diff --git a/sound/firewire/motu/Makefile b/sound/firewire/motu/Makefile
index d7819d57eadf500dfa948fd8dbfe7d63dc8887ef..37391f5c623da344eb47ba30b221ec2e0864a401 100644
--- a/sound/firewire/motu/Makefile
+++ b/sound/firewire/motu/Makefile
@@ -1,2 +1,2 @@
-snd-firewire-motu-objs := motu.o
+snd-firewire-motu-objs := motu.o amdtp-motu.o
 obj-$(CONFIG_SND_FIREWIRE_MOTU) += snd-firewire-motu.o
diff --git a/sound/firewire/motu/amdtp-motu.c b/sound/firewire/motu/amdtp-motu.c
new file mode 100644
index 0000000000000000000000000000000000000000..11e44123ad653c6072efafa8cc08589ebd069920
--- /dev/null
+++ b/sound/firewire/motu/amdtp-motu.c
@@ -0,0 +1,292 @@
+/*
+ * amdtp-motu.c - a part of driver for MOTU FireWire series
+ *
+ * Copyright (c) 2015-2017 Takashi Sakamoto <o-takashi@sakamocchi.jp>
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#include <linux/slab.h>
+#include <sound/pcm.h>
+#include "motu.h"
+
+#define CIP_FMT_MOTU		0x02
+#define MOTU_FDF_AM824		0x22
+
+struct amdtp_motu {
+	/* For timestamp processing.  */
+	unsigned int quotient_ticks_per_event;
+	unsigned int remainder_ticks_per_event;
+	unsigned int next_ticks;
+	unsigned int next_accumulated;
+	unsigned int next_cycles;
+	unsigned int next_seconds;
+
+	unsigned int pcm_chunks;
+	unsigned int pcm_byte_offset;
+};
+
+int amdtp_motu_set_parameters(struct amdtp_stream *s, unsigned int rate,
+			      struct snd_motu_packet_format *formats)
+{
+	static const struct {
+		unsigned int quotient_ticks_per_event;
+		unsigned int remainder_ticks_per_event;
+	} params[] = {
+		[CIP_SFC_44100]  = { 557, 123 },
+		[CIP_SFC_48000]  = { 512,   0 },
+		[CIP_SFC_88200]  = { 278, 282 },
+		[CIP_SFC_96000]  = { 256,   0 },
+		[CIP_SFC_176400] = { 139, 141 },
+		[CIP_SFC_192000] = { 128,   0 },
+	};
+	struct amdtp_motu *p = s->protocol;
+	unsigned int pcm_chunks, data_chunks, data_block_quadlets;
+	unsigned int delay;
+	unsigned int mode;
+	int i, err;
+
+	if (amdtp_stream_running(s))
+		return -EBUSY;
+
+	for (i = 0; i < ARRAY_SIZE(snd_motu_clock_rates); ++i) {
+		if (snd_motu_clock_rates[i] == rate) {
+			mode = i >> 1;
+			break;
+		}
+	}
+	if (i == ARRAY_SIZE(snd_motu_clock_rates))
+		return -EINVAL;
+
+	pcm_chunks = formats->fixed_part_pcm_chunks[mode] +
+		     formats->differed_part_pcm_chunks[mode];
+	data_chunks = formats->msg_chunks + pcm_chunks;
+
+	/*
+	 * Each data block includes SPH in its head. Data chunks follow with
+	 * 3 byte alignment. Padding follows with zero to conform to quadlet
+	 * alignment.
+	 */
+	data_block_quadlets = 1 + DIV_ROUND_UP(data_chunks * 3, 4);
+
+	err = amdtp_stream_set_parameters(s, rate, data_block_quadlets);
+	if (err < 0)
+		return err;
+
+	p->pcm_chunks = pcm_chunks;
+	p->pcm_byte_offset = formats->pcm_byte_offset;
+
+	/* IEEE 1394 bus requires. */
+	delay = 0x2e00;
+
+	/* For no-data or empty packets to adjust PCM sampling frequency. */
+	delay += 8000 * 3072 * s->syt_interval / rate;
+
+	p->next_seconds = 0;
+	p->next_cycles = delay / 3072;
+	p->quotient_ticks_per_event = params[s->sfc].quotient_ticks_per_event;
+	p->remainder_ticks_per_event = params[s->sfc].remainder_ticks_per_event;
+	p->next_ticks = delay % 3072;
+	p->next_accumulated = 0;
+
+	return 0;
+}
+
+static void read_pcm_s32(struct amdtp_stream *s,
+			 struct snd_pcm_runtime *runtime,
+			 __be32 *buffer, unsigned int data_blocks)
+{
+	struct amdtp_motu *p = s->protocol;
+	unsigned int channels, remaining_frames, i, c;
+	u8 *byte;
+	u32 *dst;
+
+	channels = p->pcm_chunks;
+	dst = (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 < data_blocks; ++i) {
+		byte = (u8 *)buffer + p->pcm_byte_offset;
+
+		for (c = 0; c < channels; ++c) {
+			*dst = (byte[0] << 24) | (byte[1] << 16) | byte[2];
+			byte += 3;
+			dst++;
+		}
+		buffer += s->data_block_quadlets;
+		if (--remaining_frames == 0)
+			dst = (void *)runtime->dma_area;
+	}
+}
+
+static void write_pcm_s32(struct amdtp_stream *s,
+			  struct snd_pcm_runtime *runtime,
+			  __be32 *buffer, unsigned int data_blocks)
+{
+	struct amdtp_motu *p = s->protocol;
