In kernel API of Linux FireWire subsystem, handlers of isochronous receive (IR) context can get context headers as an argument of callback. When 4 byte header is used, the context header includes isochronous packet header for each packet. When 8 byte header is used, it includes isochronous cycle as well.

ALSA IEC 61883-1/6 engine uses 4 byte header, and computes isochronous cycle from the cycle of interrupt. The usage of 8 byte header can obsolete the computation.

Furthermore, this change works well for a case that a series of packet in one interrupt includes skipped isochronous cycle,

This commit uses 8 byte header to handle isochronous cycle.

Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- sound/firewire/amdtp-stream.c | 44 +++++++++++++++-------------------- 1 file changed, 19 insertions(+), 25 deletions(-)

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index 3ada55ed5381..43f28b813386 100644 --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -56,8 +56,9 @@ #define INTERRUPT_INTERVAL 16 #define QUEUE_LENGTH 48

-#define IN_PACKET_HEADER_SIZE 4 +#define IR_HEADER_SIZE 8 // For header and timestamp. #define OUT_PACKET_HEADER_SIZE 0 +#define HEADER_TSTAMP_MASK 0x0000ffff

static void pcm_period_tasklet(unsigned long data);

@@ -456,7 +457,7 @@ static inline int queue_out_packet(struct amdtp_stream *s,

static inline int queue_in_packet(struct amdtp_stream *s) { - return queue_packet(s, IN_PACKET_HEADER_SIZE, s->max_payload_length); + return queue_packet(s, IR_HEADER_SIZE, s->max_payload_length); }

static int handle_out_packet(struct amdtp_stream *s, @@ -701,13 +702,6 @@ static inline u32 increment_cycle_count(u32 cycle, unsigned int addend) return cycle; }

-static inline u32 decrement_cycle_count(u32 cycle, unsigned int subtrahend) -{ - if (cycle < subtrahend) - cycle += 8 * CYCLES_PER_SECOND; - return cycle - subtrahend; -} - static void out_stream_callback(struct fw_iso_context *context, u32 tstamp, size_t header_length, void *header, void *private_data) @@ -745,29 +739,26 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp, struct amdtp_stream *s = private_data; unsigned int i, packets; unsigned int payload_length, max_payload_length; - __be32 *headers = header; - u32 cycle; + __be32 *ctx_header = header;

if (s->packet_index < 0) return;

/* The number of packets in buffer */ - packets = header_length / IN_PACKET_HEADER_SIZE; - - cycle = compute_cycle_count(tstamp); - - /* Align to actual cycle count for the last packet. */ - cycle = decrement_cycle_count(cycle, packets); + packets = header_length / IR_HEADER_SIZE;

/* For buffer-over-run prevention. */ max_payload_length = s->max_payload_length;

for (i = 0; i < packets; i++) { - cycle = increment_cycle_count(cycle, 1); + u32 iso_header = be32_to_cpu(ctx_header[0]); + unsigned int cycle; + + tstamp = be32_to_cpu(ctx_header[1]) & HEADER_TSTAMP_MASK; + cycle = compute_cycle_count(tstamp);

/* The number of bytes in this packet */ - payload_length = - (be32_to_cpu(headers[i]) >> ISO_DATA_LENGTH_SHIFT); + payload_length = iso_header >> ISO_DATA_LENGTH_SHIFT; if (payload_length > max_payload_length) { dev_err(&s->unit->device, "Detect jumbo payload: %04x %04x\n", @@ -777,6 +768,8 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,

if (s->handle_packet(s, payload_length, cycle, i) < 0) break; + + ctx_header += IR_HEADER_SIZE / sizeof(__be32); }

/* Queueing error or detecting invalid payload. */ @@ -797,6 +790,7 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context, void *header, void *private_data) { struct amdtp_stream *s = private_data; + __be32 *ctx_header = header; u32 cycle; unsigned int packets;

@@ -807,11 +801,10 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context, s->callbacked = true; wake_up(&s->callback_wait);

- cycle = compute_cycle_count(tstamp); - if (s->direction == AMDTP_IN_STREAM) { - packets = header_length / IN_PACKET_HEADER_SIZE; - cycle = decrement_cycle_count(cycle, packets); + tstamp = be32_to_cpu(ctx_header[1]) & HEADER_TSTAMP_MASK; + cycle = compute_cycle_count(tstamp); + context->callback.sc = in_stream_callback; if (s->flags & CIP_NO_HEADER) s->handle_packet = handle_in_packet_without_header; @@ -819,6 +812,7 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context, s->handle_packet = handle_in_packet; } else { packets = header_length / 4; + cycle = compute_cycle_count(tstamp); cycle = increment_cycle_count(cycle, QUEUE_LENGTH - packets); context->callback.sc = out_stream_callback; if (s->flags & CIP_NO_HEADER) @@ -880,7 +874,7 @@ int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed) if (s->direction == AMDTP_IN_STREAM) { dir = DMA_FROM_DEVICE; type = FW_ISO_CONTEXT_RECEIVE; - header_size = IN_PACKET_HEADER_SIZE; + header_size = IR_HEADER_SIZE; } else { dir = DMA_TO_DEVICE; type = FW_ISO_CONTEXT_TRANSMIT;