[PATCH v2 0/4] ALSA: firewire-lib: drop initial NODATA packets or empty packets

[PATCH v2 0/4] ALSA: firewire-lib: drop initial NODATA packets or empty packets

[Takashi Sakamoto]

Hi,

This patchset is take 2 of my previous one;
 * https://lore.kernel.org/alsa-devel/20210523124114.272134-1-o-takashi@sakamocchi.jp/

The devices based on BeBoB ASICs or the devices in Tascam FireWire
series transfer a batch of NODATA packet or empty packet in initial step
of streaming. To avoid processing them, current implementation uses an
option to skip processing content of tx packet during some initial
cycles. However, the hard-coded number is not enough useful.

In 1st patch, ALSA IEC 61883-1/6 packet streaming engine becomes to drop
the initial packets. As a result, The tx_init_skip_cycles argument of
amdtp_domain_start() function changes its meaning. In the following
patches, ALSA bebob driver is refactored.

Changes from v1:
 * Fix -Wunused-but-set-variable warning reported by 0day-ci
 * Add 2nd patch to obsolete unused member of structure

Takashi Sakamoto (4):
  ALSA: firewire-lib: drop initial NODATA or empty packet
  ALSA: firewire-lib: obsolete callbacked member
  ALSA: bebob: cancel switching connection order
  ALSA: bebob: distinguish M-Audio ProFire Lightbridge quirk

 sound/firewire/amdtp-stream.c       | 145 +++++++++++++++++++---------
 sound/firewire/amdtp-stream.h       |   6 +-
 sound/firewire/bebob/bebob.c        |  10 +-
 sound/firewire/bebob/bebob.h        |   1 +
 sound/firewire/bebob/bebob_stream.c |  25 ++---
 5 files changed, 122 insertions(+), 65 deletions(-)

-- 
2.27.0

[PATCH v2 1/4] ALSA: firewire-lib: drop initial NODATA or empty packet

[Takashi Sakamoto]

The devices based on BeBoB ASICs or the devices in Tascam FireWire
series transfer a batch of NODATA packet or empty packet in the beginning
of packet streaming. To avoid processing them, current implementation uses
an option to skip processing content of tx packet during some initial
cycles. However, the hard-coded number is not enough useful.

This commit drops content of packets till the packet includes any event
firstly. The function of option is to skip processing content of tx packet
with any event after dropping.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
---
 sound/firewire/amdtp-stream.c | 136 ++++++++++++++++++++++++----------
 sound/firewire/amdtp-stream.h |   3 +
 2 files changed, 100 insertions(+), 39 deletions(-)

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index 6dceb8cd6e0c..84608b856322 100644
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -49,8 +49,10 @@
 #define CIP_FMT_MASK		0x3f000000
 #define CIP_FDF_MASK		0x00ff0000
 #define CIP_FDF_SHIFT		16
+#define CIP_FDF_NO_DATA		0xff
 #define CIP_SYT_MASK		0x0000ffff
 #define CIP_SYT_NO_INFO		0xffff
+#define CIP_NO_DATA		((CIP_FDF_NO_DATA << CIP_FDF_SHIFT) | CIP_SYT_NO_INFO)
 
 #define CIP_HEADER_SIZE		(sizeof(__be32) * CIP_HEADER_QUADLETS)
 
@@ -1198,6 +1200,99 @@ static void process_tx_packets_intermediately(struct fw_iso_context *context, u3
 	}
 }
 
