1 files changed, 1021 insertions, 0 deletions

diff --git a/sound/firewire/bebob/bebob_stream.c b/sound/firewire/bebob/bebob_stream.c
new file mode 100644
index 0000000..bc4f827
--- /dev/null
+++ b/sound/firewire/bebob/bebob_stream.c
@@ -0,0 +1,1021 @@
+/*
+ * bebob_stream.c - a part of driver for BeBoB based devices
+ *
+ * Copyright (c) 2013-2014 Takashi Sakamoto
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#include "./bebob.h"
+
+#define CALLBACK_TIMEOUT	1000
+#define FW_ISO_RESOURCE_DELAY	1000
+
+/*
+ * NOTE;
+ * For BeBoB streams, Both of input and output CMP connection are important.
+ *
+ * For most devices, each CMP connection starts to transmit/receive a
+ * corresponding stream. But for a few devices, both of CMP connection needs
+ * to start transmitting stream. An example is 'M-Audio Firewire 410'.
+ */
+
+/* 128 is an arbitrary length but it seems to be enough */
+#define FORMAT_MAXIMUM_LENGTH 128
+
+const unsigned int snd_bebob_rate_table[SND_BEBOB_STRM_FMT_ENTRIES] = {
+	[0] = 32000,
+	[1] = 44100,
+	[2] = 48000,
+	[3] = 88200,
+	[4] = 96000,
+	[5] = 176400,
+	[6] = 192000,
+};
+
+/*
+ * See: Table 51: Extended Stream Format Info ‘Sampling Frequency’
+ * in Additional AVC commands (Nov 2003, BridgeCo)
+ */
+static const unsigned int bridgeco_freq_table[] = {
+	[0] = 0x02,
+	[1] = 0x03,
+	[2] = 0x04,
+	[3] = 0x0a,
+	[4] = 0x05,
+	[5] = 0x06,
+	[6] = 0x07,
+};
+
+static unsigned int
+get_formation_index(unsigned int rate)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(snd_bebob_rate_table); i++) {
+		if (snd_bebob_rate_table[i] == rate)
+			return i;
+	}
+	return -EINVAL;
+}
+
+int
+snd_bebob_stream_get_rate(struct snd_bebob *bebob, unsigned int *curr_rate)
+{
+	unsigned int tx_rate, rx_rate, trials;
+	int err;
+
+	trials = 0;
+	do {
+		err = avc_general_get_sig_fmt(bebob->unit, &tx_rate,
+					      AVC_GENERAL_PLUG_DIR_OUT, 0);
+	} while (err == -EAGAIN && ++trials < 3);
+	if (err < 0)
+		goto end;
+
+	trials = 0;
+	do {
+		err = avc_general_get_sig_fmt(bebob->unit, &rx_rate,
+					      AVC_GENERAL_PLUG_DIR_IN, 0);
+	} while (err == -EAGAIN && ++trials < 3);
+	if (err < 0)
+		goto end;
+
+	*curr_rate = rx_rate;
+	if (rx_rate == tx_rate)
+		goto end;
+
+	/* synchronize receive stream rate to transmit stream rate */
+	err = avc_general_set_sig_fmt(bebob->unit, rx_rate,
+				      AVC_GENERAL_PLUG_DIR_IN, 0);
+end:
+	return err;
+}
+
+int
+snd_bebob_stream_set_rate(struct snd_bebob *bebob, unsigned int rate)
+{
+	int err;
+
+	err = avc_general_set_sig_fmt(bebob->unit, rate,
+				      AVC_GENERAL_PLUG_DIR_OUT, 0);
+	if (err < 0)
+		goto end;
+
+	err = avc_general_set_sig_fmt(bebob->unit, rate,
+				      AVC_GENERAL_PLUG_DIR_IN, 0);
+	if (err < 0)
+		goto end;
+
+	/*
+	 * Some devices need a bit time for transition.
+	 * 300msec is got by some experiments.
+	 */
+	msleep(300);
+end:
+	return err;
+}
+
+int
+snd_bebob_stream_check_internal_clock(struct snd_bebob *bebob, bool *internal)
+{
+	struct snd_bebob_clock_spec *clk_spec = bebob->spec->clock;
+	u8 addr[AVC_BRIDGECO_ADDR_BYTES], input[7];
+	unsigned int id;
+	int err = 0;
+
+	*internal = false;
+
+	/* 1.The device has its own operation to switch source of clock */
+	if (clk_spec) {
+		err = clk_spec->get(bebob, &id);
+		if (err < 0)
+			dev_err(&bebob->unit->device,
+				"fail to get clock source: %d\n", err);
+		else if (strncmp(clk_spec->labels[id], SND_BEBOB_CLOCK_INTERNAL,
+				 strlen(SND_BEBOB_CLOCK_INTERNAL)) == 0)
+			*internal = true;
+		goto end;
+	}
+
+	/*
+	 * 2.The device don't support to switch source of clock then assumed
+	 *   to use internal clock always
+	 */
+	if (bebob->sync_input_plug < 0) {
+		*internal = true;
+		goto end;
+	}
+
+	/*
+	 * 3.The device supports to switch source of clock by an usual way.
