1/* 2 * Copyright (c) 1998-2010 Apple Computer, Inc. All rights reserved. 3 * 4 * @APPLE_LICENSE_HEADER_START@ 5 * 6 * The contents of this file constitute Original Code as defined in and 7 * are subject to the Apple Public Source License Version 1.1 (the 8 * "License"). You may not use this file except in compliance with the 9 * License. Please obtain a copy of the License at 10 * http://www.apple.com/publicsource and read it before using this file. 11 * 12 * This Original Code and all software distributed under the License are 13 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER 14 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 15 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 16 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the 17 * License for the specific language governing rights and limitations 18 * under the License. 19 * 20 * @APPLE_LICENSE_HEADER_END@ 21 */ 22 23/*! 24 * @header IOAudioEngine 25 */ 26 27#ifndef _IOKIT_IOAUDIOENGINE_H 28#define _IOKIT_IOAUDIOENGINE_H 29 30#include <IOKit/IOService.h> 31 32#ifndef IOAUDIOFAMILY_SELF_BUILD 33#include <IOKit/audio/IOAudioTypes.h> 34#else 35#include "IOAudioTypes.h" 36#endif 37#include <IOKit/IOBufferMemoryDescriptor.h> 38 39class OSDictionary; 40class OSCollection; 41class OSOrderedSet; 42class IOAudioEngineUserClient; 43class IOAudioDevice; 44class IOAudioStream; 45class IOAudioControl; 46class IOCommandGate; 47 48#define IOAUDIOENGINE_DEFAULT_NUM_ERASES_PER_BUFFER 4 49 50/*! 51 * @typedef IOAudioEnginePosition 52 * @abstract Represents a position in an audio audio engine. 53 * @discussion This position is based on the sample frame within a 54 * loop around the sample buffer, and the loop count which starts at 0 when the audio engine 55 * begins playback. 56 * @field fSampleFrame The sample frame within the buffer - starts at 0. 57 * @field fLoopCount The number of times the ring buffer has looped. 58 */ 59typedef struct { 60 UInt32 fSampleFrame; 61 UInt32 fLoopCount; 62} IOAudioEnginePosition; 63 64#define CMP_IOAUDIOENGINEPOSITION(p1, p2) \ 65 (((p1)->fLoopCount > (p2)->fLoopCount) ? 1 : \ 66 ((p1)->fLoopCount == (p2)->fLoopCount) && ((p1)->fSampleFrame > (p2)->fSampleFrame) ? 1 : \ 67 ((p1)->fLoopCount == (p2)->fLoopCount) && ((p1)->fSampleFrame == (p2)->fSampleFrame) ? 0 : -1) 68 69#define IOAUDIOENGINEPOSITION_IS_ZERO(p1) (((p1)->fLoopCount == 0) && ((p1)->fSampleFrame == 0)) 70 71/*! 72 * @class IOAudioEngine 73 * @abstract Abstract base class for a single audio audio / I/O engine. 74 * @discussion An IOAudioEngine is defined by a single I/O engine to transfer data to 75 * or from one or more sample buffers. Each sample buffer is represented by a single IOAudioStream 76 * instance. A single IOAudioEngine must contain at least one IOAudioStream, but has no upper 77 * limit on the number of IOAudioStreams it may contain. An IOAudioEngine instance may contain 78 * both input and output IOAudioStreams. 79 * 80 * An audio driver must subclass IOAudioEngine in order to provide certain services. An 81 * IOAudioEngine subclass must start and stop the I/O engine when requested. The I/O 82 * engine should be continuously running and loop around from end to beginning. While the audio 83 * engine is running, it must take a timestamp as the sample buffer(s) wrap around and start at 84 * the beginning. The CoreAudio.framework uses the timestamp to calculate the exact position of 85 * the audio engine. An IOAudioEngine subclass must implement getCurrentSampleFrame() to provide 86 * a sample position on demand. Finally, an IOAudioEngine subclass must provide clipping and 87 * format conversion routines to go to/from the CoreAudio.framework's native float format. 88 * 89 * If multiple stream formats or sample rates are allowed, the IOAudioEngine 90 * subclass must provide support for changing the hardware when a format or sample rate is 91 * changed. 92 * 93 * There are several attributes associated with a single IOAudioEngine: 94 * 95 * The IOAudioEngine superclass provides a shared status buffer that contains all of the dynamic pieces 96 * of information about the audio engine (type IOAudioEngineStatus). It runs an erase process on 97 * all of the output streams. The erase head is used to zero out the mix and sample buffers after 98 * the samples have been played. Additionally, the IOAudioEngine superclass handles the 99 * communication with the CoreAudio.framework and makes the decision to start and stop the 100 * audio engine when it detects it is in use. 101 * 102 * In order for an audio device to play back or record sound, an IOAudioEngine subclass must be created. 103 * The subclass must initialize all of the necessary hardware resources to prepare for starting the 104 * audio I/O engine. It typically will perform these tasks in the initHardware() method. A subclass 105 * may also implement a stop() method which is called as the driver is being torn down. This is 106 * typically called in preparation of removing the device from the system for removable devices. 107 * 108 * In addition to initializing the necessary hardware, there are a number of other tasks an 109 * IOAudioEngine must do during initHardware(). It must create the necessary IOAudioStream objects 110 * to match the device capabilities. Each IOAudioStream must be added using addAudioStream(). It 111 * also should create the IOAudioControls needed to control the various attributes of the audio engine: 112 * output volume, mute, input gain, input selection, analog passthru. To do that, addDefaultAudioControl() 113 * should be called with each IOAudioControl to be attached to the IOAudioEngine. In order to provide 114 * for proper synchronization, the latency of the audio engine should be specified with setSampleLatency(). 