IODMACommand.h
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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 OSDeclareDefaultStructorsWithDispatch(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 OSPtr<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 = NULL, 226 void *refCon = NULL); 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 = NULL, 256 void *refCon = NULL) __attribute__((always_inline)); 257 258 static OSPtr<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 OSPtr<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 OSPtr<IODMACommand> cloneCommand(void *refCon = NULL); 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 = NULL, 301 void *refCon = NULL); 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 402 gen32IOVMSegments(UInt64 *offset, 403 Segment32 *segments, 404 UInt32 *numSegments) 405 { 406 return genIOVMSegments(offset, segments, numSegments); 407 } 408 409 /*! @function gen64IOVMSegments 410 * @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. 411 */ 412 inline IOReturn 413 gen64IOVMSegments(UInt64 *offset, 414 Segment64 *segments, 415 UInt32 *numSegments) 416 { 417 return genIOVMSegments(offset, segments, numSegments); 418 } 419 420 IOReturn 421 genIOVMSegments(SegmentFunction segmentFunction, 422 UInt64 *offsetP, 423 void *segmentsP, 424 UInt32 *numSegmentsP); 425 426 virtual void free() APPLE_KEXT_OVERRIDE; 427 428 private: 429 IOReturn setSpecification(SegmentFunction outSegFunc, 430 const SegmentOptions * segmentOptions, 431 uint32_t mappingOptions, 432 IOMapper * mapper); 433 434 typedef IOReturn (*InternalSegmentFunction)( 435 void *reference, 436 IODMACommand *target, 437 Segment64 segment, 438 void *segments, 439 UInt32 segmentIndex); 440 441 IOReturn genIOVMSegments(uint32_t op, 442 InternalSegmentFunction outSegFunc, 443 void *reference, 444 UInt64 *offsetP, 445 void *segmentsP, 446 UInt32 *numSegmentsP); 447 448 static IOReturn clientOutputSegment( 449 void *reference, IODMACommand *target, 450 Segment64 segment, void *vSegList, UInt32 outSegIndex); 451 452 static IOReturn segmentOp( 453 void *reference, 454 IODMACommand *target, 455 Segment64 segment, 456 void *segments, 457 UInt32 segmentIndex); 458 IOReturn walkAll(uint32_t op); 459 460 public: 461 462 /*! @function prepareWithSpecification 463 * @abstract Prepare the memory for an I/O transfer with a new specification. 464 * @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. 465 * @param outSegFunc SegmentFunction to call to output one physical segment. A set of nine commonly required segment functions are provided. 466 * @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. 467 * @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0 which means any size. 468 * @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. 469 * @param maxTransferSize Maximum size of an entire transfer. Defaults to 0 indicating no maximum. 470 * @param alignment Alignment restriction, in bytes, on I/O bus addresses. Defaults to single byte alignment. 471 * @param mapper For mapping types kMapped & kBypassed mapper is used to define the hardware that will perform the mapping, defaults to the system mapper. 472 * @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. 473 * @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. 474 * @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. 475 * @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. 476 * @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. 477 */ 478 479 virtual IOReturn prepareWithSpecification(SegmentFunction outSegFunc, 480 UInt8 numAddressBits, 481 UInt64 maxSegmentSize, 482 MappingOptions mappingOptions = kMapped, 483 UInt64 maxTransferSize = 0, 484 UInt32 alignment = 1, 485 IOMapper *mapper = NULL, 486 UInt64 offset = 0, 487 UInt64 length = 0, 488 bool flushCache = true, 489 bool synchronize = true); 490 491 static IOReturn transferSegment(void *reference, 492 IODMACommand *target, 493 Segment64 segment, 494 void *segments, 495 UInt32 segmentIndex); 496 497 /*! @function getPreparedOffsetAndLength 498 * @abstract Returns the offset and length into the target IOMemoryDescriptor of a prepared IODDMACommand. 499 * @discussion If successfully prepared, returns the offset and length into the IOMemoryDescriptor. Will fail for an unprepared IODMACommand. 