+	 *   Let's check input for 'Music Sub Unit Sync Input' plug.
+	 */
+	avc_bridgeco_fill_msu_addr(addr, AVC_BRIDGECO_PLUG_DIR_IN,
+				   bebob->sync_input_plug);
+	err = avc_bridgeco_get_plug_input(bebob->unit, addr, input);
+	if (err < 0) {
+		dev_err(&bebob->unit->device,
+			"fail to get an input for MSU in plug %d: %d\n",
+			bebob->sync_input_plug, err);
+		goto end;
+	}
+
+	/*
+	 * If there are no input plugs, all of fields are 0xff.
+	 * Here check the first field. This field is used for direction.
+	 */
+	if (input[0] == 0xff) {
+		*internal = true;
+		goto end;
+	}
+
+	/*
+	 * If source of clock is internal CSR, Music Sub Unit Sync Input is
+	 * a destination of Music Sub Unit Sync Output.
+	 */
+	*internal = ((input[0] == AVC_BRIDGECO_PLUG_DIR_OUT) &&
+		     (input[1] == AVC_BRIDGECO_PLUG_MODE_SUBUNIT) &&
+		     (input[2] == 0x0c) &&
+		     (input[3] == 0x00));
+end:
+	return err;
+}
+
+static unsigned int
+map_data_channels(struct snd_bebob *bebob, struct amdtp_stream *s)
+{
+	unsigned int sec, sections, ch, channels;
+	unsigned int pcm, midi, location;
+	unsigned int stm_pos, sec_loc, pos;
+	u8 *buf, addr[AVC_BRIDGECO_ADDR_BYTES], type;
+	enum avc_bridgeco_plug_dir dir;
+	int err;
+
+	/*
+	 * The length of return value of this command cannot be expected. Here
+	 * use the maximum length of FCP.
+	 */
+	buf = kzalloc(256, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	if (s == &bebob->tx_stream)
+		dir = AVC_BRIDGECO_PLUG_DIR_OUT;
+	else
+		dir = AVC_BRIDGECO_PLUG_DIR_IN;
+
+	avc_bridgeco_fill_unit_addr(addr, dir, AVC_BRIDGECO_PLUG_UNIT_ISOC, 0);
+	err = avc_bridgeco_get_plug_ch_pos(bebob->unit, addr, buf, 256);
+	if (err < 0) {
+		dev_err(&bebob->unit->device,
+			"fail to get channel position for isoc %s plug 0: %d\n",
+			(dir == AVC_BRIDGECO_PLUG_DIR_IN) ? "in" : "out",
+			err);
+		goto end;
+	}
+	pos = 0;
+
+	/* positions in I/O buffer */
+	pcm = 0;
+	midi = 0;
+
+	/* the number of sections in AMDTP packet */
+	sections = buf[pos++];
+
+	for (sec = 0; sec < sections; sec++) {
+		/* type of this section */
+		avc_bridgeco_fill_unit_addr(addr, dir,
+					    AVC_BRIDGECO_PLUG_UNIT_ISOC, 0);
+		err = avc_bridgeco_get_plug_section_type(bebob->unit, addr,
+							 sec, &type);
+		if (err < 0) {
+			dev_err(&bebob->unit->device,
+			"fail to get section type for isoc %s plug 0: %d\n",
+				(dir == AVC_BRIDGECO_PLUG_DIR_IN) ? "in" :
+								    "out",
+				err);
+			goto end;
+		}
+		/* NoType */
+		if (type == 0xff) {
+			err = -ENOSYS;
+			goto end;
+		}
+
+		/* the number of channels in this section */
+		channels = buf[pos++];
+
+		for (ch = 0; ch < channels; ch++) {
+			/* position of this channel in AMDTP packet */
+			stm_pos = buf[pos++] - 1;
+			/* location of this channel in this section */
+			sec_loc = buf[pos++] - 1;
+
+			/*
+			 * Basically the number of location is within the
+			 * number of channels in this section. But some models
+			 * of M-Audio don't follow this. Its location for MIDI
+			 * is the position of MIDI channels in AMDTP packet.