115 * This value represents the latency between the timestamp taken at the beginning of the buffer and 116 * when the audio is actually played (or recorded) by the device. If a device is block based or if 117 * there is a need to keep the CoreAudio.framework a certain number of samples ahead of (or behind for 118 * input) the I/O head, that value should be specified using setSampleOffset(). If this is not specified 119 * the CoreAudio.framework may attempt to get as close to the I/O head as possible. 120 * 121 * The following fields in the shared IOAudioEngineStatus struct must be maintained by the subclass 122 * implementation: 123 * <pre> 124 * <t> fCurrentLoopCount - the number of times the sample buffer has wrapped around to the beginning 125 * <t> fLastLoopTime - timestamp of the most recent time that the I/O engine looped back to the 126 * beginning of the sample buffer 127 * </pre> 128 * It is critically important that the fLastLoopTime field be as accurate as possible. It is 129 * the basis for the entire timer and synchronization mechanism used by the audio system. 130 * 131 * At init time, the IOAudioEngine subclass must call setNumSampleFramesPerBuffer() to indicate how large 132 * each of the sample buffers are (measured in sample frames). Within a single IOAudioEngine, all sample 133 * buffers must be the same size and be running at the same sample rate. If different buffers/streams can 134 * be run at different rates, separate IOAudioEngines should be used. The IOAudioEngine subclass must 135 * also call setSampleRate() at init time to indicate the starting sample rate of the device. 136 * 137 */ 138 139class IOAudioEngine : public IOService 140{ 141 OSDeclareAbstractStructors(IOAudioEngine) 142 143 friend class IOAudioEngineUserClient; 144 friend class IOAudioDevice; 145 friend class IOAudioStream; 146 147public: 148 /*! @var gSampleRateWholeNumberKey */ 149 static const OSSymbol *gSampleRateWholeNumberKey; 150 /*! @var gSampleRateFractionKey */ 151 static const OSSymbol *gSampleRateFractionKey; 152 153 /*! @var numSampleFramesPerBuffer */ 154 UInt32 numSampleFramesPerBuffer; 155 156 /*! @var sampleRate 157 * The current sample rate of the audio engine in samples per second. */ 158 IOAudioSampleRate sampleRate; 159 160 /*! @var numErasesPerBuffer 161 * The number of times the erase head get scheduled to run for each 162 * cycle of the audio engine. */ 163 UInt32 numErasesPerBuffer; 164 /*! @var runEraseHead 165 * Set to true if the erase head is to run when the audio engine is running. This is the case if there are any output streams. */ 166 bool runEraseHead; 167 168 /*! @var audioEngineStopPosition 169 * When all clients have disconnected, this is set to one buffer length past the 170 * current audio engine position at the time. Then when the stop position is reached, the audio engine 171 * is stopped */ 172 IOAudioEnginePosition audioEngineStopPosition; 173 174 /*! @var isRegistered 175 * Internal state variable to keep track or whether registerService() has been called. */ 176 bool isRegistered; 177 /*! @var configurationChangeInProgress 178 * Set to true after beginConfigurationChange() and false upon a 179 * subsequent call to completeConfigurationChange() or cancelConfigurationChange(). */ 180 bool configurationChangeInProgress; 181 182 /*! @var state 183 * The current state of the IOAudioEngine - running, stopped, paused. */ 184 IOAudioEngineState state; 185 186 /*! @var status 187 * Status struct shared with the CoreAudio.framework. */ 188 IOAudioEngineStatus * status; 189 190 /*! @var audioDevice 191 * The IOAudioDevice instance to which the IOAudioEngine belongs. */ 192 IOAudioDevice * audioDevice; 193 194 /*! @var workLoop 195 * The IOWorkLoop for the audio driver - shared with the IOAudioDevice. */ 196 IOWorkLoop *workLoop; 197 /*! @var commandGate 198 * The IOCommandGate for this audio engine - attached to the driver's IOWorkLoop. */ 199 IOCommandGate *commandGate; 200 201 /*! @var inputStreams 202 * An OSSet of all of the input IOAudioStreams attached to this IOAudioEngine. */ 203 OSOrderedSet *inputStreams; 204 UInt32 maxNumInputChannels; 205 /*! @var outputStreams 206 * An OSSet of all of the output IOAudioStreams attached to this IOAudioEngine. */ 207 OSOrderedSet *outputStreams; 208 UInt32 maxNumOutputChannels; 209 /*! @var userClients 210 * An OSSet of all of the currently connected user clients. */ 211 OSSet *userClients; 212 /*! @var defaultAudioControls 213 * All of the IOAudioControls that affect this audio engine. */ 214 OSSet *defaultAudioControls; 215 216 /*! @var numActiveUserClients 217 * A total of the active user clients - those that are currently playing or 218 * recording audio. */ 219 UInt32 numActiveUserClients; 220 UInt32 sampleOffset; // used for input and output if inputSampleOffset is not set, if inputSampleOffset is set used as output only 221 222 UInt32 index; 223 bool duringStartup; 224 225protected: 226 227 /*! 228 * @var deviceStartedAudioEngine 229 * Used by the IOAudioDevice to determine responsibility for shutting 230 * the audio engine down when it is no longer needed. 