+static void drop_tx_packets_initially(struct fw_iso_context *context, u32 tstamp,
+				      size_t header_length, void *header, void *private_data)
+{
+	struct amdtp_stream *s = private_data;
+	struct amdtp_domain *d = s->domain;
+	__be32 *ctx_header;
+	unsigned int count;
+	unsigned int events;
+	int i;
+
+	if (s->packet_index < 0)
+		return;
+
+	count = header_length / s->ctx_data.tx.ctx_header_size;
+
+	// Attempt to detect any event in the batch of packets.
+	events = 0;
+	ctx_header = header;
+	for (i = 0; i < count; ++i) {
+		unsigned int payload_quads =
+			(be32_to_cpu(*ctx_header) >> ISO_DATA_LENGTH_SHIFT) / sizeof(__be32);
+		unsigned int data_blocks;
+
+		if (s->flags & CIP_NO_HEADER) {
+			data_blocks = payload_quads / s->data_block_quadlets;
+		} else {
+			__be32 *cip_headers = ctx_header + IR_CTX_HEADER_DEFAULT_QUADLETS;
+
+			if (payload_quads < CIP_HEADER_QUADLETS) {
+				data_blocks = 0;
+			} else {
+				payload_quads -= CIP_HEADER_QUADLETS;
+
+				if (s->flags & CIP_UNAWARE_SYT) {
+					data_blocks = payload_quads / s->data_block_quadlets;
+				} else {
+					u32 cip1 = be32_to_cpu(cip_headers[1]);
+
+					// NODATA packet can includes any data blocks but they are
+					// not available as event.
+					if ((cip1 & CIP_NO_DATA) == CIP_NO_DATA)
+						data_blocks = 0;
+					else
+						data_blocks = payload_quads / s->data_block_quadlets;
+				}
+			}
+		}
+
+		events += data_blocks;
+
+		ctx_header += s->ctx_data.tx.ctx_header_size / sizeof(__be32);
+	}
+
+	drop_tx_packets(context, tstamp, header_length, header, s);
+
+	if (events > 0)
+		s->ctx_data.tx.event_starts = true;
+
+	// Decide the cycle count to begin processing content of packet in IR contexts.
+	{
+		unsigned int stream_count = 0;
+		unsigned int event_starts_count = 0;
+		unsigned int cycle = UINT_MAX;
+
+		list_for_each_entry(s, &d->streams, list) {
+			if (s->direction == AMDTP_IN_STREAM) {
+				++stream_count;
+				if (s->ctx_data.tx.event_starts)
+					++event_starts_count;
+			}
+		}
+
+		if (stream_count == event_starts_count) {
+			unsigned int next_cycle;
+
+			list_for_each_entry(s, &d->streams, list) {
+				if (s->direction != AMDTP_IN_STREAM)
+					continue;
+
+				next_cycle = increment_ohci_cycle_count(s->next_cycle,
+								d->processing_cycle.tx_init_skip);
+				if (cycle == UINT_MAX ||
+				    compare_ohci_cycle_count(next_cycle, cycle) > 0)
+					cycle = next_cycle;
+
+				s->context->callback.sc = process_tx_packets_intermediately;
+			}
+
+			d->processing_cycle.tx_start = cycle;
+		}
+	}
+}
+
 static void process_ctxs_in_domain(struct amdtp_domain *d)
 {
 	struct amdtp_stream *s;
@@ -1277,20 +1372,14 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context,
 {
 	struct amdtp_stream *s = private_data;
 	struct amdtp_domain *d = s->domain;
-	const __be32 *ctx_header = header;
-	u32 cycle;
 
 	// For in-stream, first packet has come.
 	// For out-stream, prepared to transmit first packet
 	s->callbacked = true;
 
 	if (s->direction == AMDTP_IN_STREAM) {
-		cycle = compute_ohci_cycle_count(ctx_header[1]);
-
-		context->callback.sc = drop_tx_packets;
+		context->callback.sc = drop_tx_packets_initially;
 	} else {
-		cycle = compute_ohci_it_cycle(*ctx_header, s->queue_size);
-
 		if (s == d->irq_target)
 			context->callback.sc = irq_target_callback_skip;
 		else
@@ -1298,38 +1387,6 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context,
 	}
 
 	context->callback.sc(context, tstamp, header_length, header, s);
-
-	// Decide the cycle count to begin processing content of packet in IR contexts.
-	if (s->direction == AMDTP_IN_STREAM) {
-		unsigned int stream_count = 0;
-		unsigned int callbacked_count = 0;
-
-		list_for_each_entry(s, &d->streams, list) {
-			if (s->direction == AMDTP_IN_STREAM) {
-				++stream_count;
-				if (s->callbacked)
-					++callbacked_count;
-			}
-		}
-
-		if (stream_count == callbacked_count) {
-			unsigned int next_cycle;
-
-			list_for_each_entry(s, &d->streams, list) {
-				if (s->direction != AMDTP_IN_STREAM)
-					continue;
-
-				next_cycle = increment_ohci_cycle_count(s->next_cycle,
-								d->processing_cycle.tx_init_skip);
-				if (compare_ohci_cycle_count(next_cycle, cycle) > 0)
-					cycle = next_cycle;
-
-				s->context->callback.sc = process_tx_packets_intermediately;
-			}
-
-			d->processing_cycle.tx_start = cycle;
-		}
-	}
 }
 
