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ALSA: firewire-motu: use macro for magic numbers relevant to IEC 61883-1
ALSA firewire-motu driver has some magic numbers from IEC 61883-1 to operates source packet header (SPH). This commit replaces them with macros. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Link: https://lore.kernel.org/r/20210602013406.26442-2-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai <tiwai@suse.de>
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1bd1b3be86
commit
138d1bceee
1 changed files with 26 additions and 14 deletions
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@ -16,6 +16,18 @@
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#define CIP_FMT_MOTU_TX_V3 0x22
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#define MOTU_FDF_AM824 0x22
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#define TICKS_PER_CYCLE 3072
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#define CYCLES_PER_SECOND 8000
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#define TICKS_PER_SECOND (TICKS_PER_CYCLE * CYCLES_PER_SECOND)
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#define IEEE1394_SEC_MODULUS 128
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#define TRANSFER_DELAY_TICKS 0x2e00 /* 479.17 microseconds */
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#define CIP_SPH_CYCLE_SHIFT 12
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#define CIP_SPH_CYCLE_MASK 0x01fff000
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#define CIP_SPH_OFFSET_MASK 0x00000fff
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/*
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* Nominally 3125 bytes/second, but the MIDI port's clock might be
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* 1% too slow, and the bus clock 100 ppm too fast.
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@ -97,17 +109,16 @@ int amdtp_motu_set_parameters(struct amdtp_stream *s, unsigned int rate,
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p->midi_db_count = 0;
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p->midi_db_interval = rate / MIDI_BYTES_PER_SECOND;
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/* IEEE 1394 bus requires. */
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delay = 0x2e00;
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delay = TRANSFER_DELAY_TICKS;
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/* For no-data or empty packets to adjust PCM sampling frequency. */
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delay += 8000 * 3072 * s->syt_interval / rate;
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// For no-data or empty packets to adjust PCM sampling frequency.
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delay += TICKS_PER_SECOND * s->syt_interval / rate;
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p->next_seconds = 0;
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p->next_cycles = delay / 3072;
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p->next_cycles = delay / TICKS_PER_CYCLE;
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p->quotient_ticks_per_event = params[s->sfc].quotient_ticks_per_event;
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p->remainder_ticks_per_event = params[s->sfc].remainder_ticks_per_event;
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p->next_ticks = delay % 3072;
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p->next_ticks = delay % TICKS_PER_CYCLE;
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p->next_accumulated = 0;
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return 0;
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@ -363,18 +374,18 @@ static inline void compute_next_elapse_from_start(struct amdtp_motu *p)
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}
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p->next_ticks += p->quotient_ticks_per_event;
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if (p->next_ticks >= 3072) {
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p->next_ticks -= 3072;
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if (p->next_ticks >= TICKS_PER_CYCLE) {
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p->next_ticks -= TICKS_PER_CYCLE;
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p->next_cycles++;
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}
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if (p->next_cycles >= 8000) {
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p->next_cycles -= 8000;
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if (p->next_cycles >= CYCLES_PER_SECOND) {
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p->next_cycles -= CYCLES_PER_SECOND;
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p->next_seconds++;
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}
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if (p->next_seconds >= 128)
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p->next_seconds -= 128;
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if (p->next_seconds >= IEEE1394_SEC_MODULUS)
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p->next_seconds -= IEEE1394_SEC_MODULUS;
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}
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static void write_sph(struct amdtp_stream *s, __be32 *buffer, unsigned int data_blocks,
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@ -386,8 +397,9 @@ static void write_sph(struct amdtp_stream *s, __be32 *buffer, unsigned int data_
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u32 sph;
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for (i = 0; i < data_blocks; i++) {
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next_cycles = (rx_start_cycle + p->next_cycles) % 8000;
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sph = ((next_cycles << 12) | p->next_ticks) & 0x01ffffff;
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next_cycles = (rx_start_cycle + p->next_cycles) % CYCLES_PER_SECOND;
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sph = ((next_cycles << CIP_SPH_CYCLE_SHIFT) | p->next_ticks) &
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(CIP_SPH_CYCLE_MASK | CIP_SPH_OFFSET_MASK);
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*buffer = cpu_to_be32(sph);
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compute_next_elapse_from_start(p);
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