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Commit b18f0cfa authored by Takashi Sakamoto's avatar Takashi Sakamoto Committed by Takashi Iwai
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ALSA: firewire-lib: use 8 byte packet header for IT context to separate CIP header from CIP payload 



In Linux firewire subsystem, for IT context, some quadlets of isochronous
packet payload can be indicated as a part of packet header to queue to
the context.

This commit uses the packet header to split CIP headers from CIP
payload. As a result, regardless of CIP or non-CIP, context payload
includes data blocks only.

Signed-off-by: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 6007bf54

sound/firewire/amdtp-stream.c

+35 −28
Original line number Diff line number Diff line
@@ -62,6 +62,9 @@ 
#define IR_CTX_HEADER_SIZE_NO_CIP	8

#define HEADER_TSTAMP_MASK	0x0000ffff



#define IT_PKT_HEADER_SIZE_CIP		8 // For 2 CIP header.

#define IT_PKT_HEADER_SIZE_NO_CIP	0 // Nothing.



static void pcm_period_tasklet(unsigned long data);



/**
@@ -452,13 +455,10 @@ static int queue_packet(struct amdtp_stream *s, struct fw_iso_packet *params) 
}



static inline int queue_out_packet(struct amdtp_stream *s,

				   struct fw_iso_packet *params,

				   unsigned int payload_length)

				   struct fw_iso_packet *params)

{

	// No header for this packet.

	params->header_length = 0;

	params->payload_length = payload_length;

	params->skip = !!(payload_length == 0);

	params->skip =

		!!(params->header_length == 0 && params->payload_length == 0);

	return queue_packet(s, params);

}
@@ -491,41 +491,41 @@ static int handle_out_packet(struct amdtp_stream *s, unsigned int cycle, 
{

	unsigned int syt;

	unsigned int data_blocks;

	unsigned int payload_length;

	__be32 *cip_header;

	unsigned int pcm_frames;

	struct snd_pcm_substream *pcm;

	struct fw_iso_packet params = {0};

	struct {

		struct fw_iso_packet params;

		__be32 header[IT_PKT_HEADER_SIZE_CIP / sizeof(__be32)];

	} template = { {0}, {0} };



	syt = calculate_syt(s, cycle);

	data_blocks = calculate_data_blocks(s, syt);



	payload_length = data_blocks * sizeof(__be32) * s->data_block_quadlets;

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

		cip_header = buffer;

		buffer += 2;

		payload_length += 2 * sizeof(__be32);

	} else {

		cip_header = NULL;

	}



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



	if (s->flags & CIP_DBC_IS_END_EVENT)

		s->data_block_counter =

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



	if (cip_header)

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

		cip_header = (__be32 *)template.params.header;

		generate_cip_header(s, cip_header, syt);

		template.params.header_length = 2 * sizeof(__be32);

	} else {

		cip_header = NULL;

	}



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

		s->data_block_counter =

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



	trace_amdtp_packet(s, cycle, cip_header, payload_length, data_blocks,

			   index);

	template.params.payload_length =

			data_blocks * sizeof(__be32) * s->data_block_quadlets;



	if (queue_out_packet(s, &params, payload_length) < 0)

	trace_amdtp_packet(s, cycle, cip_header, template.params.payload_length,

			   data_blocks, index);



	if (queue_out_packet(s, &template.params) < 0)

		return -EIO;



	pcm = READ_ONCE(s->pcm);
@@ -878,14 +878,18 @@ int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed) 
			ctx_header_size = IR_CTX_HEADER_SIZE_CIP;

		else

			ctx_header_size = IR_CTX_HEADER_SIZE_NO_CIP;



		max_ctx_payload_size = amdtp_stream_get_max_payload(s) -

				       ctx_header_size;

	} else {

		dir = DMA_TO_DEVICE;

		type = FW_ISO_CONTEXT_TRANSMIT;

		ctx_header_size = 0;	// No effect for IT context.

	}



	max_ctx_payload_size = amdtp_stream_get_max_payload(s) -

			       ctx_header_size;

		max_ctx_payload_size = amdtp_stream_get_max_payload(s);

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

			max_ctx_payload_size -= IT_PKT_HEADER_SIZE_CIP;

	}



	err = iso_packets_buffer_init(&s->buffer, s->unit, QUEUE_LENGTH,

				      max_ctx_payload_size, dir);
@@ -918,10 +922,13 @@ int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed) 
	s->packet_index = 0;

	do {

		struct fw_iso_packet params;

		if (s->direction == AMDTP_IN_STREAM)

		if (s->direction == AMDTP_IN_STREAM) {

			err = queue_in_packet(s, &params);

		else

			err = queue_out_packet(s, &params, 0);

		} else {

			params.header_length = 0;

			params.payload_length = 0;

			err = queue_out_packet(s, &params);

		}

		if (err < 0)

			goto err_context;

	} while (s->packet_index > 0);