iokit/IOKit/IODMACommand.h

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  28 #ifndef _IODMACOMMAND_H
  29 #define _IODMACOMMAND_H
  30
  31 #include <IOKit/IOCommand.h>
  32 #include <IOKit/IOMemoryDescriptor.h>
  33 class IOMapper;
  34 class IOBufferMemoryDescriptor;
  35
  36 enum
  37 {
  38     kIODMAMapOptionMapped       = 0x00000000,
  39     kIODMAMapOptionBypassed     = 0x00000001,
  40     kIODMAMapOptionNonCoherent  = 0x00000002,
  41     kIODMAMapOptionUnmapped     = 0x00000003,
  42     kIODMAMapOptionTypeMask     = 0x0000000f,
  43
  44     kIODMAMapOptionNoCacheStore = 0x00000010,   // Memory in descriptor
  45     kIODMAMapOptionOnChip       = 0x00000020,   // Indicates DMA is on South Bridge
  46     kIODMAMapOptionIterateOnly  = 0x00000040    // DMACommand will be used as a cursor only
  47 };
  48
  49 /**************************** class IODMACommand ***************************/
  50
  51 /*!
  52     @class IODMACommand
  53     @abstract A mechanism to convert memory references to I/O bus addresses.
  54     @discussion The IODMACommand is supersedes the IOMemoryCursor and greatly enhances the functionality and power of it.  The command can be specified to output 64 bit physical addresses and also allows driver writers bypass mapping hardware or get addresses suitable for non-snooped DMA.
  55 <br><br>
  56     The command is designed to be very easily subclassable.  Most driver writers need to associate some DMA operations with their memory descriptor and usually use a C structure for that purpose.  This structure is often kept in a linked list.  This IODMACommand has built it <kern/queue.h> linkage and can be derived and 'public:' variables added, giving the developer a structure that can associate a memory descriptor with a particular dma command but will also allow the developer to generate that command and keep the state necessary for tracking it.
  57 <br><br>
  58     It is envisaged that a pool of IODMACommands will be created at driver initialisation and each command will be kept in an IOCommandPool while not in use.  However if developers wishes to maintain their own free lists that is certainly possible.  See the <kern/queue.h> and <xnu/iokit/Kernel/IOCommandPool> for sample code on manipulating the command's doubly linked list entries.
  59 <br><br>
  60     The IODMACommand can be used in a 'weak-linked' manner.  To do this you must avoid using any static member functions.  Use the, much slower but safe, weakWithSpecification function.  On success a dma command instance will be returned.  This instance can then be used to clone as many commands as is needed.  Remember deriving from this class can not be done weakly, that is no weak subclassing!
  61 */
  62
  63 class IODMACommand : public IOCommand
  64 {
  65     OSDeclareDefaultStructors(IODMACommand);
  66
  67 friend class IODMAEventSource;
  68
  69 public:
  70
  71 /*!
  72     @typedef Segment32
  73     @discussion A 32 bit I/O bus address/length pair
  74 */
  75     struct Segment32 {
  76         UInt32 fIOVMAddr, fLength;
  77     };
  78
  79 /*!
  80     @typedef Segment64
  81     @discussion A 64 bit I/O bus address/length pair
  82 */
  83     struct Segment64 {
  84         UInt64 fIOVMAddr, fLength;
  85     };
  86
  87 /*! @enum MappingOptions
  88     @abstract Mapping types to indicate the desired mapper type for translating memory descriptors into I/O DMA Bus addresses.
  89     @constant kNonCoherent      Used by drivers for non-coherent transfers, implies unmapped memmory
  90     @constant kMapped           Allow a driver to define addressing size
  91     @constant kBypassed         Allow drivers to bypass any mapper
  92     @constant kMaxMappingOptions        Internal use only
  93 */
  94     enum MappingOptions {
  95         kMapped       = kIODMAMapOptionMapped,
  96         kBypassed     = kIODMAMapOptionBypassed,
  97         kNonCoherent  = kIODMAMapOptionNonCoherent,
  98         kUnmapped     = kIODMAMapOptionUnmapped,
  99         kTypeMask     = kIODMAMapOptionTypeMask,
 100
 101         kNoCacheStore = kIODMAMapOptionNoCacheStore,    // Memory in descriptor
 102         kOnChip       = kIODMAMapOptionOnChip,          // Indicates DMA is on South Bridge
 103         kIterateOnly  = kIODMAMapOptionIterateOnly      // DMACommand will be used as a cursor only
 104     };
 105
 106     struct SegmentOptions {
 107         uint8_t  fStructSize;
 108         uint8_t  fNumAddressBits;
 109         uint64_t fMaxSegmentSize;
 110         uint64_t fMaxTransferSize;
 111         uint32_t fAlignment;
 112         uint32_t fAlignmentLength;
 113         uint32_t fAlignmentInternalSegments;
 114     };
 115
 116 /*! @enum SynchronizeOptions
 117     @abstract Options for the synchronize method.