500 * @param offset returns the starting offset in the memory descriptor the DMA command was prepared with. Pass NULL for don't care. 501 * @param length returns the length in the memory descriptor the DMA command was prepared with. Pass NULL for don't care. 502 * @result An IOReturn code. kIOReturnNotReady if the IODMACommand is not prepared. */ 503 504 virtual IOReturn getPreparedOffsetAndLength(UInt64 * offset, UInt64 * length); 505 506 UInt8 getNumAddressBits(void); 507 UInt32 getAlignment(void); 508 uint32_t getAlignmentLength(void); 509 uint32_t getAlignmentInternalSegments(void); 510 511 512 /*! @function initWithRefCon 513 * @abstract Secondary initializer for the IODMACommand class. 514 * @param refCon Reference Constant 515 * @result Can fail if super init fails. Returns true otherwise. 516 */ 517 518 virtual 519 bool initWithRefCon(void * refCon = NULL); 520 521 virtual 522 bool initWithSpecification(SegmentFunction outSegFunc, 523 const SegmentOptions * segmentOptions, 524 uint32_t mappingOptions, 525 IOMapper * mapper, 526 void * refCon); 527 528 virtual 529 IOReturn prepareWithSpecification(SegmentFunction outSegFunc, 530 const SegmentOptions * segmentOptions, 531 uint32_t mappingOptions, 532 IOMapper * mapper, 533 uint64_t offset, 534 uint64_t length, 535 bool flushCache = true, 536 bool synchronize = true); 537 538 virtual 539 OSPtr<IOBufferMemoryDescriptor> createCopyBuffer(IODirection direction, UInt64 length); 540 541 private: 542 OSMetaClassDeclareReservedUsedX86(IODMACommand, 0); 543 OSMetaClassDeclareReservedUsedX86(IODMACommand, 1); 544 OSMetaClassDeclareReservedUsedX86(IODMACommand, 2); 545 OSMetaClassDeclareReservedUsedX86(IODMACommand, 3); 546 OSMetaClassDeclareReservedUsedX86(IODMACommand, 4); 547 OSMetaClassDeclareReservedUsedX86(IODMACommand, 5); 548 OSMetaClassDeclareReservedUsedX86(IODMACommand, 6); 549 OSMetaClassDeclareReservedUnused(IODMACommand, 7); 550 OSMetaClassDeclareReservedUnused(IODMACommand, 8); 551 OSMetaClassDeclareReservedUnused(IODMACommand, 9); 552 OSMetaClassDeclareReservedUnused(IODMACommand, 10); 553 OSMetaClassDeclareReservedUnused(IODMACommand, 11); 554 OSMetaClassDeclareReservedUnused(IODMACommand, 12); 555 OSMetaClassDeclareReservedUnused(IODMACommand, 13); 556 OSMetaClassDeclareReservedUnused(IODMACommand, 14); 557 OSMetaClassDeclareReservedUnused(IODMACommand, 15); 558 559 public: 560 /*! @var fRefCon Reference Constant, client defined publicly avialable */ 561 void *fRefCon; 562 563 protected: 564 565 /*! @var fMaxSegmentSize Maximum size of one segment in a scatter/gather list */ 566 UInt64 fMaxSegmentSize; 567 568 /*! @var fMaxTransferSize 569 * Maximum size of a transfer that this memory cursor is allowed to generate */ 570 UInt64 fMaxTransferSize; 571 572 UInt32 fAlignMaskLength; 573 UInt32 fAlignMaskInternalSegments; 574 575 /*! @var fMapper 576 * Client defined mapper. */ 577 OSPtr<IOMapper> fMapper; 578 579 /*! @var fMemory 580 * memory descriptor for current I/O. */ 581 OSPtr<IOMemoryDescriptor> fMemory; 582 583 /*! @var fOutSeg The action method called when an event has been delivered */ 584 SegmentFunction fOutSeg; 585 586 /*! @var fAlignMask 587 * Alignment restriction mask. */ 588 UInt32 fAlignMask; 589 590 /*! @var fNumAddressBits 591 * Number of bits that the hardware can address */ 592 UInt32 fNumAddressBits; 593 594 /*! @var fNumSegments 595 * Number of contiguous segments required for the current memory descriptor and desired mapping */ 596 UInt32 fNumSegments; 597 598 /*! @var fMappingOptions 599 * What type of I/O virtual address mapping is required for this command */ 600 uint32_t fMappingOptions; 601 602 /*! @var fActive 603 * fActive indicates that this DMA command is currently prepared and ready to go */ 604 UInt32 fActive; 605 606 /*! @var reserved 607 * Reserved for future use. (Internal use only) */ 608 struct IODMACommandInternal *reserved; 609 }; 610 611 IOReturn 612 IODMACommand:: 613 weakWithSpecification(IODMACommand **newCommand, 614 SegmentFunction outSegFunc, 615 UInt8 numAddressBits, 616 UInt64 maxSegmentSize, 617 MappingOptions mapType, 618 UInt64 maxTransferSize, 619 UInt32 alignment, 620 IOMapper *mapper, 621 void *refCon) 622 { 623 if (!newCommand) { 624 return kIOReturnBadArgument; 625 } 626 627 IODMACommand *self = (IODMACommand *) 628 OSMetaClass::allocClassWithName("IODMACommand"); 629 if (!self) { 630 return kIOReturnUnsupported; 631 } 632 633 IOReturn ret; 634 bool inited = self-> 635 initWithSpecification(outSegFunc, 636 numAddressBits, maxSegmentSize, mapType, 637 maxTransferSize, alignment, mapper, refCon); 638 if (inited) { 639 ret = kIOReturnSuccess; 640 } else { 641 self->release(); 642 self = NULL; 643 ret = kIOReturnError; 644 } 645 646 *newCommand = self; 647 return ret; 648 }; 649 #endif /* !_IODMACOMMAND_H */