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ALSA: firewire-lib: simplify function to calculate the number of data blocks

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This function is called according to conditions between the value of
syt and streaming mode(blocking or non-blocking).

To simplify caller's work, this commit push these conditions to the
function.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Sakamoto 2015-05-22 23:00:51 +09:00 • committed by Takashi Iwai
parent a2064710ba
commit 875be09160
1 changed files with 27 additions and 22 deletions
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49
sound/firewire/amdtp.c
View file

@ -321,17 +321,25 @@ void amdtp_stream_pcm_prepare(struct amdtp_stream *s)
} }
EXPORT_SYMBOL(amdtp_stream_pcm_prepare); EXPORT_SYMBOL(amdtp_stream_pcm_prepare);
static unsigned int calculate_data_blocks(struct amdtp_stream *s) static unsigned int calculate_data_blocks(struct amdtp_stream *s,
unsigned int syt)
{ {
unsigned int phase, data_blocks; unsigned int phase, data_blocks;
if (s->flags & CIP_BLOCKING) /* Blocking mode. */
data_blocks = s->syt_interval; if (s->flags & CIP_BLOCKING) {
else if (!cip_sfc_is_base_44100(s->sfc)) { /* This module generate empty packet for 'no data'. */
/* Sample_rate / 8000 is an integer, and precomputed. */ if (syt == CIP_SYT_NO_INFO)
data_blocks = s->data_block_state; data_blocks = 0;
else
data_blocks = s->syt_interval;
/* Non-blocking mode. */
} else { } else {
phase = s->data_block_state; if (!cip_sfc_is_base_44100(s->sfc)) {
/* Sample_rate / 8000 is an integer, and precomputed. */
data_blocks = s->data_block_state;
} else {
phase = s->data_block_state;
/* /*
* This calculates the number of data blocks per packet so that * This calculates the number of data blocks per packet so that
@ -341,16 +349,17 @@ static unsigned int calculate_data_blocks(struct amdtp_stream *s)
* as possible in the sequence (to prevent underruns of the * as possible in the sequence (to prevent underruns of the
* device's buffer). * device's buffer).
*/ */
if (s->sfc == CIP_SFC_44100) if (s->sfc == CIP_SFC_44100)
/* 6 6 5 6 5 6 5 ... */ /* 6 6 5 6 5 6 5 ... */
data_blocks = 5 + ((phase & 1) ^ data_blocks = 5 + ((phase & 1) ^
(phase == 0 || phase >= 40)); (phase == 0 || phase >= 40));
else else
/* 12 11 11 11 11 ... or 23 22 22 22 22 ... */ /* 12 11 11 11 11 ... or 23 22 22 22 22 ... */
data_blocks = 11 * (s->sfc >> 1) + (phase == 0); data_blocks = 11 * (s->sfc >> 1) + (phase == 0);
if (++phase >= (80 >> (s->sfc >> 1))) if (++phase >= (80 >> (s->sfc >> 1)))
phase = 0; phase = 0;
s->data_block_state = phase; s->data_block_state = phase;
}
} }
return data_blocks; return data_blocks;
@ -647,11 +656,7 @@ static void handle_out_packet(struct amdtp_stream *s, unsigned int syt)
if (s->packet_index < 0) if (s->packet_index < 0)
return; return;
/* this module generate empty packet for 'no data' */ data_blocks = calculate_data_blocks(s, syt);
if (!(s->flags & CIP_BLOCKING) || (syt != CIP_SYT_NO_INFO))
data_blocks = calculate_data_blocks(s);
else
data_blocks = 0;
buffer = s->buffer.packets[s->packet_index].buffer; buffer = s->buffer.packets[s->packet_index].buffer;
buffer[0] = cpu_to_be32(ACCESS_ONCE(s->source_node_id_field) | buffer[0] = cpu_to_be32(ACCESS_ONCE(s->source_node_id_field) |