 /**
@@ -1409,6 +1466,7 @@ static int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed,
 	if (s->direction == AMDTP_IN_STREAM) {
 		s->ctx_data.tx.max_ctx_payload_length = max_ctx_payload_size;
 		s->ctx_data.tx.ctx_header_size = ctx_header_size;
+		s->ctx_data.tx.event_starts = false;
 	} else {
 		static const struct {
 			unsigned int data_block;
diff --git a/sound/firewire/amdtp-stream.h b/sound/firewire/amdtp-stream.h
index 467d5021624b..d3ba2e1c1522 100644
--- a/sound/firewire/amdtp-stream.h
+++ b/sound/firewire/amdtp-stream.h
@@ -138,6 +138,9 @@ struct amdtp_stream {
 			// Fixed interval of dbc between previos/current
 			// packets.
 			unsigned int dbc_interval;
+
+			// The device starts multiplexing events to the packet.
+			bool event_starts;
 		} tx;
 		struct {
 			// To generate CIP header.
-- 
2.27.0

[PATCH v2 2/4] ALSA: firewire-lib: obsolete callbacked member

[Takashi Sakamoto]

The member of callbacked in AMDTP stream structure is not used anymore.
Instead, ready_processing member is used to wake up yielding task of user
process.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
---
 sound/firewire/amdtp-stream.c | 9 ++-------
 sound/firewire/amdtp-stream.h | 3 +--
 2 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index 84608b856322..68ffbc33f692 100644
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -110,7 +110,6 @@ int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit,
 	s->packet_index = 0;
 
 	init_waitqueue_head(&s->ready_wait);
-	s->callbacked = false;
 
 	s->fmt = fmt;
 	s->process_ctx_payloads = process_ctx_payloads;
@@ -1365,7 +1364,8 @@ static void irq_target_callback_skip(struct fw_iso_context *context, u32 tstamp,
 	d->processing_cycle.rx_start = cycle;
 }
 
-// this is executed one time.
+// This is executed one time. For in-stream, first packet has come. For out-stream, prepared to
+// transmit first packet.
 static void amdtp_stream_first_callback(struct fw_iso_context *context,
 					u32 tstamp, size_t header_length,
 					void *header, void *private_data)
@@ -1373,10 +1373,6 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context,
 	struct amdtp_stream *s = private_data;
 	struct amdtp_domain *d = s->domain;
 
-	// For in-stream, first packet has come.
-	// For out-stream, prepared to transmit first packet
-	s->callbacked = true;
-
 	if (s->direction == AMDTP_IN_STREAM) {
 		context->callback.sc = drop_tx_packets_initially;
 	} else {
@@ -1536,7 +1532,6 @@ static int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed,
 	if ((s->flags & CIP_EMPTY_WITH_TAG0) || (s->flags & CIP_NO_HEADER))
 		tag |= FW_ISO_CONTEXT_MATCH_TAG0;
 
-	s->callbacked = false;
 	s->ready_processing = false;
 	err = fw_iso_context_start(s->context, -1, 0, tag);
 	if (err < 0)
diff --git a/sound/firewire/amdtp-stream.h b/sound/firewire/amdtp-stream.h
index d3ba2e1c1522..34294776f9e8 100644
--- a/sound/firewire/amdtp-stream.h
+++ b/sound/firewire/amdtp-stream.h
@@ -183,8 +183,7 @@ struct amdtp_stream {
 
