iokit/IOKit/IOMemoryDescriptor.h

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  30 #ifndef _IOMEMORYDESCRIPTOR_H
  31 #define _IOMEMORYDESCRIPTOR_H
  32
  33 #include <sys/cdefs.h>
  34
  35 #include <IOKit/IOTypes.h>
  36 #include <libkern/c++/OSContainers.h>
  37
  38 __BEGIN_DECLS
  39 #include <mach/memory_object_types.h>
  40 __END_DECLS
  41
  42 struct IOPhysicalRange
  43 {
  44     IOPhysicalAddress   address;
  45     IOByteCount         length;
  46 };
  47
  48 class IOMemoryMap;
  49 class IOMapper;
  50
  51 /*
  52  * Direction of transfer, with respect to the described memory.
  53  */
  54 enum IODirection
  55 {
  56     kIODirectionNone  = 0x0,    //                    same as VM_PROT_NONE
  57     kIODirectionIn    = 0x1,    // User land 'read',  same as VM_PROT_READ
  58     kIODirectionOut   = 0x2,    // User land 'write', same as VM_PROT_WRITE
  59     kIODirectionOutIn = kIODirectionOut | kIODirectionIn,
  60     kIODirectionInOut = kIODirectionIn  | kIODirectionOut
  61 };
  62
  63 /*
  64  * IOOptionBits used in the withOptions variant
  65  */
  66 enum {
  67     kIOMemoryDirectionMask      = 0x00000007,
  68     kIOMemoryAutoPrepare        = 0x00000008,   // Shared with Buffer MD
  69
  70     kIOMemoryTypeVirtual        = 0x00000010,
  71     kIOMemoryTypePhysical       = 0x00000020,
  72     kIOMemoryTypeUPL            = 0x00000030,
  73     kIOMemoryTypePersistentMD   = 0x00000040,   // Persistent Memory Descriptor
  74     kIOMemoryTypeUIO            = 0x00000050,
  75     kIOMemoryTypeVirtual64      = 0x00000060,
  76     kIOMemoryTypePhysical64     = 0x00000070,
  77     kIOMemoryTypeMask           = 0x000000f0,
  78
  79     kIOMemoryAsReference        = 0x00000100,
  80     kIOMemoryBufferPageable     = 0x00000400,
  81     kIOMemoryDontMap            = 0x00000800,
  82     kIOMemoryPersistent         = 0x00010000
  83 };
  84
  85 #define kIOMapperNone   ((IOMapper *) -1)
  86 #define kIOMapperSystem ((IOMapper *) 0)
  87
  88 enum
  89 {
  90     kIOMemoryPurgeableKeepCurrent = 1,
  91     kIOMemoryPurgeableNonVolatile = 2,
  92     kIOMemoryPurgeableVolatile    = 3,
  93     kIOMemoryPurgeableEmpty       = 4
  94 };
  95 enum
  96 {
  97     kIOMemoryIncoherentIOFlush   = 1,
  98     kIOMemoryIncoherentIOStore   = 2,
  99 };
 100
 101 #define IOMEMORYDESCRIPTOR_SUPPORTS_DMACOMMAND  1
 102
 103
 104 /*! @class IOMemoryDescriptor : public OSObject
 105     @abstract An abstract base class defining common methods for describing physical or virtual memory.
 106     @discussion The IOMemoryDescriptor object represents a buffer or range of memory, specified as one or more physical or virtual address ranges. It contains methods to return the memory's physically contiguous segments (fragments), for use with the IOMemoryCursor, and methods to map the memory into any address space with caching and placed mapping options. */
 107
 108 class IOMemoryDescriptor : public OSObject
 109 {
 110     friend class _IOMemoryMap;
 111     friend class IOSubMemoryDescriptor;
 112
 113     OSDeclareDefaultStructors(IOMemoryDescriptor);
 114
 115 protected:
 116 /*! @struct ExpansionData
 117     @discussion This structure will be used to expand the capablilties of this class in the future.
 118     */
 119     struct ExpansionData {
 120         void *                          devicePager;
 121         unsigned int                    pagerContig:1;
 122         unsigned int                    unused:31;
 123         IOMemoryDescriptor *            memory;
 124     };
 125
 126 /*! @var reserved
 127     Reserved for future use.  (Internal use only)  */
 128     ExpansionData * reserved;
 129
 130 protected:
 131     OSSet *             _mappings;
 132     IOOptionBits        _flags;
 133     void *              _memEntry;
 134
 135     IODirection         _direction;        /* DEPRECATED: use _flags instead. direction of transfer */
 136     IOByteCount         _length;           /* length of all ranges */
 137     IOOptionBits        _tag;
 138
 139 public:
 140 typedef IOOptionBits DMACommandOps;
 141     virtual IOPhysicalAddress getSourceSegment( IOByteCount offset,
 142                                                 IOByteCount * length );
 143     OSMetaClassDeclareReservedUsed(IOMemoryDescriptor, 0);
 144
 145 /*! @function initWithOptions
 146     @abstract Master initialiser for all variants of memory descriptors.  For a more complete description see IOMemoryDescriptor::withOptions.
 147     @discussion Note this function can be used to re-init a previously created memory descriptor.
 148     @result true on success, false on failure. */
 149     virtual bool initWithOptions(void *         buffers,
 150                                  UInt32         count,
 151                                  UInt32         offset,
 152                                  task_t         task,
 153                                  IOOptionBits   options,
 154                                  IOMapper *     mapper = kIOMapperSystem);
 155     OSMetaClassDeclareReservedUsed(IOMemoryDescriptor, 1);
 156
 157     virtual addr64_t getPhysicalSegment64( IOByteCount offset,
 158                                             IOByteCount * length );
 159     OSMetaClassDeclareReservedUsed(IOMemoryDescriptor, 2);
 160
 161
 162 /*! @function setPurgeable
 163     @abstract Control the purgeable status of a memory descriptors memory.