231 */ 232 bool deviceStartedAudioEngine; 233 234protected: 235 struct ExpansionData { 236 UInt32 pauseCount; 237 IOBufferMemoryDescriptor *statusDescriptor; 238 IOBufferMemoryDescriptor *bytesInInputBufferArrayDescriptor; 239 IOBufferMemoryDescriptor *bytesInOutputBufferArrayDescriptor; 240 UInt32 mixClipOverhead; 241 OSArray *streams; 242 UInt32 inputSampleOffset; 243 UInt32 commandGateStatus; // <rdar://8518215> 244 SInt32 commandGateUsage; // <rdar://8518215> 245 }; 246 247 ExpansionData *reserved; 248 249// static UInt32 sInstanceCount; 250 251public: 252 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 0); 253 virtual IOReturn performFormatChange(IOAudioStream *audioStream, const IOAudioStreamFormat *newFormat, const IOAudioStreamFormatExtension *formatExtension, const IOAudioSampleRate *newSampleRate); 254 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 1); 255 virtual IOBufferMemoryDescriptor * getStatusDescriptor(); 256 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 2); 257 virtual IOReturn getNearestStartTime(IOAudioStream *audioStream, IOAudioTimeStamp *ioTimeStamp, bool isInput); 258 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 3); 259 virtual IOBufferMemoryDescriptor * getBytesInInputBufferArrayDescriptor(); 260 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 4); 261 virtual IOBufferMemoryDescriptor * getBytesInOutputBufferArrayDescriptor(); 262 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 5); 263 /*! 264 * @function eraseOutputSamples 265 * @abstract This function allows for the actual erasing of the mix and sample buffer to be overridden by 266 * a child class. 267 * @param mixBuf Pointer to the IOAudioFamily allocated mix buffer. 268 * @param sampleBuf Pointer to the child class' sample buffer. 269 * @param firstSampleFrame Index to the first sample frame to erase. 270 * @param numSampleFrames Number of sample frames to erase. 271 * @param streamFormat Format of the data to be erased. 272 * @param audioStream Pointer to stream object that corresponds to the sample buffer being erased. 273 * @result Must return kIOReturnSuccess if the samples have been erased. 274 */ 275 virtual IOReturn eraseOutputSamples(const void *mixBuf, void *sampleBuf, UInt32 firstSampleFrame, UInt32 numSampleFrames, const IOAudioStreamFormat *streamFormat, IOAudioStream *audioStream); 276 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 6); 277 /*! 278 * @function setClockIsStable 279 * @abstract This function sets a flag that CoreAudio uses to select its sample rate tracking algorithm. Set 280 * this to TRUE unless that results in dropped audio. If the driver is experiencing unexplained dropouts 281 * setting this FALSE might help. 282 * @param clockIsStable TRUE tells CoreAudio to use an agressive PLL to quickly lock to the engine's sample rate 283 * while FALSE tells CoreAudio to adjust more slowly to perceived sample rate changes that might just be the 284 * result of an unstable clock. 285 */ 286 virtual void setClockIsStable(bool clockIsStable); 287 288 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 7); 289 /*! 290 * @function setMixClipOverhead 291 * @abstract Used to tell IOAudioFamily when the watchdog timer must fire by. 292 * @discussion setMixClipOverhead allows an audio engine to tell IOAudioFamily how much time 293 * an engine will take to mix and clip its samples, in percent. 294 * The default value is 10, meaning 10%. This will cause IOAudioFamily to make 295 * the watchdog timer fire when there is just over 10% of the time to complete 296 * a buffer set left (e.g. 51 samples when the HAL is using a buffer size of 512 297 * samples). 298 * @param newMixClipOverhead How much time per buffer should be made available for the 299 * mix and clip routines to run. Valid values are 1 through 99, inclusive. 300 * @result return no error 301 */ 302 virtual void setMixClipOverhead(UInt32 newMixClipOverhead); 303 304 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 8); 305 /*! 306 * @function setClockDomain 307 * @abstract Sets a property that CoreAudio uses to determine how devices are synchronized. If an audio device can tell that it is 308 * synchronized to another engine, it should set this value to that engine's clock domain. If an audio device can be a clock master, it may publish 309 * its own clock domain for other devices to use. 310 * @param clockDomain is the unique ID of another engine that this engine realizes it is synchronized to, use the default value kIOAudioNewClockDomain 311 * to have IOAudioEngine create a unique clock domain. 312 */ 313 virtual void setClockDomain(UInt32 clockDomain = kIOAudioNewClockDomain); 314 315 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 9); 316 /*! 317 * @function convertInputSamplesVBR 318 * @abstract Override this method if you want to return a different number of sample frames than was requested. 319 */ 320 virtual IOReturn convertInputSamplesVBR(const void *sampleBuf, void *destBuf, UInt32 firstSampleFrame, UInt32 &numSampleFrames, const IOAudioStreamFormat *streamFormat, IOAudioStream *audioStream); 321 322 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 10); 323 /*! 324 * @function setInputSampleOffset 325 * @abstract set the offset CoreAudio will read from off the current read pointer 326 * @param numSamples size of offset in sample 327 */ 328 virtual void setInputSampleOffset(UInt32 numSamples); 329 330 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 11); 331 /*! 332 * @function setOutputSampleOffset 333 * @abstract set the offset CoreAudio will write at off the current write pointer 334 * @param numSamples size of offset in sample 335 */ 336 virtual void setOutputSampleOffset(UInt32 numSamples); 337 338protected: 339 340 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 12); 341 virtual IOReturn createUserClient(task_t task, void *securityID, UInt32 type, IOAudioEngineUserClient **newUserClient, OSDictionary *properties); 342 343public: 344 345 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 13); 346 /*! 