ALSA: firewire-lib: add a quirk of packet without valid EOH in CIP format

In IEC 61883-1, when two quadlets CIP header is used, the most significant
bit in second CIP header stands. However, packets from units with MOTU
protocol version 3 have a quirk without this flag. Current packet streaming
layer handles this as protocol error.

This commit adds a new enumeration constant for this quirk, to handle MOTU
protocol version 3.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/amdtp-stream.c

@@ -480,8 +480,9 @@ static int handle_in_packet(struct amdtp_stream *s,
 	 * This module supports 'Two-quadlet CIP header with SYT field'.
 	 * For convenience, also check FMT field is AM824 or not.
 	 */
-	if (((cip_header[0] & CIP_EOH_MASK) == CIP_EOH) ||
-	    ((cip_header[1] & CIP_EOH_MASK) != CIP_EOH)) {
+	if ((((cip_header[0] & CIP_EOH_MASK) == CIP_EOH) ||
+	     ((cip_header[1] & CIP_EOH_MASK) != CIP_EOH)) &&
+	    (!(s->flags & CIP_HEADER_WITHOUT_EOH))) {
 		dev_info_ratelimited(&s->unit->device,
 				"Invalid CIP header for AMDTP: %08X:%08X\n",
 				cip_header[0], cip_header[1]);

sound/firewire/amdtp-stream.h

@@ -29,6 +29,8 @@
  * @CIP_JUMBO_PAYLOAD: Only for in-stream. The number of data blocks in an
  *	packet is larger than IEC 61883-6 defines. Current implementation
  *	allows 5 times as large as IEC 61883-6 defines.
+ * @CIP_HEADER_WITHOUT_EOH: Only for in-stream. CIP Header doesn't include
+ *	valid EOH.
  */
 enum cip_flags {
 	CIP_NONBLOCKING		= 0x00,
@@ -39,6 +41,7 @@ enum cip_flags {
 	CIP_SKIP_DBC_ZERO_CHECK	= 0x10,
 	CIP_EMPTY_HAS_WRONG_DBC	= 0x20,
 	CIP_JUMBO_PAYLOAD	= 0x40,
+	CIP_HEADER_WITHOUT_EOH	= 0x80,
 };
 
 /**