pcm_native.c

linux 内核源代码

	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 
				  snd_pcm_hw_rule_mulkdiv, (void*) 8,
				  SNDRV_PCM_HW_PARAM_PERIOD_BYTES, SNDRV_PCM_HW_PARAM_FRAME_BITS, -1);
	if (err < 0)
		return err;
	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 
				  snd_pcm_hw_rule_muldivk, (void*) 1000000,
				  SNDRV_PCM_HW_PARAM_PERIOD_TIME, SNDRV_PCM_HW_PARAM_RATE, -1);
	if (err < 0)
		return err;
	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 
				  snd_pcm_hw_rule_mul, NULL,
				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, SNDRV_PCM_HW_PARAM_PERIODS, -1);
	if (err < 0)
		return err;
	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 
				  snd_pcm_hw_rule_mulkdiv, (void*) 8,
				  SNDRV_PCM_HW_PARAM_BUFFER_BYTES, SNDRV_PCM_HW_PARAM_FRAME_BITS, -1);
	if (err < 0)
		return err;
	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 
				  snd_pcm_hw_rule_muldivk, (void*) 1000000,
				  SNDRV_PCM_HW_PARAM_BUFFER_TIME, SNDRV_PCM_HW_PARAM_RATE, -1);
	if (err < 0)
		return err;
	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 
				  snd_pcm_hw_rule_muldivk, (void*) 8,
				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, SNDRV_PCM_HW_PARAM_FRAME_BITS, -1);
	if (err < 0)
		return err;
	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 
				  snd_pcm_hw_rule_muldivk, (void*) 8,
				  SNDRV_PCM_HW_PARAM_BUFFER_SIZE, SNDRV_PCM_HW_PARAM_FRAME_BITS, -1);
	if (err < 0)
		return err;
	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_TIME, 
				  snd_pcm_hw_rule_mulkdiv, (void*) 1000000,
				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, SNDRV_PCM_HW_PARAM_RATE, -1);
	if (err < 0)
		return err;
	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_TIME, 
				  snd_pcm_hw_rule_mulkdiv, (void*) 1000000,
				  SNDRV_PCM_HW_PARAM_BUFFER_SIZE, SNDRV_PCM_HW_PARAM_RATE, -1);
	if (err < 0)
		return err;
	return 0;
}

int snd_pcm_hw_constraints_complete(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_pcm_hardware *hw = &runtime->hw;
	int err;
	unsigned int mask = 0;

        if (hw->info & SNDRV_PCM_INFO_INTERLEAVED)
		mask |= 1 << SNDRV_PCM_ACCESS_RW_INTERLEAVED;
        if (hw->info & SNDRV_PCM_INFO_NONINTERLEAVED)
		mask |= 1 << SNDRV_PCM_ACCESS_RW_NONINTERLEAVED;
	if (hw->info & SNDRV_PCM_INFO_MMAP) {
		if (hw->info & SNDRV_PCM_INFO_INTERLEAVED)
			mask |= 1 << SNDRV_PCM_ACCESS_MMAP_INTERLEAVED;
		if (hw->info & SNDRV_PCM_INFO_NONINTERLEAVED)
			mask |= 1 << SNDRV_PCM_ACCESS_MMAP_NONINTERLEAVED;
		if (hw->info & SNDRV_PCM_INFO_COMPLEX)
			mask |= 1 << SNDRV_PCM_ACCESS_MMAP_COMPLEX;
	}
	err = snd_pcm_hw_constraint_mask(runtime, SNDRV_PCM_HW_PARAM_ACCESS, mask);
	snd_assert(err >= 0, return -EINVAL);

	err = snd_pcm_hw_constraint_mask64(runtime, SNDRV_PCM_HW_PARAM_FORMAT, hw->formats);
	snd_assert(err >= 0, return -EINVAL);

	err = snd_pcm_hw_constraint_mask(runtime, SNDRV_PCM_HW_PARAM_SUBFORMAT, 1 << SNDRV_PCM_SUBFORMAT_STD);
	snd_assert(err >= 0, return -EINVAL);

	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_CHANNELS,
					   hw->channels_min, hw->channels_max);
	snd_assert(err >= 0, return -EINVAL);

