diff --git a/media/libaudiohal/StreamHalHidl.h b/media/libaudiohal/StreamHalHidl.h
index e0a067e..377acb4 100644
--- a/media/libaudiohal/StreamHalHidl.h
+++ b/media/libaudiohal/StreamHalHidl.h
@@ -67,6 +67,19 @@
 
     virtual status_t dump(int fd);
 
+    // Start a stream operating in mmap mode.
+    virtual status_t start();
+
+    // Stop a stream operating in mmap mode.
+    virtual status_t stop();
+
+    // Retrieve information on the data buffer in mmap mode.
+    virtual status_t createMmapBuffer(int32_t minSizeFrames,
+                                      struct audio_mmap_buffer_info *info);
+
+    // Get current read/write position in the mmap buffer
+    virtual status_t getMmapPosition(struct audio_mmap_position *position);
+
   protected:
     // Subclasses can not be constructed directly by clients.
     explicit StreamHalHidl(IStream *stream);