diff options
| author | Takashi Sakamoto <o-takashi@sakamocchi.jp> | 2017-03-31 22:06:07 +0900 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2017-04-05 21:31:40 +0200 |
| commit | 3b196c394dd9f8f34064f5814bb287757c80ee35 (patch) | |
| tree | 12d983371d7a3ed87e194b7021a1ecf8d00fe367 /sound/firewire/amdtp-stream.h | |
| parent | ff0fb5aaa8799701aa01bd1f2cdaf93ce98bbe60 (diff) | |
ALSA: firewire-lib: add no-header packet processing
As long as investigating Fireface 400, IEC 61883-1/6 is not applied to
its packet streaming protocol. Remarks of the specific protocol are:
* Each packet doesn't include CIP headers.
* 64,0 and 128,0 kHz are supported.
* The device doesn't necessarily transmit 8,000 packets per second.
* 0, 1, 2, 3 are used as tag for rx isochronous packets, however 0 is
used for tx isochronous packets.
On the other hand, there's a common feature. The number of data blocks
transferred in a second is the same as sampling transmission frequency.
Current ALSA IEC 61883-1/6 engine already has a method to calculate it and
this driver can utilize it for rx packets, as well as tx packets.
This commit adds support for the transferring protocol. CIP_NO_HEADERS
flag is newly added. When this flag is set:
* Both of 0 (without CIP header) and 1 (with CIP header) are used as tag
to handle incoming isochronous packet.
* 0 (without CIP header) is used as tag to transfer outgoing isochronous
packet.
* Skip CIP header evaluation.
* Use unique way to calculate the quadlets of isochronous packet payload.
In ALSA PCM interface, 128.0 kHz is not supported, and the ALSA
IEC 61883-1/6 engine doesn't support 64.0 kHz. These modes are dropped.
The sequence of rx packet has a remarkable quirk about tag. This will be
described in later commits.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/firewire/amdtp-stream.h')
| -rw-r--r-- | sound/firewire/amdtp-stream.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/sound/firewire/amdtp-stream.h b/sound/firewire/amdtp-stream.h index a31dfd849821..2bd4de4c7bb7 100644 --- a/sound/firewire/amdtp-stream.h +++ b/sound/firewire/amdtp-stream.h @@ -31,6 +31,7 @@ * 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. + * @CIP_NO_HEADERS: a lack of headers in packets */ enum cip_flags { CIP_NONBLOCKING = 0x00, @@ -42,6 +43,7 @@ enum cip_flags { CIP_EMPTY_HAS_WRONG_DBC = 0x20, CIP_JUMBO_PAYLOAD = 0x40, CIP_HEADER_WITHOUT_EOH = 0x80, + CIP_NO_HEADER = 0x100, }; /** @@ -104,6 +106,10 @@ struct amdtp_stream { struct fw_iso_context *context; struct iso_packets_buffer buffer; int packet_index; + int tag; + int (*handle_packet)(struct amdtp_stream *s, + unsigned int payload_quadlets, unsigned int cycle, + unsigned int index); /* For CIP headers. */ unsigned int source_node_id_field; |