IOInterleavedMemoryDescriptor.h
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 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28 29 #ifndef _IOINTERLEAVEDMEMORYDESCRIPTOR_H 30 #define _IOINTERLEAVEDMEMORYDESCRIPTOR_H 31 32 #include <IOKit/IOMemoryDescriptor.h> 33 #include <libkern/c++/OSPtr.h> 34 35 /*! @class IOInterleavedMemoryDescriptor : public IOMemoryDescriptor 36 * @abstract The IOInterleavedMemoryDescriptor object describes a memory area made up of portions of several other IOMemoryDescriptors. 37 * @discussion The IOInterleavedMemoryDescriptor object represents interleaved ranges of memory, specified as an ordered list of portions of individual IOMemoryDescriptors. The portions are chained end-to-end to make up a single contiguous buffer. */ 38 39 class IOInterleavedMemoryDescriptor : public IOMemoryDescriptor 40 { 41 OSDeclareDefaultStructors(IOInterleavedMemoryDescriptor); 42 43 protected: 44 45 IOByteCount _descriptorCapacity; 46 UInt32 _descriptorCount; 47 IOMemoryDescriptor ** _descriptors; 48 IOByteCount * _descriptorOffsets; 49 IOByteCount * _descriptorLengths; 50 bool _descriptorPrepared; 51 52 virtual void free() APPLE_KEXT_OVERRIDE; 53 54 public: 55 56 /*! @function withCapacity 57 * @abstract Create an IOInterleavedMemoryDescriptor to describe a memory area made up of several other IOMemoryDescriptors. 58 * @discussion This method creates and initializes an IOInterleavedMemoryDescriptor for memory consisting of portions of a number of other IOMemoryDescriptors, chained end-to-end (in the order they appear in the array) to represent a single contiguous memory buffer. 59 * @param capacity The maximum number of IOMemoryDescriptors that may be subsequently added to this IOInterleavedMemoryDescriptor. 60 * @param direction An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures. 61 * @result The created IOInterleavedMemoryDescriptor on success, to be released by the caller, or zero on failure. */ 62 63 static OSPtr<IOInterleavedMemoryDescriptor> withCapacity( IOByteCount capacity, 64 IODirection direction); 65 66 /*! @function initWithCapacity 67 * @abstract Initialize an IOInterleavedMemoryDescriptor to describe a memory area made up of several other IOMemoryDescriptors. 68 * @discussion This method initializes an IOInterleavedMemoryDescriptor for memory consisting of portions of a number of other IOMemoryDescriptors, chained end-to-end (in the order they appear in the array) to represent a single contiguous memory buffer. 69 * @param capacity The maximum number of IOMemoryDescriptors that may be subsequently added to this IOInterleavedMemoryDescriptor. 70 * @param direction An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures. 71 * @result The created IOInterleavedMemoryDescriptor on success, to be released by the caller, or zero on failure. */ 72 73 virtual bool initWithCapacity( IOByteCount capacity, 74 IODirection direction ); 75 76 /*! @function clearMemoryDescriptors 77 * @abstract Clear all of the IOMemoryDescriptors currently contained in and reset the IOInterleavedMemoryDescriptor. 78 * @discussion Clears each IOMemoryDescriptor by completing (if needed) and releasing. The IOInterleavedMemoryDescriptor is then reset and may accept new descriptors up to the capacity specified when it was created. 79 * @param direction An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures. */ 80 81 virtual void clearMemoryDescriptors( IODirection direction = kIODirectionNone ); 82 83 /*! @function setMemoryDescriptor 84 * @abstract Add a portion of an IOMemoryDescriptor to the IOInterleavedMemoryDescriptor. 85 * @discussion This method adds the portion of an IOMemoryDescriptor described by the offset and length parameters to the end of the IOInterleavedMemoryDescriptor. A single IOMemoryDescriptor may be added as many times as there is room for it. The offset and length must describe a portion entirely within the IOMemoryDescriptor. 86 * @param descriptor An IOMemoryDescriptor to be added to the IOInterleavedMemoryDescriptor. Its direction must be compatible with that of the IOInterleavedMemoryDescriptor. 87 * @param offset The offset into the IOMemoryDescriptor of the portion that will be added to the virtualized buffer. 88 * @param length The length of the portion of the IOMemoryDescriptor to be added to the virtualized buffer. 89 * @result Returns true the portion was successfully added. */ 90 91 virtual bool setMemoryDescriptor( IOMemoryDescriptor * descriptor, 92 IOByteCount offset, 93 IOByteCount length ); 94 95 /*! @function getPhysicalSegment 96 * @abstract Break a memory descriptor into its physically contiguous segments. 97 * @discussion This method returns the physical address of the byte at the given offset into the memory, and optionally the length of the physically contiguous segment from that offset. 98 * @param offset A byte offset into the memory whose physical address to return. 99 * @param length If non-zero, getPhysicalSegment will store here the length of the physically contiguous segement at the given offset. 100 * @result A physical address, or zero if the offset is beyond the length of the memory. */ 101 102 virtual addr64_t getPhysicalSegment( IOByteCount offset, 103 IOByteCount * length, 104 IOOptionBits options = 0 ) APPLE_KEXT_OVERRIDE; 105 106 /*! @function prepare 107 * @abstract Prepare the memory for an I/O transfer. 108 * @discussion This involves paging in the memory, if necessary, and wiring it down for the duration of the transfer. The complete() method completes the processing of the memory after the I/O transfer finishes. This method need not called for non-pageable memory. 109 * @param forDirection The direction of the I/O to be performed, or kIODirectionNone for the direction specified by the memory descriptor. 110 * @result An IOReturn code. */ 111 112 virtual IOReturn prepare(IODirection forDirection = kIODirectionNone) APPLE_KEXT_OVERRIDE; 113 114 /*! @function complete 115 * @abstract Complete processing of the memory after an I/O transfer finishes. 116 * @discussion This method should not be called unless a prepare was previously issued; the prepare() and complete() must occur in pairs, before and after an I/O transfer involving pageable memory. 117 * @param forDirection The direction of the I/O just completed, or kIODirectionNone for the direction specified by the memory descriptor. 118 * @result An IOReturn code. */ 119 120 virtual IOReturn complete(IODirection forDirection = kIODirectionNone) APPLE_KEXT_OVERRIDE; 121 }; 122 123 #endif /* !_IOINTERLEAVEDMEMORYDESCRIPTOR_H */