diff --git a/sound/firewire/tascam/Makefile b/sound/firewire/tascam/Makefile
index 1555206..d06c737 100644
--- a/sound/firewire/tascam/Makefile
+++ b/sound/firewire/tascam/Makefile
@@ -1,2 +1,2 @@
-snd-firewire-tascam-objs := tascam-proc.o tascam.o
+snd-firewire-tascam-objs := tascam-proc.o amdtp-tascam.o tascam.o
 obj-$(CONFIG_SND_FIREWIRE_TASCAM) += snd-firewire-tascam.o
diff --git a/sound/firewire/tascam/amdtp-tascam.c b/sound/firewire/tascam/amdtp-tascam.c
new file mode 100644
index 0000000..9dd0fcc
--- /dev/null
+++ b/sound/firewire/tascam/amdtp-tascam.c
@@ -0,0 +1,243 @@
+/*
+ * amdtp-tascam.c - a part of driver for TASCAM FireWire series
+ *
+ * Copyright (c) 2015 Takashi Sakamoto
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#include <sound/pcm.h>
+#include "tascam.h"
+
+#define AMDTP_FMT_TSCM_TX	0x1e
+#define AMDTP_FMT_TSCM_RX	0x3e
+
+struct amdtp_tscm {
+	unsigned int pcm_channels;
+
+	void (*transfer_samples)(struct amdtp_stream *s,
+				 struct snd_pcm_substream *pcm,
+				 __be32 *buffer, unsigned int frames);
+};
+
+int amdtp_tscm_set_parameters(struct amdtp_stream *s, unsigned int rate)
+{
+	struct amdtp_tscm *p = s->protocol;
+	unsigned int data_channels;
+
+	if (amdtp_stream_running(s))
+		return -EBUSY;
+
+	data_channels = p->pcm_channels;
+
+	/* Packets in in-stream have extra 2 data channels. */
+	if (s->direction == AMDTP_IN_STREAM)
+		data_channels += 2;
+
+	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)
+{
+	struct amdtp_tscm *p = s->protocol;
+	struct snd_pcm_runtime *runtime = pcm->runtime;
+	unsigned int channels, remaining_frames, i, c;
+	const u32 *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[c] = cpu_to_be32(*src);
+			src++;
+		}
+		buffer += s->data_block_quadlets;
+		if (--remaining_frames == 0)
+			src = (void *)runtime->dma_area;
+	}
+}
+
+static void write_pcm_s16(struct amdtp_stream *s,
+			  struct snd_pcm_substream *pcm,
+			  __be32 *buffer, unsigned int frames)
+{
+	struct amdtp_tscm *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[c] = cpu_to_be32(*src << 16);
+			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)
+{
+	struct amdtp_tscm *p = s->protocol;
+	struct snd_pcm_runtime *runtime = pcm->runtime;
+	unsigned int channels, remaining_frames, i, c;
+	u32 *dst;
+
+	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;
+
+	/* The first data channel is for event counter. */
+	buffer += 1;
+
+	for (i = 0; i < frames; ++i) {
+		for (c = 0; c < channels; ++c) {
+			*dst = be32_to_cpu(buffer[c]);
+			dst++;
+		}
+		buffer += s->data_block_quadlets;
+		if (--remaining_frames == 0)
+			dst = (void *)runtime->dma_area;
+	}
+}
+
+static void write_pcm_silence(struct amdtp_stream *s, __be32 *buffer,
+			      unsigned int data_blocks)
+{
+	struct amdtp_tscm *p = s->protocol;
+	unsigned int channels, i, c;
+
+	channels = p->pcm_channels;
+
+	for (i = 0; i < data_blocks; ++i) {
+		for (c = 0; c < channels; ++c)
+			buffer[c] = 0x00000000;
+		buffer += s->data_block_quadlets;
+	}
+}
+
+int amdtp_tscm_add_pcm_hw_constraints(struct amdtp_stream *s,
+				      struct snd_pcm_runtime *runtime)
+{
+	int err;
+
+	/*