347 * @function setAttributeForConnection 348 * @abstract Generic method to set some attribute of the audio engine, specific to one connection. 349 * @discussion IOAudioEngine subclasses may implement this method to allow arbitrary attribute/value pairs to be set, specific to one connection. 350 * @param attribute Defines the attribute to be set. 351 * @param value The new value for the attribute. 352 * @result an IOReturn code. 353 */ 354 355 virtual IOReturn setAttributeForConnection( SInt32 connectIndex, UInt32 attribute, uintptr_t value ); 356 357 // OSMetaClassDeclareReservedUsed(IOAudioEngine, 14); 358 /*! @function getAttributeForConnection 359 * @abstract Generic method to retrieve some attribute of the audio engine, specific to one connection. 360 * @discussion IOAudioEngine subclasses may implement this method to allow arbitrary attribute/value pairs to be returned, specific to one connection. 361 * @param attribute Defines the attribute to be returned. Some defined attributes are:<br> 362 * @param value Returns the value for the attribute. 363 * @result an IOReturn code. 364 */ 365 366 virtual IOReturn getAttributeForConnection( SInt32 connectIndex, UInt32 attribute, uintptr_t * value ); 367 368private: 369 OSMetaClassDeclareReservedUsed(IOAudioEngine, 0); 370 OSMetaClassDeclareReservedUsed(IOAudioEngine, 1); 371 OSMetaClassDeclareReservedUsed(IOAudioEngine, 2); 372 OSMetaClassDeclareReservedUsed(IOAudioEngine, 3); 373 OSMetaClassDeclareReservedUsed(IOAudioEngine, 4); 374 OSMetaClassDeclareReservedUsed(IOAudioEngine, 5); 375 OSMetaClassDeclareReservedUsed(IOAudioEngine, 6); 376 OSMetaClassDeclareReservedUsed(IOAudioEngine, 7); 377 OSMetaClassDeclareReservedUsed(IOAudioEngine, 8); 378 OSMetaClassDeclareReservedUsed(IOAudioEngine, 9); 379 OSMetaClassDeclareReservedUsed(IOAudioEngine, 10); 380 OSMetaClassDeclareReservedUsed(IOAudioEngine, 11); 381 OSMetaClassDeclareReservedUsed(IOAudioEngine, 12); 382 OSMetaClassDeclareReservedUsed(IOAudioEngine, 13); 383 OSMetaClassDeclareReservedUsed(IOAudioEngine, 14); 384 385 OSMetaClassDeclareReservedUnused(IOAudioEngine, 15); 386 OSMetaClassDeclareReservedUnused(IOAudioEngine, 16); 387 OSMetaClassDeclareReservedUnused(IOAudioEngine, 17); 388 OSMetaClassDeclareReservedUnused(IOAudioEngine, 18); 389 OSMetaClassDeclareReservedUnused(IOAudioEngine, 19); 390 OSMetaClassDeclareReservedUnused(IOAudioEngine, 20); 391 OSMetaClassDeclareReservedUnused(IOAudioEngine, 21); 392 OSMetaClassDeclareReservedUnused(IOAudioEngine, 22); 393 OSMetaClassDeclareReservedUnused(IOAudioEngine, 23); 394 OSMetaClassDeclareReservedUnused(IOAudioEngine, 24); 395 OSMetaClassDeclareReservedUnused(IOAudioEngine, 25); 396 OSMetaClassDeclareReservedUnused(IOAudioEngine, 26); 397 OSMetaClassDeclareReservedUnused(IOAudioEngine, 27); 398 OSMetaClassDeclareReservedUnused(IOAudioEngine, 28); 399 OSMetaClassDeclareReservedUnused(IOAudioEngine, 29); 400 OSMetaClassDeclareReservedUnused(IOAudioEngine, 30); 401 OSMetaClassDeclareReservedUnused(IOAudioEngine, 31); 402 OSMetaClassDeclareReservedUnused(IOAudioEngine, 32); 403 OSMetaClassDeclareReservedUnused(IOAudioEngine, 33); 404 OSMetaClassDeclareReservedUnused(IOAudioEngine, 34); 405 OSMetaClassDeclareReservedUnused(IOAudioEngine, 35); 406 OSMetaClassDeclareReservedUnused(IOAudioEngine, 36); 407 OSMetaClassDeclareReservedUnused(IOAudioEngine, 37); 408 OSMetaClassDeclareReservedUnused(IOAudioEngine, 38); 409 OSMetaClassDeclareReservedUnused(IOAudioEngine, 39); 410 OSMetaClassDeclareReservedUnused(IOAudioEngine, 40); 411 OSMetaClassDeclareReservedUnused(IOAudioEngine, 41); 412 OSMetaClassDeclareReservedUnused(IOAudioEngine, 42); 413 OSMetaClassDeclareReservedUnused(IOAudioEngine, 43); 414 OSMetaClassDeclareReservedUnused(IOAudioEngine, 44); 415 OSMetaClassDeclareReservedUnused(IOAudioEngine, 45); 416 OSMetaClassDeclareReservedUnused(IOAudioEngine, 46); 417 OSMetaClassDeclareReservedUnused(IOAudioEngine, 47); 418 419public: 420 /*! 421 * @function createDictionaryFromSampleRate 422 * @abstract Generates a dictionary matching the given sample rate. 423 * @discussion This is an internal routine used to generate a dictionary matching the given sample rate. It is used to generate a sample rate dictionary for the I/O Registry - used by the 424 * CoreAudio.framework. 425 * @result Returns the newly create OSDictionary. 426 */ 427 static OSDictionary *createDictionaryFromSampleRate(const IOAudioSampleRate *sampleRate, OSDictionary *rateDict = 0); 428 429 /*! 430 * @function createSampleRateFromDictionary 431 * @abstract Generates a sample rate from an OSDictionary. 432 * @discussion This is an internal routine used to generate a sample rate from an OSDictionary. It is used to generate a sample rate give a new OSDictionary from the IORegistry - coming 433 * from the CoreAudio.framework. 434 * @result Returns the sample rate. 435 */ 436 static IOAudioSampleRate *createSampleRateFromDictionary(const OSDictionary *rateDict, IOAudioSampleRate *sampleRate = 0); 437 438 /*! 439 * @function init 440 * @abstract Performs initialization of a newly allocated IOAudioEngine. 