 164     @discussion Buffers may be allocated with the ability to have their purgeable status changed - IOBufferMemoryDescriptor with the kIOMemoryPurgeable option, VM_FLAGS_PURGEABLE may be passed to vm_allocate() in user space to allocate such buffers. The purgeable status of such a buffer may be controlled with setPurgeable(). The process of making a purgeable memory descriptor non-volatile and determining its previous state is atomic - if a purgeable memory descriptor is made nonvolatile and the old state is returned as kIOMemoryPurgeableVolatile, then the memory's previous contents are completely intact and will remain so until the memory is made volatile again.  If the old state is returned as kIOMemoryPurgeableEmpty then the memory was reclaimed while it was in a volatile state and its previous contents have been lost.
 165     @param newState - the desired new purgeable state of the memory:<br>
 166     kIOMemoryPurgeableKeepCurrent - make no changes to the memory's purgeable state.<br>
 167     kIOMemoryPurgeableVolatile    - make the memory volatile - the memory may be reclaimed by the VM system without saving its contents to backing store.<br>
 168     kIOMemoryPurgeableNonVolatile - make the memory nonvolatile - the memory is treated as with usual allocations and must be saved to backing store if paged.<br>
 169     kIOMemoryPurgeableEmpty       - make the memory volatile, and discard any pages allocated to it.
 170     @param oldState - if non-NULL, the previous purgeable state of the memory is returned here:<br>
 171     kIOMemoryPurgeableNonVolatile - the memory was nonvolatile.<br>
 172     kIOMemoryPurgeableVolatile    - the memory was volatile but its content has not been discarded by the VM system.<br>
 173     kIOMemoryPurgeableEmpty       - the memory was volatile and has been discarded by the VM system.<br>
 174     @result An IOReturn code. */
 175
 176     virtual IOReturn setPurgeable( IOOptionBits newState,
 177                                     IOOptionBits * oldState );
 178     OSMetaClassDeclareReservedUsed(IOMemoryDescriptor, 3);
 179
 180 /*! @function performOperation
 181     @abstract Perform an operation on the memory descriptor's memory.
 182     @discussion This method performs some operation on a range of the memory descriptor's memory. When a memory descriptor's memory is not mapped, it should be more efficient to use this method than mapping the memory to perform the operation virtually.
 183     @param options The operation to perform on the memory:<br>
 184     kIOMemoryIncoherentIOFlush - pass this option to store to memory and flush any data in the processor cache for the memory range, with synchronization to ensure the data has passed through all levels of processor cache. It may not be supported on all architectures. This type of flush may be used for non-coherent I/O such as AGP - it is NOT required for PCI coherent operations. The memory descriptor must have been previously prepared.<br>
 185     kIOMemoryIncoherentIOStore - pass this option to store to memory any data in the processor cache for the memory range, with synchronization to ensure the data has passed through all levels of processor cache. It may not be supported on all architectures. This type of flush may be used for non-coherent I/O such as AGP - it is NOT required for PCI coherent operations. The memory descriptor must have been previously prepared.
 186     @param offset A byte offset into the memory descriptor's memory.
 187     @param length The length of the data range.
 188     @result An IOReturn code. */
 189
 190     virtual IOReturn performOperation( IOOptionBits options,
 191                                         IOByteCount offset, IOByteCount length );
 192     OSMetaClassDeclareReservedUsed(IOMemoryDescriptor, 4);
 193
 194 #if !(defined(__ppc__) && defined(KPI_10_4_0_PPC_COMPAT))
 195     // Used for dedicated communications for IODMACommand
 196     virtual IOReturn dmaCommandOperation(DMACommandOps op, void *vData, UInt dataSize) const;
 197     OSMetaClassDeclareReservedUsed(IOMemoryDescriptor, 5);
 198 #endif
 199
 200 private:
 201 #if (defined(__ppc__) && defined(KPI_10_4_0_PPC_COMPAT))
 202     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 5);
 203 #endif
 204     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 6);
 205     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 7);
 206     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 8);
 207     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 9);
 208     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 10);
 209     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 11);
 210     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 12);
 211     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 13);
 212     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 14);
 213     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 15);
 214
 215 protected:
 216     virtual void free();
 217 public:
 218     static void initialize( void );
 219
 220 public:
 221 /*! @function withAddress
 222     @abstract Create an IOMemoryDescriptor to describe one virtual range of the kernel task.
 223     @discussion This method creates and initializes an IOMemoryDescriptor for memory consisting of a single virtual memory range mapped into the kernel map.
 224     @param address The virtual address of the first byte in the memory.
 225     @param withLength The length of memory.
 226     @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.
 227     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 228
 229     static IOMemoryDescriptor * withAddress(void *       address,
 230                                             IOByteCount  withLength,
 231                                             IODirection  withDirection);
 232
 233 /*! @function withAddress
 234     @abstract Create an IOMemoryDescriptor to describe one virtual range of the specified map.
 235     @discussion This method creates and initializes an IOMemoryDescriptor for memory consisting of a single virtual memory range mapped into the specified map.
 236     @param address The virtual address of the first byte in the memory.
 237     @param withLength The length of memory.
 238     @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.
 239     @param withTask The task the virtual ranges are mapped into.
 240     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 241
 242     static IOMemoryDescriptor * withAddress(vm_address_t address,
 243                                             IOByteCount  withLength,
 244                                             IODirection  withDirection,
 245                                             task_t       withTask);
 246
 247 /*! @function withPhysicalAddress
 248     @abstract Create an IOMemoryDescriptor to describe one physical range.
 249     @discussion This method creates and initializes an IOMemoryDescriptor for memory consisting of a single physical memory range.
 250     @param address The physical address of the first byte in the memory.
 251     @param withLength The length of memory.
 252     @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.
 253     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 254
 255     static IOMemoryDescriptor * withPhysicalAddress(
 256                                 IOPhysicalAddress       address,
 257                                 IOByteCount             withLength,
 258                                 IODirection             withDirection );
 259
 260 /*! @function withRanges
 261     @abstract Create an IOMemoryDescriptor to describe one or more virtual ranges.
 262     @discussion This method creates and initializes an IOMemoryDescriptor for memory consisting of an array of virtual memory ranges each mapped into a specified source task.
 263     @param ranges An array of IOVirtualRange structures which specify the virtual ranges in the specified map which make up the memory to be described.
 264     @param withCount The member count of the ranges array.
 265     @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.
 266     @param withTask The task each of the virtual ranges are mapped into.
