1/* 2 * Copyright (c) 2005 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 _IODMACOMMAND_H 29#define _IODMACOMMAND_H 30 31#include <IOKit/IOCommand.h> 32#include <IOKit/IOMemoryDescriptor.h> 33class IOMapper; 34 35/**************************** class IODMACommand ***************************/ 36 37/*! 38 @class IODMACommand 39 @abstract A mechanism to convert memory references to I/O bus addresses. 40 @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. 41<br><br> 42 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. 43<br><br> 44 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. 45<br><br> 46 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! 47*/ 48 49class IODMACommand : public IOCommand 50{ 51 OSDeclareDefaultStructors(IODMACommand); 52 53friend class IODMAEventSource; 54 55public: 56 57/*! 58 @typedef Segment32 59 @discussion A 32 bit I/O bus address/length pair 60*/ 61 struct Segment32 { 62 UInt32 fIOVMAddr, fLength; 63 }; 64 65/*! 66 @typedef Segment64 67 @discussion A 64 bit I/O bus address/length pair 68*/ 69 struct Segment64 { 70 UInt64 fIOVMAddr, fLength; 71 }; 72 73/*! @enum MappingOptions 74 @abstract Mapping types to indicate the desired mapper type for translating memory descriptors into I/O DMA Bus addresses. 75 @constant kNonCoherent Used by drivers for non-coherent transfers, implies unmapped memmory 76 @constant kMapped Allow a driver to define addressing size 77 @constant kBypassed Allow drivers to bypass any mapper 78 @constant kMaxMappingOptions Internal use only 79*/ 80 enum MappingOptions { 81 kMapped = 0x00000000, 82 kBypassed = 0x00000001, 83 kNonCoherent = 0x00000002, 84 kTypeMask = 0x0000000f, 85 86 kNoCacheStore = 0x00000010, // Memory in descriptor 87 kOnChip = 0x00000020, // Indicates DMA is on South Bridge 88 kIterateOnly = 0x00000040 // DMACommand will be used as a cursor only 89 }; 90 91/*! @enum SynchronizeOptions 92 @abstract Options for the synchronize method. 93 @constant kForceDoubleBuffer Copy the entire prepared range to a new page aligned buffer. 94*/ 95 enum SynchronizeOptions { 96 kForceDoubleBuffer = 0x01000000 97 }; 98 99/*! 100 @typedef SegmentFunction 101 @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. 102 @param segment The 64Bit I/O bus address and length. 103 @param segments Base of the output vector of DMA address length pairs. 104 @param segmentIndex Index to output 'segment' in the 'segments' array. 105 @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. 106*/ 107 typedef bool (*SegmentFunction)(IODMACommand *target, 108 Segment64 segment, 109 void *segments, 110 UInt32 segmentIndex); 111 112 // -------------- Preimplemented output functions ---------------- 113 114/*! @function OutputHost32 115 @abstract Output host natural Segment32 output segment function. 116*/ 117 static bool OutputHost32(IODMACommand *target, 118 Segment64 seg, void *segs, UInt32 ind); 119 120/*! @defined kIODMACommandOutputHost32 121 @abstract Output host natural Segment32 output segment function. 122 */ 123#define kIODMACommandOutputHost32 (IODMACommand::OutputHost32) 124 125/*! @function OutputBig32 126 @abstract Output big-endian Segment32 output segment function. 127*/ 128 static bool OutputBig32(IODMACommand *target, 129 Segment64 seg, void *segs, UInt32 ind); 130 131/*! @defined kIODMACommandOutputBig32 132 @abstract Output big-endian Segment32 output segment function. 133 */ 134#define kIODMACommandOutputBig32 (IODMACommand::OutputBig32) 135 136/*! @function OutputLittle32 137 @abstract Output little-endian Segment32 output segment function. 138*/ 139 static bool OutputLittle32(IODMACommand *target, 140 Segment64 seg, void *segs, UInt32 ind); 141 142/*! @defined kIODMACommandOutputLittle32 143 @abstract Output little-endian Segment32 output segment function. 144*/ 145#define kIODMACommandOutputLittle32 (IODMACommand::OutputLittle32) 146 147/*! @function OutputHost64 148 @abstract Output host natural Segment64 output segment function. 149*/ 150 static bool OutputHost64(IODMACommand *target, 151 Segment64 seg, void *segs, UInt32 ind); 152 153/*! @defined kIODMACommandOutputHost64 154 @abstract Output host natural Segment64 output segment function. 155*/ 156#define kIODMACommandOutputHost64 (IODMACommand::OutputHost64) 157 158/*! @function OutputBig64 159 @abstract Output big-endian Segment64 output segment function. 