 118     @constant kForceDoubleBuffer Copy the entire prepared range to a new page aligned buffer.
 119 */
 120     enum SynchronizeOptions {
 121         kForceDoubleBuffer = 0x01000000
 122     };
 123
 124 /*!
 125     @typedef SegmentFunction
 126     @discussion Pointer to a C function that translates a 64 segment and outputs a single desired segment to the array at the requested index. There are a group of pre-implemented SegmentFunctions that may be usefull to the developer below.
 127     @param segment The 64Bit I/O bus address and length.
 128     @param segments Base of the output vector of DMA address length pairs.
 129     @param segmentIndex Index to output 'segment' in the 'segments' array.
 130     @result Returns true if segment encoding succeeded.  false may be returned if the current segment does not fit in an output segment, i.e. a 38bit address wont fit into a 32 encoding.
 131 */
 132     typedef bool (*SegmentFunction)(IODMACommand *target,
 133                                     Segment64 segment,
 134                                     void     *segments,
 135                                     UInt32    segmentIndex);
 136
 137     // -------------- Preimplemented output functions ----------------
 138
 139 /*! @function OutputHost32
 140     @abstract Output host natural Segment32 output segment function.
 141 */
 142     static bool OutputHost32(IODMACommand *target,
 143             Segment64 seg, void *segs, UInt32 ind);
 144
 145 /*! @defined kIODMACommandOutputHost32
 146     @abstract Output host natural Segment32 output segment function.
 147  */
 148 #define kIODMACommandOutputHost32   (IODMACommand::OutputHost32)
 149
 150 /*! @function OutputBig32
 151     @abstract Output big-endian Segment32 output segment function.
 152 */
 153     static bool OutputBig32(IODMACommand *target,
 154             Segment64 seg, void *segs, UInt32 ind);
 155
 156 /*! @defined kIODMACommandOutputBig32
 157     @abstract Output big-endian Segment32 output segment function.
 158  */
 159 #define kIODMACommandOutputBig32    (IODMACommand::OutputBig32)
 160
 161 /*! @function OutputLittle32
 162     @abstract Output little-endian Segment32 output segment function.
 163 */
 164     static bool OutputLittle32(IODMACommand *target,
 165             Segment64 seg, void *segs, UInt32 ind);
 166
 167 /*! @defined kIODMACommandOutputLittle32
 168     @abstract Output little-endian Segment32 output segment function.
 169 */
 170 #define kIODMACommandOutputLittle32 (IODMACommand::OutputLittle32)
 171
 172 /*! @function OutputHost64
 173     @abstract Output host natural Segment64 output segment function.
 174 */
 175     static bool OutputHost64(IODMACommand *target,
 176             Segment64 seg, void *segs, UInt32 ind);
 177
 178 /*! @defined kIODMACommandOutputHost64
 179     @abstract Output host natural Segment64 output segment function.
 180 */
 181 #define kIODMACommandOutputHost64   (IODMACommand::OutputHost64)
 182
 183 /*! @function OutputBig64
 184     @abstract Output big-endian Segment64 output segment function.
 185 */
 186     static bool OutputBig64(IODMACommand *target,
 187             Segment64 seg, void *segs, UInt32 ind);
 188
 189 /*! @defined kIODMACommandOutputBig64
 190     @abstract Output big-endian Segment64 output segment function.
 191 */
 192 #define kIODMACommandOutputBig64    (IODMACommand::OutputBig64)
 193
 194 /*! @function OutputLittle64
 195     @abstract Output little-endian Segment64 output segment function.
 196 */
 197     static bool OutputLittle64(IODMACommand *target,
 198             Segment64 seg, void *segs, UInt32 ind);
 199
 200 /*! @defined kIODMACommandOutputLittle64
 201     @abstract Output little-endian Segment64 output segment function.
 202 */
 203 #define kIODMACommandOutputLittle64 (IODMACommand::OutputLittle64)
 204
 205 /*! @function withSpecification
 206     @abstract Creates and initializes an IODMACommand in one operation.
 207     @discussion Factory function to create and initialize an IODMACommand in one operation.
 208     @param outSegFunc SegmentFunction to call to output one physical segment. A set of nine commonly required segment functions are provided.
 209     @param numAddressBits Number of bits that the hardware uses on its internal address bus. Typically 32 but may be more on modern hardware.  A 0 implies no-restriction other than that implied by the output segment function.
 210     @param maxSegmentSize Maximum allowable size for one segment.  If 0 is passed the maximum segment size is unlimited.