 267     @param asReference If false, the IOMemoryDescriptor object will make a copy of the ranges array, otherwise, the array will be used in situ, avoiding an extra allocation.
 268     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 269
 270      static IOMemoryDescriptor * withRanges(IOVirtualRange * ranges,
 271                                             UInt32           withCount,
 272                                             IODirection      withDirection,
 273                                             task_t           withTask,
 274                                             bool             asReference = false);
 275
 276 #if !(defined(__ppc__) && defined(KPI_10_4_0_PPC_COMPAT))
 277 /*! @function withAddressRange
 278     @abstract Create an IOMemoryDescriptor to describe one virtual range of the specified map.
 279     @discussion This method creates and initializes an IOMemoryDescriptor for memory consisting of a single virtual memory range mapped into the specified map.
 280     @param address The virtual address of the first byte in the memory.
 281     @param withLength The length of memory.
 282     @param options
 283         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.
 284         kIOMemoryNoAutoPrepare Indicates that the temporary AutoPrepare of kernel_task memory should not be performed.
 285     @param task The task the virtual ranges are mapped into.
 286     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 287
 288     static IOMemoryDescriptor * withAddressRange(
 289                                        mach_vm_address_t address,
 290                                        mach_vm_size_t    length,
 291                                        IOOptionBits      options,
 292                                task_t            task);
 293
 294 /*! @function withAddressRanges
 295     @abstract Create an IOMemoryDescriptor to describe one or more virtual ranges.
 296     @discussion This method creates and initializes an IOMemoryDescriptor for memory consisting of an array of virtual memory ranges each mapped into a specified source task.
 297     @param ranges An array of IOAddressRange structures which specify the virtual ranges in the specified map which make up the memory to be described. IOAddressRange is the 64bit version of IOVirtualRange.
 298     @param rangeCount The member count of the ranges array.
 299     @param options
 300         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.
 301         kIOMemoryAsReference   For options:type = Virtual or Physical this indicate that the memory descriptor need not copy the ranges array into local memory.  This is an optimisation to try to minimise unnecessary allocations.
 302         kIOMemoryNoAutoPrepare Indicates that the temporary AutoPrepare of kernel_task memory should not be performed.
 303     @param task The task each of the virtual ranges are mapped into.
 304     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 305
 306     static IOMemoryDescriptor * withAddressRanges(
 307                                        IOAddressRange * ranges,
 308                                        UInt32           rangeCount,
 309                                        IOOptionBits     options,
 310                                        task_t           withTask);
 311 #endif
 312
 313 /*! @function withOptions
 314     @abstract Master initialiser for all variants of memory descriptors.
 315     @discussion This method creates and initializes an IOMemoryDescriptor for memory it has three main variants: Virtual, Physical & mach UPL.  These variants are selected with the options parameter, see below.  This memory descriptor needs to be prepared before it can be used to extract data from the memory described.  However we temporarily have setup a mechanism that automatically prepares kernel_task memory descriptors at creation time.
 316
 317
 318     @param buffers A pointer to an array of IOVirtualRanges or IOPhysicalRanges if the options:type is Virtual or Physical.  For type UPL it is a upl_t returned by the mach/memory_object_types.h apis, primarily used internally by the UBC.
 319
 320     @param count options:type = Virtual or Physical count contains a count of the number of entires in the buffers array.  For options:type = UPL this field contains a total length.
 321
 322     @param offset Only used when options:type = UPL, in which case this field contains an offset for the memory within the buffers upl.
 323
 324     @param task Only used options:type = Virtual, The task each of the virtual ranges are mapped into.
 325
 326     @param options
 327         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.
 328         kIOMemoryTypeMask (options:type)        kIOMemoryTypeVirtual, kIOMemoryTypePhysical, kIOMemoryTypeUPL Indicates that what type of memory basic memory descriptor to use.  This sub-field also controls the interpretation of the buffers, count, offset & task parameters.
 329         kIOMemoryAsReference    For options:type = Virtual or Physical this indicate that the memory descriptor need not copy the ranges array into local memory.  This is an optimisation to try to minimise unnecessary allocations.
 330         kIOMemoryBufferPageable Only used by the IOBufferMemoryDescriptor as an indication that the kernel virtual memory is in fact pageable and we need to use the kernel pageable submap rather than the default map.
 331         kIOMemoryNoAutoPrepare  Indicates that the temporary AutoPrepare of kernel_task memory should not be performed.
 332
 333     @param mapper Which IOMapper should be used to map the in-memory physical addresses into I/O space addresses.  Defaults to 0 which indicates that the system mapper is to be used, if present.
 334
 335     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 336
 337     static IOMemoryDescriptor *withOptions(void *       buffers,
 338                                            UInt32       count,
 339                                            UInt32       offset,
 340                                            task_t       task,
 341                                            IOOptionBits options,
 342                                            IOMapper *   mapper = kIOMapperSystem);
 343
 344 /*! @function withPhysicalRanges
 345     @abstract Create an IOMemoryDescriptor to describe one or more physical ranges.
 346     @discussion  This method creates and initializes an IOMemoryDescriptor for memory consisting of an array of physical memory ranges.
 347     @param ranges An array of IOPhysicalRange structures which specify the physical ranges which make up the memory to be described.
 348     @param withCount The member count of the ranges array.
 349     @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.
 350     @param asReference If false, the IOMemoryDescriptor object will make a copy of the ranges array, otherwise, the array will be used in situ, avoiding an extra allocation.
 351     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 352
 353     static IOMemoryDescriptor * withPhysicalRanges(
 354                                             IOPhysicalRange *   ranges,
 355                                             UInt32              withCount,
 356                                             IODirection         withDirection,
 357                                             bool                asReference = false);
 358
 359 /*! @function withSubRange
 360     @abstract Create an IOMemoryDescriptor to describe a subrange of an existing descriptor.
 361     @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.
 362     @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.
 363     @param offset A byte offset into the parent memory descriptor's memory.
 364     @param length The length of the subrange.
 365     @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. This is used over the direction of the parent descriptor.
 366     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 367
 368     static IOMemoryDescriptor * withSubRange(IOMemoryDescriptor *of,
 369                                              IOByteCount offset,
 370                                              IOByteCount length,
 371                                              IODirection withDirection);
 372
 373 /*! @function withPersistentMemoryDescriptor
 374     @abstract Copy constructor that generates a new memory descriptor if the backing memory for the same task's virtual address and length has changed.
