ALSA: firewire-lib: add list of packet descriptor

In current implementation of ALSA IEC 61883-1/6 packet streaming engine,
16 packets are handled in one interrupt of isochronous context of OHCI
1394.

Overall packet processing runs for each. However, this is not better in
a point to split the processing into several parts.

This commit is an attempt to add intermediate representation for
parameters required for the parts.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/amdtp-stream.c

@@ -936,6 +936,13 @@ int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed)
 	else
 		s->tag = TAG_CIP;
 
+	s->pkt_descs = kcalloc(INTERRUPT_INTERVAL, sizeof(*s->pkt_descs),
+			       GFP_KERNEL);
+	if (!s->pkt_descs) {
+		err = -ENOMEM;
+		goto err_context;
+	}
+
 	s->packet_index = 0;
 	do {
 		struct fw_iso_packet params;
@@ -947,7 +954,7 @@ int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed)
 			err = queue_out_packet(s, &params);
 		}
 		if (err < 0)
-			goto err_context;
+			goto err_pkt_descs;
 	} while (s->packet_index > 0);
 
 	/* NOTE: TAG1 matches CIP. This just affects in stream. */
@@ -958,12 +965,13 @@ int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed)
 	s->callbacked = false;
 	err = fw_iso_context_start(s->context, -1, 0, tag);
 	if (err < 0)
-		goto err_context;
+		goto err_pkt_descs;
 
 	mutex_unlock(&s->mutex);
 
 	return 0;
-
+err_pkt_descs:
+	kfree(s->pkt_descs);
 err_context:
 	fw_iso_context_destroy(s->context);
 	s->context = ERR_PTR(-1);
@@ -1059,6 +1067,7 @@ void amdtp_stream_stop(struct amdtp_stream *s)
 	fw_iso_context_destroy(s->context);
 	s->context = ERR_PTR(-1);
 	iso_packets_buffer_destroy(&s->buffer, s->unit);
+	kfree(s->pkt_descs);
 
 	s->callbacked = false;
 

sound/firewire/amdtp-stream.h

@@ -94,6 +94,14 @@ enum amdtp_stream_direction {
 	AMDTP_IN_STREAM
 };
 
+struct pkt_desc {
+	u32 cycle;
+	u32 syt;
+	unsigned int data_blocks;
+	unsigned int data_block_counter;
+	__be32 *ctx_payload;
+};
+
 struct amdtp_stream;
 typedef unsigned int (*amdtp_stream_process_data_blocks_t)(
 						struct amdtp_stream *s,
@@ -110,6 +118,7 @@ struct amdtp_stream {
 	struct fw_iso_context *context;
 	struct iso_packets_buffer buffer;
 	int packet_index;
+	struct pkt_desc *pkt_descs;
 	int tag;
 	union {
 		struct {