 	// To start processing content of packets at the same cycle in several contexts for
 	// each direction.
-	bool callbacked:1;
-	bool ready_processing:1;
+	bool ready_processing;
 	wait_queue_head_t ready_wait;
 	unsigned int next_cycle;
 
-- 
2.27.0

[PATCH v2 3/4] ALSA: bebob: cancel switching connection order

[Takashi Sakamoto]

The order to establish connection seems to be meaningless.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
---
 sound/firewire/bebob/bebob_stream.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/sound/firewire/bebob/bebob_stream.c b/sound/firewire/bebob/bebob_stream.c
index df764171f84b..975670a29a72 100644
--- a/sound/firewire/bebob/bebob_stream.c
+++ b/sound/firewire/bebob/bebob_stream.c
@@ -623,7 +623,6 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob)
 
 	if (!amdtp_stream_running(&bebob->rx_stream)) {
 		enum snd_bebob_clock_type src;
-		struct amdtp_stream *master, *slave;
 		unsigned int curr_rate;
 		unsigned int tx_init_skip_cycles;
 
@@ -637,19 +636,11 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob)
 		if (err < 0)
 			return err;
 
-		if (src != SND_BEBOB_CLOCK_TYPE_SYT) {
-			master = &bebob->tx_stream;
-			slave = &bebob->rx_stream;
-		} else {
-			master = &bebob->rx_stream;
-			slave = &bebob->tx_stream;
-		}
-
-		err = start_stream(bebob, master);
+		err = start_stream(bebob, &bebob->rx_stream);
 		if (err < 0)
 			goto error;
 
-		err = start_stream(bebob, slave);
+		err = start_stream(bebob, &bebob->tx_stream);
 		if (err < 0)
 			goto error;
 
-- 
2.27.0

[PATCH v2 4/4] ALSA: bebob: distinguish M-Audio ProFire Lightbridge quirk

[Takashi Sakamoto]

In former commit, ALSA IEC 61883-1/6 packet streaming engine drops
initial tx packets till the packet includes any event. This allows ALSA
bebob driver not to give option to skip initial packet since the engine
does drop the initial packet.

However, M-Audio ProFire Lightbridge has a quirk to stop packet
transmission after start multiplexing event to the packet. After several
thousands cycles, it restart packet transmission again.

This commit specializes the usage of initial skip option for the model.
Additionally, this commit expands timeout enough to wait processing
content of tx packet.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
---
 sound/firewire/bebob/bebob.c        | 10 +++++++++-
 sound/firewire/bebob/bebob.h        |  1 +
 sound/firewire/bebob/bebob_stream.c | 12 +++++++-----
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/sound/firewire/bebob/bebob.c b/sound/firewire/bebob/bebob.c
index 90e98a6d1546..5938aa325f5e 100644
--- a/sound/firewire/bebob/bebob.c
+++ b/sound/firewire/bebob/bebob.c
@@ -64,6 +64,7 @@ static DECLARE_BITMAP(devices_used, SNDRV_CARDS);
 #define MODEL_MAUDIO_AUDIOPHILE_BOTH	0x00010060
 #define MODEL_MAUDIO_FW1814		0x00010071
 #define MODEL_MAUDIO_PROJECTMIX		0x00010091
+#define MODEL_MAUDIO_PROFIRELIGHTBRIDGE	0x000100a1
 
 static int
 name_device(struct snd_bebob *bebob)
@@ -210,6 +211,13 @@ do_registration(struct work_struct *work)
 	if (err < 0)
 		goto error;
 