+			 */
+			if (sec_loc >= channels)
+				sec_loc = ch;
+
+			switch (type) {
+			/* for MIDI conformant data channel */
+			case 0x0a:
+				/* AMDTP_MAX_CHANNELS_FOR_MIDI is 1. */
+				if ((midi > 0) && (stm_pos != midi)) {
+					err = -ENOSYS;
+					goto end;
+				}
+				s->midi_position = stm_pos;
+				midi = stm_pos;
+				break;
+			/* for PCM data channel */
+			case 0x01:	/* Headphone */
+			case 0x02:	/* Microphone */
+			case 0x03:	/* Line */
+			case 0x04:	/* SPDIF */
+			case 0x05:	/* ADAT */
+			case 0x06:	/* TDIF */
+			case 0x07:	/* MADI */
+			/* for undefined/changeable signal  */
+			case 0x08:	/* Analog */
+			case 0x09:	/* Digital */
+			default:
+				location = pcm + sec_loc;
+				if (location >= AMDTP_MAX_CHANNELS_FOR_PCM) {
+					err = -ENOSYS;
+					goto end;
+				}
+				s->pcm_positions[location] = stm_pos;
+				break;
+			}
+		}
+
+		if (type != 0x0a)
+			pcm += channels;
+		else
+			midi += channels;
+	}
+end:
+	kfree(buf);
+	return err;
+}
+
+static int
+init_both_connections(struct snd_bebob *bebob)
+{
+	int err;
+
+	err = cmp_connection_init(&bebob->in_conn,
+				  bebob->unit, CMP_INPUT, 0);
+	if (err < 0)
+		goto end;
+
+	err = cmp_connection_init(&bebob->out_conn,
+				  bebob->unit, CMP_OUTPUT, 0);
+	if (err < 0)
+		cmp_connection_destroy(&bebob->in_conn);
+end:
+	return err;
+}
+
+static int
+check_connection_used_by_others(struct snd_bebob *bebob, struct amdtp_stream *s)
+{
+	struct cmp_connection *conn;
+	bool used;
+	int err;
+
+	if (s == &bebob->tx_stream)
+		conn = &bebob->out_conn;
+	else
+		conn = &bebob->in_conn;
+
+	err = cmp_connection_check_used(conn, &used);
+	if ((err >= 0) && used && !amdtp_stream_running(s)) {
+		dev_err(&bebob->unit->device,
+			"Connection established by others: %cPCR[%d]\n",
+			(conn->direction == CMP_OUTPUT) ? 'o' : 'i',
+			conn->pcr_index);
+		err = -EBUSY;
+	}
+
+	return err;
+}
+
+static int
+make_both_connections(struct snd_bebob *bebob, unsigned int rate)
+{
+	int index, pcm_channels, midi_channels, err = 0;
+
+	if (bebob->connected)
+		goto end;
+
+	/* confirm params for both streams */
+	index = get_formation_index(rate);
+	pcm_channels = bebob->tx_stream_formations[index].pcm;
+	midi_channels = bebob->tx_stream_formations[index].midi;
+	amdtp_stream_set_parameters(&bebob->tx_stream,
+				    rate, pcm_channels, midi_channels * 8);
+	pcm_channels = bebob->rx_stream_formations[index].pcm;
+	midi_channels = bebob->rx_stream_formations[index].midi;
+	amdtp_stream_set_parameters(&bebob->rx_stream,
+				    rate, pcm_channels, midi_channels * 8);
+
+	/* establish connections for both streams */
+	err = cmp_connection_establish(&bebob->out_conn,
+			amdtp_stream_get_max_payload(&bebob->tx_stream));
+	if (err < 0)
+		goto end;
+	err = cmp_connection_establish(&bebob->in_conn,
+			amdtp_stream_get_max_payload(&bebob->rx_stream));
+	if (err < 0) {
+		cmp_connection_break(&bebob->out_conn);
+		goto end;
+	}
+
+	bebob->connected = true;
+end:
+	return err;
+}
+
+static void
+break_both_connections(struct snd_bebob *bebob)
+{
+	cmp_connection_break(&bebob->in_conn);
+	cmp_connection_break(&bebob->out_conn);
+
+	bebob->connected = false;
+
+	/* These models seems to be in transition state for a longer time. */
+	if (bebob->maudio_special_quirk != NULL)
+		msleep(200);
+}
+
+static void
+destroy_both_connections(struct snd_bebob *bebob)
+{
+	break_both_connections(bebob);
+
+	cmp_connection_destroy(&bebob->in_conn);
+	cmp_connection_destroy(&bebob->out_conn);
+}
+
+static int