441 * @discussion This function is responsible for initialization of all of the general attributes of 442 * a new IOAudioEngine. It initializes instance variables to their default 443 * values and allocates the shared status buffer. Subclasses will likely want to override this method 444 * and do all of their common initialization in their implementation. They do need to be sure to call 445 * IOAudioEngine's implementation of init and pay attention to the return value. 446 * @param properties The default properties for the IOAudioEngine. 447 * @result Returns true if initialization was successful. 448 */ 449 virtual bool init(OSDictionary *properties); 450 451 /*! 452 * @function free 453 * @abstract Frees all of the resources allocated by the IOAudioEngine. 454 * @discussion Do not call this directly. This is called automatically by the system when the instance's 455 * refcount goes to 0. To decrement the refcount, call release() on the object. 456 */ 457 virtual void free(); 458 459 /*! 460 * @function getWorkLoop 461 * @abstract Returns the IOWorkLoop for the driver. 462 */ 463 virtual IOWorkLoop *getWorkLoop() const; 464 465 /*! 466 * @function getCommandGate 467 * @abstract Returns the IOCommandGate for this IOAudioEngine. 468 */ 469 virtual IOCommandGate *getCommandGate() const; 470 471 /*! 472 * @function start 473 * @abstract A simple cover function for start(IOService *, IOAudioDevice *) that assumes the provider 474 * is the IOAudioDevice. 475 * @discussion Subclasses will want to override start(IOService *, IOAudioDevice *) rather than this 476 * one. 477 * @param provider The service provider for the IOAudioEngine (the IOAudioDevice in this case). 478 * @result Returns true if the IOAudioEngine was successfully started. 479 */ 480 virtual bool start(IOService *provider); 481 482 /*! 483 * @function start 484 * @abstract Standard IOKit start() routine called to start an IOService. 485 * @discussion This function is called in order to prepare the IOAudioEngine for use. It does NOT 486 * mean that the audio I/O engine itself should be started. This implementation gets the IOWorkLoop 487 * from the IOAudioDevice and allocates an IOCommandGate. Finally it calls initHardware() in which 488 * all of the subclass-specific device initialization should be done. Upon return from initHardware() 489 * all IOAudioStreams should be created and added to the audio engine. Also, all IOAudioControls 490 * for this IOAudioEngine should be created and attached. 491 * @param provider The service provider for the IOAudioEngine. 492 * @param device The IOAudioDevice to which this IOAudioEngine belongs. 493 * @result Returns true if the service was successfully started. 494 */ 495 virtual bool start(IOService *provider, IOAudioDevice *device); 496 497 /*! 498 * @function initHardware 499 * @abstract This function is called by start() to provide a convenient place for the subclass to 500 * perform its hardware initialization. 501 * @discussion Upon return from this function, all IOAudioStreams and IOAudioControls should be created 502 * and the audio engine should be ready to be started when a client requests that playback begin. 503 * @function provider The service provider numb for this audio engine - typically the IOAudioDevice. 504 * @result Returns true if the hardware was successfully initialized. 505 */ 506 virtual bool initHardware(IOService *provider); 507 508 /*! 509 * @function stop 510 * @abstract Stops the service and prepares for the driver to be terminated. 511 * @discussion This function is called before the driver is terminated and usually means that the device 512 * has been removed from the system. 513 * @param provider The service provider for the IOAudioEngine. 514 */ 515 virtual void stop(IOService *provider); 516 517 /*! 518 * @function registerService 519 * @abstract Called when this audio engine is ready to begin vending services. 520 * @discussion This function is called by IOAudioDevice::activateAudioEngine() once the audio engine 521 * has been fully initialized and is ready to begin audio playback. 522 * @param options 523 */ 524 virtual void registerService(IOOptionBits options = 0); 525 526 virtual void setAudioDevice(IOAudioDevice *device); 527 virtual void setIndex(UInt32 index); 528 529 virtual void setDescription(const char *description); 530 531 /*! 532 * @function newUserClient 533 * @abstract Requests a new user client object for this service. 534 * @discussion This function is called automatically by I/O Kit when a user process attempts 535 * to connect to this service. It allocates a new IOAudioEngineUserClient object and increments 536 * the number of connections for this audio engine. If this is the first user client for this IOAudioEngine, 537 * it calls startAudioEngine(). There is no need to call this function directly. 538 * A derived class that requires overriding of newUserClient should override the version with the properties 539 * parameter for Intel targets, and without the properties parameter for PPC targets. The #if __i386__ directive 540 * can be used to select between the two behaviors. 541 * @param task The task requesting the new user client. 542 * @param securityID Optional security paramater passed in by the client - ignored. 543 * @param type Optional user client type passed in by the client - ignored. 544 * @param handler The new IOUserClient * must be stored in this param on a successful completion. 545 * @param properties A dictionary of additional properties for the connection. 546 * @result Returns kIOReturnSuccess on success. May also result kIOReturnError or kIOReturnNoMemory. 