160*/ 161 static bool OutputBig64(IODMACommand *target, 162 Segment64 seg, void *segs, UInt32 ind); 163 164/*! @defined kIODMACommandOutputBig64 165 @abstract Output big-endian Segment64 output segment function. 166*/ 167#define kIODMACommandOutputBig64 (IODMACommand::OutputBig64) 168 169/*! @function OutputLittle64 170 @abstract Output little-endian Segment64 output segment function. 171*/ 172 static bool OutputLittle64(IODMACommand *target, 173 Segment64 seg, void *segs, UInt32 ind); 174 175/*! @defined kIODMACommandOutputLittle64 176 @abstract Output little-endian Segment64 output segment function. 177*/ 178#define kIODMACommandOutputLittle64 (IODMACommand::OutputLittle64) 179 180/*! @function withSpecification 181 @abstract Creates and initializes an IODMACommand in one operation. 182 @discussion Factory function to create and initialize an IODMACommand in one operation. 183 @param outSegFunc SegmentFunction to call to output one physical segment. A set of nine commonly required segment functions are provided. 184 @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. 185 @param maxSegmentSize Maximum allowable size for one segment. If 0 is passed the maximum segment size is unlimited. 186 @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. 187 @param maxTransferSize Maximum size of an entire transfer. Defaults to 0 indicating no maximum. 188 @param alignment Alignment restriction, in bytes, on I/O bus addresses. Defaults to single byte alignment. 189 @param mapper For mapping types kMapped & kBypassed mapper is used to define the hardware that will perform the mapping, defaults to the system mapper. 190 @result Returns a new memory cursor if successfully created and initialized, 0 otherwise. 191*/ 192 static IODMACommand * 193 withSpecification(SegmentFunction outSegFunc, 194 UInt8 numAddressBits, 195 UInt64 maxSegmentSize, 196 MappingOptions mappingOptions = kMapped, 197 UInt64 maxTransferSize = 0, 198 UInt32 alignment = 1, 199 IOMapper *mapper = 0, 200 void *refCon = 0); 201 202/*! @function weakWithSpecification 203 @abstract Creates and initialises an IODMACommand in one operation if this version of the operating system supports it. 204 @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.). 205 @param newCommand Output reference variable of the newly created IODMACommand. 206 @param outSegFunc SegmentFunction to call to output one physical segment. A set of nine commonly required segment functions are provided. 207 @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. 208 @param maxSegmentSize Maximum allowable size for one segment. Zero is treated as an unlimited segment size. 209 @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. 210 @param maxTransferSize Maximum size of an entire transfer. Defaults to 0 indicating no maximum. 211 @param alignment Alignment restriction, in bytes, on I/O bus addresses. Defaults to single byte alignment. 212 @param mapper For mapping types kMapped & kBypassed mapper is used to define the hardware that will perform the mapping, defaults to the system mapper. 213 @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. 214*/ 215 // Note that the function has the attribute always_inline. 216 // The point of this function is to make a call into the kernel 217 // without generating an undefined symbol. If the client could call 218 // the code as a function then the goal of no undefined symbols 219 // would be lost thus defeating the purpose. 220 static inline IOReturn weakWithSpecification 221 (IODMACommand **newCommand, 222 SegmentFunction outSegFunc, 223 UInt8 numAddressBits, 224 UInt64 maxSegmentSize, 225 MappingOptions mapType = kMapped, 226 UInt64 maxTransferSize = 0, 227 UInt32 alignment = 1, 228 IOMapper *mapper = 0, 229 void *refCon = 0) __attribute__((always_inline)); 230 231/*! 232 @function cloneCommand 233 @abstract Creates a new command based on the specification of the current one. 234 @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. 235 @result Returns a new memory cursor if successfully created and initialised, 0 otherwise. 236*/ 237 virtual IODMACommand *cloneCommand(void *refCon = 0); 238 239/*! @function initWithSpecification 240 @abstract Primary initializer for the IODMACommand class. 241 @param outSegFunc SegmentFunction to call to output one physical segment. A set of nine commonly required segment functions are provided. 242 @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. 