ALSA: firewire-lib: code refactoring for generation of data block sequence

This commit dissolves sequence generator in terms of the number of data
blocks per packet.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210522013303.49596-6-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 77ae75e..2620951 100644 (file)
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -357,26 +357,41 @@ void amdtp_stream_pcm_prepare(struct amdtp_stream *s)
 }
 EXPORT_SYMBOL(amdtp_stream_pcm_prepare);
 
-static unsigned int calculate_data_blocks(unsigned int *data_block_state,
-                               bool is_blocking, bool is_no_info,
-                               unsigned int syt_interval, enum cip_sfc sfc)
+static void pool_blocking_data_blocks(struct amdtp_stream *s, struct seq_desc *descs,
+                                     const unsigned int seq_size, unsigned int seq_tail,
+                                     unsigned int count)
 {
-       unsigned int data_blocks;
+       const unsigned int syt_interval = s->syt_interval;
+       int i;
+
+       for (i = 0; i < count; ++i) {
+               struct seq_desc *desc = descs + seq_tail;
 
-       /* Blocking mode. */
-       if (is_blocking) {
-               /* This module generate empty packet for 'no data'. */
-               if (is_no_info)
-                       data_blocks = 0;
+               if (desc->syt_offset != CIP_SYT_NO_INFO)
+                       desc->data_blocks = syt_interval;
                else
-                       data_blocks = syt_interval;
-       /* Non-blocking mode. */
-       } else {
+                       desc->data_blocks = 0;
+
+               seq_tail = (seq_tail + 1) % seq_size;
+       }
+}
+
+static void pool_ideal_nonblocking_data_blocks(struct amdtp_stream *s, struct seq_desc *descs,
+                                              const unsigned int seq_size, unsigned int seq_tail,
+                                              unsigned int count)
+{
+       const enum cip_sfc sfc = s->sfc;
+       unsigned int state = s->ctx_data.rx.data_block_state;
+       int i;
+
+       for (i = 0; i < count; ++i) {
+               struct seq_desc *desc = descs + seq_tail;
+
                if (!cip_sfc_is_base_44100(sfc)) {
                        // Sample_rate / 8000 is an integer, and precomputed.
-                       data_blocks = *data_block_state;
+                       desc->data_blocks = state;
                } else {
-                       unsigned int phase = *data_block_state;
+                       unsigned int phase = state;
 
                /*
                 * This calculates the number of data blocks per packet so that
@@ -388,18 +403,19 @@ static unsigned int calculate_data_blocks(unsigned int *data_block_state,
                 */
                        if (sfc == CIP_SFC_44100)
                                /* 6 6 5 6 5 6 5 ... */
-                               data_blocks = 5 + ((phase & 1) ^
-                                                  (phase == 0 || phase >= 40));
+                               desc->data_blocks = 5 + ((phase & 1) ^ (phase == 0 || phase >= 40));
                        else
                                /* 12 11 11 11 11 ... or 23 22 22 22 22 ... */
-                               data_blocks = 11 * (sfc >> 1) + (phase == 0);
+                               desc->data_blocks = 11 * (sfc >> 1) + (phase == 0);
                        if (++phase >= (80 >> (sfc >> 1)))
                                phase = 0;
-                       *data_block_state = phase;
+                       state = phase;
                }
+
+               seq_tail = (seq_tail + 1) % seq_size;
        }
 
-       return data_blocks;
+       s->ctx_data.rx.data_block_state = state;
 }
 
 static unsigned int calculate_syt_offset(unsigned int *last_syt_offset,
@@ -467,24 +483,15 @@ static void pool_ideal_seq_descs(struct amdtp_stream *s, unsigned int count)
        struct seq_desc *descs = s->ctx_data.rx.seq.descs;
        unsigned int seq_tail = s->ctx_data.rx.seq.tail;
        const unsigned int seq_size = s->ctx_data.rx.seq.size;
-       const unsigned int syt_interval = s->syt_interval;
-       const enum cip_sfc sfc = s->sfc;
-       const bool is_blocking = !!(s->flags & CIP_BLOCKING);
-       int i;
 
        pool_ideal_syt_offsets(s, descs, seq_size, seq_tail, count);
 
-       for (i = 0; i < count; ++i) {
-               struct seq_desc *desc = s->ctx_data.rx.seq.descs + seq_tail;
-
-               desc->data_blocks = calculate_data_blocks(&s->ctx_data.rx.data_block_state,
-                               is_blocking, desc->syt_offset == CIP_SYT_NO_INFO,
-                               syt_interval, sfc);
-
-               seq_tail = (seq_tail + 1) % seq_size;
-       }
+       if (s->flags & CIP_BLOCKING)
+               pool_blocking_data_blocks(s, descs, seq_size, seq_tail, count);
+       else
+               pool_ideal_nonblocking_data_blocks(s, descs, seq_size, seq_tail, count);
 
-       s->ctx_data.rx.seq.tail = seq_tail;
+       s->ctx_data.rx.seq.tail = (seq_tail + count) % seq_size;
 }
 
 static void update_pcm_pointers(struct amdtp_stream *s,