audio: add methods and structures for streamin MMAP mode

Bug: 33398120
Test: make marlin-eng with ENABLE_TREBLE true
Change-Id: I65c5c7ba0a94ba47dca78ace38ef3ae75ea7e3bf

audio/2.0/IStream.hal

@@ -227,4 +227,56 @@ interface IStream {
      * @param fd dump file descriptor.
      */
     debugDump(handle fd);
+
+    /*
+     * Called by the framework to start a stream operating in mmap mode.
+     * createMmapBuffer() must be called before calling start().
+     * Function only implemented by streams operating in mmap mode.
+     *
+     * @return retval OK in case the success.
+     *                NOT_SUPPORTED on non mmap mode streams
+     *                INVALID_STATE if called out of sequence
+     */
+    start() generates (Result retval);
+
+    /**
+     * Called by the framework to stop a stream operating in mmap mode.
+     * Function only implemented by streams operating in mmap mode.
+     *
+     * @return retval OK in case the succes.
+     *                NOT_SUPPORTED on non mmap mode streams
+     *                INVALID_STATE if called out of sequence
+     */
+    stop() generates (Result retval) ;
+
+    /*
+     * Called by the framework to retrieve information on the mmap buffer used for audio
+     * samples transfer.
+     * Function only implemented by streams operating in mmap mode.
+     *
+     * @param minSizeFrames minimum buffer size requested. The actual buffer
+     *                     size returned in struct MmapBufferInfo can be larger.
+     * @return retval OK in case the success.
+     *                NOT_SUPPORTED on non mmap mode streams
+     *                NOT_INITIALIZED in case of memory allocation error
+     *                INVALID_ARGUMENTS if the requested buffer size is too large
+     *                INVALID_STATE if called out of sequence
+     * @return info    a MmapBufferInfo struct containing information on the MMMAP buffer created.
+     */
+    createMmapBuffer(int32_t minSizeFrames)
+            generates (Result retval, MmapBufferInfo info);
+
+    /*
+     * Called by the framework to read current read/write position in the mmap buffer
+     * with associated time stamp.
+     * Function only implemented by streams operating in mmap mode.
+     *
+     * @return retval OK in case the success.
+     *                NOT_SUPPORTED on non mmap mode streams
+     *                INVALID_STATE if called out of sequence
+     * @return position a MmapPosition struct containing current HW read/write position in frames
+     *                  with associated time stamp.
+     */
+    getMmapPosition()
+            generates (Result retval, MmapPosition position);
 };

audio/2.0/types.hal

@@ -70,3 +70,22 @@ struct DeviceAddress {
     string busAddress;      // used for BUS
     string rSubmixAddress;  // used for REMOTE_SUBMIX
 };
+
+/*
+ * Mmap buffer descriptor returned by IStream.createMmapBuffer().
+ * Used by streams opened in mmap mode.
+ */
+struct MmapBufferInfo {
+    memory  sharedMemory;         // mmap memory buffer
+    int32_t bufferSizeFrames;     // total buffer size in frames
+    int32_t burstSizeFrames;      // transfer size granularity in frames
+};
+
+/*
+ * Mmap buffer read/write position returned by IStream.getMmapPosition().
+ * Used by streams opened in mmap mode.
+ */
+struct MmapPosition {
+    int64_t  timeNanoseconds; // time stamp in ns, CLOCK_MONOTONIC
+    int32_t  positionFrames;  // increasing 32 bit frame count reset when IStream.stop() is called
+};