ALSA: firewire-tascam: code refactoring for TASCAM data block processing layer

This is code refactoring for TASCAM data block processing layer so that
it can receive list of packet descriptor.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/tascam/amdtp-tascam.c

@@ -32,19 +32,24 @@ int amdtp_tscm_set_parameters(struct amdtp_stream *s, unsigned int rate)
 	return amdtp_stream_set_parameters(s, rate, data_channels);
 }
 
-static void write_pcm_s32(struct amdtp_stream *s,
-			  struct snd_pcm_substream *pcm,
-			  __be32 *buffer, unsigned int frames)
+static void write_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
+			  __be32 *buffer, unsigned int frames,
+			  unsigned int pcm_frames)
 {
 	struct amdtp_tscm *p = s->protocol;
+	unsigned int channels = p->pcm_channels;
 	struct snd_pcm_runtime *runtime = pcm->runtime;
-	unsigned int channels, remaining_frames, i, c;
+	unsigned int pcm_buffer_pointer;
+	int remaining_frames;
 	const u32 *src;
+	int i, c;
+
+	pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
+	pcm_buffer_pointer %= runtime->buffer_size;
 
-	channels = p->pcm_channels;
 	src = (void *)runtime->dma_area +
-			frames_to_bytes(runtime, s->pcm_buffer_pointer);
-	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
+				frames_to_bytes(runtime, pcm_buffer_pointer);
+	remaining_frames = runtime->buffer_size - pcm_buffer_pointer;
 
 	for (i = 0; i < frames; ++i) {
 		for (c = 0; c < channels; ++c) {
@@ -57,19 +62,24 @@ static void write_pcm_s32(struct amdtp_stream *s,
 	}
 }
 
-static void read_pcm_s32(struct amdtp_stream *s,
-			 struct snd_pcm_substream *pcm,
-			 __be32 *buffer, unsigned int frames)
+static void read_pcm_s32(struct amdtp_stream *s, struct snd_pcm_substream *pcm,
+			 __be32 *buffer, unsigned int frames,
+			 unsigned int pcm_frames)
 {
 	struct amdtp_tscm *p = s->protocol;
+	unsigned int channels = p->pcm_channels;
 	struct snd_pcm_runtime *runtime = pcm->runtime;
-	unsigned int channels, remaining_frames, i, c;
+	unsigned int pcm_buffer_pointer;
+	int remaining_frames;
 	u32 *dst;
+	int i, c;
+
+	pcm_buffer_pointer = s->pcm_buffer_pointer + pcm_frames;
+	pcm_buffer_pointer %= runtime->buffer_size;
 
-	channels = p->pcm_channels;
 	dst  = (void *)runtime->dma_area +
-			frames_to_bytes(runtime, s->pcm_buffer_pointer);
-	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
+				frames_to_bytes(runtime, pcm_buffer_pointer);
+	remaining_frames = runtime->buffer_size - pcm_buffer_pointer;
 
 	/* The first data channel is for event counter. */
 	buffer += 1;
@@ -169,13 +179,12 @@ static unsigned int process_tx_data_blocks(struct amdtp_stream *s,
 					   const struct pkt_desc *desc,
 					   struct snd_pcm_substream *pcm)
 {
-	unsigned int pcm_frames;
+	unsigned int pcm_frames = 0;
 
 	if (pcm) {
-		read_pcm_s32(s, pcm, desc->ctx_payload, desc->data_blocks);
-		pcm_frames = desc->data_blocks;
-	} else {
-		pcm_frames = 0;
+		read_pcm_s32(s, pcm, desc->ctx_payload, desc->data_blocks,
+			     pcm_frames);
+		pcm_frames += desc->data_blocks;
 	}
 
 	read_status_messages(s, desc->ctx_payload, desc->data_blocks);
@@ -187,14 +196,14 @@ static unsigned int process_rx_data_blocks(struct amdtp_stream *s,
 					   const struct pkt_desc *desc,
 					   struct snd_pcm_substream *pcm)
 {
-	unsigned int pcm_frames;
+	unsigned int pcm_frames = 0;
 
 	if (pcm) {
-		write_pcm_s32(s, pcm, desc->ctx_payload, desc->data_blocks);
-		pcm_frames = desc->data_blocks;
+		write_pcm_s32(s, pcm, desc->ctx_payload, desc->data_blocks,
+			      pcm_frames);
+		pcm_frames += desc->data_blocks;
 	} else {
 		write_pcm_silence(s, desc->ctx_payload, desc->data_blocks);
-		pcm_frames = 0;
 	}
 
 	return pcm_frames;