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| author |   Takashi Sakamoto <o-takashi@sakamocchi.jp> | 2021-06-02 10:34:04 +0900 |
|---|---|---|
| committer |   Takashi Iwai <tiwai@suse.de> | 2021-06-02 08:59:29 +0200 |
| commit | 138d1bceee6a3baaf2555725bf5b3e44b02a65e4 (patch) | |
| tree | 9f5791c16ab1596704ac70a03131d86b310d99ec /sound/firewire | |
| parent | ALSA: bebob: perform sequence replay for media clock recovery (diff) | |
| download | linux-dev-138d1bceee6a3baaf2555725bf5b3e44b02a65e4.tar.xz linux-dev-138d1bceee6a3baaf2555725bf5b3e44b02a65e4.zip | |
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>
Diffstat (limited to 'sound/firewire')
| -rw-r--r-- | sound/firewire/motu/amdtp-motu.c | 40 |
1 files changed, 26 insertions, 14 deletions
diff --git a/sound/firewire/motu/amdtp-motu.c b/sound/firewire/motu/amdtp-motu.c index 18bf433f43b6..89638e1fbb69 100644 --- a/sound/firewire/motu/amdtp-motu.c +++ b/sound/firewire/motu/amdtp-motu.c @@ -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); |