+get_sync_mode(struct snd_bebob *bebob, enum cip_flags *sync_mode)
+{
+	/* currently this module doesn't support SYT-Match mode */
+	*sync_mode = CIP_SYNC_TO_DEVICE;
+	return 0;
+}
+
+static int
+start_stream(struct snd_bebob *bebob, struct amdtp_stream *stream,
+	     unsigned int rate)
+{
+	struct cmp_connection *conn;
+	int err = 0;
+
+	if (stream == &bebob->rx_stream)
+		conn = &bebob->in_conn;
+	else
+		conn = &bebob->out_conn;
+
+	/* channel mapping */
+	if (bebob->maudio_special_quirk == NULL) {
+		err = map_data_channels(bebob, stream);
+		if (err < 0)
+			goto end;
+	}
+
+	/* start amdtp stream */
+	err = amdtp_stream_start(stream,
+				 conn->resources.channel,
+				 conn->speed);
+end:
+	return err;
+}
+
+int snd_bebob_stream_init_duplex(struct snd_bebob *bebob)
+{
+	int err;
+
+	err = init_both_connections(bebob);
+	if (err < 0)
+		goto end;
+
+	err = amdtp_stream_init(&bebob->tx_stream, bebob->unit,
+				AMDTP_IN_STREAM, CIP_BLOCKING);
+	if (err < 0) {
+		amdtp_stream_destroy(&bebob->tx_stream);
+		destroy_both_connections(bebob);
+		goto end;
+	}
+	/* See comments in next function */
+	init_completion(&bebob->bus_reset);
+	bebob->tx_stream.flags |= CIP_SKIP_INIT_DBC_CHECK;
+	/*
+	 * At high sampling rate, M-Audio special firmware transmits empty
+	 * packet with the value of dbc incremented by 8 but the others are
+	 * valid to IEC 61883-1.
+	 */
+	if (bebob->maudio_special_quirk)
+		bebob->tx_stream.flags |= CIP_EMPTY_HAS_WRONG_DBC;
+
+	err = amdtp_stream_init(&bebob->rx_stream, bebob->unit,
+				AMDTP_OUT_STREAM, CIP_BLOCKING);
+	if (err < 0) {
+		amdtp_stream_destroy(&bebob->tx_stream);
+		amdtp_stream_destroy(&bebob->rx_stream);
+		destroy_both_connections(bebob);
+	}
+	/*
+	 * The firmware for these devices ignore MIDI messages in more than
+	 * first 8 data blocks of an received AMDTP packet.
+	 */
+	if (bebob->spec == &maudio_fw410_spec ||
+	    bebob->spec == &maudio_special_spec)
+		bebob->rx_stream.rx_blocks_for_midi = 8;
+end:
+	return err;
+}
+
+int snd_bebob_stream_start_duplex(struct snd_bebob *bebob, unsigned int rate)
+{
+	struct snd_bebob_rate_spec *rate_spec = bebob->spec->rate;
+	struct amdtp_stream *master, *slave;
+	atomic_t *slave_substreams;
+	enum cip_flags sync_mode;
+	unsigned int curr_rate;
+	bool updated = false;
+	int err = 0;
+
+	/*
+	 * Normal BeBoB firmware has a quirk at bus reset to transmits packets
+	 * with discontinuous value in dbc field.
+	 *
+	 * This 'struct completion' is used to call .update() at first to update
+	 * connections/streams. Next following codes handle streaming error.
+	 */
+	if (amdtp_streaming_error(&bebob->tx_stream)) {
+		if (completion_done(&bebob->bus_reset))
+			reinit_completion(&bebob->bus_reset);
+
+		updated = (wait_for_completion_interruptible_timeout(
+				&bebob->bus_reset,
+				msecs_to_jiffies(FW_ISO_RESOURCE_DELAY)) > 0);
+	}
+
+	mutex_lock(&bebob->mutex);
+
+	/* Need no substreams */
+	if (atomic_read(&bebob->playback_substreams) == 0 &&
+	    atomic_read(&bebob->capture_substreams)  == 0)
+		goto end;
+
+	err = get_sync_mode(bebob, &sync_mode);
+	if (err < 0)
+		goto end;
+	if (sync_mode == CIP_SYNC_TO_DEVICE) {
+		master = &bebob->tx_stream;
+		slave  = &bebob->rx_stream;
+		slave_substreams = &bebob->playback_substreams;
+	} else {
+		master = &bebob->rx_stream;
+		slave  = &bebob->tx_stream;
+		slave_substreams = &bebob->capture_substreams;
+	}
+
+	/*
+	 * Considering JACK/FFADO streaming:
+	 * TODO: This can be removed hwdep functionality becomes popular.