 211     @param mappingOptions is the type of mapping that is required to translate an IOMemoryDescriptor into the desired number of bits.  For instance if your hardware only supports 32 bits but must run on machines with > 4G of RAM some mapping will be required.  Number of bits will be specified in numAddressBits, see below.This parameter can take 3 values:- kNonCoherent - used for non-coherent hardware transfers, Mapped - Validate that all I/O bus generated addresses are within the number of addressing bits specified, Bypassed indicates that bypassed addressing is required, this is used when the hardware transferes are into coherent memory but no mapping is required.  See also prepare() for failure cases.
 212     @param maxTransferSize Maximum size of an entire transfer.  Defaults to 0 indicating no maximum.
 213     @param alignment Alignment restriction, in bytes, on I/O bus addresses.  Defaults to single byte alignment.
 214     @param mapper For mapping types kMapped & kBypassed mapper is used to define the hardware that will perform the mapping, defaults to the system mapper.
 215     @param refCon Reference Constant
 216     @result Returns a new IODMACommand if successfully created and initialized, 0 otherwise.
 217 */
 218     static IODMACommand *
 219         withSpecification(SegmentFunction  outSegFunc,
 220                           UInt8            numAddressBits,
 221                           UInt64           maxSegmentSize,
 222                           MappingOptions   mappingOptions = kMapped,
 223                           UInt64           maxTransferSize = 0,
 224                           UInt32           alignment = 1,
 225                           IOMapper        *mapper = 0,
 226                           void            *refCon = 0);
 227
 228 /*! @function weakWithSpecification
 229     @abstract Creates and initialises an IODMACommand in one operation if this version of the operating system supports it.
 230     @discussion Factory function to create and initialise an IODMACommand in one operation.  The function allows a developer to 'weak' link with IODMACommand.  This function will return kIOReturnUnsupported if the IODMACommand is unavailable.  This function is actually fairly slow so it will be better to call it once then clone the successfully create command using cloneCommand (q.v.).
 231     @param newCommand Output reference variable of the newly created IODMACommand.
 232     @param outSegFunc SegmentFunction to call to output one physical segment. A set of nine commonly required segment functions are provided.
 233     @param numAddressBits Number of bits that the hardware uses on its internal address bus. Typically 32 but may be more on modern hardware.  A 0 implies no-restriction other than that implied by the output segment function.
 234     @param maxSegmentSize Maximum allowable size for one segment. Zero is treated as an unlimited segment size.
 235     @param mapType is the type of mapping that is required to translate an IOMemoryDescriptor into the desired number of bits.  For instance if your hardware only supports 32 bits but must run on machines with > 4G of RAM some mapping will be required.  Number of bits will be specified in numAddressBits, see below.  This parameter can take 3 values:- kNonCoherent - used for non-coherent hardware transfers, Mapped - Validate that all I/O bus generated addresses are within the number of addressing bits specified, Bypassed indicates that bypassed addressing is required, this is used when the hardware transfers are into coherent memory but no mapping is required.  See also prepare() for failure cases.
 236     @param maxTransferSize Maximum size of an entire transfer.  Defaults to 0 indicating no maximum.
 237     @param alignment Alignment restriction, in bytes, on I/O bus addresses.  Defaults to single byte alignment.
 238     @param mapper For mapping types kMapped & kBypassed mapper is used to define the hardware that will perform the mapping, defaults to the system mapper.
 239     @param refCon Reference Constant
 240     @result kIOReturnSuccess if everything is OK, otherwise kIOReturnBadArgument if newCommand is NULL, kIOReturnUnsupported if the kernel doesn't export IODMACommand or IOReturnError if the new command fails to init, q.v. initWithSpecification.
 241 */
 242     // Note that the function has the attribute always_inline.
 243     // The point of this function is to make a call into the kernel
 244     // without generating an undefined symbol.  If the client could call
 245     // the code as a function then the goal of no undefined symbols
 246     // would be lost thus defeating the purpose.
 247     static inline IOReturn weakWithSpecification
 248             (IODMACommand   **newCommand,
 249              SegmentFunction outSegFunc,
 250              UInt8           numAddressBits,
 251              UInt64          maxSegmentSize,
 252              MappingOptions  mapType = kMapped,
 253              UInt64          maxTransferSize = 0,
 254              UInt32          alignment = 1,
 255              IOMapper       *mapper = 0,
 256              void           *refCon = 0) __attribute__((always_inline));
 257
 258     static IODMACommand *
 259         withSpecification(SegmentFunction        outSegFunc,
 260                           const SegmentOptions * segmentOptions,
 261                           uint32_t               mappingOptions,
 262                           IOMapper             * mapper,
 263                           void                 * refCon);
 264
 265
 266 /*! @function withRefCon
 267     @abstract Creates and initializes an unspecified IODMACommand.
