iokit/IOKit/IOMultiMemoryDescriptor.h

   1 /*
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  28
  29 #ifndef _IOMULTIMEMORYDESCRIPTOR_H
  30 #define _IOMULTIMEMORYDESCRIPTOR_H
  31
  32 #include <IOKit/IOMemoryDescriptor.h>
  33
  34 /*! @class IOMultiMemoryDescriptor : public IOMemoryDescriptor
  35  *   @abstract The IOMultiMemoryDescriptor object describes a memory area made up of several other IOMemoryDescriptors.
  36  *   @discussion The IOMultiMemoryDescriptor object represents multiple ranges of memory, specified as an ordered list of IOMemoryDescriptors.  The descriptors are chained end-to-end to make up a single contiguous buffer. */
  37
  38 class IOMultiMemoryDescriptor : public IOMemoryDescriptor
  39 {
  40         OSDeclareDefaultStructors(IOMultiMemoryDescriptor);
  41
  42 protected:
  43
  44         IOMemoryDescriptor ** _descriptors;
  45         UInt32                _descriptorsCount;
  46         bool                  _descriptorsIsAllocated;
  47
  48         virtual void free() APPLE_KEXT_OVERRIDE;
  49
  50 public:
  51
  52 /*! @function withDescriptors
  53  *   @abstract Create an IOMultiMemoryDescriptor to describe a memory area made up of several other IOMemoryDescriptors.
  54  *   @discussion This method creates and initializes an IOMultiMemoryDescriptor for memory consisting 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.  Passing the descriptor array as a reference will avoid an extra allocation.
  55  *   @param descriptors An array of IOMemoryDescriptors which make up the memory to be described.
  56  *   @param withCount The object count for the descriptors array.
  57  *   @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
  58  *   @param asReference If false, the IOMultiMemoryDescriptor object will make a copy of the descriptors array, otherwise, the array will be used in situ, avoiding an extra allocation.
  59  *   @result The created IOMultiMemoryDescriptor on success, to be released by the caller, or zero on failure. */
  60
  61         static IOMultiMemoryDescriptor * withDescriptors(
  62                 IOMemoryDescriptor ** descriptors,
  63                 UInt32                withCount,
  64                 IODirection           withDirection,
  65                 bool                  asReference = false );
  66
  67 /*! @function withDescriptors
  68  *   @abstract Initialize an IOMultiMemoryDescriptor to describe a memory area made up of several other IOMemoryDescriptors.
  69  *   @discussion This method initializes an IOMultiMemoryDescriptor for memory consisting 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.  Passing the descriptor array as a reference will avoid an extra allocation.
  70  *   @param descriptors An array of IOMemoryDescriptors which make up the memory to be described.
  71  *   @param withCount The object count for the descriptors array.
  72  *   @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
  73  *   @param asReference If false, the IOMultiMemoryDescriptor object will make a copy of the descriptors array, otherwise, the array will be used in situ, avoiding an extra allocation.
  74  *   @result The created IOMultiMemoryDescriptor on success, to be released by the caller, or zero on failure. */
  75
  76         virtual bool initWithDescriptors(
  77                 IOMemoryDescriptor ** descriptors,
  78                 UInt32                withCount,
  79                 IODirection           withDirection,
  80                 bool                  asReference = false );
  81
  82 /*! @function getPhysicalSegment
  83  *   @abstract Break a memory descriptor into its physically contiguous segments.
  84  *   @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.
  85  *   @param offset A byte offset into the memory whose physical address to return.
  86  *   @param length If non-zero, getPhysicalSegment will store here the length of the physically contiguous segement at the given offset.
  87  *   @result A physical address, or zero if the offset is beyond the length of the memory. */
  88
  89         virtual addr64_t getPhysicalSegment( IOByteCount   offset,
  90             IOByteCount * length,
  91             IOOptionBits  options = 0 ) APPLE_KEXT_OVERRIDE;
  92
  93 /*! @function prepare
  94  *   @abstract Prepare the memory for an I/O transfer.
  95  *   @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 needn't called for non-pageable memory.
  96  *   @param forDirection The direction of the I/O just completed, or kIODirectionNone for the direction specified by the memory descriptor.
  97  *   @result An IOReturn code. */
  98
  99         virtual IOReturn prepare(IODirection forDirection = kIODirectionNone) APPLE_KEXT_OVERRIDE;
 100
 101 /*! @function complete
 102  *   @abstract Complete processing of the memory after an I/O transfer finishes.
 103  *   @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.
 104  *   @param forDirection The direction of the I/O just completed, or kIODirectionNone for the direction specified by the memory descriptor.
 105  *   @result An IOReturn code. */
 106
 107         virtual IOReturn complete(IODirection forDirection = kIODirectionNone) APPLE_KEXT_OVERRIDE;
 108
 109         virtual IOReturn setPurgeable(IOOptionBits newState, IOOptionBits * oldState) APPLE_KEXT_OVERRIDE;
 110
 111 /*! @function getPageCounts
 112  *   @abstract Retrieve the number of resident and/or dirty pages encompassed by an IOMemoryDescriptor.
 113  *   @discussion This method returns the number of resident and/or dirty pages encompassed by an IOMemoryDescriptor.
 114  *   @param residentPageCount - If non-null, a pointer to a byte count that will return the number of resident pages encompassed by this IOMemoryDescriptor.
 115  *   @param dirtyPageCount - If non-null, a pointer to a byte count that will return the number of dirty pages encompassed by this IOMemoryDescriptor.
 116  *   @result An IOReturn code. */
 117
 118         IOReturn getPageCounts(IOByteCount * residentPageCount,
 119             IOByteCount * dirtyPageCount);
 120
 121         virtual uint64_t getPreparationID( void ) APPLE_KEXT_OVERRIDE;
 122
 123 #define IOMULTIMEMORYDESCRIPTOR_SUPPORTS_GETPAGECOUNTS  1
 124
 125 private:
 126         virtual IOReturn doMap(vm_map_t           addressMap,
 127             IOVirtualAddress * atAddress,
 128             IOOptionBits       options,
 129             IOByteCount        sourceOffset = 0,
 130             IOByteCount        length = 0 ) APPLE_KEXT_OVERRIDE;
 131 };
 132
 133 #endif /* !_IOMULTIMEMORYDESCRIPTOR_H */