547 */ 548 virtual IOReturn newUserClient(task_t task, void *securityID, UInt32 type, IOUserClient **handler); 549 virtual IOReturn newUserClient(task_t task, void *securityID, UInt32 type, OSDictionary *properties, IOUserClient **handler); 550 551 /*! 552 * @function addAudioStream 553 * @abstract Adds an IOAudioStream to the audio engine. 554 * @discussion This function is called by the driver to add an IOAudioStream to the audio engine. This must be called at least once to make sure the audio engine has at least one IOAudioStream. 555 * @param stream The IOAudioStream to be added. 556 * @result Returns kIOReturnSuccess if the stream was successfully added. 557 */ 558 virtual IOReturn addAudioStream(IOAudioStream *stream); 559 560 virtual IOAudioStream *getAudioStream(IOAudioStreamDirection direction, UInt32 channelID); 561 562 virtual void lockAllStreams(); 563 virtual void unlockAllStreams(); 564 565 virtual void updateChannelNumbers(); 566 567 /*! 568 * @function resetStatusBuffer 569 * @abstract Resets the status buffer to its default values. 570 * @discussion This is called during startAudioEngine() and resumeAudioEngine() to clear out the status buffer 571 * in preparation of starting up the I/O engine. There is no need to call this directly. 572 */ 573 virtual void resetStatusBuffer(); 574 575 /*! 576 * @function clearAllSampleBuffers 577 * @abstract Zeros out all of the sample and mix buffers associated with the IOAudioEngine 578 * @discussion This is called during resumeAudioEngine() since the audio engine gets started back at the 579 * beginning of the sample buffer. 580 */ 581 virtual void clearAllSampleBuffers(); 582 583 /*! 584 * @function getCurrentSampleFrame 585 * @abstract Gets the current sample frame from the IOAudioEngine subclass. 586 * @result 587 */ 588 virtual UInt32 getCurrentSampleFrame() = 0; 589 590 /*! 591 * @function startAudioEngine 592 * @abstract Starts the audio I/O engine. 593 * @discussion This method is called automatically when the audio engine is placed into use the first time. 594 * This must be overridden by the subclass. No call to the superclass's implementation is 595 * necessary. The subclass's implementation must start up the audio I/O engine. This includes any audio 596 * engine that needs to be started as well as any interrupts that need to be enabled. Upon successfully 597 * starting the engine, the subclass's implementation must call setState(kIOAudioEngineRunning). If 598 * it has also checked the state using getState() earlier in the implementation, the stateLock must be 599 * acquired for the entire initialization process (using IORecursiveLockLock(stateLock) and 600 * IORecursiveLockUnlock(stateLock)) to ensure that the state remains consistent. See the general class 601 * comments for an example. 602 * @result Must return kIOReturnSuccess on a successful start of the engine. 603 */ 604 virtual IOReturn startAudioEngine(); 605 606 /*! 607 * @function stopAudioEngine 608 * @abstract Stops the audio I/O engine. 609 * @discussion This method is called automatically when the last client disconnects from this audio engine. 610 * It must be overridden by the subclass. No call to the superclass's implementation is necessary. 611 * The subclass's implementation must stop the audio I/O engine. The audio engine (if it exists) should 612 * be stopped and any interrupts disabled. Upon successfully stopping the engine, the subclass must call 613 * setState(kAudioEngineStopped). If it has also checked the state using getState() earlier in the 614 * implementation, the stateLock must be acquired for the entire initialization process (using 615 * IORecursiveLockLock(stateLock) and IORecursiveLockUnlock(stateLock)) to ensure that the state remains 616 * consistent. 617 * @result Must return kIOReturnSuccess on a successful stop of the engine. 618 */ 619 virtual IOReturn stopAudioEngine(); 620 virtual IOReturn pauseAudioEngine(); 621 virtual IOReturn resumeAudioEngine(); 622 623 /*! 624 * @function performAudioEngineStart 625 * @abstract Called to start the audio I/O engine 626 * @discussion This method is called by startAudioEngine(). This must be overridden by the subclass. 627 * No call to the superclass' implementation is necessary. The subclass' implementation must start up the 628 * audio I/O engine. This includes any audio engine that needs to be started as well as any interrupts 629 * that need to be enabled. 630 * @result Must return kIOReturnSuccess on a successful start of the engine. 631 */ 632 virtual IOReturn performAudioEngineStart(); 633 634 /*! 635 * @function performAudioEngineStop 636 * @abstract Called to stop the audio I/O engine 637 * @discussion This method is called by stopAudioEngine() and pauseAudioEngine. 638 * This must be overridden by the subclass. No call to the superclass' implementation is 639 * necessary. The subclass' implementation must stop the audio I/O engine. This includes any audio 640 * engine that needs to be stopped as well as any interrupts that need to be disabled. 641 * @result Must return kIOReturnSuccess on a successful stop of the engine. 642 */ 643 virtual IOReturn performAudioEngineStop(); 644 645 /*! 646 * @function getState 647 * @abstract Returns the current state of the IOAudioEngine. 648 * @discussion If this method is called in preparation for calling setState(), the stateLock must 649 * be acquired before the first call to getState() and held until after the last call to setState(). 650 * Be careful not to return from the code acquiring the lock while the lock is being held. That 651 * will cause a deadlock situation. 