 268     @discussion Factory function to create and initialize an unspecified IODMACommand. prepareWithSpecification() must be used to prepare the IODMACommand before use.
 269     @param refCon Reference Constant
 270     @result Returns a new IODMACommand if successfully created and initialized, 0 otherwise.
 271 */
 272     static IODMACommand * withRefCon(void * refCon);
 273
 274 /*!
 275     @function cloneCommand
 276     @abstract Creates a new command based on the specification of the current one.
 277     @discussion Factory function to create and initialise an IODMACommand in one operation.  The current command's specification will be duplicated in the new object, but however none of its state will be duplicated.  This means that it is safe to clone a command even if it is currently active and running, however you must be certain that the command to be duplicated does have a valid reference for the duration.
 278     @result Returns a new IODMACommand if successfully created and initialised, 0 otherwise.
 279 */
 280     virtual IODMACommand *cloneCommand(void *refCon = 0);
 281
 282 /*! @function initWithSpecification
 283     @abstract Primary initializer for the IODMACommand class.
 284     @param outSegFunc SegmentFunction to call to output one physical segment. A set of nine commonly required segment functions are provided.
 285     @param numAddressBits Number of bits that the hardware uses on its internal address bus. Typically 32 but may be more on modern hardware.  A 0 implies no-restriction other than that implied by the output segment function.
 286     @param maxSegmentSize Maximum allowable size for one segment.  Defaults to 0 which means any size.
 287     @param mappingOptions is the type of mapping that is required to translate an IOMemoryDescriptor into the desired number of bits.  For instance if your hardware only supports 32 bits but must run on machines with > 4G of RAM some mapping will be required.  Number of bits will be specified in numAddressBits, see below.This parameter can take 3 values:- kNonCoherent - used for non-coherent hardware transfers, Mapped - Validate that all I/O bus generated addresses are within the number of addressing bits specified, Bypassed indicates that bypassed addressing is required, this is used when the hardware transferes are into coherent memory but no mapping is required.  See also prepare() for failure cases.
 288     @param maxTransferSize Maximum size of an entire transfer.  Defaults to 0 indicating no maximum.
 289     @param alignment Alignment restriction, in bytes, on I/O bus addresses.  Defaults to single byte alignment.
 290     @param mapper For mapping types kMapped & kBypassed mapper is used to define the hardware that will perform the mapping, defaults to the system mapper.
 291     @param refCon Reference Constant
 292     @result Can fail if the mapping type is not recognised, if one of the 3 mandatory parameters are set to 0, if a 32 bit output function is selected when more than 32 bits of address is required or, if kBypassed is requested on a machine that doesn't support bypassing.  Returns true otherwise.
 293 */
 294     virtual bool initWithSpecification( SegmentFunction  outSegFunc,
 295                                         UInt8     numAddressBits,
 296                                         UInt64    maxSegmentSize,
 297                                         MappingOptions mappingOptions = kMapped,
 298                                         UInt64    maxTransferSize = 0,
 299                                         UInt32    alignment = 1,
 300                                         IOMapper *mapper = 0,
 301                                         void     *refCon = 0);
 302
 303 /*! @function setMemoryDescriptor
 304     @abstract Sets and resets the DMACommand's current memory descriptor
 305     @discussion The DMA command will configure itself based on the information that it finds in the memory descriptor.  It looks for things like the direction of the memory descriptor and whether the current memory descriptor is already mapped into some IOMMU.  As a programmer convenience it can also prepare the DMA command immediately.  See prepare().  Note the IODMACommand is designed to used multiple times with a succession of memory descriptors, making the pooling of commands possible.  It is an error though to attempt to reset a currently prepared() DMA command.  Warning: This routine may block so never try to autoprepare an IODMACommand while in a gated context, i.e. one of the WorkLoops action call outs.
 306     @param mem A pointer to the current I/Os memory descriptor.
 307     @param autoPrepare An optional boolean variable that will call the prepare() function automatically after the memory descriptor is processed. Defaults to true.
 308     @result Returns kIOReturnSuccess, kIOReturnBusy if currently prepared, kIOReturnNoSpace if the length(mem) >= Maximum Transfer Size or the error codes returned by prepare() (qv).
 309 */
 310     virtual IOReturn setMemoryDescriptor(const IOMemoryDescriptor *mem,
 311                                          bool autoPrepare = true);
 312
 313 /*! @function clearMemoryDescriptor
 314     @abstract Clears the DMACommand's current memory descriptor
 315     @discussion completes and invalidates the cache if the DMA command is currently active, copies all data from bounce buffers if necessary and releases all resources acquired during setMemoryDescriptor.
 316     @param autoComplete An optional boolean variable that will call the complete() function automatically before the memory descriptor is processed. Defaults to true.