 375     @discussion If the original memory descriptor's address and length is still backed by the same real memory, i.e. the user hasn't deallocated and the reallocated memory at the same address then the original memory descriptor is returned with a additional reference.  Otherwise we build a totally new memory descriptor with the same characteristics as the previous one but with a new view of the vm.  Note not legal to call this function with anything except an IOGeneralMemoryDescriptor that was created with the kIOMemoryPersistent option.
 376     @param originalMD The memory descriptor to be duplicated.
 377     @result Either the original memory descriptor with an additional retain or a new memory descriptor, 0 for a bad original memory descriptor or some other resource shortage. */
 378     static IOMemoryDescriptor *
 379         withPersistentMemoryDescriptor(IOMemoryDescriptor *originalMD);
 380
 381 /*! @function initWithAddress
 382     @abstract Initialize or reinitialize an IOMemoryDescriptor to describe one virtual range of the kernel task.
 383     @discussion This method initializes an IOMemoryDescriptor for memory consisting of a single virtual memory range mapped into the kernel map. An IOMemoryDescriptor can be re-used by calling initWithAddress or initWithRanges again on an existing instance -- note this behavior is not commonly supported in other IOKit classes, although it is supported here.
 384     @param address The virtual address of the first byte in the memory.
 385     @param withLength The length of memory.
 386     @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.
 387     @result true on success, false on failure. */
 388
 389     virtual bool initWithAddress(void *       address,
 390                                  IOByteCount  withLength,
 391                                  IODirection  withDirection) = 0;
 392
 393 /*! @function initWithAddress
 394     @abstract Initialize or reinitialize an IOMemoryDescriptor to describe one virtual range of the specified map.
 395     @discussion This method initializes an IOMemoryDescriptor for memory consisting of a single virtual memory range mapped into the specified map. An IOMemoryDescriptor can be re-used by calling initWithAddress or initWithRanges again on an existing instance -- note this behavior is not commonly supported in other IOKit classes, although it is supported here.
 396     @param address The virtual address of the first byte in the memory.
 397     @param withLength The length of memory.
 398     @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.
 399     @param withTask The task the virtual ranges are mapped into.
 400     @result true on success, false on failure. */
 401
 402     virtual bool initWithAddress(vm_address_t address,
 403                                  IOByteCount  withLength,
 404                                  IODirection  withDirection,
 405                                  task_t       withTask) = 0;
 406
 407 /*! @function initWithPhysicalAddress
 408     @abstract Initialize or reinitialize an IOMemoryDescriptor to describe one physical range.
 409     @discussion This method initializes an IOMemoryDescriptor for memory consisting of a single physical memory range. An IOMemoryDescriptor can be re-used by calling initWithAddress or initWithRanges again on an existing instance -- note this behavior is not commonly supported in other IOKit classes, although it is supported here.
 410     @param address The physical address of the first byte in the memory.
 411     @param withLength The length of memory.
 412     @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.
 413     @result true on success, false on failure. */
 414
 415     virtual bool initWithPhysicalAddress(
 416                                  IOPhysicalAddress      address,
 417                                  IOByteCount            withLength,
 418                                  IODirection            withDirection ) = 0;
 419
 420 /*! @function initWithRanges
 421     @abstract Initialize or reinitialize an IOMemoryDescriptor to describe one or more virtual ranges.
 422     @discussion This method initializes an IOMemoryDescriptor for memory consisting of an array of virtual memory ranges each mapped into a specified source task. An IOMemoryDescriptor can be re-used by calling initWithAddress or initWithRanges again on an existing instance -- note this behavior is not commonly supported in other IOKit classes, although it is supported here.
 423     @param ranges An array of IOVirtualRange structures which specify the virtual ranges in the specified map which make up the memory to be described.
 424     @param withCount The member count of the ranges array.
 425     @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.
 426     @param withTask The task each of the virtual ranges are mapped into.
 427     @param asReference If false, the IOMemoryDescriptor object will make a copy of the ranges array, otherwise, the array will be used in situ, avoiding an extra allocation.
 428     @result true on success, false on failure. */
 429
 430     virtual bool initWithRanges(IOVirtualRange * ranges,
 431                                 UInt32           withCount,
 432                                 IODirection      withDirection,
 433                                 task_t           withTask,
 434                                 bool             asReference = false) = 0;
 435
 436 /*! @function initWithPhysicalRanges
 437     @abstract Initialize or reinitialize an IOMemoryDescriptor to describe one or more physical ranges.
 438     @discussion  This method initializes an IOMemoryDescriptor for memory consisting of an array of physical memory ranges. An IOMemoryDescriptor can be re-used by calling initWithAddress or initWithRanges again on an existing instance -- note this behavior is not commonly supported in other IOKit classes, although it is supported here.
 439     @param ranges An array of IOPhysicalRange structures which specify the physical ranges which make up the memory to be described.
 440     @param withCount The member count of the ranges array.
 441     @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.
 442     @param asReference If false, the IOMemoryDescriptor object will make a copy of the ranges array, otherwise, the array will be used in situ, avoiding an extra allocation.
 443     @result true on success, false on failure. */
 444
 445     virtual bool initWithPhysicalRanges(IOPhysicalRange * ranges,
 446                                         UInt32           withCount,
 447                                         IODirection      withDirection,
 448                                         bool             asReference = false) = 0;
 449
 450 /*! @function getDirection
 451     @abstract Accessor to get the direction the memory descriptor was created with.
 452     @discussion This method returns the direction the memory descriptor was created with.
 453     @result The direction. */
 454
 455     virtual IODirection getDirection() const;
 456
 457 /*! @function getLength
 458     @abstract Accessor to get the length of the memory descriptor (over all its ranges).
 459     @discussion This method returns the total length of the memory described by the descriptor, ie. the sum of its ranges' lengths.
 460     @result The byte count. */
 461
 462     virtual IOByteCount getLength() const;
 463
 464 /*! @function setTag
 465     @abstract Set the tag for the memory descriptor.
 466     @discussion This method sets the tag for the memory descriptor. Tag bits are not interpreted by IOMemoryDescriptor.
