sound/firewire/tascam/tascam-pcm.c

Source file repositories/reference/linux-study-clean/sound/firewire/tascam/tascam-pcm.c

File Facts

System
Linux kernel
Corpus path
sound/firewire/tascam/tascam-pcm.c
Extension
.c
Size
7050 bytes
Lines
276
Domain
Driver Families
Bucket
sound/firewire
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (clock != SND_TSCM_CLOCK_INTERNAL || tscm->substreams_counter > 0) {
			unsigned int frames_per_period = d->events_per_period;
			unsigned int frames_per_buffer = d->events_per_buffer;
			unsigned int rate;

			err = snd_tscm_stream_get_rate(tscm, &rate);
			if (err < 0)
				goto err_locked;
			substream->runtime->hw.rate_min = rate;
			substream->runtime->hw.rate_max = rate;

			err = snd_pcm_hw_constraint_minmax(substream->runtime,
							   SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
							   frames_per_period, frames_per_period);
			if (err < 0)
				goto err_locked;

			err = snd_pcm_hw_constraint_minmax(substream->runtime,
							   SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
							   frames_per_buffer, frames_per_buffer);
			if (err < 0)
				goto err_locked;
		}
	}

	snd_pcm_set_sync(substream);

	return 0;
err_locked:
	snd_tscm_stream_lock_release(tscm);
	return err;
}

static int pcm_close(struct snd_pcm_substream *substream)
{
	struct snd_tscm *tscm = substream->private_data;

	snd_tscm_stream_lock_release(tscm);

	return 0;
}

static int pcm_hw_params(struct snd_pcm_substream *substream,
			 struct snd_pcm_hw_params *hw_params)
{
	struct snd_tscm *tscm = substream->private_data;
	int err = 0;

	if (substream->runtime->state == SNDRV_PCM_STATE_OPEN) {
		unsigned int rate = params_rate(hw_params);
		unsigned int frames_per_period = params_period_size(hw_params);
		unsigned int frames_per_buffer = params_buffer_size(hw_params);

		guard(mutex)(&tscm->mutex);
		err = snd_tscm_stream_reserve_duplex(tscm, rate,
					frames_per_period, frames_per_buffer);
		if (err >= 0)
			++tscm->substreams_counter;
	}

	return err;
}

static int pcm_hw_free(struct snd_pcm_substream *substream)
{
	struct snd_tscm *tscm = substream->private_data;

	guard(mutex)(&tscm->mutex);

	if (substream->runtime->state != SNDRV_PCM_STATE_OPEN)
		--tscm->substreams_counter;

	snd_tscm_stream_stop_duplex(tscm);

	return 0;
}

static int pcm_capture_prepare(struct snd_pcm_substream *substream)
{
	struct snd_tscm *tscm = substream->private_data;
	struct snd_pcm_runtime *runtime = substream->runtime;
	int err;

	guard(mutex)(&tscm->mutex);

	err = snd_tscm_stream_start_duplex(tscm, runtime->rate);
	if (err >= 0)
		amdtp_stream_pcm_prepare(&tscm->tx_stream);

	return err;

Annotation

Implementation Notes