+	 */
+	err = check_connection_used_by_others(bebob, master);
+	if (err < 0)
+		goto end;
+
+	/*
+	 * packet queueing error or detecting discontinuity
+	 *
+	 * At bus reset, connections should not be broken here. So streams need
+	 * to be re-started. This is a reason to use SKIP_INIT_DBC_CHECK flag.
+	 */
+	if (amdtp_streaming_error(master))
+		amdtp_stream_stop(master);
+	if (amdtp_streaming_error(slave))
+		amdtp_stream_stop(slave);
+	if (!updated &&
+	    !amdtp_stream_running(master) && !amdtp_stream_running(slave))
+		break_both_connections(bebob);
+
+	/* stop streams if rate is different */
+	err = rate_spec->get(bebob, &curr_rate);
+	if (err < 0) {
+		dev_err(&bebob->unit->device,
+			"fail to get sampling rate: %d\n", err);
+		goto end;
+	}
+	if (rate == 0)
+		rate = curr_rate;
+	if (rate != curr_rate) {
+		amdtp_stream_stop(master);
+		amdtp_stream_stop(slave);
+		break_both_connections(bebob);
+	}
+
+	/* master should be always running */
+	if (!amdtp_stream_running(master)) {
+		amdtp_stream_set_sync(sync_mode, master, slave);
+		bebob->master = master;
+
+		/*
+		 * NOTE:
+		 * If establishing connections at first, Yamaha GO46
+		 * (and maybe Terratec X24) don't generate sound.
+		 *
+		 * For firmware customized by M-Audio, refer to next NOTE.
+		 */
+		if (bebob->maudio_special_quirk == NULL) {
+			err = rate_spec->set(bebob, rate);
+			if (err < 0) {
+				dev_err(&bebob->unit->device,
+					"fail to set sampling rate: %d\n",
+					err);
+				goto end;
+			}
+		}
+
+		err = make_both_connections(bebob, rate);
+		if (err < 0)
+			goto end;
+
+		err = start_stream(bebob, master, rate);
+		if (err < 0) {
+			dev_err(&bebob->unit->device,
+				"fail to run AMDTP master stream:%d\n", err);
+			break_both_connections(bebob);
+			goto end;
+		}
+
+		/*
+		 * NOTE:
+		 * The firmware customized by M-Audio uses these commands to
+		 * start transmitting stream. This is not usual way.
+		 */
+		if (bebob->maudio_special_quirk != NULL) {
+			err = rate_spec->set(bebob, rate);
+			if (err < 0) {
+				dev_err(&bebob->unit->device,
+					"fail to ensure sampling rate: %d\n",
+					err);
+				amdtp_stream_stop(master);
+				break_both_connections(bebob);
+				goto end;
+			}
+		}
+
+		/* wait first callback */
+		if (!amdtp_stream_wait_callback(master, CALLBACK_TIMEOUT)) {
+			amdtp_stream_stop(master);
+			break_both_connections(bebob);
+			err = -ETIMEDOUT;
+			goto end;
+		}
+	}
+
+	/* start slave if needed */
+	if (atomic_read(slave_substreams) > 0 && !amdtp_stream_running(slave)) {
+		err = start_stream(bebob, slave, rate);
+		if (err < 0) {
+			dev_err(&bebob->unit->device,
+				"fail to run AMDTP slave stream:%d\n", err);
+			amdtp_stream_stop(master);
+			break_both_connections(bebob);
+			goto end;
+		}
+
+		/* wait first callback */
+		if (!amdtp_stream_wait_callback(slave, CALLBACK_TIMEOUT)) {
+			amdtp_stream_stop(slave);
+			amdtp_stream_stop(master);
+			break_both_connections(bebob);
+			err = -ETIMEDOUT;
+		}
+	}
+end:
+	mutex_unlock(&bebob->mutex);
+	return err;
+}
+
+void snd_bebob_stream_stop_duplex(struct snd_bebob *bebob)
+{
+	struct amdtp_stream *master, *slave;
+	atomic_t *master_substreams, *slave_substreams;
+
+	mutex_lock(&bebob->mutex);
+
+	if (bebob->master == &bebob->rx_stream) {