 467     @param tag The tag. */
 468
 469     virtual void setTag( IOOptionBits tag );
 470
 471 /*! @function getTag
 472     @abstract Accessor to the retrieve the tag for the memory descriptor.
 473     @discussion This method returns the tag for the memory descriptor. Tag bits are not interpreted by IOMemoryDescriptor.
 474     @result The tag. */
 475
 476     virtual IOOptionBits getTag( void );
 477
 478 /*! @function readBytes
 479     @abstract Copy data from the memory descriptor's buffer to the specified buffer.
 480     @discussion This method copies data from the memory descriptor's memory at the given offset, to the caller's buffer.
 481     @param offset A byte offset into the memory descriptor's memory.
 482     @param bytes The caller supplied buffer to copy the data to.
 483     @param withLength The length of the data to copy.
 484     @result The number of bytes copied, zero will be returned if the specified offset is beyond the length of the descriptor. */
 485
 486     virtual IOByteCount readBytes(IOByteCount offset,
 487                                 void * bytes, IOByteCount withLength);
 488
 489 /*! @function writeBytes
 490     @abstract Copy data to the memory descriptor's buffer from the specified buffer.
 491     @discussion This method copies data to the memory descriptor's memory at the given offset, from the caller's buffer.
 492     @param offset A byte offset into the memory descriptor's memory.
 493     @param bytes The caller supplied buffer to copy the data from.
 494     @param withLength The length of the data to copy.
 495     @result The number of bytes copied, zero will be returned if the specified offset is beyond the length of the descriptor. */
 496
 497     virtual IOByteCount writeBytes(IOByteCount offset,
 498                                 const void * bytes, IOByteCount withLength);
 499
 500 /*! @function getPhysicalSegment
 501     @abstract Break a memory descriptor into its physically contiguous segments.
 502     @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.
 503     @param offset A byte offset into the memory whose physical address to return.
 504     @param length If non-zero, getPhysicalSegment will store here the length of the physically contiguous segement at the given offset.
 505     @result A physical address, or zero if the offset is beyond the length of the memory. */
 506
 507     virtual IOPhysicalAddress getPhysicalSegment(IOByteCount offset,
 508                                                  IOByteCount * length) = 0;
 509
 510 /*! @function getPhysicalAddress
 511     @abstract Return the physical address of the first byte in the memory.
 512     @discussion This method returns the physical address of the  first byte in the memory. It is most useful on memory known to be physically contiguous.
 513     @result A physical address. */
 514
 515     /* inline */ IOPhysicalAddress getPhysicalAddress();
 516         /* { return( getPhysicalSegment( 0, 0 )); } */
 517
 518     /* DEPRECATED */ /* USE INSTEAD: map(), readBytes(), writeBytes() */
 519     /* DEPRECATED */ virtual void * getVirtualSegment(IOByteCount offset,
 520     /* DEPRECATED */                                    IOByteCount * length) = 0;
 521     /* DEPRECATED */ /* USE INSTEAD: map(), readBytes(), writeBytes() */
 522
 523 /*! @function prepare
 524     @abstract Prepare the memory for an I/O transfer.
 525     @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.  Note that the prepare call is not thread safe and it is expected that the client will more easily be able to guarantee single threading a particular memory descriptor.
 526     @param forDirection The direction of the I/O just completed, or kIODirectionNone for the direction specified by the memory descriptor.
 527     @result An IOReturn code. */
 528
 529     virtual IOReturn prepare(IODirection forDirection = kIODirectionNone) = 0;
 530
 531 /*! @function complete
 532     @abstract Complete processing of the memory after an I/O transfer finishes.
 533     @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.  In 10.3 or greater systems the direction argument to complete is not longer respected.  The direction is totally determined at prepare() time.
 534     @param forDirection DEPRECATED The direction of the I/O just completed, or kIODirectionNone for the direction specified by the memory descriptor.
 535     @result An IOReturn code. */
 536
 537     virtual IOReturn complete(IODirection forDirection = kIODirectionNone) = 0;
 538
 539     /*
 540      * Mapping functions.
 541      */
 542
 543 /*! @function map
 544     @abstract Maps a IOMemoryDescriptor into a task.
 545     @discussion This is the general purpose method to map all or part of the memory described by a memory descriptor into a task at any available address, or at a fixed address if possible. Caching & read-only options may be set for the mapping. The mapping is represented as a returned reference to a IOMemoryMap object, which may be shared if the mapping is compatible with an existing mapping of the IOMemoryDescriptor. The IOMemoryMap object returned should be released only when the caller has finished accessing the mapping, as freeing the object destroys the mapping.
 546     @param intoTask Sets the target task for the mapping. Pass kernel_task for the kernel address space.
 547     @param atAddress If a placed mapping is requested, atAddress specifies its address, and the kIOMapAnywhere should not be set. Otherwise, atAddress is ignored.
 548     @param options Mapping options are defined in IOTypes.h,<br>
 549         kIOMapAnywhere should be passed if the mapping can be created anywhere. If not set, the atAddress parameter sets the location of the mapping, if it is available in the target map.<br>
 550         kIOMapDefaultCache to inhibit the cache in I/O areas, kIOMapCopybackCache in general purpose RAM.<br>
 551         kIOMapInhibitCache, kIOMapWriteThruCache, kIOMapCopybackCache to set the appropriate caching.<br>
 552         kIOMapReadOnly to allow only read only accesses to the memory - writes will cause and access fault.<br>
 553         kIOMapReference will only succeed if the mapping already exists, and the IOMemoryMap object is just an extra reference, ie. no new mapping will be created.<br>
 554         kIOMapUnique allows a special kind of mapping to be created that may be used with the IOMemoryMap::redirect() API. These mappings will not be shared as is the default - there will always be a unique mapping created for the caller, not an existing mapping with an extra reference.<br>
 555     @param offset Is a beginning offset into the IOMemoryDescriptor's memory where the mapping starts. Zero is the default to map all the memory.
 556     @param length Is the length of the mapping requested for a subset of the IOMemoryDescriptor. Zero is the default to map all the memory.