243 @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0 which means any size. 244 @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. 245 @param maxTransferSize Maximum size of an entire transfer. Defaults to 0 indicating no maximum. 246 @param alignment Alignment restriction, in bytes, on I/O bus addresses. Defaults to single byte alignment. 247 @param mapper For mapping types kMapped & kBypassed mapper is used to define the hardware that will perform the mapping, defaults to the system mapper. 248 @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. 249*/ 250 virtual bool initWithSpecification( SegmentFunction outSegFunc, 251 UInt8 numAddressBits, 252 UInt64 maxSegmentSize, 253 MappingOptions mappingOptions = kMapped, 254 UInt64 maxTransferSize = 0, 255 UInt32 alignment = 1, 256 IOMapper *mapper = 0, 257 void *refCon = 0); 258 259/*! @function setMemoryDescriptor 260 @abstract Sets and resets the DMACommand's current memory descriptor 261 @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. 262 @param mem A pointer to the current I/Os memory descriptor. 263 @param autoPrepare An optional boolean variable that will call the prepare() function automatically after the memory descriptor is processed. Defaults to true. 264 @result Returns kIOReturnSuccess, kIOReturnBusy if currently prepared, kIOReturnNoSpace if the length(mem) >= Maximum Transfer Size or the error codes returned by prepare() (qv). 265*/ 266 virtual IOReturn setMemoryDescriptor(const IOMemoryDescriptor *mem, 267 bool autoPrepare = true); 268 269/*! @function clearMemoryDescriptor 270 @abstract Clears the DMACommand's current memory descriptor 271 @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. 272 @param autoComplete An optional boolean variable that will call the complete() function automatically before the memory descriptor is processed. Defaults to true. 273*/ 274 virtual IOReturn clearMemoryDescriptor(bool autoComplete = true); 275 276/*! @function getMemoryDescriptor 277 @abstract Get the current memory descriptor 278*/ 279 virtual const IOMemoryDescriptor *getMemoryDescriptor() const; 280 281/*! @function prepare 282 @abstract Prepare the memory for an I/O transfer. 283 @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. 284 @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. 285 @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. 286 @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. 287 @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. 288 @result An IOReturn code. */ 289 290 virtual IOReturn prepare(UInt64 offset = 0, UInt64 length = 0, bool flushCache = true, bool synchronize = true); 291 292/*! @function complete 293 @abstract Complete processing of DMA mappings after an I/O transfer is finished. 294 @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 295 @param invalidCache Invalidate the caches for the memory descriptor. Defaults to true for kNonCoherent and is ignored by the other types. 296 @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. 297 @result kIOReturnNotReady if not prepared, kIOReturnSuccess otherwise. */ 298 299 virtual IOReturn complete(bool invalidateCache = true, bool synchronize = true); 300 301/*! @function synchronize 302 @abstract Bring IOMemoryDescriptor and IODMACommand buffers into sync. 303 @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. 304 @param options Specifies the direction of the copy: 305 kIODirectionOut copy IOMemoryDesciptor memory to any IODMACommand buffers. By default this action takes place automatically at prepare(). 306 kIODirectionIn copy any IODMACommand buffers back to the IOMemoryDescriptor. By default this action takes place automatically at complete(). 307 kForceDoubleBuffer copy the entire prepared range to a new page aligned buffer. 308 @result kIOReturnNotReady if not prepared, kIOReturnBadArgument if invalid options are passed, kIOReturnSuccess otherwise. */ 309 310 virtual IOReturn synchronize(IOOptionBits options); 311 312/*! @function genIOVMSegments 313 @abstract Generates a physical scatter/gather for the current DMA command 314 @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. 315 @param offset input/output parameter, defines the starting and ending offset in the memory descriptor, relative to any offset passed to the prepare() method. 316 @param segments Void pointer to base of output physical scatter/gather list. Always passed directly onto the SegmentFunction. 