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