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Commit 3b196c39 authored by Takashi Sakamoto's avatar Takashi Sakamoto Committed by Takashi Iwai
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ALSA: firewire-lib: add no-header packet processing 



As long as investigating Fireface 400, IEC 61883-1/6 is not applied to
its packet streaming protocol. Remarks of the specific protocol are:
 * Each packet doesn't include CIP headers.
 * 64,0 and 128,0 kHz are supported.
 * The device doesn't necessarily transmit 8,000 packets per second.
 * 0, 1, 2, 3 are used as tag for rx isochronous packets, however 0 is
   used for tx isochronous packets.

On the other hand, there's a common feature. The number of data blocks
transferred in a second is the same as sampling transmission frequency.
Current ALSA IEC 61883-1/6 engine already has a method to calculate it and
this driver can utilize it for rx packets, as well as tx packets.

This commit adds support for the transferring protocol. CIP_NO_HEADERS
flag is newly added. When this flag is set:
 * Both of 0 (without CIP header) and 1 (with CIP header) are used as tag
   to handle incoming isochronous packet.
 * 0 (without CIP header) is used as tag to transfer outgoing isochronous
   packet.
 * Skip CIP header evaluation.
 * Use unique way to calculate the quadlets of isochronous packet payload.

In ALSA PCM interface, 128.0 kHz is not supported, and the ALSA
IEC 61883-1/6 engine doesn't support 64.0 kHz. These modes are dropped.

The sequence of rx packet has a remarkable quirk about tag. This will be
described in later commits.

Signed-off-by: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent ff0fb5aa

sound/firewire/amdtp-stream.c

+75 −5
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 


/* isochronous header parameters */

#define ISO_DATA_LENGTH_SHIFT	16

#define TAG_NO_CIP_HEADER	0

#define TAG_CIP			1



/* common isochronous packet header parameters */
@@ -234,11 +235,15 @@ EXPORT_SYMBOL(amdtp_stream_set_parameters); 
unsigned int amdtp_stream_get_max_payload(struct amdtp_stream *s)

{

	unsigned int multiplier = 1;

	unsigned int header_size = 0;



	if (s->flags & CIP_JUMBO_PAYLOAD)

		multiplier = 5;

	if (!(s->flags & CIP_NO_HEADER))

		header_size = 8;



	return 8 + s->syt_interval * s->data_block_quadlets * 4 * multiplier;

	return header_size +

		s->syt_interval * s->data_block_quadlets * 4 * multiplier;

}

EXPORT_SYMBOL(amdtp_stream_get_max_payload);
@@ -380,7 +385,7 @@ static int queue_packet(struct amdtp_stream *s, unsigned int header_length, 
		goto end;



	p.interrupt = IS_ALIGNED(s->packet_index + 1, INTERRUPT_INTERVAL);

	p.tag = TAG_CIP;

	p.tag = s->tag;

	p.header_length = header_length;

	if (payload_length > 0)

		p.payload_length = payload_length;
@@ -457,6 +462,34 @@ static int handle_out_packet(struct amdtp_stream *s, 
	return 0;

}



static int handle_out_packet_without_header(struct amdtp_stream *s,

			unsigned int payload_length, unsigned int cycle,

			unsigned int index)

{

	__be32 *buffer;

	unsigned int syt;

	unsigned int data_blocks;

	unsigned int pcm_frames;

	struct snd_pcm_substream *pcm;



	buffer = s->buffer.packets[s->packet_index].buffer;

	syt = calculate_syt(s, cycle);

	data_blocks = calculate_data_blocks(s, syt);

	pcm_frames = s->process_data_blocks(s, buffer, data_blocks, &syt);

	s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;



	payload_length = data_blocks * 4 * s->data_block_quadlets;

	if (queue_out_packet(s, payload_length) < 0)

		return -EIO;



	pcm = ACCESS_ONCE(s->pcm);

	if (pcm && pcm_frames > 0)

		update_pcm_pointers(s, pcm, pcm_frames);



	/* No need to return the number of handled data blocks. */

	return 0;

}



static int handle_in_packet(struct amdtp_stream *s,

			    unsigned int payload_length, unsigned int cycle,

			    unsigned int index)
@@ -573,6 +606,30 @@ static int handle_in_packet(struct amdtp_stream *s, 
	return 0;