	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_RATE,
					   hw->rate_min, hw->rate_max);
	snd_assert(err >= 0, return -EINVAL);

	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
					   hw->period_bytes_min, hw->period_bytes_max);
	snd_assert(err >= 0, return -EINVAL);

	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIODS,
					   hw->periods_min, hw->periods_max);
	snd_assert(err >= 0, return -EINVAL);

	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
					   hw->period_bytes_min, hw->buffer_bytes_max);
	snd_assert(err >= 0, return -EINVAL);

	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 
				  snd_pcm_hw_rule_buffer_bytes_max, substream,
				  SNDRV_PCM_HW_PARAM_BUFFER_BYTES, -1);
	if (err < 0)
		return err;

	/* FIXME: remove */
	if (runtime->dma_bytes) {
		err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 0, runtime->dma_bytes);
		snd_assert(err >= 0, return -EINVAL);
	}

	if (!(hw->rates & (SNDRV_PCM_RATE_KNOT | SNDRV_PCM_RATE_CONTINUOUS))) {
		err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE, 
					  snd_pcm_hw_rule_rate, hw,
					  SNDRV_PCM_HW_PARAM_RATE, -1);
		if (err < 0)
			return err;
	}

	/* FIXME: this belong to lowlevel */
	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_TICK_TIME,
				     1000000 / HZ, 1000000 / HZ);
	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);

	return 0;
}

static void pcm_release_private(struct snd_pcm_substream *substream)
{
	snd_pcm_unlink(substream);
}

void snd_pcm_release_substream(struct snd_pcm_substream *substream)
{
	substream->ref_count--;
	if (substream->ref_count > 0)
		return;

	snd_pcm_drop(substream);
	if (substream->hw_opened) {
		if (substream->ops->hw_free != NULL)
			substream->ops->hw_free(substream);
		substream->ops->close(substream);
		substream->hw_opened = 0;
	}
	if (substream->pcm_release) {
		substream->pcm_release(substream);
		substream->pcm_release = NULL;
	}
	snd_pcm_detach_substream(substream);
}

EXPORT_SYMBOL(snd_pcm_release_substream);

int snd_pcm_open_substream(struct snd_pcm *pcm, int stream,
			   struct file *file,
			   struct snd_pcm_substream **rsubstream)
{
	struct snd_pcm_substream *substream;
	int err;

	err = snd_pcm_attach_substream(pcm, stream, file, &substream);
	if (err < 0)
		return err;
	if (substream->ref_count > 1) {
		*rsubstream = substream;
		return 0;
	}

	err = snd_pcm_hw_constraints_init(substream);
	if (err < 0) {
		snd_printd("snd_pcm_hw_constraints_init failed\n");
		goto error;
	}

	if ((err = substream->ops->open(substream)) < 0)
		goto error;

	substream->hw_opened = 1;

	err = snd_pcm_hw_constraints_complete(substream);
	if (err < 0) {
		snd_printd("snd_pcm_hw_constraints_complete failed\n");
		goto error;
	}

	*rsubstream = substream;
	return 0;

 error:
	snd_pcm_release_substream(substream);
	return err;
}

EXPORT_SYMBOL(snd_pcm_open_substream);

static int snd_pcm_open_file(struct file *file,
			     struct snd_pcm *pcm,
			     int stream,
			     struct snd_pcm_file **rpcm_file)
{
	struct snd_pcm_file *pcm_file;
	struct snd_pcm_substream *substream;
	struct snd_pcm_str *str;
	int err;

	snd_assert(rpcm_file != NULL, return -EINVAL);
	*rpcm_file = NULL;

	err = snd_pcm_open_substream(pcm, stream, file, &substream);
	if (err < 0)
		return err;

	pcm_file = kzalloc(sizeof(*pcm_file), GFP_KERNEL);
	if (pcm_file == NULL) {
		snd_pcm_release_substream(substream);
		return -ENOMEM;
	}
	pcm_file->substream = substream;
	if (substream->ref_count == 1) {
		str = substream->pstr;
		substream->file = pcm_file;
		substream->pcm_release = pcm_release_private;
	}
	file->private_data = pcm_file;
	*rpcm_file = pcm_file;
	return 0;
}

