1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ANDROID_AUDIO_MMAP_STREAM_INTERFACE_H 18 #define ANDROID_AUDIO_MMAP_STREAM_INTERFACE_H 19 20 #include <system/audio.h> 21 #include <media/AudioClient.h> 22 #include <utils/Errors.h> 23 #include <utils/RefBase.h> 24 25 namespace android { 26 27 class MmapStreamCallback; 28 29 class MmapStreamInterface : public virtual RefBase 30 { 31 public: 32 33 /** 34 * Values for direction argument passed to openMmapStream() 35 */ 36 typedef enum { 37 DIRECTION_OUTPUT = 0, /**< open a playback mmap stream */ 38 DIRECTION_INPUT, /**< open a capture mmap stream */ 39 } stream_direction_t; 40 41 /** 42 * Open a playback or capture stream in MMAP mode at the audio HAL. 43 * 44 * \note This method is implemented by AudioFlinger 45 * 46 * \param[in] direction open a playback or capture stream. 47 * \param[in] attr audio attributes defining the main use case for this stream 48 * \param[in,out] config audio parameters (sampling rate, format ...) for the stream. 49 * Requested parameters as input, 50 * Actual parameters as output 51 * \param[in] client a AudioClient struct describing the first client using this stream. 52 * \param[in,out] deviceId audio device the stream should preferably be routed to/from 53 * Requested as input, 54 * Actual as output 55 * \param[in,out] sessionId audio sessionId for the stream 56 * Requested as input, may be AUDIO_SESSION_ALLOCATE 57 * Actual as output 58 * \param[in] callback the MmapStreamCallback interface used by AudioFlinger to notify 59 * condition changes affecting the stream operation 60 * \param[out] interface the MmapStreamInterface interface controlling the created stream 61 * \param[out] same unique handle as the one used for the first client stream started. 62 * \return OK if the stream was successfully created. 63 * NO_INIT if AudioFlinger is not properly initialized 64 * BAD_VALUE if the stream cannot be opened because of invalid arguments 65 * INVALID_OPERATION if the stream cannot be opened because of platform limitations 66 */ 67 static status_t openMmapStream(stream_direction_t direction, 68 const audio_attributes_t *attr, 69 audio_config_base_t *config, 70 const AudioClient& client, 71 audio_port_handle_t *deviceId, 72 audio_session_t *sessionId, 73 const sp<MmapStreamCallback>& callback, 74 sp<MmapStreamInterface>& interface, 75 audio_port_handle_t *handle); 76 77 /** 78 * Retrieve information on the mmap buffer used for audio samples transfer. 79 * Must be called before any other method after opening the stream or entering standby. 80 * 81 * \param[in] min_size_frames minimum buffer size requested. The actual buffer 82 * size returned in struct audio_mmap_buffer_info can be larger. 83 * \param[out] info address at which the mmap buffer information should be returned. 84 * 85 * \return OK if the buffer was allocated. 86 * NO_INIT in case of initialization error 87 * BAD_VALUE if the requested buffer size is too large 88 * INVALID_OPERATION if called out of sequence (e.g. buffer already allocated) 89 */ 90 virtual status_t createMmapBuffer(int32_t minSizeFrames, 91 struct audio_mmap_buffer_info *info) = 0; 92 93 /** 94 * Read current read/write position in the mmap buffer with associated time stamp. 95 * 96 * \param[out] position address at which the mmap read/write position should be returned. 97 * 98 * \return OK if the position is successfully returned. 99 * NO_INIT in case of initialization error 100 * NOT_ENOUGH_DATA if the position cannot be retrieved 101 * INVALID_OPERATION if called before createMmapBuffer() 102 */ 103 virtual status_t getMmapPosition(struct audio_mmap_position *position) = 0; 104 105 /** 106 * Start a stream operating in mmap mode. 107 * createMmapBuffer() must be called before calling start() 108 * 109 * \param[in] client a AudioClient struct describing the client starting on this stream. 110 * \param[out] handle unique handle for this instance. Used with stop(). 111 * \return OK in case of success. 112 * NO_INIT in case of initialization error 113 * INVALID_OPERATION if called out of sequence 114 */ 115 virtual status_t start(const AudioClient& client, audio_port_handle_t *handle) = 0; 116 117 /** 118 * Stop a stream operating in mmap mode. 119 * Must be called after start() 120 * 121 * \param[in] handle unique handle allocated by start(). 122 * \return OK in case of success. 123 * NO_INIT in case of initialization error 124 * INVALID_OPERATION if called out of sequence 125 */ 126 virtual status_t stop(audio_port_handle_t handle) = 0; 127 128 /** 129 * Put a stream operating in mmap mode into standby. 130 * Must be called after createMmapBuffer(). Cannot be called if any client is active. 131 * It is recommended to place a mmap stream into standby as often as possible when no client is 132 * active to save power. 133 * 134 * \return OK in case of success. 135 * NO_INIT in case of initialization error 136 * INVALID_OPERATION if called out of sequence 137 */ 138 virtual status_t standby() = 0; 139 140 protected: 141 // Subclasses can not be constructed directly by clients. 142 MmapStreamInterface() {} 143 144 // The destructor automatically closes the stream. 145 virtual ~MmapStreamInterface() {} 146 }; 147 148 } // namespace android 149 150 #endif // ANDROID_AUDIO_MMAP_STREAM_INTERFACE_H 151
