ALSA: firewire-lib: enable CIP_DBC_IS_END_EVENT for both directions of stream

Commit c8bdf49b("ALSA: fireworks/firewire-lib: Add a quirk for the
meaning of dbc") adds CIP_DBC_IS_END_EVENT flag just for tx packets.
However, MOTU FireWire series has this quirk for rx packets.

This commit allows both directions with the flag.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/amdtp-stream.c

@@ -426,6 +426,10 @@ static int handle_out_packet(struct amdtp_stream *s, unsigned int cycle,
 	data_blocks = calculate_data_blocks(s, syt);
 	pcm_frames = s->process_data_blocks(s, buffer + 2, data_blocks, &syt);
 
+	if (s->flags & CIP_DBC_IS_END_EVENT)
+		s->data_block_counter =
+				(s->data_block_counter + data_blocks) & 0xff;
+
 	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) |
@@ -435,7 +439,9 @@ static int handle_out_packet(struct amdtp_stream *s, unsigned int cycle,
 				((s->fdf << CIP_FDF_SHIFT) & CIP_FDF_MASK) |
 				(syt & CIP_SYT_MASK));
 
-	s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;
+	if (!(s->flags & CIP_DBC_IS_END_EVENT))
+		s->data_block_counter =
+				(s->data_block_counter + data_blocks) & 0xff;
 	payload_length = 8 + data_blocks * 4 * s->data_block_quadlets;
 
 	trace_out_packet(s, cycle, buffer, payload_length, index);

sound/firewire/amdtp-stream.h

@@ -18,8 +18,8 @@
  *	SYT_INTERVAL samples, with these two types alternating so that
  *	the overall sample rate comes out right.
  * @CIP_EMPTY_WITH_TAG0: Only for in-stream. Empty in-packets have TAG0.
- * @CIP_DBC_IS_END_EVENT: Only for in-stream. The value of dbc in an in-packet
- *	corresponds to the end of event in the packet. Out of IEC 61883.
+ * @CIP_DBC_IS_END_EVENT: The value of dbc in an packet corresponds to the end
+ * of event in the packet. Out of IEC 61883.
  * @CIP_WRONG_DBS: Only for in-stream. The value of dbs is wrong in in-packets.
  *	The value of data_block_quadlets is used instead of reported value.
  * @CIP_SKIP_DBC_ZERO_CHECK: Only for in-stream.  Packets with zero in dbc is