317 @param numSegments Input/output parameter Number of segments that can fit in the segment array and returns number of segments generated. 318 @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. 319*/ 320 virtual IOReturn genIOVMSegments(UInt64 *offset, 321 void *segments, 322 UInt32 *numSegments); 323 324private: 325 virtual UInt64 transfer( IOOptionBits transferOp, UInt64 offset, void * buffer, UInt64 length ); 326 327public: 328 329/*! @function writeBytes 330 @abstract Copy data to the IODMACommand's buffer from the specified buffer. 331 @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. 332 @param offset A byte offset into the IODMACommand's memory, relative to the prepared offset. 333 @param bytes The caller supplied buffer to copy the data from. 334 @param length The length of the data to copy. 335 @result The number of bytes copied, zero will be returned if the specified offset is beyond the prepared length of the IODMACommand. */ 336 337 UInt64 writeBytes(UInt64 offset, const void *bytes, UInt64 length); 338 339/*! @function readBytes 340 @abstract Copy data from the IODMACommand's buffer to the specified buffer. 341 @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. 342 @param offset A byte offset into the IODMACommand's memory, relative to the prepared offset. 343 @param bytes The caller supplied buffer to copy the data to. 344 @param length The length of the data to copy. 345 @result The number of bytes copied, zero will be returned if the specified offset is beyond the prepared length of the IODMACommand. */ 346 347 UInt64 readBytes(UInt64 offset, void *bytes, UInt64 length); 348 349/*! @function gen32IOVMSegments 350 @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. 351*/ 352 inline IOReturn gen32IOVMSegments(UInt64 *offset, 353 Segment32 *segments, 354 UInt32 *numSegments) 355 { return genIOVMSegments(offset, segments, numSegments); }; 356 357/*! @function gen64IOVMSegments 358 @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. 359*/ 360 inline IOReturn gen64IOVMSegments(UInt64 *offset, 361 Segment64 *segments, 362 UInt32 *numSegments) 363 { return genIOVMSegments(offset, segments, numSegments); }; 364 365 IOReturn 366 genIOVMSegments(SegmentFunction segmentFunction, 367 UInt64 *offsetP, 368 void *segmentsP, 369 UInt32 *numSegmentsP); 370 371 virtual void free(); 372 373private: 374 typedef IOReturn (*InternalSegmentFunction)( 375 void *reference, 376 IODMACommand *target, 377 Segment64 segment, 378 void *segments, 379 UInt32 segmentIndex); 380 381 IOReturn genIOVMSegments(uint32_t op, 382 InternalSegmentFunction outSegFunc, 383 void *reference, 384 UInt64 *offsetP, 385 void *segmentsP, 386 UInt32 *numSegmentsP); 387 388 static IOReturn clientOutputSegment( 389 void *reference, IODMACommand *target, 390 Segment64 segment, void *vSegList, UInt32 outSegIndex); 391 392 static IOReturn segmentOp( 393 void *reference, 394 IODMACommand *target, 395 Segment64 segment, 396 void *segments, 397 UInt32 segmentIndex); 398 IOReturn walkAll(UInt8 op); 399 400public: 401 402/*! @function prepareWithSpecification 403 @abstract Prepare the memory for an I/O transfer with a new specification. 404 @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. 405 @param outSegFunc SegmentFunction to call to output one physical segment. A set of nine commonly required segment functions are provided. 406 @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. 407 @param maxSegmentSize Maximum allowable size for one segment. Defaults to 0 which means any size. 408 @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. 409 @param maxTransferSize Maximum size of an entire transfer. Defaults to 0 indicating no maximum. 410 @param alignment Alignment restriction, in bytes, on I/O bus addresses. Defaults to single byte alignment. 411 @param mapper For mapping types kMapped & kBypassed mapper is used to define the hardware that will perform the mapping, defaults to the system mapper. 412 @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. 413 @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. 414 @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. 415 @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. 416 @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. 