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Commit 9863874f authored by Takashi Sakamoto's avatar Takashi Sakamoto Committed by Takashi Iwai
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ALSA: firewire-lib: add support for source packet header field in CIP header 



In IEC 61883-1, CIP headers can have a SPH field. When a packet has 1 in
SPH field of its CIP header, the packet has a source packet headers. A
source packet header consists of 32 bit field (= 1 quadlet) and it
transfers time stamp, which is the same value as the lower 25 bits of the
IEEE 1394 CYCLE_TIMER register and the rest is zero.

This commit just supports source packet header field because IEC 61883-1
includes ambiguity the position of this header and its count. Each
protocol layer is allowed to have actual implementation according its
requirements.

Signed-off-by: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent a04513f8

sound/firewire/amdtp-stream.c

+6 −2
Original line number Diff line number Diff line
@@ -37,6 +37,8 @@ 
#define CIP_SID_MASK		0x3f000000

#define CIP_DBS_MASK		0x00ff0000

#define CIP_DBS_SHIFT		16

#define CIP_SPH_MASK		0x00000400

#define CIP_SPH_SHIFT		10

#define CIP_DBC_MASK		0x000000ff

#define CIP_FMT_SHIFT		24

#define CIP_FMT_MASK		0x3f000000
@@ -426,6 +428,7 @@ static int handle_out_packet(struct amdtp_stream *s, unsigned int cycle, 


	buffer[0] = cpu_to_be32(ACCESS_ONCE(s->source_node_id_field) |

				(s->data_block_quadlets << CIP_DBS_SHIFT) |

				((s->sph << CIP_SPH_SHIFT) & CIP_SPH_MASK) |

				s->data_block_counter);

	buffer[1] = cpu_to_be32(CIP_EOH |

				((s->fmt << CIP_FMT_SHIFT) & CIP_FMT_MASK) |
@@ -454,7 +457,7 @@ static int handle_in_packet(struct amdtp_stream *s, 
{

	__be32 *buffer;

	u32 cip_header[2];

	unsigned int fmt, fdf, syt;

	unsigned int sph, fmt, fdf, syt;

	unsigned int data_block_quadlets, data_block_counter, dbc_interval;

	unsigned int data_blocks;

	struct snd_pcm_substream *pcm;
@@ -482,8 +485,9 @@ static int handle_in_packet(struct amdtp_stream *s, 
	}



	/* Check valid protocol or not. */

	sph = (cip_header[0] & CIP_SPH_MASK) >> CIP_SPH_SHIFT;

	fmt = (cip_header[1] & CIP_FMT_MASK) >> CIP_FMT_SHIFT;

	if (fmt != s->fmt) {

	if (sph != s->sph || fmt != s->fmt) {

		dev_info_ratelimited(&s->unit->device,

				     "Detect unexpected protocol: %08x %08x\n",

				     cip_header[0], cip_header[1]);

sound/firewire/amdtp-stream.h

+1 −0
Original line number Diff line number Diff line
@@ -106,6 +106,7 @@ struct amdtp_stream { 
	unsigned int source_node_id_field;

	unsigned int data_block_quadlets;

	unsigned int data_block_counter;

	unsigned int sph;

	unsigned int fmt;

	unsigned int fdf;

	/* quirk: fixed interval of dbc between previos/current packets. */