 317 */
 318     virtual IOReturn clearMemoryDescriptor(bool autoComplete = true);
 319
 320 /*! @function getMemoryDescriptor
 321     @abstract Get the current memory descriptor
 322 */
 323     virtual const IOMemoryDescriptor *getMemoryDescriptor() const;
 324
 325 /*! @function getIOMemoryDescriptor
 326     @abstract Get the memory descriptor to be used for DMA
 327 */
 328     IOMemoryDescriptor * getIOMemoryDescriptor() const;
 329
 330 /*! @function prepare
 331     @abstract Prepare the memory for an I/O transfer.
 332     @discussion Allocate the mapping resources neccessary for this transfer, specifying a sub range of the IOMemoryDescriptor that will be the target of the I/O.  The complete() method frees these resources.  Data may be copied to buffers for kIODirectionOut memory descriptors, depending on hardware mapping resource availabilty or alignment restrictions.  It should be noted that the this function may block and should only be called on the clients context, i.e never call this routine while gated; also the call itself is not thread safe though this should be an issue as each IODMACommand is independant.
 333     @param offset defines the starting offset in the memory descriptor the DMA command will operate on. genIOVMSegments will produce its results based on the offset and length passed to the prepare method.
 334     @param length defines the ending position in the memory descriptor the DMA command will operate on. genIOVMSegments will produce its results based on the offset and length passed to the prepare method.
 335     @param flushCache Flush the caches for the memory descriptor and make certain that the memory cycles are complete.  Defaults to true for kNonCoherent and is ignored by the other types.
 336     @param synchronize Copy any buffered data back from the target IOMemoryDescriptor.  Defaults to true, if synchronize() is being used to explicitly copy data, passing false may avoid an unneeded copy.
 337     @result An IOReturn code. */
 338
 339     virtual IOReturn prepare(UInt64 offset = 0, UInt64 length = 0, bool flushCache = true, bool synchronize = true);
 340
 341 /*! @function complete
 342     @abstract Complete processing of DMA mappings after an I/O transfer is finished.
 343     @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
 344     @param invalidateCache Invalidate the caches for the memory descriptor.  Defaults to true for kNonCoherent and is ignored by the other types.
 345     @param synchronize Copy any buffered data back to the target IOMemoryDescriptor.  Defaults to true, if synchronize() is being used to explicitly copy data, passing false may avoid an unneeded copy.
 346     @result kIOReturnNotReady if not prepared, kIOReturnSuccess otherwise. */
 347
 348     virtual IOReturn complete(bool invalidateCache = true, bool synchronize = true);
 349
 350 /*! @function synchronize
 351     @abstract Bring IOMemoryDescriptor and IODMACommand buffers into sync.
 352     @discussion This method should not be called unless a prepare was previously issued. If needed a caller may synchronize any IODMACommand buffers with the original IOMemoryDescriptor buffers.
 353     @param options Specifies the direction of the copy:
 354         kIODirectionOut copy IOMemoryDesciptor memory to any IODMACommand buffers. By default this action takes place automatically at prepare().
 355         kIODirectionIn copy any IODMACommand buffers back to the IOMemoryDescriptor. By default this action takes place automatically at complete().
 356         kForceDoubleBuffer copy the entire prepared range to a new page aligned buffer.
 357     @result kIOReturnNotReady if not prepared, kIOReturnBadArgument if invalid options are passed, kIOReturnSuccess otherwise. */
 358
 359     virtual IOReturn synchronize(IOOptionBits options);
 360
 361 /*! @function genIOVMSegments
 362     @abstract Generates a physical scatter/gather for the current DMA command
 363     @discussion Generates a list of physical segments from the given memory descriptor, relative to the current position of the descriptor.  The constraints that are set during initialisation will be respected. This function maintains the state across multiple calls for efficiency.  However the state is discarded if the new offset is not the expected one.
 364     @param offset input/output parameter, defines the starting and ending offset in the memory descriptor, relative to any offset passed to the prepare() method.
 365     @param segments Void pointer to base of output physical scatter/gather list.  Always passed directly onto the SegmentFunction.
 366     @param numSegments Input/output parameter Number of segments that can fit in the segment array and returns number of segments generated.
 367     @result kIOReturnSuccess on success, kIOReturnOverrun if the memory descriptor is exhausted, kIOReturnMessageTooLarge if the output segment function's address bits has insufficient resolution for a segment, kIOReturnNotReady if the DMA command has not be prepared, kIOReturnBadArgument if the DMA command doesn't have a memory descriptor yet or some of the parameters are NULL and kIOReturnNotReady if the DMA command is not prepared.
 368 */
 369     virtual IOReturn genIOVMSegments(UInt64 *offset,
 370                                      void   *segments,
 371                                      UInt32 *numSegments);
 372
 373 private:
 374     virtual UInt64 transfer( IOOptionBits transferOp, UInt64 offset, void * buffer, UInt64 length );
 375
 376 public:
 377
 378 /*! @function writeBytes
 379     @abstract Copy data to the IODMACommand's buffer from the specified buffer.
