audio: add audio_dma device driver.

Signed-off-by: ZhongAn <zhongan@pinecone.net>

drivers/audio/Kconfig

@@ -492,4 +492,10 @@ config AUDIO_I2S
 	depends on AUDIO
 	depends on I2S
 
+config AUDIO_DMA
+        bool "Audio DMA"
+        select AUDIO_DRIVER_SPECIFIC_BUFFERS
+        depends on AUDIO
+        depends on DMA
+
 endif # DRIVERS_AUDIO

drivers/audio/Make.defs

@@ -93,6 +93,10 @@ ifeq ($(CONFIG_AUDIO_I2S),y)
 CSRCS += audio_i2s.c
 endif
 
+ifeq ($(CONFIG_AUDIO_DMA),y)
+CSRCS += audio_dma.c
+endif
+
 # Include Audio driver support
 
 DEPPATH += --dep-path audio

include/nuttx/audio/audio_dma.h

@@ -0,0 +1,41 @@
+/****************************************************************************
+ * include/nuttx/audio/audio_dma.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_AUDIO_AUDIO_DMA_H
+#define __INCLUDE_NUTTX_AUDIO_AUDIO_DMA_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/audio/audio.h>
+#include <nuttx/dma/dma.h>
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+struct audio_lowerhalf_s *audio_dma_initialize(struct dma_dev_s *dma_dev,
+                                               uint8_t chan_num,
+                                               bool playback,
+                                               uint8_t fifo_width,
+                                               uintptr_t fifo_addr);
+#endif