+	 * Our implementation allows this protocol to deliver 24 bit sample in
+	 * 32bit data channel.
+	 */
+	err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
+	if (err < 0)
+		return err;
+
+	return amdtp_stream_add_pcm_hw_constraints(s, runtime);
+}
+
+void amdtp_tscm_set_pcm_format(struct amdtp_stream *s, snd_pcm_format_t format)
+{
+	struct amdtp_tscm *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;
+	}
+}
+
+static unsigned int process_tx_data_blocks(struct amdtp_stream *s,
+					   __be32 *buffer,
+					   unsigned int data_blocks,
+					   unsigned int *syt)
+{
+	struct amdtp_tscm *p = (struct amdtp_tscm *)s->protocol;
+	struct snd_pcm_substream *pcm;
+
+	pcm = ACCESS_ONCE(s->pcm);
+	if (data_blocks > 0 && pcm)
+		p->transfer_samples(s, pcm, buffer, data_blocks);
+
+	/* A place holder for control messages. */
+
+	return data_blocks;
+}
+
+static unsigned int process_rx_data_blocks(struct amdtp_stream *s,
+					   __be32 *buffer,
+					   unsigned int data_blocks,
+					   unsigned int *syt)
+{
+	struct amdtp_tscm *p = (struct amdtp_tscm *)s->protocol;
+	struct snd_pcm_substream *pcm;
+
+	/* This field is not used. */
+	*syt = 0x0000;
+
+	pcm = ACCESS_ONCE(s->pcm);
+	if (pcm)
+		p->transfer_samples(s, pcm, buffer, data_blocks);
+	else
+		write_pcm_silence(s, buffer, data_blocks);
+
+	return data_blocks;
+}
+
+int amdtp_tscm_init(struct amdtp_stream *s, struct fw_unit *unit,
+		    enum amdtp_stream_direction dir, unsigned int pcm_channels)
+{
+	amdtp_stream_process_data_blocks_t process_data_blocks;
+	struct amdtp_tscm *p;
+	unsigned int fmt;
+	int err;
+
+	if (dir == AMDTP_IN_STREAM) {
+		fmt = AMDTP_FMT_TSCM_TX;
+		process_data_blocks = process_tx_data_blocks;
+	} else {
+		fmt = AMDTP_FMT_TSCM_RX;
+		process_data_blocks = process_rx_data_blocks;
+	}
+
+	err = amdtp_stream_init(s, unit, dir,
+				CIP_NONBLOCKING | CIP_SKIP_DBC_ZERO_CHECK, fmt,
+				process_data_blocks, sizeof(struct amdtp_tscm));
+	if (err < 0)
+		return 0;
+
+	/* Use fixed value for FDF field. */
+	s->fdf = 0x00;
+
+	/* This protocol uses fixed number of data channels for PCM samples. */
+	p = s->protocol;
+	p->pcm_channels = pcm_channels;
+
+	return 0;
+}
diff --git a/sound/firewire/tascam/tascam.h b/sound/firewire/tascam/tascam.h
index 9ecc550..195be0b 100644
--- a/sound/firewire/tascam/tascam.h
+++ b/sound/firewire/tascam/tascam.h
@@ -21,8 +21,11 @@
 #include <sound/core.h>
 #include <sound/initval.h>
 #include <sound/info.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
 
 #include "../lib.h"
+#include "../amdtp-stream.h"
 
 struct snd_tscm_spec {
 	const char *const name;
@@ -51,6 +54,13 @@
 #define TSCM_OFFSET_FIRMWARE_ARM	0x0008
 #define TSCM_OFFSET_FIRMWARE_HW		0x000c
 
+int amdtp_tscm_init(struct amdtp_stream *s, struct fw_unit *unit,
+		  enum amdtp_stream_direction dir, unsigned int pcm_channels);
+int amdtp_tscm_set_parameters(struct amdtp_stream *s, unsigned int rate);
+int amdtp_tscm_add_pcm_hw_constraints(struct amdtp_stream *s,
+				      struct snd_pcm_runtime *runtime);
+void amdtp_tscm_set_pcm_format(struct amdtp_stream *s, snd_pcm_format_t format);
+
 void snd_tscm_proc_init(struct snd_tscm *tscm);
 
 #endif