 557     @result A reference to an IOMemoryMap object representing the mapping, which can supply the virtual address of the mapping and other information. The mapping may be shared with multiple callers - multiple maps are avoided if a compatible one exists. The IOMemoryMap object returned should be released only when the caller has finished accessing the mapping, as freeing the object destroys the mapping. The IOMemoryMap instance also retains the IOMemoryDescriptor it maps while it exists. */
 558
 559     virtual IOMemoryMap *       map(
 560         task_t          intoTask,
 561         IOVirtualAddress        atAddress,
 562         IOOptionBits            options,
 563         IOByteCount             offset = 0,
 564         IOByteCount             length = 0 );
 565
 566 /*! @function map
 567     @abstract Maps a IOMemoryDescriptor into the kernel map.
 568     @discussion This is a shortcut method to map all the memory described by a memory descriptor into the kernel map at any available address. See the full version of the map method for further details.
 569     @param options Mapping options as in the full version of the map method, with kIOMapAnywhere assumed.
 570     @result See the full version of the map method. */
 571
 572     virtual IOMemoryMap *       map(
 573         IOOptionBits            options = 0 );
 574
 575 /*! @function setMapping
 576     @abstract Establishes an already existing mapping.
 577     @discussion This method tells the IOMemoryDescriptor about a mapping that exists, but was created elsewhere. It allows later callers of the map method to share this externally created mapping. The IOMemoryMap object returned is created to represent it. This method is not commonly needed.
 578     @param task Address space in which the mapping exists.
 579     @param mapAddress Virtual address of the mapping.
 580     @param options Caching and read-only attributes of the mapping.
 581     @result A IOMemoryMap object created to represent the mapping. */
 582
 583     virtual IOMemoryMap *       setMapping(
 584         task_t          task,
 585         IOVirtualAddress        mapAddress,
 586         IOOptionBits            options = 0 );
 587
 588     // Following methods are private implementation
 589
 590     // make virtual
 591     IOReturn redirect( task_t safeTask, bool redirect );
 592
 593     IOReturn handleFault(
 594         void *                  pager,
 595         vm_map_t                addressMap,
 596         IOVirtualAddress        address,
 597         IOByteCount             sourceOffset,
 598         IOByteCount             length,
 599         IOOptionBits            options );
 600
 601 protected:
 602     virtual IOMemoryMap *       makeMapping(
 603         IOMemoryDescriptor *    owner,
 604         task_t          intoTask,
 605         IOVirtualAddress        atAddress,
 606         IOOptionBits            options,
 607         IOByteCount             offset,
 608         IOByteCount             length );
 609
 610     virtual void                addMapping(
 611         IOMemoryMap *           mapping );
 612
 613     virtual void                removeMapping(
 614         IOMemoryMap *           mapping );
 615
 616     virtual IOReturn doMap(
 617         vm_map_t                addressMap,
 618         IOVirtualAddress *      atAddress,
 619         IOOptionBits            options,
 620         IOByteCount             sourceOffset = 0,
 621         IOByteCount             length = 0 );
 622
 623     virtual IOReturn doUnmap(
 624         vm_map_t                addressMap,
 625         IOVirtualAddress        logical,
 626         IOByteCount             length );
 627 };
 628
 629 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 630
 631 /*! @class IOMemoryMap : public OSObject
 632     @abstract An abstract base class defining common methods for describing a memory mapping.
 633     @discussion The IOMemoryMap object represents a mapped range of memory, described by a IOMemoryDescriptor. The mapping may be in the kernel or a non-kernel task and has processor cache mode attributes. IOMemoryMap instances are created by IOMemoryDescriptor when it creates mappings in its map method, and returned to the caller. */
 634
 635 class IOMemoryMap : public OSObject
 636 {
 637     OSDeclareAbstractStructors(IOMemoryMap)
 638
 639 public:
 640 /*! @function getVirtualAddress
 641     @abstract Accessor to the virtual address of the first byte in the mapping.
 642     @discussion This method returns the virtual address of the first byte in the mapping.
 643     @result A virtual address. */
 644
 645     virtual IOVirtualAddress    getVirtualAddress() = 0;
 646
 647 /*! @function getPhysicalSegment
 648     @abstract Break a mapping into its physically contiguous segments.
 649     @discussion This method returns the physical address of the byte at the given offset into the mapping, and optionally the length of the physically contiguous segment from that offset. It functions similarly to IOMemoryDescriptor::getPhysicalSegment.
 650     @param offset A byte offset into the mapping whose physical address to return.
 651     @param length If non-zero, getPhysicalSegment will store here the length of the physically contiguous segement at the given offset.
 652     @result A physical address, or zero if the offset is beyond the length of the mapping. */
 653
 654     virtual IOPhysicalAddress   getPhysicalSegment(IOByteCount offset,
 655                                                    IOByteCount * length) = 0;
 656
 657 /*! @function getPhysicalAddress
 658     @abstract Return the physical address of the first byte in the mapping.
 659     @discussion This method returns the physical address of the  first byte in the mapping. It is most useful on mappings known to be physically contiguous.
 660     @result A physical address. */
 661
 662     /* inline */ IOPhysicalAddress getPhysicalAddress();
 663         /* { return( getPhysicalSegment( 0, 0 )); } */
 664
 665 /*! @function getLength
 666     @abstract Accessor to the length of the mapping.
 667     @discussion This method returns the length of the mapping.
 668     @result A byte count. */
 669
 670     virtual IOByteCount         getLength() = 0;
 671
 672 /*! @function getAddressTask
 673     @abstract Accessor to the task of the mapping.
 674     @discussion This method returns the mach task the mapping exists in.
 675     @result A mach task_t. */
 676
 677     virtual task_t              getAddressTask() = 0;
 678
 679 /*! @function getMemoryDescriptor
 680     @abstract Accessor to the IOMemoryDescriptor the mapping was created from.
 681     @discussion This method returns the IOMemoryDescriptor the mapping was created from.
 682     @result An IOMemoryDescriptor reference, which is valid while the IOMemoryMap object is retained. It should not be released by the caller. */
 683
 684     virtual IOMemoryDescriptor * getMemoryDescriptor() = 0;
 685
 686 /*! @function getMapOptions
 687     @abstract Accessor to the options the mapping was created with.
 688     @discussion This method returns the options to IOMemoryDescriptor::map the mapping was created with.