 380     @discussion This method copies data to the IODMACommand's memory at the given offset, from the caller's buffer. The IODMACommand must be prepared, and the offset is relative to the prepared offset.
 381     @param offset A byte offset into the IODMACommand's memory, relative to the prepared offset.
 382     @param bytes The caller supplied buffer to copy the data from.
 383     @param length The length of the data to copy.
 384     @result The number of bytes copied, zero will be returned if the specified offset is beyond the prepared length of the IODMACommand. */
 385
 386     UInt64 writeBytes(UInt64 offset, const void *bytes, UInt64 length);
 387
 388 /*! @function readBytes
 389     @abstract Copy data from the IODMACommand's buffer to the specified buffer.
 390     @discussion This method copies data from the IODMACommand's memory at the given offset, to the caller's buffer. The IODMACommand must be prepared, and the offset is relative to the prepared offset.
 391     @param offset A byte offset into the IODMACommand's memory, relative to the prepared offset.
 392     @param bytes The caller supplied buffer to copy the data to.
 393     @param length The length of the data to copy.
 394     @result The number of bytes copied, zero will be returned if the specified offset is beyond the prepared length of the IODMACommand. */
 395
 396     UInt64 readBytes(UInt64 offset, void *bytes, UInt64 length);
 397
 398 /*! @function gen32IOVMSegments
 399     @abstract Helper function for a type checked call to genIOVMSegments(qv), for use with an IODMACommand set up with the output function kIODMACommandOutputHost32, kIODMACommandOutputBig32, or kIODMACommandOutputLittle32. If the output function of the IODMACommand is not a 32 bit function, results will be incorrect.
 400 */
 401     inline IOReturn gen32IOVMSegments(UInt64   *offset,
 402                                       Segment32 *segments,
 403                                       UInt32     *numSegments)
 404     { return genIOVMSegments(offset, segments, numSegments); }
 405
 406 /*! @function gen64IOVMSegments
 407     @abstract Helper function for a type checked call to genIOVMSegments(qv), for use with an IODMACommand set up with the output function kIODMACommandOutputHost64, kIODMACommandOutputBig64, or kIODMACommandOutputLittle64. If the output function of the IODMACommand is not a 64 bit function, results will be incorrect.
 408 */
 409     inline IOReturn gen64IOVMSegments(UInt64    *offset,
 410                                       Segment64 *segments,
 411                                       UInt32    *numSegments)
 412     { return genIOVMSegments(offset, segments, numSegments); }
 413
 414     IOReturn
 415     genIOVMSegments(SegmentFunction segmentFunction,
 416                     UInt64 *offsetP,
 417                     void   *segmentsP,
 418                     UInt32 *numSegmentsP);
 419
 420     virtual void free() APPLE_KEXT_OVERRIDE;
 421
 422 private:
 423     IOReturn setSpecification(SegmentFunction        outSegFunc,
 424                               const SegmentOptions * segmentOptions,
 425                               uint32_t               mappingOptions,
 426                               IOMapper             * mapper);
 427
 428     typedef IOReturn (*InternalSegmentFunction)(
 429                                     void         *reference,
 430                                     IODMACommand *target,
 431                                     Segment64     segment,
 432                                     void         *segments,
 433                                     UInt32        segmentIndex);
 434
 435     IOReturn genIOVMSegments(uint32_t op,
 436                                   InternalSegmentFunction outSegFunc,
 437                                   void   *reference,
 438                                   UInt64 *offsetP,
 439                                   void   *segmentsP,
 440                                   UInt32 *numSegmentsP);
 441
 442     static IOReturn clientOutputSegment(
 443             void *reference, IODMACommand *target,
 444             Segment64 segment, void *vSegList, UInt32 outSegIndex);
 445
 446     static IOReturn segmentOp(
 447                         void         *reference,
 448                         IODMACommand *target,
 449                         Segment64     segment,
 450                         void         *segments,
 451                         UInt32        segmentIndex);
 452     IOReturn walkAll(UInt8 op);
 453
 454 public:
 455
 456 /*! @function prepareWithSpecification
 457     @abstract Prepare the memory for an I/O transfer with a new specification.
 458     @discussion Allocate the mapping resources neccessary for this transfer, specifying a sub range of the IOMemoryDescriptor that will be the target of the I/O.  The complete() method frees these resources.  Data may be copied to buffers for kIODirectionOut memory descriptors, depending on hardware mapping resource availabilty or alignment restrictions.  It should be noted that the this function may block and should only be called on the clients context, i.e never call this routine while gated; also the call itself is not thread safe though this should be an issue as each IODMACommand is independant.