+		slave  = &bebob->tx_stream;
+		master = &bebob->rx_stream;
+		slave_substreams  = &bebob->capture_substreams;
+		master_substreams = &bebob->playback_substreams;
+	} else {
+		slave  = &bebob->rx_stream;
+		master = &bebob->tx_stream;
+		slave_substreams  = &bebob->playback_substreams;
+		master_substreams = &bebob->capture_substreams;
+	}
+
+	if (atomic_read(slave_substreams) == 0) {
+		amdtp_stream_pcm_abort(slave);
+		amdtp_stream_stop(slave);
+
+		if (atomic_read(master_substreams) == 0) {
+			amdtp_stream_pcm_abort(master);
+			amdtp_stream_stop(master);
+			break_both_connections(bebob);
+		}
+	}
+
+	mutex_unlock(&bebob->mutex);
+}
+
+void snd_bebob_stream_update_duplex(struct snd_bebob *bebob)
+{
+	/* vs. XRUN recovery due to discontinuity at bus reset */
+	mutex_lock(&bebob->mutex);
+
+	if ((cmp_connection_update(&bebob->in_conn) < 0) ||
+	    (cmp_connection_update(&bebob->out_conn) < 0)) {
+		amdtp_stream_pcm_abort(&bebob->rx_stream);
+		amdtp_stream_pcm_abort(&bebob->tx_stream);
+		amdtp_stream_stop(&bebob->rx_stream);
+		amdtp_stream_stop(&bebob->tx_stream);
+		break_both_connections(bebob);
+	} else {
+		amdtp_stream_update(&bebob->rx_stream);
+		amdtp_stream_update(&bebob->tx_stream);
+	}
+
+	/* wake up stream_start_duplex() */
+	if (!completion_done(&bebob->bus_reset))
+		complete_all(&bebob->bus_reset);
+
+	mutex_unlock(&bebob->mutex);
+}
+
+void snd_bebob_stream_destroy_duplex(struct snd_bebob *bebob)
+{
+	mutex_lock(&bebob->mutex);
+
+	amdtp_stream_pcm_abort(&bebob->rx_stream);
+	amdtp_stream_pcm_abort(&bebob->tx_stream);
+
+	amdtp_stream_stop(&bebob->rx_stream);
+	amdtp_stream_stop(&bebob->tx_stream);
+
+	amdtp_stream_destroy(&bebob->rx_stream);
+	amdtp_stream_destroy(&bebob->tx_stream);
+
+	destroy_both_connections(bebob);
+
+	mutex_unlock(&bebob->mutex);
+}
+
+/*
+ * See: Table 50: Extended Stream Format Info Format Hierarchy Level 2’
+ * in Additional AVC commands (Nov 2003, BridgeCo)
+ * Also 'Clause 12 AM824 sequence adaption layers' in IEC 61883-6:2005
+ */
+static int
+parse_stream_formation(u8 *buf, unsigned int len,
+		       struct snd_bebob_stream_formation *formation)
+{
+	unsigned int i, e, channels, format;
+
+	/*
+	 * this module can support a hierarchy combination that:
+	 *  Root:	Audio and Music (0x90)
+	 *  Level 1:	AM824 Compound  (0x40)
+	 */
+	if ((buf[0] != 0x90) || (buf[1] != 0x40))
+		return -ENOSYS;
+
+	/* check sampling rate */
+	for (i = 0; i < ARRAY_SIZE(bridgeco_freq_table); i++) {
+		if (buf[2] == bridgeco_freq_table[i])
+			break;
+	}
+	if (i == ARRAY_SIZE(bridgeco_freq_table))
+		return -ENOSYS;
+
+	/* Avoid double count by different entries for the same rate. */
+	memset(&formation[i], 0, sizeof(struct snd_bebob_stream_formation));
+
+	for (e = 0; e < buf[4]; e++) {
+		channels = buf[5 + e * 2];
+		format = buf[6 + e * 2];
+
+		switch (format) {
+		/* IEC 60958 Conformant, currently handled as MBLA */
+		case 0x00:
+		/* Multi bit linear audio */
+		case 0x06:	/* Raw */
+			formation[i].pcm += channels;
+			break;
+		/* MIDI Conformant */
+		case 0x0d:
+			formation[i].midi += channels;
+			break;
+		/* IEC 61937-3 to 7 */
+		case 0x01:
+		case 0x02:
+		case 0x03:
+		case 0x04:
+		case 0x05:
+		/* Multi bit linear audio */
+		case 0x07:	/* DVD-Audio */