static int snd_pcm_playback_open(struct inode *inode, struct file *file)
{
	struct snd_pcm *pcm;

	pcm = snd_lookup_minor_data(iminor(inode),
				    SNDRV_DEVICE_TYPE_PCM_PLAYBACK);
	return snd_pcm_open(file, pcm, SNDRV_PCM_STREAM_PLAYBACK);
}

static int snd_pcm_capture_open(struct inode *inode, struct file *file)
{
	struct snd_pcm *pcm;

	pcm = snd_lookup_minor_data(iminor(inode),
				    SNDRV_DEVICE_TYPE_PCM_CAPTURE);
	return snd_pcm_open(file, pcm, SNDRV_PCM_STREAM_CAPTURE);
}

static int snd_pcm_open(struct file *file, struct snd_pcm *pcm, int stream)
{
	int err;
	struct snd_pcm_file *pcm_file;
	wait_queue_t wait;

	if (pcm == NULL) {
		err = -ENODEV;
		goto __error1;
	}
	err = snd_card_file_add(pcm->card, file);
	if (err < 0)
		goto __error1;
	if (!try_module_get(pcm->card->module)) {
		err = -EFAULT;
		goto __error2;
	}
	init_waitqueue_entry(&wait, current);
	add_wait_queue(&pcm->open_wait, &wait);
	mutex_lock(&pcm->open_mutex);
	while (1) {
		err = snd_pcm_open_file(file, pcm, stream, &pcm_file);
		if (err >= 0)
			break;
		if (err == -EAGAIN) {
			if (file->f_flags & O_NONBLOCK) {
				err = -EBUSY;
				break;
			}
		} else
			break;
		set_current_state(TASK_INTERRUPTIBLE);
		mutex_unlock(&pcm->open_mutex);
		schedule();
		mutex_lock(&pcm->open_mutex);
		if (signal_pending(current)) {
			err = -ERESTARTSYS;
			break;
		}
	}
	remove_wait_queue(&pcm->open_wait, &wait);
	mutex_unlock(&pcm->open_mutex);
	if (err < 0)
		goto __error;
	return err;

      __error:
	module_put(pcm->card->module);
      __error2:
      	snd_card_file_remove(pcm->card, file);
      __error1:
      	return err;
}

static int snd_pcm_release(struct inode *inode, struct file *file)
{
	struct snd_pcm *pcm;
	struct snd_pcm_substream *substream;
	struct snd_pcm_file *pcm_file;

	pcm_file = file->private_data;
	substream = pcm_file->substream;
	snd_assert(substream != NULL, return -ENXIO);
	pcm = substream->pcm;
	fasync_helper(-1, file, 0, &substream->runtime->fasync);
	mutex_lock(&pcm->open_mutex);
	snd_pcm_release_substream(substream);
	kfree(pcm_file);
	mutex_unlock(&pcm->open_mutex);
	wake_up(&pcm->open_wait);
	module_put(pcm->card->module);
	snd_card_file_remove(pcm->card, file);
	return 0;
}

static snd_pcm_sframes_t snd_pcm_playback_rewind(struct snd_pcm_substream *substream,
						 snd_pcm_uframes_t frames)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	snd_pcm_sframes_t appl_ptr;
	snd_pcm_sframes_t ret;
	snd_pcm_sframes_t hw_avail;

	if (frames == 0)
		return 0;

	snd_pcm_stream_lock_irq(substream);
	switch (runtime->status->state) {
	case SNDRV_PCM_STATE_PREPARED:
		break;
	case SNDRV_PCM_STATE_DRAINING:
	case SNDRV_PCM_STATE_RUNNING:
		if (snd_pcm_update_hw_ptr(substream) >= 0)
			break;
		/* Fall through */
	case SNDRV_PCM_STATE_XRUN:
		ret = -EPIPE;
		goto __end;
	default:
		ret = -EBADFD;
		goto __end;
	}