+	// M-Audio ProFire Lightbridge has a quirk to transfer packets with discontinuous cycle or
+	// data block counter in early stage of packet streaming. The cycle span from the first
+	// packet with event is variable.
+	if (bebob->entry->vendor_id == VEN_MAUDIO1 &&
+	    bebob->entry->model_id == MODEL_MAUDIO_PROFIRELIGHTBRIDGE)
+		bebob->discontinuity_quirk = true;
+
 	err = snd_bebob_stream_init_duplex(bebob);
 	if (err < 0)
 		goto error;
@@ -476,7 +484,7 @@ static const struct ieee1394_device_id bebob_id_table[] = {
 	/* M-Audio NRV10 */
 	SND_BEBOB_DEV_ENTRY(VEN_MAUDIO1, 0x00010081, &maudio_nrv10_spec),
 	/* M-Audio, ProFireLightbridge */
-	SND_BEBOB_DEV_ENTRY(VEN_MAUDIO1, 0x000100a1, &spec_normal),
+	SND_BEBOB_DEV_ENTRY(VEN_MAUDIO1, MODEL_MAUDIO_PROFIRELIGHTBRIDGE, &spec_normal),
 	/* Firewire 1814 */
 	SND_BEBOB_DEV_ENTRY(VEN_MAUDIO1, 0x00010070, NULL),	/* bootloader */
 	SND_BEBOB_DEV_ENTRY(VEN_MAUDIO1, MODEL_MAUDIO_FW1814,
diff --git a/sound/firewire/bebob/bebob.h b/sound/firewire/bebob/bebob.h
index 4e0ed84adbee..cba6793bfdb2 100644
--- a/sound/firewire/bebob/bebob.h
+++ b/sound/firewire/bebob/bebob.h
@@ -115,6 +115,7 @@ struct snd_bebob {
 
 	/* For BeBoB version quirk. */
 	unsigned int version;
+	bool discontinuity_quirk;
 
 	struct amdtp_domain domain;
 };
diff --git a/sound/firewire/bebob/bebob_stream.c b/sound/firewire/bebob/bebob_stream.c
index 975670a29a72..91306da1bafe 100644
--- a/sound/firewire/bebob/bebob_stream.c
+++ b/sound/firewire/bebob/bebob_stream.c
@@ -7,7 +7,7 @@
 
 #include "./bebob.h"
 
-#define READY_TIMEOUT_MS	2500
+#define READY_TIMEOUT_MS	4000
 
 /*
  * NOTE;
@@ -644,12 +644,14 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob)
 		if (err < 0)
 			goto error;
 
-		// Some devices transfer isoc packets with discontinuous counter in the beginning
-		// of packet streaming.
-		if (bebob->version < 2)
-			tx_init_skip_cycles = 3200;
+		if (!bebob->discontinuity_quirk)
+			tx_init_skip_cycles = 0;
 		else
 			tx_init_skip_cycles = 16000;
+
+		// MEMO: In the early stage of packet streaming, the device transfers NODATA packets.
+		// After several hundred cycles, it begins to multiplex event into the packet with
+		// syt information.
 		err = amdtp_domain_start(&bebob->domain, tx_init_skip_cycles);
 		if (err < 0)
 			goto error;
-- 
2.27.0

Re: [PATCH v2 0/4] ALSA: firewire-lib: drop initial NODATA packets or empty packets

[Takashi Iwai]

On Mon, 24 May 2021 05:13:42 +0200,
Takashi Sakamoto wrote:
> 
> Hi,
> 
> This patchset is take 2 of my previous one;
>  * https://lore.kernel.org/alsa-devel/20210523124114.272134-1-o-takashi@sakamocchi.jp/
> 
> The devices based on BeBoB ASICs or the devices in Tascam FireWire
> series transfer a batch of NODATA packet or empty packet in initial step
> of streaming. To avoid processing them, current implementation uses an
> option to skip processing content of tx packet during some initial
> cycles. However, the hard-coded number is not enough useful.
> 
> In 1st patch, ALSA IEC 61883-1/6 packet streaming engine becomes to drop
> the initial packets. As a result, The tx_init_skip_cycles argument of
> amdtp_domain_start() function changes its meaning. In the following
> patches, ALSA bebob driver is refactored.
> 
> Changes from v1:
>  * Fix -Wunused-but-set-variable warning reported by 0day-ci
>  * Add 2nd patch to obsolete unused member of structure
> 
> Takashi Sakamoto (4):
>   ALSA: firewire-lib: drop initial NODATA or empty packet
>   ALSA: firewire-lib: obsolete callbacked member
>   ALSA: bebob: cancel switching connection order
>   ALSA: bebob: distinguish M-Audio ProFire Lightbridge quirk

Applied all four patches now.  Thanks.


Takashi