+		case 0x0c:	/* High Precision */
+		/* One Bit Audio */
+		case 0x08:	/* (Plain) Raw */
+		case 0x09:	/* (Plain) SACD */
+		case 0x0a:	/* (Encoded) Raw */
+		case 0x0b:	/* (Encoded) SACD */
+		/* Synchronization Stream (Stereo Raw audio) */
+		case 0x40:
+		/* Don't care */
+		case 0xff:
+		default:
+			return -ENOSYS;	/* not supported */
+		}
+	}
+
+	if (formation[i].pcm  > AMDTP_MAX_CHANNELS_FOR_PCM ||
+	    formation[i].midi > AMDTP_MAX_CHANNELS_FOR_MIDI)
+		return -ENOSYS;
+
+	return 0;
+}
+
+static int
+fill_stream_formations(struct snd_bebob *bebob, enum avc_bridgeco_plug_dir dir,
+		       unsigned short pid)
+{
+	u8 *buf;
+	struct snd_bebob_stream_formation *formations;
+	unsigned int len, eid;
+	u8 addr[AVC_BRIDGECO_ADDR_BYTES];
+	int err;
+
+	buf = kmalloc(FORMAT_MAXIMUM_LENGTH, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	if (dir == AVC_BRIDGECO_PLUG_DIR_IN)
+		formations = bebob->rx_stream_formations;
+	else
+		formations = bebob->tx_stream_formations;
+
+	for (eid = 0; eid < SND_BEBOB_STRM_FMT_ENTRIES; eid++) {
+		len = FORMAT_MAXIMUM_LENGTH;
+		avc_bridgeco_fill_unit_addr(addr, dir,
+					    AVC_BRIDGECO_PLUG_UNIT_ISOC, pid);
+		err = avc_bridgeco_get_plug_strm_fmt(bebob->unit, addr, buf,
+						     &len, eid);
+		/* No entries remained. */
+		if (err == -EINVAL && eid > 0) {
+			err = 0;
+			break;
+		} else if (err < 0) {
+			dev_err(&bebob->unit->device,
+			"fail to get stream format %d for isoc %s plug %d:%d\n",
+				eid,
+				(dir == AVC_BRIDGECO_PLUG_DIR_IN) ? "in" :
+								    "out",
+				pid, err);
+			break;
+		}
+
+		err = parse_stream_formation(buf, len, formations);
+		if (err < 0)
+			break;
+	}
+
+	kfree(buf);
+	return err;
+}
+
+static int
+seek_msu_sync_input_plug(struct snd_bebob *bebob)
+{
+	u8 plugs[AVC_PLUG_INFO_BUF_BYTES], addr[AVC_BRIDGECO_ADDR_BYTES];
+	unsigned int i;
+	enum avc_bridgeco_plug_type type;
+	int err;
+
+	/* Get the number of Music Sub Unit for both direction. */
+	err = avc_general_get_plug_info(bebob->unit, 0x0c, 0x00, 0x00, plugs);
+	if (err < 0) {
+		dev_err(&bebob->unit->device,
+			"fail to get info for MSU in/out plugs: %d\n",
+			err);
+		goto end;
+	}
+
+	/* seek destination plugs for 'MSU sync input' */
+	bebob->sync_input_plug = -1;
+	for (i = 0; i < plugs[0]; i++) {
+		avc_bridgeco_fill_msu_addr(addr, AVC_BRIDGECO_PLUG_DIR_IN, i);
+		err = avc_bridgeco_get_plug_type(bebob->unit, addr, &type);
+		if (err < 0) {
+			dev_err(&bebob->unit->device,
+				"fail to get type for MSU in plug %d: %d\n",
+				i, err);
+			goto end;
+		}
+
+		if (type == AVC_BRIDGECO_PLUG_TYPE_SYNC) {
+			bebob->sync_input_plug = i;
+			break;
+		}
+	}
+end:
+	return err;
+}
+
+int snd_bebob_stream_discover(struct snd_bebob *bebob)
+{
+	struct snd_bebob_clock_spec *clk_spec = bebob->spec->clock;
+	u8 plugs[AVC_PLUG_INFO_BUF_BYTES], addr[AVC_BRIDGECO_ADDR_BYTES];
+	enum avc_bridgeco_plug_type type;
+	unsigned int i;
+	int err;
+
+	/* the number of plugs for isoc in/out, ext in/out  */
+	err = avc_general_get_plug_info(bebob->unit, 0x1f, 0x07, 0x00, plugs);
+	if (err < 0) {
+		dev_err(&bebob->unit->device,
+		"fail to get info for isoc/external in/out plugs: %d\n",
+			err);
+		goto end;
+	}
+
+	/*
+	 * This module supports at least one isoc input plug and one isoc
+	 * output plug.