 459     @param outSegFunc SegmentFunction to call to output one physical segment. A set of nine commonly required segment functions are provided.
 460     @param numAddressBits Number of bits that the hardware uses on its internal address bus. Typically 32 but may be more on modern hardware.  A 0 implies no-restriction other than that implied by the output segment function.
 461     @param maxSegmentSize Maximum allowable size for one segment.  Defaults to 0 which means any size.
 462     @param mappingOptions is the type of mapping that is required to translate an IOMemoryDescriptor into the desired number of bits.  For instance if your hardware only supports 32 bits but must run on machines with > 4G of RAM some mapping will be required.  Number of bits will be specified in numAddressBits, see below.This parameter can take 3 values:- kNonCoherent - used for non-coherent hardware transfers, Mapped - Validate that all I/O bus generated addresses are within the number of addressing bits specified, Bypassed indicates that bypassed addressing is required, this is used when the hardware transferes are into coherent memory but no mapping is required.  See also prepare() for failure cases.
 463     @param maxTransferSize Maximum size of an entire transfer.  Defaults to 0 indicating no maximum.
 464     @param alignment Alignment restriction, in bytes, on I/O bus addresses.  Defaults to single byte alignment.
 465     @param mapper For mapping types kMapped & kBypassed mapper is used to define the hardware that will perform the mapping, defaults to the system mapper.
 466     @param offset defines the starting offset in the memory descriptor the DMA command will operate on. genIOVMSegments will produce its results based on the offset and length passed to the prepare method.
 467     @param length defines the ending position in the memory descriptor the DMA command will operate on. genIOVMSegments will produce its results based on the offset and length passed to the prepare method.
 468     @param flushCache Flush the caches for the memory descriptor and make certain that the memory cycles are complete.  Defaults to true for kNonCoherent and is ignored by the other types.
 469     @param synchronize Copy any buffered data back from the target IOMemoryDescriptor.  Defaults to true, if synchronize() is being used to explicitly copy data, passing false may avoid an unneeded copy.
 470     @result An IOReturn code. Can fail if the mapping type is not recognised, if one of the 3 mandatory parameters are set to 0, if a 32 bit output function is selected when more than 32 bits of address is required or, if kBypassed is requested on a machine that doesn't support bypassing.
 471 */
 472
 473     virtual IOReturn prepareWithSpecification(SegmentFunction   outSegFunc,
 474                                               UInt8             numAddressBits,
 475                                               UInt64            maxSegmentSize,
 476                                               MappingOptions    mappingOptions = kMapped,
 477                                               UInt64            maxTransferSize = 0,
 478                                               UInt32            alignment = 1,
 479                                               IOMapper          *mapper = 0,
 480                                               UInt64            offset = 0,
 481                                               UInt64            length = 0,
 482                                               bool              flushCache = true,
 483                                               bool              synchronize = true);
 484
 485     static IOReturn transferSegment(void         *reference,
 486                                     IODMACommand *target,
 487                                     Segment64     segment,
 488                                     void         *segments,
 489                                     UInt32        segmentIndex);
 490
 491 /*! @function getPreparedOffsetAndLength
 492     @abstract Returns the offset and length into the target IOMemoryDescriptor of a prepared IODDMACommand.
 493     @discussion If successfully prepared, returns the offset and length into the IOMemoryDescriptor. Will fail for an unprepared IODMACommand.
 494     @param offset returns the starting offset in the memory descriptor the DMA command was prepared with. Pass NULL for don't care.
 495     @param length returns the length in the memory descriptor the DMA command was prepared with. Pass NULL for don't care.
 496     @result An IOReturn code. kIOReturnNotReady if the IODMACommand is not prepared. */
 497
 498     virtual IOReturn getPreparedOffsetAndLength(UInt64 * offset, UInt64 * length);
 499
 500     UInt8    getNumAddressBits(void);
 501     UInt32   getAlignment(void);
 502     uint32_t getAlignmentLength(void);
 503     uint32_t getAlignmentInternalSegments(void);
 504
 505
 506 /*! @function initWithRefCon
 507     @abstract Secondary initializer for the IODMACommand class.
 508     @param refCon Reference Constant
 509     @result Can fail if super init fails.  Returns true otherwise.