}



static int handle_in_packet_without_header(struct amdtp_stream *s,

			unsigned int payload_quadlets, unsigned int cycle,

			unsigned int index)

{

	__be32 *buffer;

	unsigned int data_blocks;

	struct snd_pcm_substream *pcm;

	unsigned int pcm_frames;



	buffer = s->buffer.packets[s->packet_index].buffer;

	data_blocks = payload_quadlets / s->data_block_quadlets;

	pcm_frames = s->process_data_blocks(s, buffer, data_blocks, NULL);

	s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;



	if (queue_in_packet(s) < 0)

		return -EIO;



	pcm = ACCESS_ONCE(s->pcm);

	if (pcm && pcm_frames > 0)

		update_pcm_pointers(s, pcm, pcm_frames);



	return 0;

}



/*

 * In CYCLE_TIMER register of IEEE 1394, 7 bits are used to represent second. On

 * the other hand, in DMA descriptors of 1394 OHCI, 3 bits are used to represent
@@ -616,7 +673,7 @@ static void out_stream_callback(struct fw_iso_context *context, u32 tstamp, 


	for (i = 0; i < packets; ++i) {

		cycle = increment_cycle_count(cycle, 1);

		if (handle_out_packet(s, 0, cycle, i) < 0) {

		if (s->handle_packet(s, 0, cycle, i) < 0) {

			s->packet_index = -1;

			amdtp_stream_pcm_abort(s);

			return;
@@ -663,7 +720,7 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp, 
			break;

		}



		if (handle_in_packet(s, payload_length, cycle, i) < 0)

		if (s->handle_packet(s, payload_length, cycle, i) < 0)

			break;

	}
@@ -699,10 +756,18 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context, 
		packets = header_length / IN_PACKET_HEADER_SIZE;

		cycle = decrement_cycle_count(cycle, packets);

		context->callback.sc = in_stream_callback;

		if (s->flags & CIP_NO_HEADER)

			s->handle_packet = handle_in_packet_without_header;

		else

			s->handle_packet = handle_in_packet;

	} else {

		packets = header_length / 4;

		cycle = increment_cycle_count(cycle, QUEUE_LENGTH - packets);

		context->callback.sc = out_stream_callback;

		if (s->flags & CIP_NO_HEADER)

			s->handle_packet = handle_out_packet_without_header;

		else

			s->handle_packet = handle_out_packet;

	}



	s->start_cycle = cycle;
@@ -782,6 +847,11 @@ int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed) 


	amdtp_stream_update(s);



	if (s->flags & CIP_NO_HEADER)

		s->tag = TAG_NO_CIP_HEADER;

	else

		s->tag = TAG_CIP;



	s->packet_index = 0;

	do {

		if (s->direction == AMDTP_IN_STREAM)
@@ -794,7 +864,7 @@ int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed) 


	/* NOTE: TAG1 matches CIP. This just affects in stream. */

	tag = FW_ISO_CONTEXT_MATCH_TAG1;

	if (s->flags & CIP_EMPTY_WITH_TAG0)

	if ((s->flags & CIP_EMPTY_WITH_TAG0) || (s->flags & CIP_NO_HEADER))

		tag |= FW_ISO_CONTEXT_MATCH_TAG0;



	s->callbacked = false;

sound/firewire/amdtp-stream.h

+6 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
 *	allows 5 times as large as IEC 61883-6 defines.

 * @CIP_HEADER_WITHOUT_EOH: Only for in-stream. CIP Header doesn't include

 *	valid EOH.

 * @CIP_NO_HEADERS: a lack of headers in packets

 */

enum cip_flags {

	CIP_NONBLOCKING		= 0x00,
@@ -42,6 +43,7 @@ enum cip_flags { 
	CIP_EMPTY_HAS_WRONG_DBC	= 0x20,

	CIP_JUMBO_PAYLOAD	= 0x40,

	CIP_HEADER_WITHOUT_EOH	= 0x80,

	CIP_NO_HEADER		= 0x100,

};



/**
@@ -104,6 +106,10 @@ struct amdtp_stream { 
	struct fw_iso_context *context;

	struct iso_packets_buffer buffer;

	int packet_index;

	int tag;

	int (*handle_packet)(struct amdtp_stream *s,

			unsigned int payload_quadlets, unsigned int cycle,

			unsigned int index);



	/* For CIP headers. */

	unsigned int source_node_id_field;