652 * @result The current state of the IOAudioEngine: kIOAudioEngineRunning, kIOAudioEngineStopped. 653 */ 654 virtual IOAudioEngineState getState(); 655 656 /*! 657 * @function getSampleRate 658 * @abstract Returns the sample rate of the IOAudioEngine in samples per second. 659 */ 660 virtual const IOAudioSampleRate *getSampleRate(); 661 662 virtual IOReturn hardwareSampleRateChanged(const IOAudioSampleRate *sampleRate); 663 664 /*! 665 * @function getRunEraseHead 666 * @abstract Returns true if the audio engine will run the erase head when the audio engine is running. 667 */ 668 virtual bool getRunEraseHead(); 669 670 /*! 671 * @function getStatus 672 * @abstract Returns a pointer to the shared status buffer. 673 */ 674 virtual const IOAudioEngineStatus *getStatus(); 675 676 /*! 677 * @function timerCallback 678 * @abstract A static method used as a callback for the IOAudioDevice timer services. 679 * @discussion This method implements the IOAudioDevice::TimerEvent type. 680 * @param arg1 The IOAudioEngine that is the target of the event. 681 * @param device The IOAudioDevice that sent the timer event. 682 */ 683 static void timerCallback(OSObject *arg1, IOAudioDevice *device); 684 685 /*! 686 * @function timerFired 687 * @abstract Indicates the timer has fired. 688 * @discussion This method is called by timerCallback to indicate the timer has fired. This method calls performErase() and performFlush() to do erase head processing and 689 * audio engine flushing each time the timer event fires. 690 */ 691 virtual void timerFired(); 692 693 /*! 694 * @function getTimerInterval 695 * @abstract Gets the timer interval for use by the timer event. 696 * @discussion This method is called each time the timer event is enabled through addTimer(). The default 697 * implementation is set to return a value such that the timer event runs n times each cycle of the audio 698 * engine through the sample buffer. The value n is stored as the instance variable: numErasesPerBuffer. 699 * The default value of numErasesPerBuffer is set to IOAUDIOENGINE_DEFAULT_NUM_ERASES_PER_BUFFER which is 4. 700 * A subclass may change the value of numErasesPerBuffer or override getTimerInterval. If it is overridden, 701 * the subclass should call the superclass's implementation, compare its interval with the superclass's and 702 * return the smaller of the two. 703 * @result Returns the interval for the timer event. 704 */ 705 virtual AbsoluteTime getTimerInterval(); 706 707 /*! 708 * @function performErase 709 * @abstract Performs erase head processing. 710 * @discussion This method is called automatically each time the timer event fires and erases the sample 711 * buffer and mix buffer from the previous location up to the current location of the audio engine. 712 */ 713 virtual void performErase(); 714 715 /*! 716 * @function performFlush 717 * @abstract Performs the flush operation. 718 * @discussion This method is called automatically each time the timer event fires. It stops the audio engine 719 * if there are no more clients and the audio engine is passed the latest flush ending position. 720 */ 721 virtual void performFlush(); 722 723 virtual void stopEngineAtPosition(IOAudioEnginePosition *endingPosition); 724 725 virtual IOReturn mixOutputSamples(const void *sourceBuf, void *mixBuf, UInt32 firstSampleFrame, UInt32 numSampleFrames, const IOAudioStreamFormat *streamFormat, IOAudioStream *audioStream); 726 virtual IOReturn clipOutputSamples(const void *mixBuf, void *sampleBuf, UInt32 firstSampleFrame, UInt32 numSampleFrames, const IOAudioStreamFormat *streamFormat, IOAudioStream *audioStream); 727 virtual void resetClipPosition(IOAudioStream *audioStream, UInt32 clipSampleFrame); 728 virtual IOReturn convertInputSamples(const void *sampleBuf, void *destBuf, UInt32 firstSampleFrame, UInt32 numSampleFrames, const IOAudioStreamFormat *streamFormat, IOAudioStream *audioStream); 729 730 virtual void takeTimeStamp(bool incrementLoopCount = true, AbsoluteTime *timestamp = NULL); 731 virtual IOReturn getLoopCountAndTimeStamp(UInt32 *loopCount, AbsoluteTime *timestamp); 732 733 virtual IOReturn calculateSampleTimeout(AbsoluteTime *sampleInterval, UInt32 numSampleFrames, IOAudioEnginePosition *startingPosition, AbsoluteTime *wakeupTime); 734 735 virtual IOReturn performFormatChange(IOAudioStream *audioStream, const IOAudioStreamFormat *newFormat, const IOAudioSampleRate *newSampleRate); 736 737 virtual void beginConfigurationChange(); 738 virtual void completeConfigurationChange(); 739 virtual void cancelConfigurationChange(); 740 741 virtual IOReturn addDefaultAudioControl(IOAudioControl *defaultAudioControl); 742 virtual IOReturn removeDefaultAudioControl(IOAudioControl *defaultAudioControl); 743 virtual void removeAllDefaultAudioControls(); 744 745 virtual OSString *getGlobalUniqueID(); 746 virtual OSString *getLocalUniqueID(); 747 748protected: 749 750 /*! 751 * @function initKeys 752 * @abstract Generates the OSSymbols with the keys. 753 * @discussion Do not call this directly. This is an internal initialization routine. 754 */ 755 static void initKeys(); 756 757 virtual void setNumSampleFramesPerBuffer(UInt32 numSampleFrames); 758 virtual UInt32 getNumSampleFramesPerBuffer(); 759 760 /*! 761 * @function setState 762 * @abstract Indicates that the audio engine is in the specified state. 763 * @discussion This method simply sets the internal state of the audio engine to the specified state. It does not 764 * affect a change to the state. It does however keep other internal state-related attributes consistent. 