 689     @result Options for the mapping, including cache settings. */
 690
 691     virtual IOOptionBits        getMapOptions() = 0;
 692
 693 /*! @function unmap
 694     @abstract Force the IOMemoryMap to unmap, without destroying the object.
 695     @discussion IOMemoryMap instances will unmap themselves upon free, ie. when the last client with a reference calls release. This method forces the IOMemoryMap to destroy the mapping it represents, regardless of the number of clients. It is not generally used.
 696     @result An IOReturn code. */
 697
 698     virtual IOReturn            unmap() = 0;
 699
 700     virtual void                taskDied() = 0;
 701
 702 /*! @function redirect
 703     @abstract Replace the memory mapped in a process with new backing memory.
 704     @discussion An IOMemoryMap created with the kIOMapUnique option to IOMemoryDescriptor::map() can remapped to a new IOMemoryDescriptor backing object. If the new IOMemoryDescriptor is specified as NULL, client access to the memory map is blocked until a new backing object has been set. By blocking access and copying data, the caller can create atomic copies of the memory while the client is potentially reading or writing the memory.
 705     @param newBackingMemory The IOMemoryDescriptor that represents the physical memory that is to be now mapped in the virtual range the IOMemoryMap represents. If newBackingMemory is NULL, any access to the mapping will hang (in vm_fault()) until access has been restored by a new call to redirect() with non-NULL newBackingMemory argument.
 706     @param options Mapping options are defined in IOTypes.h, and are documented in IOMemoryDescriptor::map()
 707     @param offset As with IOMemoryDescriptor::map(), a beginning offset into the IOMemoryDescriptor's memory where the mapping starts. Zero is the default.
 708     @result An IOReturn code. */
 709
 710     virtual IOReturn            redirect(IOMemoryDescriptor * newBackingMemory,
 711                                          IOOptionBits         options,
 712                                          IOByteCount          offset = 0) = 0;
 713 };
 714
 715 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 716
 717 // The following classes are private implementation of IOMemoryDescriptor - they
 718 // should not be referenced directly, just through the public API's in the
 719 // IOMemoryDescriptor class. For example, an IOGeneralMemoryDescriptor instance
 720 // might be created by IOMemoryDescriptor::withAddress(), but there should be
 721 // no need to reference as anything but a generic IOMemoryDescriptor *.
 722
 723 // Also these flags should not overlap with the options to
 724 //      IOMemoryDescriptor::initWithRanges(... IOOptionsBits options);
 725
 726 enum {
 727     kIOMemoryPreparedReadOnly   = 0x00008000,
 728 };
 729
 730 class IOGeneralMemoryDescriptor : public IOMemoryDescriptor
 731 {
 732     OSDeclareDefaultStructors(IOGeneralMemoryDescriptor);
 733
 734 public:
 735     union Ranges {
 736         IOVirtualRange   *v;
 737         IOAddressRange   *v64;
 738         IOPhysicalRange  *p;
 739         void             *uio;
 740     };
 741 protected:
 742     Ranges              _ranges;
 743     unsigned            _rangesCount;       /* number of address ranges in list */
 744     bool                _rangesIsAllocated; /* is list allocated by us? */
 745
 746     task_t              _task;               /* task where all ranges are mapped to */
 747
 748     union {
 749         IOVirtualRange  v;
 750         IOPhysicalRange p;
 751     }                   _singleRange;      /* storage space for a single range */
 752
 753     unsigned            _wireCount;        /* number of outstanding wires */
 754
 755     /* DEPRECATED */ vm_address_t _cachedVirtualAddress;  /* a cached virtual-to-physical */
 756
 757     /* DEPRECATED */ IOPhysicalAddress  _cachedPhysicalAddress;
 758
 759     bool                _initialized;      /* has superclass been initialized? */
 760
 761     virtual void free();
 762
 763 #if !(defined(__ppc__) && defined(KPI_10_4_0_PPC_COMPAT))
 764     virtual IOReturn dmaCommandOperation(DMACommandOps op, void *vData, UInt dataSize) const;
 765 #endif
 766
 767 private:
 768
 769     /* DEPRECATED */ virtual void setPosition(IOByteCount position);
 770     /* DEPRECATED */ virtual void mapIntoKernel(unsigned rangeIndex);
 771     /* DEPRECATED */ virtual void unmapFromKernel();
 772
 773     // Internal APIs may be made virtual at some time in the future.
 774     IOReturn wireVirtual(IODirection forDirection);
 775     void *createNamedEntry();
 776
 777     // Internal
 778     OSData *        _memoryEntries;
 779     unsigned int    _pages;
 780     ppnum_t         _highestPage;
 781     uint32_t        __iomd_reservedA;
 782     uint32_t        __iomd_reservedB;
 783     uint32_t        __iomd_reservedC;
 784
 785 public:
 786     /*
 787      * IOMemoryDescriptor required methods
 788      */
 789
 790     // Master initaliser
 791     virtual bool initWithOptions(void *         buffers,
 792                                  UInt32         count,
 793                                  UInt32         offset,
 794                                  task_t         task,
 795                                  IOOptionBits   options,
 796                                  IOMapper *     mapper = kIOMapperSystem);
 797
 798     // Secondary initialisers
 799     virtual bool initWithAddress(void *         address,
 800                                  IOByteCount    withLength,
 801                                  IODirection    withDirection);
 802
 803     virtual bool initWithAddress(vm_address_t   address,
 804                                  IOByteCount    withLength,
 805                                  IODirection    withDirection,
 806                                  task_t         withTask);
 807
 808     virtual bool initWithPhysicalAddress(
 809                                  IOPhysicalAddress      address,
 810                                  IOByteCount            withLength,
 811                                  IODirection            withDirection );
 812
 813     virtual bool initWithRanges(        IOVirtualRange * ranges,
 814                                         UInt32           withCount,
 815                                         IODirection      withDirection,
 816                                         task_t           withTask,
 817                                         bool             asReference = false);
 818
 819     virtual bool initWithPhysicalRanges(IOPhysicalRange * ranges,
 820                                         UInt32           withCount,
 821                                         IODirection      withDirection,
 822                                         bool             asReference = false);