+	 */
+	if ((plugs[0] == 0) || (plugs[1] == 0)) {
+		err = -ENOSYS;
+		goto end;
+	}
+
+	avc_bridgeco_fill_unit_addr(addr, AVC_BRIDGECO_PLUG_DIR_IN,
+				    AVC_BRIDGECO_PLUG_UNIT_ISOC, 0);
+	err = avc_bridgeco_get_plug_type(bebob->unit, addr, &type);
+	if (err < 0) {
+		dev_err(&bebob->unit->device,
+			"fail to get type for isoc in plug 0: %d\n", err);
+		goto end;
+	} else if (type != AVC_BRIDGECO_PLUG_TYPE_ISOC) {
+		err = -ENOSYS;
+		goto end;
+	}
+	err = fill_stream_formations(bebob, AVC_BRIDGECO_PLUG_DIR_IN, 0);
+	if (err < 0)
+		goto end;
+
+	avc_bridgeco_fill_unit_addr(addr, AVC_BRIDGECO_PLUG_DIR_OUT,
+				    AVC_BRIDGECO_PLUG_UNIT_ISOC, 0);
+	err = avc_bridgeco_get_plug_type(bebob->unit, addr, &type);
+	if (err < 0) {
+		dev_err(&bebob->unit->device,
+			"fail to get type for isoc out plug 0: %d\n", err);
+		goto end;
+	} else if (type != AVC_BRIDGECO_PLUG_TYPE_ISOC) {
+		err = -ENOSYS;
+		goto end;
+	}
+	err = fill_stream_formations(bebob, AVC_BRIDGECO_PLUG_DIR_OUT, 0);
+	if (err < 0)
+		goto end;
+
+	/* count external input plugs for MIDI */
+	bebob->midi_input_ports = 0;
+	for (i = 0; i < plugs[2]; i++) {
+		avc_bridgeco_fill_unit_addr(addr, AVC_BRIDGECO_PLUG_DIR_IN,
+					    AVC_BRIDGECO_PLUG_UNIT_EXT, i);
+		err = avc_bridgeco_get_plug_type(bebob->unit, addr, &type);
+		if (err < 0) {
+			dev_err(&bebob->unit->device,
+			"fail to get type for external in plug %d: %d\n",
+				i, err);
+			goto end;
+		} else if (type == AVC_BRIDGECO_PLUG_TYPE_MIDI) {
+			bebob->midi_input_ports++;
+		}
+	}
+
+	/* count external output plugs for MIDI */
+	bebob->midi_output_ports = 0;
+	for (i = 0; i < plugs[3]; i++) {
+		avc_bridgeco_fill_unit_addr(addr, AVC_BRIDGECO_PLUG_DIR_OUT,
+					    AVC_BRIDGECO_PLUG_UNIT_EXT, i);
+		err = avc_bridgeco_get_plug_type(bebob->unit, addr, &type);
+		if (err < 0) {
+			dev_err(&bebob->unit->device,
+			"fail to get type for external out plug %d: %d\n",
+				i, err);
+			goto end;
+		} else if (type == AVC_BRIDGECO_PLUG_TYPE_MIDI) {
+			bebob->midi_output_ports++;
+		}
+	}
+
+	/* for check source of clock later */
+	if (!clk_spec)
+		err = seek_msu_sync_input_plug(bebob);
+end:
+	return err;
+}
+
+void snd_bebob_stream_lock_changed(struct snd_bebob *bebob)
+{
+	bebob->dev_lock_changed = true;
+	wake_up(&bebob->hwdep_wait);
+}
+
+int snd_bebob_stream_lock_try(struct snd_bebob *bebob)
+{
+	int err;
+
+	spin_lock_irq(&bebob->lock);
+
+	/* user land lock this */
+	if (bebob->dev_lock_count < 0) {
+		err = -EBUSY;
+		goto end;
+	}
+
+	/* this is the first time */
+	if (bebob->dev_lock_count++ == 0)
+		snd_bebob_stream_lock_changed(bebob);
+	err = 0;
+end:
+	spin_unlock_irq(&bebob->lock);
+	return err;
+}
+
+void snd_bebob_stream_lock_release(struct snd_bebob *bebob)
+{
+	spin_lock_irq(&bebob->lock);
+
+	if (WARN_ON(bebob->dev_lock_count <= 0))
+		goto end;
+	if (--bebob->dev_lock_count == 0)
+		snd_bebob_stream_lock_changed(bebob);
+end:
+	spin_unlock_irq(&bebob->lock);
+}