ALSA: firewire-lib: add replay target to cache sequence of packet

In design of audio and music unit in IEEE 1394 bus, feedback of
effective sampling transfer frequency (STF) is delivered by packets
transferred from device. The devices supported by ALSA firewire stack
are categorized to three groups regarding to it.

 * Group 1:
   * Echo Audio Fireworks board module
   * Oxford Semiconductor OXFW971 ASIC
   * Digidesign Digi00x family
   * Tascam FireWire series
   * RME Fireface series

 * Group 2:
   * BridgeCo. DM1000/DM1100/DM1500 ASICs for BeBoB solution
   * TC Applied Technologies DICE ASICs

 * Group 3:
   * Mark of the Unicord FireWire series

In group 1, the effective STF is determined by the sequence of the number
of events per packet. In group 2, the sequence of presentation timestamp
expressed in syt field of CIP header is interpreted as well. In group 3,
the presentation timestamp is expressed in source packet header (SPH) of
each data block.

I note that some models doesn't take care of effective STF with large
internal buffer. It's reasonable to name it as group 0:

 * Group 0
   * Oxford Semiconductor OXFW970 ASIC

The effective STF is known to be slightly different from nominal STF for
all of devices, and to be different between the devices. Furthermore, the
effective STF is known to be shifted for long-period transmission. This
makes it hard for software to satisfy the effective STF when processing
packets to the device.

The effective STF is deterministic as a result of analyzing the batch of
packet transferred from the device. For the analysis, caching the sequence
of parameter in the packet is required.

This commit adds an option so that AMDTP domain structure takes AMDTP
stream structure to cache the sequence of parameters in packet transferred
from the device. The parameters are offset ticks of syt field against the
cycle to receive the packet and the number of data blocks per packet.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210527122611.173711-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 11 insertions, 1 deletions

diff --git a/sound/firewire/amdtp-stream.h b/sound/firewire/amdtp-stream.h
index 34294776f9e8..ddfb885b6113 100644
--- a/sound/firewire/amdtp-stream.h
+++ b/sound/firewire/amdtp-stream.h
@@ -141,6 +141,12 @@ struct amdtp_stream {
 
 			// The device starts multiplexing events to the packet.
 			bool event_starts;
+
+			struct {
+				struct seq_desc *descs;
+				unsigned int size;
+				unsigned int tail;
+			} cache;
 		} tx;
 		struct {
 			// To generate CIP header.
@@ -292,6 +298,10 @@ struct amdtp_domain {
 		unsigned int tx_start;
 		unsigned int rx_start;
 	} processing_cycle;
+
+	struct {
+		bool enable;
+	} replay;
 };
 
 int amdtp_domain_init(struct amdtp_domain *d);
@@ -300,7 +310,7 @@ void amdtp_domain_destroy(struct amdtp_domain *d);
 int amdtp_domain_add_stream(struct amdtp_domain *d, struct amdtp_stream *s,
 			    int channel, int speed);
 
-int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles);
+int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles, bool replay_seq);
 void amdtp_domain_stop(struct amdtp_domain *d);
 
 static inline int amdtp_domain_set_events_per_period(struct amdtp_domain *d,