ALSA: firewire: remove support for 16 bit PCM samples in playback substream

In IEC 61883-6, AM824 is described as format of data block. In this
format, one data block consists of several data channels, which is aligned
to 32 bit. One data channel has 8 bit label field and 24 bit data field.
PCM frames are transferred in Multi Bit Linear Audio (MBLA) data channel.
This channel can include 16/20/24 bit PCM sample.

As long as I know, models which support IEC 61883-1/6 doesn't allow to
switch bit length of PCM sample in MBLA data channel. They always
transmit/receive PCM frames of 24 bit length. This can be seen for the
other models which support protocols similar to IEC 61883-1/6.

On the other hand, current drivers for these protocols supports 16 bit
length PCM sample in playback substream. In this case, PCM sample is put
into the MBLA data channel with 8 bit padding in LSB side. Although 16
bit PCM sample is major because it's in CD format, this doesn't represent
device capability as is.

This commit removes support for 16 bit PCM samples in playback substream.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 2 insertions, 69 deletions

diff --git a/sound/firewire/amdtp-am824.c b/sound/firewire/amdtp-am824.c
index bebddc60fde8..23ccddb20de1 100644
--- a/sound/firewire/amdtp-am824.c
+++ b/sound/firewire/amdtp-am824.c
@@ -38,10 +38,6 @@ struct amdtp_am824 {
 	u8 pcm_positions[AM824_MAX_CHANNELS_FOR_PCM];
 	u8 midi_position;
 
-	void (*transfer_samples)(struct amdtp_stream *s,
-				 struct snd_pcm_substream *pcm,
-				 __be32 *buffer, unsigned int frames);
-
 	unsigned int frame_multiplier;
 };
 
@@ -177,32 +173,6 @@ static void write_pcm_s32(struct amdtp_stream *s,
 	}
 }
 
-static void write_pcm_s16(struct amdtp_stream *s,
-			  struct snd_pcm_substream *pcm,
-			  __be32 *buffer, unsigned int frames)
-{
-	struct amdtp_am824 *p = s->protocol;
-	struct snd_pcm_runtime *runtime = pcm->runtime;
-	unsigned int channels, remaining_frames, i, c;
-	const u16 *src;
-
-	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;
-
-	for (i = 0; i < frames; ++i) {
-		for (c = 0; c < channels; ++c) {
-			buffer[p->pcm_positions[c]] =
-					cpu_to_be32((*src << 8) | 0x42000000);
-			src++;
-		}
-		buffer += s->data_block_quadlets;
-		if (--remaining_frames == 0)
-			src = (void *)runtime->dma_area;
-	}
-}
-
 static void read_pcm_s32(struct amdtp_stream *s,
 			 struct snd_pcm_substream *pcm,
 			 __be32 *buffer, unsigned int frames)
@@ -242,43 +212,6 @@ static void write_pcm_silence(struct amdtp_stream *s,
 }
 
 /**
- * amdtp_am824_set_pcm_format - set the PCM format
- * @s: the AMDTP stream to configure
- * @format: the format of the ALSA PCM device
- *
- * The sample format must be set after the other parameters (rate/PCM channels/
- * MIDI) and before the stream is started, and must not be changed while the
- * stream is running.
- */
-void amdtp_am824_set_pcm_format(struct amdtp_stream *s, snd_pcm_format_t format)
-{
-	struct amdtp_am824 *p = s->protocol;
-
-	if (WARN_ON(amdtp_stream_pcm_running(s)))
-		return;
-
-	switch (format) {
-	default:
-		WARN_ON(1);
-		/* fall through */
-	case SNDRV_PCM_FORMAT_S16:
-		if (s->direction == AMDTP_OUT_STREAM) {
-			p->transfer_samples = write_pcm_s16;
-			break;
-		}
-		WARN_ON(1);
-		/* fall through */
-	case SNDRV_PCM_FORMAT_S32:
-		if (s->direction == AMDTP_OUT_STREAM)
-			p->transfer_samples = write_pcm_s32;
-		else
-			p->transfer_samples = read_pcm_s32;
-		break;
-	}
-}
-EXPORT_SYMBOL_GPL(amdtp_am824_set_pcm_format);
-
-/**
  * amdtp_am824_add_pcm_hw_constraints - add hw constraints for PCM substream
  * @s:		the AMDTP stream for AM824 data block, must be initialized.
  * @runtime:	the PCM substream runtime
@@ -407,7 +340,7 @@ static unsigned int process_rx_data_blocks(struct amdtp_stream *s, __be32 *buffe
 	unsigned int pcm_frames;
 
 	if (pcm) {
-		p->transfer_samples(s, pcm, buffer, data_blocks);
+		write_pcm_s32(s, pcm, buffer, data_blocks);
 		pcm_frames = data_blocks * p->frame_multiplier;
 	} else {
 		write_pcm_silence(s, buffer, data_blocks);
@@ -428,7 +361,7 @@ static unsigned int process_tx_data_blocks(struct amdtp_stream *s, __be32 *buffe
 	unsigned int pcm_frames;
 
 	if (pcm) {
-		p->transfer_samples(s, pcm, buffer, data_blocks);
+		read_pcm_s32(s, pcm, buffer, data_blocks);
 		pcm_frames = data_blocks * p->frame_multiplier;
 	} else {
 		pcm_frames = 0;