 823
 824 #if !(defined(__ppc__) && defined(KPI_10_4_0_PPC_COMPAT))
 825     virtual addr64_t getPhysicalSegment64( IOByteCount offset,
 826                                             IOByteCount * length );
 827 #endif
 828
 829     virtual IOPhysicalAddress getPhysicalSegment(IOByteCount offset,
 830                                                  IOByteCount * length);
 831
 832     virtual IOPhysicalAddress getSourceSegment(IOByteCount offset,
 833                                                IOByteCount * length);
 834
 835     /* DEPRECATED */ virtual void * getVirtualSegment(IOByteCount offset,
 836     /* DEPRECATED */                                    IOByteCount * length);
 837
 838     virtual IOReturn prepare(IODirection forDirection = kIODirectionNone);
 839
 840     virtual IOReturn complete(IODirection forDirection = kIODirectionNone);
 841
 842     virtual IOReturn doMap(
 843         vm_map_t                addressMap,
 844         IOVirtualAddress *      atAddress,
 845         IOOptionBits            options,
 846         IOByteCount             sourceOffset = 0,
 847         IOByteCount             length = 0 );
 848
 849     virtual IOReturn doUnmap(
 850         vm_map_t                addressMap,
 851         IOVirtualAddress        logical,
 852         IOByteCount             length );
 853     virtual bool serialize(OSSerialize *s) const;
 854
 855     // Factory method for cloning a persistent IOMD, see IOMemoryDescriptor
 856     static IOMemoryDescriptor *
 857         withPersistentMemoryDescriptor(IOGeneralMemoryDescriptor *originalMD);
 858 };
 859
 860 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 861
 862 class IOSubMemoryDescriptor : public IOMemoryDescriptor
 863 {
 864     friend class IOMemoryDescriptor;
 865
 866     OSDeclareDefaultStructors(IOSubMemoryDescriptor);
 867
 868 protected:
 869     IOMemoryDescriptor * _parent;
 870     IOByteCount          _start;
 871
 872     virtual void free();
 873
 874     virtual bool initWithAddress(void *       address,
 875                                  IOByteCount    withLength,
 876                                  IODirection  withDirection);
 877
 878     virtual bool initWithAddress(vm_address_t address,
 879                                  IOByteCount    withLength,
 880                                  IODirection  withDirection,
 881                                  task_t       withTask);
 882
 883     virtual bool initWithPhysicalAddress(
 884                                  IOPhysicalAddress      address,
 885                                  IOByteCount            withLength,
 886                                  IODirection            withDirection );
 887
 888     virtual bool initWithRanges(        IOVirtualRange * ranges,
 889                                         UInt32           withCount,
 890                                         IODirection      withDirection,
 891                                         task_t           withTask,
 892                                         bool             asReference = false);
 893
 894     virtual bool initWithPhysicalRanges(IOPhysicalRange * ranges,
 895                                         UInt32           withCount,
 896                                         IODirection      withDirection,
 897                                         bool             asReference = false);
 898
 899     IOMemoryDescriptor::withAddress;
 900     IOMemoryDescriptor::withPhysicalAddress;
 901     IOMemoryDescriptor::withPhysicalRanges;
 902     IOMemoryDescriptor::withRanges;
 903     IOMemoryDescriptor::withSubRange;
 904
 905 #if !(defined(__ppc__) && defined(KPI_10_4_0_PPC_COMPAT))
 906     // used by IODMACommand
 907     virtual IOReturn dmaCommandOperation(DMACommandOps op, void *vData, UInt dataSize) const;
 908 #endif
 909
 910 public:
 911     /*
 912      * Initialize or reinitialize an IOSubMemoryDescriptor to describe
 913      * a subrange of an existing descriptor.
 914      *
 915      * An IOSubMemoryDescriptor can be re-used by calling initSubRange
 916      * again on an existing instance -- note that this behavior is not
 917      * commonly supported in other IOKit classes, although it is here.
 918      */
 919     virtual bool initSubRange( IOMemoryDescriptor * parent,
 920                                 IOByteCount offset, IOByteCount length,
 921                                 IODirection withDirection );
 922
 923     /*
 924      * IOMemoryDescriptor required methods
 925      */
 926
 927 #if !(defined(__ppc__) && defined(KPI_10_4_0_PPC_COMPAT))
 928     virtual addr64_t getPhysicalSegment64( IOByteCount offset,
 929                                             IOByteCount * length );
 930 #endif
 931
 932     virtual IOPhysicalAddress getPhysicalSegment(IOByteCount offset,
 933                                                  IOByteCount * length);
 934
 935     virtual IOPhysicalAddress getSourceSegment(IOByteCount offset,
 936                                                IOByteCount * length);
 937
 938     virtual IOByteCount readBytes(IOByteCount offset,
 939                                 void * bytes, IOByteCount withLength);
 940
 941     virtual IOByteCount writeBytes(IOByteCount offset,
 942                                 const void * bytes, IOByteCount withLength);
 943
 944     virtual void * getVirtualSegment(IOByteCount offset,
 945                                         IOByteCount * length);
 946
 947     virtual IOReturn prepare(IODirection forDirection = kIODirectionNone);
 948
 949     virtual IOReturn complete(IODirection forDirection = kIODirectionNone);
 950
 951     // make virtual
 952     IOReturn redirect( task_t safeTask, bool redirect );
 953
 954     virtual bool serialize(OSSerialize *s) const;
 955
 956     virtual IOReturn setPurgeable( IOOptionBits newState,
 957                                     IOOptionBits * oldState );
 958     virtual IOReturn performOperation( IOOptionBits options,
 959                                         IOByteCount offset, IOByteCount length );
 960
 961 protected:
 962     virtual IOMemoryMap *       makeMapping(
 963         IOMemoryDescriptor *    owner,
 964         task_t          intoTask,
 965         IOVirtualAddress        atAddress,
 966         IOOptionBits            options,
 967         IOByteCount             offset,
 968         IOByteCount             length );
 969
 970     virtual IOReturn doMap(
 971         vm_map_t                addressMap,
 972         IOVirtualAddress *      atAddress,
 973         IOOptionBits            options,
 974         IOByteCount             sourceOffset = 0,
 975         IOByteCount             length = 0 );
 976 };
 977
 978 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 979
 980 #endif /* !_IOMEMORYDESCRIPTOR_H */