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>

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index 646e8e3..a03b37b 100644 (file)
--- 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 +385,7 @@ 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;
+       p.tag = s->tag;
        p.header_length = header_length;
        if (payload_length > 0)
                p.payload_length = payload_length;
@@ -457,6 +462,34 @@ static int handle_out_packet(struct amdtp_stream *s,
        return 0;
 }
 
+static int handle_out_packet_without_header(struct amdtp_stream *s,
+                       unsigned int payload_length, unsigned int cycle,
+                       unsigned int index)
+{
+       __be32 *buffer;
+       unsigned int syt;
+       unsigned int data_blocks;
+       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_length, unsigned int cycle,
                            unsigned int index)
@@ -573,6 +606,30 @@ end:
        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
@@ -616,7 +673,7 @@ static void out_stream_callback(struct fw_iso_context *context, u32 tstamp,
 
        for (i = 0; i < packets; ++i) {
                cycle = increment_cycle_count(cycle, 1);
-               if (handle_out_packet(s, 0, cycle, i) < 0) {
+               if (s->handle_packet(s, 0, cycle, i) < 0) {
                        s->packet_index = -1;
                        amdtp_stream_pcm_abort(s);
                        return;
@@ -663,7 +720,7 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,
                        break;
                }
 
-               if (handle_in_packet(s, payload_length, cycle, i) < 0)
+               if (s->handle_packet(s, payload_length, cycle, i) < 0)
                        break;
        }
 
@@ -699,10 +756,18 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context,
                packets = header_length / IN_PACKET_HEADER_SIZE;
                cycle = decrement_cycle_count(cycle, packets);
                context->callback.sc = in_stream_callback;
+               if (s->flags & CIP_NO_HEADER)
+                       s->handle_packet = handle_in_packet_without_header;
+               else
+                       s->handle_packet = handle_in_packet;
        } else {
                packets = header_length / 4;
                cycle = increment_cycle_count(cycle, QUEUE_LENGTH - packets);
                context->callback.sc = out_stream_callback;
+               if (s->flags & CIP_NO_HEADER)
+                       s->handle_packet = handle_out_packet_without_header;
+               else
+                       s->handle_packet = handle_out_packet;
        }
 
        s->start_cycle = cycle;
@@ -782,6 +847,11 @@ int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed)
 
        amdtp_stream_update(s);
 
+       if (s->flags & CIP_NO_HEADER)
+               s->tag = TAG_NO_CIP_HEADER;
+       else
+               s->tag = TAG_CIP;
+
        s->packet_index = 0;
        do {
                if (s->direction == AMDTP_IN_STREAM)
@@ -794,7 +864,7 @@ 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..2bd4de4 100644 (file)
--- 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;