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 <utils/Errors.h> 22 #include <utils/RefBase.h> 23 24 namespace android { 25 26 class MmapStreamCallback; 27 28 class MmapStreamInterface : public virtual RefBase 29 { 30 public: 31 32 /** 33 * Values for direction argument passed to openMmapStream() 34 */ 35 typedef enum { 36 DIRECTION_OUTPUT = 0, /**< open a playback mmap stream */ 37 DIRECTION_INPUT, /**< open a capture mmap stream */ 38 } stream_direction_t; 39 40 class Client { 41 public: 42 uid_t clientUid; 43 pid_t clientPid; 44 String16 packageName; 45 }; 46 /** 47 * Open a playback or capture stream in MMAP mode at the audio HAL. 48 * 49 * \note This method is implemented by AudioFlinger 50 * 51 * \param[in] direction open a playback or capture stream. 52 * \param[in] attr audio attributes defining the main use case for this stream 53 * \param[in,out] config audio parameters (sampling rate, format ...) for the stream. 54 * Requested parameters as input, 55 * Actual parameters as output 56 * \param[in] client a Client struct describing the first client using this stream. 57 * \param[in,out] deviceId audio device the stream should preferably be routed to/from 58 * Requested as input, 59 * Actual as output 60 * \param[in] callback the MmapStreamCallback interface used by AudioFlinger to notify 61 * condition changes affecting the stream operation 62 * \param[out] interface the MmapStreamInterface interface controlling the created stream 63 * \return OK if the stream was successfully created. 64 * NO_INIT if AudioFlinger is not properly initialized 65 * BAD_VALUE if the stream cannot be opened because of invalid arguments 66 * INVALID_OPERATION if the stream cannot be opened because of platform limitations 67 */ 68 static status_t openMmapStream(stream_direction_t direction, 69 const audio_attributes_t *attr, 70 audio_config_base_t *config, 71 const Client& client, 72 audio_port_handle_t *deviceId, 73 const sp<MmapStreamCallback>& callback, 74 sp<MmapStreamInterface>& interface); 75 76 /** 77 * Retrieve information on the mmap buffer used for audio samples transfer. 78 * Must be called before any other method after opening the stream or entering standby. 79 * 80 * \param[in] min_size_frames minimum buffer size requested. The actual buffer 81 * size returned in struct audio_mmap_buffer_info can be larger. 82 * \param[out] info address at which the mmap buffer information should be returned. 83 * 84 * \return OK if the buffer was allocated. 85 * NO_INIT in case of initialization error 86 * BAD_VALUE if the requested buffer size is too large 87 * INVALID_OPERATION if called out of sequence (e.g. buffer already allocated) 88 */ 89 virtual status_t createMmapBuffer(int32_t minSizeFrames, 90 struct audio_mmap_buffer_info *info) = 0; 91 92 /** 93 * Read current read/write position in the mmap buffer with associated time stamp. 94 * 95 * \param[out] position address at which the mmap read/write position should be returned. 96 * 97 * \return OK if the position is successfully returned. 98 * NO_INIT in case of initialization error 99 * NOT_ENOUGH_DATA if the position cannot be retrieved 100 * INVALID_OPERATION if called before createMmapBuffer() 101 */ 102 virtual status_t getMmapPosition(struct audio_mmap_position *position) = 0; 103 104 /** 105 * Start a stream operating in mmap mode. 106 * createMmapBuffer() must be called before calling start() 107 * 108 * \param[in] client a Client struct describing the client starting on this stream. 109 * \param[out] handle unique handle for this instance. Used with stop(). 110 * \return OK in case of success. 111 * NO_INIT in case of initialization error 112 * INVALID_OPERATION if called out of sequence 113 */ 114 virtual status_t start(const Client& client, audio_port_handle_t *handle) = 0; 115 116 /** 117 * Stop a stream operating in mmap mode. 118 * Must be called after start() 119 * 120 * \param[in] handle unique handle allocated by start(). 121 * \return OK in case of success. 122 * NO_INIT in case of initialization error 123 * INVALID_OPERATION if called out of sequence 124 */ 125 virtual status_t stop(audio_port_handle_t handle) = 0; 126 127 /** 128 * Put a stream operating in mmap mode into standby. 129 * Must be called after createMmapBuffer(). Cannot be called if any client is active. 130 * It is recommended to place a mmap stream into standby as often as possible when no client is 131 * active to save power. 132 * 133 * \return OK in case of success. 134 * NO_INIT in case of initialization error 135 * INVALID_OPERATION if called out of sequence 136 */ 137 virtual status_t standby() = 0; 138 139 protected: 140 // Subclasses can not be constructed directly by clients. MmapStreamInterface()141 MmapStreamInterface() {} 142 143 // The destructor automatically closes the stream. ~MmapStreamInterface()144 virtual ~MmapStreamInterface() {} 145 }; 146 147 } // namespace android 148 149 #endif // ANDROID_AUDIO_MMAP_STREAM_INTERFACE_H 150