765 * For example, it enables or disables the timer as needed when the state changes to running or stopped. 766 * @param newState The state the audio engine is in. 767 * @result Returns the old state. 768 */ 769 virtual IOAudioEngineState setState(IOAudioEngineState newState); 770 771 /*! 772 * @function setSampleRate 773 * @abstract Records the sample rate of the audio engine. 774 * @discussion This method must be called during initialization of a new audio engine to record the audio engine's 775 * initial sample rate. It also is intended to be used to record changes to the sample rate during use. 776 * Currently changing sample rates after the audio engine has been started is not supported. 777 * It may require that the sample buffers be re-sized. This will be available in an upcoming release. 778 * @param newSampleRate The sample rate of the audio engine in samples per second. 779 */ 780 virtual void setSampleRate(const IOAudioSampleRate *newSampleRate); 781 782 /*! 783 * @function setSampleLatency 784 * @abstract Sets the sample latency for the audio engine. 785 * @discussion The sample latency represents the number of samples ahead of the playback head 786 * that it is safe to write into the sample buffer. The audio device API will never write 787 * closer to the playback head than the number of samples specified. For input audio engines 788 * the number of samples is behind the record head. 789 */ 790 virtual void setSampleLatency(UInt32 numSamples); 791 virtual void setOutputSampleLatency(UInt32 numSamples); 792 virtual void setInputSampleLatency(UInt32 numSamples); 793 virtual void setSampleOffset(UInt32 numSamples); 794 795 /*! 796 * @function setRunEraseHead 797 * @abstract Tells the audio engine whether or not to run the erase head. 798 * @discussion By default, output audio engines run the erase head and input audio engines do not. This method can 799 * be called after setDirection() is called in order to change the default behavior. 800 * @param runEraseHead The audio engine will run the erase head if this value is true. 801 */ 802 virtual void setRunEraseHead(bool runEraseHead); 803 804 /*! 805 * @function clientClosed 806 * @abstract Called automatically when a user client closes its connection to the audio engine. 807 * @discussion This method decrements the number of connections to the audio engine and if they reach 808 * zero, the audio engine is called with a call to stopAudioEngine(). This method should not be called directly. 809 * @param client The user client that has disconnected. 810 */ 811 virtual void clientClosed(IOAudioEngineUserClient *client); 812 813 /*! 814 * @function addTimer 815 * @abstract Enables the timer event for the audio engine. 816 * @discussion There is a timer event needed by the IOAudioEngine for processing the erase head 817 * and performing flushing operations. When the timer fires, the method timerFired() is ultimately 818 * called which in turn calls performErase() and performFlush(). This is called automatically 819 * to enable the timer event for this audio engine. It is called by setState() when the audio engine state 820 * is set to kIOAudioEngineRunning. When the timer is no longer needed, removeTimer() is called. 821 * There is no need to call this directly. 822 */ 823 virtual void addTimer(); 824 825 /*! 826 * @function removeTimer 827 * @abstract Disables the timer event for the audio engine. 828 * @discussion This method is called automatically to disable the timer event for this audio engine. 829 * There is need to call it directly. This method is called by setState() when the audio engine state 830 * is changed from kIOAudioEngineRunning to one of the stopped states. 831 */ 832 virtual void removeTimer(); 833 834 virtual void sendFormatChangeNotification(IOAudioStream *audioStream); 835 virtual void sendNotification(UInt32 notificationType); 836 837 virtual IOReturn createUserClient(task_t task, void *securityID, UInt32 type, IOAudioEngineUserClient **newUserClient); 838 839 static IOReturn _addUserClientAction(OSObject *target, void *arg0, void *arg1, void *arg2, void *arg3); // <rdar://7529580> 840 static IOReturn addUserClientAction(OSObject *owner, void *arg1, void *arg2, void *arg3, void *arg4); 841 static IOReturn _removeUserClientAction(OSObject *target, void *arg0, void *arg1, void *arg2, void *arg3); // <rdar://7529580> 842 static IOReturn removeUserClientAction(OSObject *owner, void *arg1, void *arg2, void *arg3, void *arg4); 843 static IOReturn detachUserClientsAction(OSObject *owner, void *arg1, void *arg2, void *arg3, void *arg4); 844 845 virtual IOReturn addUserClient(IOAudioEngineUserClient *newUserClient); 846 virtual IOReturn removeUserClient(IOAudioEngineUserClient *userClient); 847 virtual IOReturn detachUserClients(); 848 849 virtual IOReturn startClient(IOAudioEngineUserClient *userClient); 850 virtual IOReturn stopClient(IOAudioEngineUserClient *userClient); 851 852 virtual IOReturn incrementActiveUserClients(); 853 virtual IOReturn decrementActiveUserClients(); 854 855 virtual void detachAudioStreams(); 856 void setWorkLoopOnAllAudioControls(IOWorkLoop *wl); 857 858 static inline void lockStreamForIO(IOAudioStream *stream); 859 static inline void unlockStreamForIO(IOAudioStream *stream); 860 861 // These aren't virtual by design 862 UInt32 getNextStreamID(IOAudioStream * newStream); 863 IOAudioStream * getStreamForID(UInt32 streamID); 864 865 static void setCommandGateUsage(IOAudioEngine *engine, bool increment); // <rdar://8518215> 866 867}; 868 869#endif /* _IOKIT_IOAUDIOENGINE_H */ 870