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

Signed-off-by: default avatarTakashi Sakamoto <>
Signed-off-by: default avatarTakashi Iwai <>
parent a04513f8
......@@ -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) |
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) {
"Detect unexpected protocol: %08x %08x\n",
cip_header[0], cip_header[1]);
......@@ -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. */
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