+	unsigned int channels, remaining_frames, i, c;
+	u8 *byte;
+	const u32 *src;
+
+	channels = p->pcm_chunks;
+	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 < data_blocks; ++i) {
+		byte = (u8 *)buffer + p->pcm_byte_offset;
+
+		for (c = 0; c < channels; ++c) {
+			byte[0] = (*src >> 24) & 0xff;
+			byte[1] = (*src >> 16) & 0xff;
+			byte[2] = (*src >>  8) & 0xff;
+			byte += 3;
+			src++;
+		}
+
+		buffer += s->data_block_quadlets;
+		if (--remaining_frames == 0)
+			src = (void *)runtime->dma_area;
+	}
+}
+
+static void write_pcm_silence(struct amdtp_stream *s, __be32 *buffer,
+			      unsigned int data_blocks)
+{
+	struct amdtp_motu *p = s->protocol;
+	unsigned int channels, i, c;
+	u8 *byte;
+
+	channels = p->pcm_chunks;
+
+	for (i = 0; i < data_blocks; ++i) {
+		byte = (u8 *)buffer + p->pcm_byte_offset;
+
+		for (c = 0; c < channels; ++c) {
+			byte[0] = 0;
+			byte[1] = 0;
+			byte[2] = 0;
+			byte += 3;
+		}
+
+		buffer += s->data_block_quadlets;
+	}
+}
+
+int amdtp_motu_add_pcm_hw_constraints(struct amdtp_stream *s,
+				      struct snd_pcm_runtime *runtime)
+{
+	int err;
+
+	/* TODO: how to set an constraint for exactly 24bit PCM sample? */
+	err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
+	if (err < 0)
+		return err;
+
+	return amdtp_stream_add_pcm_hw_constraints(s, runtime);
+}
+
+static unsigned int process_tx_data_blocks(struct amdtp_stream *s,
+				__be32 *buffer, unsigned int data_blocks,
+				unsigned int *syt)
+{
+	struct snd_pcm_substream *pcm;
+
+	pcm = ACCESS_ONCE(s->pcm);
+	if (data_blocks > 0 && pcm)
+		read_pcm_s32(s, pcm->runtime, buffer, data_blocks);
+
+	return data_blocks;
+}
+
+static inline void compute_next_elapse_from_start(struct amdtp_motu *p)
+{
+	p->next_accumulated += p->remainder_ticks_per_event;
+	if (p->next_accumulated >= 441) {
+		p->next_accumulated -= 441;
+		p->next_ticks++;
+	}
+
+	p->next_ticks += p->quotient_ticks_per_event;
+	if (p->next_ticks >= 3072) {
+		p->next_ticks -= 3072;
+		p->next_cycles++;
+	}
+
+	if (p->next_cycles >= 8000) {
+		p->next_cycles -= 8000;
+		p->next_seconds++;
+	}
+
+	if (p->next_seconds >= 128)
+		p->next_seconds -= 128;
+}
+
+static void write_sph(struct amdtp_stream *s, __be32 *buffer,
+		      unsigned int data_blocks)
+{
+	struct amdtp_motu *p = s->protocol;
+	unsigned int next_cycles;
+	unsigned int i;
+	u32 sph;
+
+	for (i = 0; i < data_blocks; i++) {
+		next_cycles = (s->start_cycle + p->next_cycles) % 8000;
+		sph = ((next_cycles << 12) | p->next_ticks) & 0x01ffffff;
+		*buffer = cpu_to_be32(sph);
+
+		compute_next_elapse_from_start(p);
+
+		buffer += s->data_block_quadlets;
+	}
+}
+
+static unsigned int process_rx_data_blocks(struct amdtp_stream *s,
+				__be32 *buffer, unsigned int data_blocks,
+				unsigned int *syt)
+{
+	struct snd_pcm_substream *pcm;
+
+	/* Not used. */
+	*syt = 0xffff;
+
+	/* TODO: how to interact control messages between userspace? */
+
+	pcm = ACCESS_ONCE(s->pcm);
+	if (pcm)
+		write_pcm_s32(s, pcm->runtime, buffer, data_blocks);
+	else
+		write_pcm_silence(s, buffer, data_blocks);
+
+	write_sph(s, buffer, data_blocks);
+
+	return data_blocks;
+}
+
+int amdtp_motu_init(struct amdtp_stream *s, struct fw_unit *unit,
+		    enum amdtp_stream_direction dir,
+		    const struct snd_motu_protocol *const protocol)
+{
+	amdtp_stream_process_data_blocks_t process_data_blocks;
+	int fmt = CIP_FMT_MOTU;
+	int flags = CIP_BLOCKING;
+	int err;
+
+	if (dir == AMDTP_IN_STREAM) {
+		process_data_blocks = process_tx_data_blocks;
+	} else {
+		process_data_blocks = process_rx_data_blocks;
+		flags |= CIP_DBC_IS_END_EVENT;
+	}
+
+	err = amdtp_stream_init(s, unit, dir, flags, fmt, process_data_blocks,
+				sizeof(struct amdtp_motu));
+	if (err < 0)
+		return err;
+
+	s->sph = 1;
+	s->fdf = MOTU_FDF_AM824;
+
+	return 0;
+}
diff --git a/sound/firewire/motu/motu.h b/sound/firewire/motu/motu.h
index cb6b57353cc160c1e6824fc3792aec234c2466e9..cd1b3dd3e3712d6b2a0d4e22cd6ab93785015b8c 100644
--- a/sound/firewire/motu/motu.h
+++ b/sound/firewire/motu/motu.h
@@ -19,12 +19,12 @@
 
