new IOBufferMemoryDescriptor preloaded with bytes (copied).
	213	* The descriptor's length and capacity are set to the input buffer's size.
	214	*/
	215	static IOBufferMemoryDescriptor * withBytes(
	216	const void * bytes,
	217	vm_size_t withLength,
	218	IODirection withDirection,
	219	bool withContiguousMemory = false);
	220
	221	/*
	222	* setLength:
	223	*
	224	* Change the buffer length of the memory descriptor. When a new buffer
	225	* is created, the initial length of the buffer is set to be the same as
	226	* the capacity. The length can be adjusted via setLength for a shorter
	227	* transfer (there is no need to create more buffer descriptors when you
	228	* can reuse an existing one, even for different transfer sizes). Note
	229	* that the specified length must not exceed the capacity of the buffer.
	230	*/
	231	virtual void setLength(vm_size_t length);
	232
	233	/*
	234	* setDirection:
	235	*
	236	* Change the direction of the transfer. This method allows one to redirect
	237	* the descriptor's transfer direction. This eliminates the need to destroy
	238	* and create new buffers when different transfer directions are needed.
	239	*/
	240	virtual void setDirection(IODirection direction);
	241
	242	/*
	243	* getCapacity:
	244	*
	245	* Get the buffer capacity
	246	*/
	247	virtual vm_size_t getCapacity() const;
	248
	249	/*
	250	* getBytesNoCopy:
	251	*
	252	* Return the virtual address of the beginning of the buffer
	253	*/
	254	virtual void *getBytesNoCopy();
	255
	256	/*
	257	* getBytesNoCopy:
	258	*
	259	* Return the virtual address of an offset from the beginning of the buffer
	260	*/
	261	virtual void *getBytesNoCopy(vm_size_t start, vm_size_t withLength);
	262
	263	/*
	264	* appendBytes:
	265	*
	266	* Add some data to the end of the buffer. This method automatically
	267	* maintains the memory descriptor buffer length. Note that appendBytes
	268	* will not copy past the end of the memory descriptor's current capacity.
	269	*/
	270	virtual bool appendBytes(const void *bytes, vm_size_t withLength);
0c530ab8	271
b0d623f7 A	272	#ifndef __LP64__
b0d623f7 A	273	virtual void * getVirtualSegment(IOByteCount offset,
3e170ce0	274	IOByteCount * length) APPLE_KEXT_OVERRIDE APPLE_KEXT_DEPRECATED; /* use getBytesNoCopy() instead */
b0d623f7	275	#endif /* !__LP64__ */
1c79356b A	276	};
	277
	278	#endif /* !_IOBUFFERMEMORYDESCRIPTOR_H */