	hw_avail = snd_pcm_playback_hw_avail(runtime);
	if (hw_avail <= 0) {
		ret = 0;
		goto __end;
	}
	if (frames > (snd_pcm_uframes_t)hw_avail)
		frames = hw_avail;
	else
		frames -= frames % runtime->xfer_align;
	appl_ptr = runtime->control->appl_ptr - frames;
	if (appl_ptr < 0)
		appl_ptr += runtime->boundary;
	runtime->control->appl_ptr = appl_ptr;
	if (runtime->status->state == SNDRV_PCM_STATE_RUNNING &&
	    runtime->sleep_min)
		snd_pcm_tick_prepare(substream);
	ret = frames;
 __end:
	snd_pcm_stream_unlock_irq(substream);
	return ret;
}

static snd_pcm_sframes_t snd_pcm_capture_rewind(struct snd_pcm_substream *substream,
						snd_pcm_uframes_t frames)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	snd_pcm_sframes_t appl_ptr;
	snd_pcm_sframes_t ret;
	snd_pcm_sframes_t hw_avail;

	if (frames == 0)
		return 0;

	snd_pcm_stream_lock_irq(substream);
	switch (runtime->status->state) {
	case SNDRV_PCM_STATE_PREPARED:
	case SNDRV_PCM_STATE_DRAINING:
		break;
	case SNDRV_PCM_STATE_RUNNING:
		if (snd_pcm_update_hw_ptr(substream) >= 0)
			break;
		/* Fall through */
	case SNDRV_PCM_STATE_XRUN:
		ret = -EPIPE;
		goto __end;
	default:
		ret = -EBADFD;
		goto __end;
	}

	hw_avail = snd_pcm_capture_hw_avail(runtime);
	if (hw_avail <= 0) {
		ret = 0;
		goto __end;
	}
	if (frames > (snd_pcm_uframes_t)hw_avail)
		frames = hw_avail;
	else
		frames -= frames % runtime->xfer_align;
	appl_ptr = runtime->control->appl_ptr - frames;
	if (appl_ptr < 0)
		appl_ptr += runtime->boundary;
	runtime->control->appl_ptr = appl_ptr;
	if (runtime->status->state == SNDRV_PCM_STATE_RUNNING &&
	    runtime->sleep_min)
		snd_pcm_tick_prepare(substream);
	ret = frames;
 __end:
	snd_pcm_stream_unlock_irq(substream);
	return ret;
}

static snd_pcm_sframes_t snd_pcm_playback_forward(struct snd_pcm_substream *substream,
						  snd_pcm_uframes_t frames)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	snd_pcm_sframes_t appl_ptr;
	snd_pcm_sframes_t ret;
	snd_pcm_sframes_t avail;

	if (frames == 0)
		return 0;

	snd_pcm_stream_lock_irq(substream);
	switch (runtime->status->state) {
	case SNDRV_PCM_STATE_PREPARED:
	case SNDRV_PCM_STATE_PAUSED:
		break;
	case SNDRV_PCM_STATE_DRAINING:
	case SNDRV_PCM_STATE_RUNNING:
		if (snd_pcm_update_hw_ptr(substream) >= 0)
			break;
		/* Fall through */
	case SNDRV_PCM_STATE_XRUN:
		ret = -EPIPE;
		goto __end;
	default:
		ret = -EBADFD;
		goto __end;
	}

	avail = snd_pcm_playback_avail(runtime);
	if (avail <= 0) {
		ret = 0;
		goto __end;
	}
	if (frames > (snd_pcm_uframes_t)avail)
		frames = avail;
	else
		frames -= frames % runtime->xfer_align;
	appl_ptr = runtime->control->appl_ptr + frames;
	if (appl_ptr >= (snd_pcm_sframes_t)runtime->boundary)
		appl_ptr -= runtime->boundary;
	runtime->control->appl_ptr = appl_ptr;
	if (runtime->status->state == SNDRV_PCM_STATE_RUNNING &&
	    runtime->sleep_min)
		snd_pcm_tick_prepare(substream);
	ret = frames;
 __end:
	snd_pcm_stream_unlock_irq(substream);
	return ret;
}

static snd_pcm_sframes_t snd_pcm_capture_forward(struct