diff --git a/sound/firewire/amdtp-am824.c b/sound/firewire/amdtp-am824.c
index 7adaba356579..5d99a9921d50 100644
--- a/sound/firewire/amdtp-am824.c
+++ b/sound/firewire/amdtp-am824.c
@@ -52,6 +52,34 @@ int amdtp_am824_set_parameters(struct amdtp_stream *s, unsigned int rate,
 }
 EXPORT_SYMBOL_GPL(amdtp_am824_set_parameters);
 
+/**
+ * amdtp_am824_set_pcm_position - set an index of data channel for a channel
+ *				  of PCM frame
+ * @s: the AMDTP stream
+ * @index: the index of data channel in an data block
+ * @position: the channel of PCM frame
+ */
+void amdtp_am824_set_pcm_position(struct amdtp_stream *s, unsigned int index,
+				 unsigned int position)
+{
+	if (index < s->pcm_channels)
+		s->pcm_positions[index] = position;
+}
+EXPORT_SYMBOL_GPL(amdtp_am824_set_pcm_position);
+
+/**
+ * amdtp_am824_set_midi_position - set a index of data channel for MIDI
+ *				   conformant data channel
+ * @s: the AMDTP stream
+ * @position: the index of data channel in an data block
+ */
+void amdtp_am824_set_midi_position(struct amdtp_stream *s,
+				   unsigned int position)
+{
+	s->midi_position = position;
+}
+EXPORT_SYMBOL_GPL(amdtp_am824_set_midi_position);
+
 /**
  * amdtp_am824_add_pcm_hw_constraints - add hw constraints for PCM substream
  * @s:		the AMDTP stream for AM824 data block, must be initialized.
diff --git a/sound/firewire/amdtp-am824.h b/sound/firewire/amdtp-am824.h
index 4aaed9048d82..7c21e9972fad 100644
--- a/sound/firewire/amdtp-am824.h
+++ b/sound/firewire/amdtp-am824.h
@@ -10,6 +10,12 @@ int amdtp_am824_set_parameters(struct amdtp_stream *s, unsigned int rate,
 			       unsigned int midi_ports,
 			       bool double_pcm_frames);
 
+void amdtp_am824_set_pcm_position(struct amdtp_stream *s, unsigned int index,
+				 unsigned int position);
+
+void amdtp_am824_set_midi_position(struct amdtp_stream *s,
+				   unsigned int position);
+
 int amdtp_am824_add_pcm_hw_constraints(struct amdtp_stream *s,
 				       struct snd_pcm_runtime *runtime);
 
diff --git a/sound/firewire/bebob/bebob_stream.c b/sound/firewire/bebob/bebob_stream.c
index fa510f30cf8f..cf6402d371e7 100644
--- a/sound/firewire/bebob/bebob_stream.c
+++ b/sound/firewire/bebob/bebob_stream.c
@@ -338,7 +338,7 @@ map_data_channels(struct snd_bebob *bebob, struct amdtp_stream *s)
 					err = -ENOSYS;
 					goto end;
 				}
-				s->midi_position = stm_pos;
+				amdtp_am824_set_midi_position(s, stm_pos);
 				midi = stm_pos;
 				break;
 			/* for PCM data channel */
@@ -358,7 +358,8 @@ map_data_channels(struct snd_bebob *bebob, struct amdtp_stream *s)
 					err = -ENOSYS;
 					goto end;
 				}
-				s->pcm_positions[location] = stm_pos;
+				amdtp_am824_set_pcm_position(s, location,
+							     stm_pos);
 				break;
 			}
 		}
diff --git a/sound/firewire/dice/dice-stream.c b/sound/firewire/dice/dice-stream.c
index 89483818785e..2108f7f1a764 100644
--- a/sound/firewire/dice/dice-stream.c
+++ b/sound/firewire/dice/dice-stream.c
@@ -141,8 +141,9 @@ static int start_stream(struct snd_dice *dice, struct amdtp_stream *stream,
 		pcm_chs /= 2;
 
 		for (i = 0; i < pcm_chs; i++) {
-			stream->pcm_positions[i] = i * 2;
-			stream->pcm_positions[i + pcm_chs] = i * 2 + 1;
+			amdtp_am824_set_pcm_position(stream, i, i * 2);
+			amdtp_am824_set_pcm_position(stream, i + pcm_chs,
+						     i * 2 + 1);
 		}
 	}