ALSA: firewire-lib: code refactoring for calculation of context payload

It's convenient to calculate the size of context payload apart from
the size of isochronous packet payload.

This commit adds a helper function for it.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210520040154.80450-3-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 f178cb5..3613529 100644 (file)
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -313,6 +313,19 @@ int amdtp_stream_set_parameters(struct amdtp_stream *s, unsigned int rate,
 }
 EXPORT_SYMBOL(amdtp_stream_set_parameters);
 
+// The CIP header is processed in context header apart from context payload.
+static int amdtp_stream_get_max_ctx_payload_size(struct amdtp_stream *s)
+{
+       unsigned int multiplier;
+
+       if (s->flags & CIP_JUMBO_PAYLOAD)
+               multiplier = IR_JUMBO_PAYLOAD_MAX_SKIP_CYCLES;
+       else
+               multiplier = 1;
+
+       return s->syt_interval * s->data_block_quadlets * sizeof(__be32) * multiplier;
+}
+
 /**
  * amdtp_stream_get_max_payload - get the stream's packet size
  * @s: the AMDTP stream
@@ -322,16 +335,14 @@ EXPORT_SYMBOL(amdtp_stream_set_parameters);
  */
 unsigned int amdtp_stream_get_max_payload(struct amdtp_stream *s)
 {
-       unsigned int multiplier = 1;
-       unsigned int cip_header_size = 0;
+       unsigned int cip_header_size;
 
-       if (s->flags & CIP_JUMBO_PAYLOAD)
-               multiplier = IR_JUMBO_PAYLOAD_MAX_SKIP_CYCLES;
        if (!(s->flags & CIP_NO_HEADER))
                cip_header_size = CIP_HEADER_SIZE;
+       else
+               cip_header_size = 0;
 
-       return cip_header_size +
-               s->syt_interval * s->data_block_quadlets * sizeof(__be32) * multiplier;
+       return cip_header_size + amdtp_stream_get_max_ctx_payload_size(s);
 }
 EXPORT_SYMBOL(amdtp_stream_get_max_payload);
 
@@ -1140,27 +1151,21 @@ static int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed,
        }
 
        // initialize packet buffer.
-       max_ctx_payload_size = amdtp_stream_get_max_payload(s);
        if (s->direction == AMDTP_IN_STREAM) {
                dir = DMA_FROM_DEVICE;
                type = FW_ISO_CONTEXT_RECEIVE;
-               if (!(s->flags & CIP_NO_HEADER)) {
-                       max_ctx_payload_size -= CIP_HEADER_SIZE;
+               if (!(s->flags & CIP_NO_HEADER))
                        ctx_header_size = IR_CTX_HEADER_SIZE_CIP;
-               } else {
+               else
                        ctx_header_size = IR_CTX_HEADER_SIZE_NO_CIP;
-               }
        } else {
                dir = DMA_TO_DEVICE;
                type = FW_ISO_CONTEXT_TRANSMIT;
                ctx_header_size = 0;    // No effect for IT context.
-
-               if (!(s->flags & CIP_NO_HEADER))
-                       max_ctx_payload_size -= IT_PKT_HEADER_SIZE_CIP;
        }
+       max_ctx_payload_size = amdtp_stream_get_max_ctx_payload_size(s);
 
-       err = iso_packets_buffer_init(&s->buffer, s->unit, queue_size,
-                                     max_ctx_payload_size, dir);
+       err = iso_packets_buffer_init(&s->buffer, s->unit, queue_size, max_ctx_payload_size, dir);
        if (err < 0)
                goto err_unlock;
        s->queue_size = queue_size;