iokit/IOKit/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
  34 /*! @class IOInterleavedMemoryDescriptor : public IOMemoryDescriptor
  35     @abstract The IOInterleavedMemoryDescriptor object describes a memory area made up of portions of several other IOMemoryDescriptors.
  36     @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. */
  37
  38 class IOInterleavedMemoryDescriptor : public IOMemoryDescriptor
  39 {
  40     OSDeclareDefaultStructors(IOInterleavedMemoryDescriptor);
  41
  42 protected:
  43
  44     IOByteCount           _descriptorCapacity;
  45     UInt32                _descriptorCount;
  46     IOMemoryDescriptor ** _descriptors;
  47     IOByteCount         * _descriptorOffsets;
  48     IOByteCount         * _descriptorLengths;
  49     bool                  _descriptorPrepared;
  50
  51     virtual void free();
  52
  53 public:
  54
  55 /*! @function withCapacity
  56     @abstract Create an IOInterleavedMemoryDescriptor to describe a memory area made up of several other IOMemoryDescriptors.
  57     @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.
  58     @param capacity The maximum number of IOMemoryDescriptors that may be subsequently added to this IOInterleavedMemoryDescriptor.
  59     @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.
  60     @result The created IOInterleavedMemoryDescriptor on success, to be released by the caller, or zero on failure. */
  61
  62     static IOInterleavedMemoryDescriptor * withCapacity( IOByteCount           capacity,
  63                                                          IODirection           direction);
  64
  65 /*! @function initWithCapacity
  66     @abstract Initialize an IOInterleavedMemoryDescriptor to describe a memory area made up of several other IOMemoryDescriptors.
  67     @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.
  68     @param capacity The maximum number of IOMemoryDescriptors that may be subsequently added to this IOInterleavedMemoryDescriptor.
  69     @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.
  70     @result The created IOInterleavedMemoryDescriptor on success, to be released by the caller, or zero on failure. */
  71
  72     virtual bool initWithCapacity( IOByteCount           capacity,
  73                                    IODirection           direction );
  74
  75 /*! @function clearMemoryDescriptors
  76     @abstract Clear all of the IOMemoryDescriptors currently contained in and reset the IOInterleavedMemoryDescriptor.
  77     @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.
  78     @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. */
  79
  80     virtual void clearMemoryDescriptors( IODirection direction = kIODirectionNone );
  81
  82 /*! @function setMemoryDescriptor
  83     @abstract Add a portion of an IOMemoryDescriptor to the IOInterleavedMemoryDescriptor.
  84     @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.
  85     @param descriptor An IOMemoryDescriptor to be added to the IOInterleavedMemoryDescriptor.  Its direction must be compatible with that of the IOInterleavedMemoryDescriptor.
  86     @param offset The offset into the IOMemoryDescriptor of the portion that will be added to the virtualized buffer.
  87     @param length The length of the portion of the IOMemoryDescriptor to be added to the virtualized buffer.
  88     @result Returns true the portion was successfully added. */
  89
  90     virtual bool setMemoryDescriptor( IOMemoryDescriptor * descriptor,
  91                                       IOByteCount offset,
  92                                       IOByteCount length );
  93
  94 /*! @function getPhysicalSegment
  95     @abstract Break a memory descriptor into its physically contiguous segments.
  96     @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.
  97     @param offset A byte offset into the memory whose physical address to return.
  98     @param length If non-zero, getPhysicalSegment will store here the length of the physically contiguous segement at the given offset.
  99     @result A physical address, or zero if the offset is beyond the length of the memory. */
 100
 101     virtual addr64_t getPhysicalSegment( IOByteCount   offset,
 102                                          IOByteCount * length,
 103                                          IOOptionBits  options = 0 );
 104
 105 /*! @function prepare
 106     @abstract Prepare the memory for an I/O transfer.
 107     @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.
 108     @param forDirection The direction of the I/O to be performed, or kIODirectionNone for the direction specified by the memory descriptor.
 109     @result An IOReturn code. */
 110
 111     virtual IOReturn prepare(IODirection forDirection = kIODirectionNone);
 112
 113 /*! @function complete
 114     @abstract Complete processing of the memory after an I/O transfer finishes.
 115     @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.
 116     @param forDirection The direction of the I/O just completed, or kIODirectionNone for the direction specified by the memory descriptor.
 117     @result An IOReturn code. */
 118
 119     virtual IOReturn complete(IODirection forDirection = kIODirectionNone);
 120 };
 121
 122 #endif /* !_IOINTERLEAVEDMEMORYDESCRIPTOR_H */