 #include <sound/control.h>
 #include <sound/core.h>
+#include <sound/pcm.h>
 
 #include "../lib.h"
+#include "../amdtp-stream.h"
 
 struct snd_motu_packet_format {
-	unsigned char midi_flag_offset;
-	unsigned char midi_byte_offset;
 	unsigned char pcm_byte_offset;
 
 	unsigned char msg_chunks;
@@ -46,6 +46,8 @@ struct snd_motu {
 	/* For packet streaming */
 	struct snd_motu_packet_format tx_packet_formats;
 	struct snd_motu_packet_format rx_packet_formats;
+	struct amdtp_stream tx_stream;
+	struct amdtp_stream rx_stream;
 };
 
 enum snd_motu_spec_flags {
@@ -97,4 +99,11 @@ struct snd_motu_spec {
 	const struct snd_motu_protocol *const protocol;
 };
 
+int amdtp_motu_init(struct amdtp_stream *s, struct fw_unit *unit,
+		    enum amdtp_stream_direction dir,
+		    const struct snd_motu_protocol *const protocol);
+int amdtp_motu_set_parameters(struct amdtp_stream *s, unsigned int rate,
+			      struct snd_motu_packet_format *formats);
+int amdtp_motu_add_pcm_hw_constraints(struct amdtp_stream *s,
+				      struct snd_pcm_runtime *runtime);
 #endif