 510 */
 511
 512     virtual
 513     bool initWithRefCon(void * refCon = 0);
 514
 515     virtual
 516     bool initWithSpecification(SegmentFunction        outSegFunc,
 517                                const SegmentOptions * segmentOptions,
 518                                uint32_t               mappingOptions,
 519                                IOMapper             * mapper,
 520                                void                 * refCon);
 521
 522     virtual
 523     IOReturn prepareWithSpecification(SegmentFunction        outSegFunc,
 524                                       const SegmentOptions * segmentOptions,
 525                                       uint32_t               mappingOptions,
 526                                       IOMapper             * mapper,
 527                                       uint64_t               offset,
 528                                       uint64_t               length,
 529                                       bool                   flushCache = true,
 530                                       bool                   synchronize = true);
 531
 532     virtual
 533     IOBufferMemoryDescriptor * createCopyBuffer(IODirection direction, UInt64 length);
 534
 535 private:
 536     OSMetaClassDeclareReservedUsed(IODMACommand,  0);
 537     OSMetaClassDeclareReservedUsed(IODMACommand,  1);
 538     OSMetaClassDeclareReservedUsed(IODMACommand,  2);
 539     OSMetaClassDeclareReservedUsed(IODMACommand,  3);
 540     OSMetaClassDeclareReservedUsed(IODMACommand,  4);
 541     OSMetaClassDeclareReservedUsed(IODMACommand,  5);
 542     OSMetaClassDeclareReservedUsed(IODMACommand,  6);
 543     OSMetaClassDeclareReservedUnused(IODMACommand,  7);
 544     OSMetaClassDeclareReservedUnused(IODMACommand,  8);
 545     OSMetaClassDeclareReservedUnused(IODMACommand,  9);
 546     OSMetaClassDeclareReservedUnused(IODMACommand, 10);
 547     OSMetaClassDeclareReservedUnused(IODMACommand, 11);
 548     OSMetaClassDeclareReservedUnused(IODMACommand, 12);
 549     OSMetaClassDeclareReservedUnused(IODMACommand, 13);
 550     OSMetaClassDeclareReservedUnused(IODMACommand, 14);
 551     OSMetaClassDeclareReservedUnused(IODMACommand, 15);
 552
 553 public:
 554 /*! @var fRefCon Reference Constant, client defined publicly avialable */
 555     void *fRefCon;
 556
 557 protected:
 558
 559 /*! @var fMaxSegmentSize Maximum size of one segment in a scatter/gather list */
 560     UInt64  fMaxSegmentSize;
 561
 562 /*! @var fMaxTransferSize
 563     Maximum size of a transfer that this memory cursor is allowed to generate */
 564     UInt64  fMaxTransferSize;
 565
 566     UInt32  fAlignMaskLength;
 567     UInt32  fAlignMaskInternalSegments;
 568
 569 /*! @var fMapper
 570     Client defined mapper. */
 571     IOMapper *fMapper;
 572
 573 /*! @var fMemory
 574     memory descriptor for current I/O. */
 575     const IOMemoryDescriptor *fMemory;
 576
 577 /*! @var fOutSeg The action method called when an event has been delivered */
 578     SegmentFunction fOutSeg;
 579
 580 /*! @var fAlignMask
 581     Alignment restriction mask. */
 582     UInt32  fAlignMask;
 583
 584 /*! @var fNumAddressBits
 585     Number of bits that the hardware can address */
 586     UInt32 fNumAddressBits;
 587
 588 /*! @var fNumSegments
 589     Number of contiguous segments required for the current memory descriptor and desired mapping */
 590     UInt32  fNumSegments;
 591
 592 /*! @var fMappingOptions
 593     What type of I/O virtual address mapping is required for this command */
 594     uint32_t  fMappingOptions;
 595
 596 /*! @var fActive
 597     fActive indicates that this DMA command is currently prepared and ready to go */
 598     UInt32 fActive;
 599
 600 /*! @var reserved
 601     Reserved for future use.  (Internal use only)  */
 602     struct IODMACommandInternal * reserved;
 603 };
 604
 605 IOReturn IODMACommand::
 606 weakWithSpecification(IODMACommand **newCommand,
 607                       SegmentFunction  outSegFunc,
 608                       UInt8     numAddressBits,
 609                       UInt64    maxSegmentSize,
 610                       MappingOptions mapType,
 611                       UInt64    maxTransferSize,
 612                       UInt32    alignment,
 613                       IOMapper *mapper,
 614                       void     *refCon)
 615 {
 616     if (!newCommand)
 617         return kIOReturnBadArgument;
 618
 619     IODMACommand *self = (IODMACommand *)
 620         OSMetaClass::allocClassWithName("IODMACommand");
 621     if (!self)
 622         return kIOReturnUnsupported;
 623
 624     IOReturn ret;
 625     bool inited = self->
 626         initWithSpecification(outSegFunc,
 627                               numAddressBits, maxSegmentSize, mapType,
 628                               maxTransferSize, alignment, mapper, refCon);
 629     if (inited)
 630         ret =  kIOReturnSuccess;
 631     else {
 632         self->release();
 633         self = 0;
 634         ret = kIOReturnError;
 635     }
 636
 637     *newCommand = self;
 638     return ret;
 639 };
 640 #endif /* !_IODMACOMMAND_H */
 641