[alsa-devel] [PATCH 08/13] ALSA: firewire-lib: add no-header packet processing
Takashi Sakamoto
o-takashi at sakamocchi.jp
Sat Feb 11 15:25:04 CET 2017
As long as invesigating 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 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 AMDTP stream layer already has a method to calculate it and
this driver can utilize it for rx 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 proper way to calculate the quadlets of isochronous packet payload.
In ALSA userspace interface, 128.0 kHz is not supported, and the AMDTP
stream layer 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 at sakamocchi.jp>
---
sound/firewire/amdtp-stream.c | 84 ++++++++++++++++++++++++++++++++++++++++---
sound/firewire/amdtp-stream.h | 2 ++
2 files changed, 81 insertions(+), 5 deletions(-)
diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index 112ad03..74c0ba9 100644
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -27,6 +27,7 @@
/* isochronous header parameters */
#define ISO_DATA_LENGTH_SHIFT 16
+#define TAG_NO_CIP_HEADER 0
#define TAG_CIP 1
/* common isochronous packet header parameters */
@@ -234,11 +235,15 @@ EXPORT_SYMBOL(amdtp_stream_set_parameters);
unsigned int amdtp_stream_get_max_payload(struct amdtp_stream *s)
{
unsigned int multiplier = 1;
+ unsigned int header_size = 0;
if (s->flags & CIP_JUMBO_PAYLOAD)
multiplier = 5;
+ if (!(s->flags & CIP_NO_HEADER))
+ header_size = 8;
- return 8 + s->syt_interval * s->data_block_quadlets * 4 * multiplier;
+ return header_size +
+ s->syt_interval * s->data_block_quadlets * 4 * multiplier;
}
EXPORT_SYMBOL(amdtp_stream_get_max_payload);
@@ -380,7 +385,10 @@ static int queue_packet(struct amdtp_stream *s, unsigned int header_length,
goto end;
p.interrupt = IS_ALIGNED(s->packet_index + 1, INTERRUPT_INTERVAL);
- p.tag = TAG_CIP;
+ if (s->flags & CIP_NO_HEADER)
+ p.tag = TAG_NO_CIP_HEADER;
+ else
+ p.tag = TAG_CIP;
p.header_length = header_length;
if (payload_length > 0)
p.payload_length = payload_length;
@@ -457,6 +465,34 @@ static int handle_out_packet(struct amdtp_stream *s, unsigned int cycle,
return 0;
}
+static int handle_out_packet_without_header(struct amdtp_stream *s,
+ unsigned int cycle, unsigned int index)
+{
+ __be32 *buffer;
+ unsigned int syt;
+ unsigned int data_blocks;
+ unsigned int payload_length;
+ unsigned int pcm_frames;
+ struct snd_pcm_substream *pcm;
+
+ buffer = s->buffer.packets[s->packet_index].buffer;
+ syt = calculate_syt(s, cycle);
+ data_blocks = calculate_data_blocks(s, syt);
+ pcm_frames = s->process_data_blocks(s, buffer, data_blocks, &syt);
+ s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;
+
+ payload_length = data_blocks * 4 * s->data_block_quadlets;
+ if (queue_out_packet(s, payload_length) < 0)
+ return -EIO;
+
+ pcm = ACCESS_ONCE(s->pcm);
+ if (pcm && pcm_frames > 0)
+ update_pcm_pointers(s, pcm, pcm_frames);
+
+ /* No need to return the number of handled data blocks. */
+ return 0;
+}
+
static int handle_in_packet(struct amdtp_stream *s,
unsigned int payload_quadlets, unsigned int cycle,
unsigned int index)
@@ -572,6 +608,30 @@ static int handle_in_packet(struct amdtp_stream *s,
return 0;
}
+static int handle_in_packet_without_header(struct amdtp_stream *s,
+ unsigned int payload_quadlets, unsigned int cycle,
+ unsigned int index)
+{
+ __be32 *buffer;
+ unsigned int data_blocks;
+ struct snd_pcm_substream *pcm;
+ unsigned int pcm_frames;
+
+ buffer = s->buffer.packets[s->packet_index].buffer;
+ data_blocks = payload_quadlets / s->data_block_quadlets;
+ pcm_frames = s->process_data_blocks(s, buffer, data_blocks, NULL);
+ s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;
+
+ if (queue_in_packet(s) < 0)
+ return -EIO;
+
+ pcm = ACCESS_ONCE(s->pcm);
+ if (pcm && pcm_frames > 0)
+ update_pcm_pointers(s, pcm, pcm_frames);
+
+ return 0;
+}
+
/*
* In CYCLE_TIMER register of IEEE 1394, 7 bits are used to represent second. On
* the other hand, in DMA descriptors of 1394 OHCI, 3 bits are used to represent
@@ -603,6 +663,8 @@ static void out_stream_callback(struct fw_iso_context *context, u32 tstamp,
{
struct amdtp_stream *s = private_data;
unsigned int i, packets = header_length / 4;
+ int (*handler)(struct amdtp_stream *s, unsigned int cycle,
+ unsigned int index);
u32 cycle;
if (s->packet_index < 0)
@@ -613,9 +675,14 @@ static void out_stream_callback(struct fw_iso_context *context, u32 tstamp,
/* Align to actual cycle count for the last packet. */
cycle = increment_cycle_count(cycle, QUEUE_LENGTH - packets);
+ if (s->flags & CIP_NO_HEADER)
+ handler = handle_out_packet_without_header;
+ else
+ handler = handle_out_packet;
+
for (i = 0; i < packets; ++i) {
cycle = increment_cycle_count(cycle, 1);
- if (handle_out_packet(s, cycle, i) < 0) {
+ if (handler(s, cycle, i) < 0) {
s->packet_index = -1;
amdtp_stream_pcm_abort(s);
return;
@@ -633,6 +700,8 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,
unsigned int i, packets;
unsigned int payload_quadlets, max_payload_quadlets;
__be32 *headers = header;
+ int (*handler)(struct amdtp_stream *s, unsigned int payload_quadlets,
+ unsigned int cycle, unsigned int index);
u32 cycle;
if (s->packet_index < 0)
@@ -649,6 +718,11 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,
/* For buffer-over-run prevention. */
max_payload_quadlets = amdtp_stream_get_max_payload(s) / 4;
+ if (s->flags & CIP_NO_HEADER)
+ handler = handle_in_packet_without_header;
+ else
+ handler = handle_in_packet;
+
for (i = 0; i < packets; i++) {
cycle = increment_cycle_count(cycle, 1);
@@ -662,7 +736,7 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,
break;
}
- if (handle_in_packet(s, payload_quadlets, cycle, i) < 0)
+ if (handler(s, payload_quadlets, cycle, i) < 0)
break;
}
@@ -793,7 +867,7 @@ int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed)
/* NOTE: TAG1 matches CIP. This just affects in stream. */
tag = FW_ISO_CONTEXT_MATCH_TAG1;
- if (s->flags & CIP_EMPTY_WITH_TAG0)
+ if ((s->flags & CIP_EMPTY_WITH_TAG0) || (s->flags & CIP_NO_HEADER))
tag |= FW_ISO_CONTEXT_MATCH_TAG0;
s->callbacked = false;
diff --git a/sound/firewire/amdtp-stream.h b/sound/firewire/amdtp-stream.h
index a31dfd8..b155955 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,
};
/**
--
2.9.3
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