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ALSA: firewire-motu: use macro for magic numbers relevant to IEC 61883-1

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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>
This commit is contained in:
Takashi Sakamoto 2021-06-02 10:34:04 +09:00 committed by Takashi Iwai
parent 1bd1b3be86
commit 138d1bceee
1 changed files with 26 additions and 14 deletions
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40
sound/firewire/motu/amdtp-motu.c
View File

@ -16,6 +16,18 @@
#define CIP_FMT_MOTU_TX_V3 0x22
#define MOTU_FDF_AM824 0x22
#define TICKS_PER_CYCLE 3072
#define CYCLES_PER_SECOND 8000
#define TICKS_PER_SECOND (TICKS_PER_CYCLE * CYCLES_PER_SECOND)
#define IEEE1394_SEC_MODULUS 128
#define TRANSFER_DELAY_TICKS 0x2e00 /* 479.17 microseconds */
#define CIP_SPH_CYCLE_SHIFT 12
#define CIP_SPH_CYCLE_MASK 0x01fff000
#define CIP_SPH_OFFSET_MASK 0x00000fff
/*
* Nominally 3125 bytes/second, but the MIDI port's clock might be
* 1% too slow, and the bus clock 100 ppm too fast.
@ -97,17 +109,16 @@ int amdtp_motu_set_parameters(struct amdtp_stream *s, unsigned int rate,
p->midi_db_count = 0;
p->midi_db_interval = rate / MIDI_BYTES_PER_SECOND;
/* IEEE 1394 bus requires. */
delay = 0x2e00;
delay = TRANSFER_DELAY_TICKS;
/* For no-data or empty packets to adjust PCM sampling frequency. */
delay += 8000 * 3072 * s->syt_interval / rate;
// For no-data or empty packets to adjust PCM sampling frequency.
delay += TICKS_PER_SECOND * s->syt_interval / rate;
p->next_seconds = 0;
p->next_cycles = delay / 3072;
p->next_cycles = delay / TICKS_PER_CYCLE;
p->quotient_ticks_per_event = params[s->sfc].quotient_ticks_per_event;
p->remainder_ticks_per_event = params[s->sfc].remainder_ticks_per_event;
p->next_ticks = delay % 3072;
p->next_ticks = delay % TICKS_PER_CYCLE;
p->next_accumulated = 0;
return 0;
@ -363,18 +374,18 @@ static inline void compute_next_elapse_from_start(struct amdtp_motu *p)
}
p->next_ticks += p->quotient_ticks_per_event;
if (p->next_ticks >= 3072) {
p->next_ticks -= 3072;
if (p->next_ticks >= TICKS_PER_CYCLE) {
p->next_ticks -= TICKS_PER_CYCLE;
p->next_cycles++;
}
if (p->next_cycles >= 8000) {
p->next_cycles -= 8000;
if (p->next_cycles >= CYCLES_PER_SECOND) {
p->next_cycles -= CYCLES_PER_SECOND;
p->next_seconds++;
}
if (p->next_seconds >= 128)
p->next_seconds -= 128;
if (p->next_seconds >= IEEE1394_SEC_MODULUS)
p->next_seconds -= IEEE1394_SEC_MODULUS;
}
static void write_sph(struct amdtp_stream *s, __be32 *buffer, unsigned int data_blocks,
@ -386,8 +397,9 @@ static void write_sph(struct amdtp_stream *s, __be32 *buffer, unsigned int data_
u32 sph;
for (i = 0; i < data_blocks; i++) {
next_cycles = (rx_start_cycle + p->next_cycles) % 8000;
sph = ((next_cycles << 12) | p->next_ticks) & 0x01ffffff;
next_cycles = (rx_start_cycle + p->next_cycles) % CYCLES_PER_SECOND;
sph = ((next_cycles << CIP_SPH_CYCLE_SHIFT) | p->next_ticks) &
(CIP_SPH_CYCLE_MASK | CIP_SPH_OFFSET_MASK);
*buffer = cpu_to_be32(sph);
compute_next_elapse_from_start(p);