1/*
2 * Copyright (c) 1998-2000 Apple Computer, 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
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27 */
28
29#ifndef _IOSUBMEMORYDESCRIPTOR_H
30#define _IOSUBMEMORYDESCRIPTOR_H
31
32#include <IOKit/IOMemoryDescriptor.h>
33
34/*! @class IOSubMemoryDescriptor : public IOMemoryDescriptor
35    @abstract The IOSubMemoryDescriptor object describes a memory area made up of a portion of another IOMemoryDescriptor.
36    @discussion The IOSubMemoryDescriptor object represents a subrange of memory, specified as a portion of another IOMemoryDescriptor. */
37
38class IOSubMemoryDescriptor : public IOMemoryDescriptor
39{
40    OSDeclareDefaultStructors(IOSubMemoryDescriptor);
41
42protected:
43    IOMemoryDescriptor * _parent;
44    IOByteCount 	 _start;
45
46    virtual void free();
47
48public:
49/*! @function withSubRange
50    @abstract Create an IOMemoryDescriptor to describe a subrange of an existing descriptor.
51    @discussion  This method creates and initializes an IOMemoryDescriptor for memory consisting of a subrange of the specified memory descriptor. The parent memory descriptor is retained by the new descriptor.
52    @param of The parent IOMemoryDescriptor of which a subrange is to be used for the new descriptor, which will be retained by the subrange IOMemoryDescriptor.
53    @param offset A byte offset into the parent memory descriptor's memory.
54    @param length The length of the subrange.
55    @param options
56        kIOMemoryDirectionMask (options:direction)	This nibble indicates the I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
57    @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
58
59    static IOSubMemoryDescriptor *	withSubRange(IOMemoryDescriptor *of,
60					     IOByteCount offset,
61					     IOByteCount length,
62					     IOOptionBits options);
63
64    /*
65     * Initialize or reinitialize an IOSubMemoryDescriptor to describe
66     * a subrange of an existing descriptor.
67     *
68     * An IOSubMemoryDescriptor can be re-used by calling initSubRange
69     * again on an existing instance -- note that this behavior is not
70     * commonly supported in other IOKit classes, although it is here.
71     */
72    virtual bool initSubRange( IOMemoryDescriptor * parent,
73				IOByteCount offset, IOByteCount length,
74				IODirection withDirection );
75
76    /*
77     * IOMemoryDescriptor required methods
78     */
79
80    virtual addr64_t getPhysicalSegment( IOByteCount   offset,
81                                         IOByteCount * length,
82                                         IOOptionBits  options = 0 );
83
84    virtual IOReturn prepare(IODirection forDirection = kIODirectionNone);
85
86    virtual IOReturn complete(IODirection forDirection = kIODirectionNone);
87
88#ifdef __LP64__
89    virtual
90#endif /* __LP64__ */
91    IOReturn redirect( task_t safeTask, bool redirect );
92
93    virtual IOReturn setPurgeable( IOOptionBits newState,
94                                    IOOptionBits * oldState );
95
96    // support map() on kIOMemoryTypeVirtual without prepare()
97    virtual IOMemoryMap * 	makeMapping(
98	IOMemoryDescriptor *	owner,
99	task_t			intoTask,
100	IOVirtualAddress	atAddress,
101	IOOptionBits		options,
102	IOByteCount		offset,
103	IOByteCount		length );
104
105	virtual uint64_t getPreparationID( void );
106
107};
108
109#endif /* !_IOSUBMEMORYDESCRIPTOR_H */
110