417*/ 418 419 virtual IOReturn prepareWithSpecification(SegmentFunction outSegFunc, 420 UInt8 numAddressBits, 421 UInt64 maxSegmentSize, 422 MappingOptions mappingOptions = kMapped, 423 UInt64 maxTransferSize = 0, 424 UInt32 alignment = 1, 425 IOMapper *mapper = 0, 426 UInt64 offset = 0, 427 UInt64 length = 0, 428 bool flushCache = true, 429 bool synchronize = true); 430 431 static IOReturn transferSegment( 432 void *reference, 433 IODMACommand *target, 434 Segment64 segment, 435 void *segments, 436 UInt32 segmentIndex); 437 438/*! @function getPreparedOffsetAndLength 439 @abstract Returns the offset and length into the target IOMemoryDescriptor of a prepared IODDMACommand. 440 @discussion If successfully prepared, returns the offset and length into the IOMemoryDescriptor. Will fail for an unprepared IODMACommand. 441 @param offset returns the starting offset in the memory descriptor the DMA command was prepared with. Pass NULL for don't care. 442 @param length returns the length in the memory descriptor the DMA command was prepared with. Pass NULL for don't care. 443 @result An IOReturn code. kIOReturnNotReady if the IODMACommand is not prepared. */ 444 445 virtual IOReturn getPreparedOffsetAndLength(UInt64 * offset, UInt64 * length); 446 447 UInt8 getNumAddressBits(void); 448 UInt32 getAlignment(void); 449 450private: 451 OSMetaClassDeclareReservedUsed(IODMACommand, 0); 452 OSMetaClassDeclareReservedUsed(IODMACommand, 1); 453 OSMetaClassDeclareReservedUsed(IODMACommand, 2); 454 OSMetaClassDeclareReservedUnused(IODMACommand, 3); 455 OSMetaClassDeclareReservedUnused(IODMACommand, 4); 456 OSMetaClassDeclareReservedUnused(IODMACommand, 5); 457 OSMetaClassDeclareReservedUnused(IODMACommand, 6); 458 OSMetaClassDeclareReservedUnused(IODMACommand, 7); 459 OSMetaClassDeclareReservedUnused(IODMACommand, 8); 460 OSMetaClassDeclareReservedUnused(IODMACommand, 9); 461 OSMetaClassDeclareReservedUnused(IODMACommand, 10); 462 OSMetaClassDeclareReservedUnused(IODMACommand, 11); 463 OSMetaClassDeclareReservedUnused(IODMACommand, 12); 464 OSMetaClassDeclareReservedUnused(IODMACommand, 13); 465 OSMetaClassDeclareReservedUnused(IODMACommand, 14); 466 OSMetaClassDeclareReservedUnused(IODMACommand, 15); 467 468public: 469/*! @var fRefCon Reference Constant, client defined publicly avialable */ 470 void *fRefCon; 471 472protected: 473 474/*! @var fMaxSegmentSize Maximum size of one segment in a scatter/gather list */ 475 UInt64 fMaxSegmentSize; 476 477/*! @var fMaxTransferSize 478 Maximum size of a transfer that this memory cursor is allowed to generate */ 479 UInt64 fMaxTransferSize; 480 481/*! @var fBypassMask 482 Mask to be ored into the address to bypass the given iommu's mapping. */ 483 UInt64 fBypassMask; 484 485/*! @var fMapper 486 Client defined mapper. */ 487 IOMapper *fMapper; 488 489/*! @var fMemory 490 memory descriptor for current I/O. */ 491 const IOMemoryDescriptor *fMemory; 492 493/*! @var fOutSeg The action method called when an event has been delivered */ 494 SegmentFunction fOutSeg; 495 496/*! @var fAlignMask 497 Alignment restriction mask. */ 498 UInt32 fAlignMask; 499 500/*! @var fNumAddressBits 501 Number of bits that the hardware can address */ 502 UInt32 fNumAddressBits; 503 504/*! @var fNumSegments 505 Number of contiguous segments required for the current memory descriptor and desired mapping */ 506 UInt32 fNumSegments; 507 508/*! @var fMappingOptions 509 What type of I/O virtual address mapping is required for this command */ 510 MappingOptions fMappingOptions; 511 512/*! @var fActive 513 fActive indicates that this DMA command is currently prepared and ready to go */ 514 UInt32 fActive; 515 516/*! @var reserved 517 Reserved for future use. (Internal use only) */ 518 struct IODMACommandInternal * reserved; 519}; 520 521IOReturn IODMACommand:: 522weakWithSpecification(IODMACommand **newCommand, 523 SegmentFunction outSegFunc, 524 UInt8 numAddressBits, 525 UInt64 maxSegmentSize, 526 MappingOptions mapType, 527 UInt64 maxTransferSize, 528 UInt32 alignment, 529 IOMapper *mapper, 530 void *refCon) 531{ 532 if (!newCommand) 533 return kIOReturnBadArgument; 534 535 IODMACommand *self = (IODMACommand *) 536 OSMetaClass::allocClassWithName("IODMACommand"); 537 if (!self) 538 return kIOReturnUnsupported; 539 540 IOReturn ret; 541 bool inited = self-> 542 initWithSpecification(outSegFunc, 543 numAddressBits, maxSegmentSize, mapType, 544 maxTransferSize, alignment, mapper, refCon); 545 if (inited) 546 ret = kIOReturnSuccess; 547 else { 548 self->release(); 549 self = 0; 550 ret = kIOReturnError; 551 } 552 553 *newCommand = self; 554 return ret; 555}; 556#endif /* !_IODMACOMMAND_H */ 557 558