pcm_native.c

linux 内核源代码

	}
	if (copy_from_user(params, _params, sizeof(*params))) {
		err = -EFAULT;
		goto out;
	}
	err = snd_pcm_hw_params(substream, params);
	if (copy_to_user(_params, params, sizeof(*params))) {
		if (!err)
			err = -EFAULT;
	}
out:
	kfree(params);
	return err;
}

static int snd_pcm_hw_free(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime;
	int result = 0;

	snd_assert(substream != NULL, return -ENXIO);
	runtime = substream->runtime;
	snd_assert(runtime != NULL, return -ENXIO);
	snd_pcm_stream_lock_irq(substream);
	switch (runtime->status->state) {
	case SNDRV_PCM_STATE_SETUP:
	case SNDRV_PCM_STATE_PREPARED:
		break;
	default:
		snd_pcm_stream_unlock_irq(substream);
		return -EBADFD;
	}
	snd_pcm_stream_unlock_irq(substream);
	if (atomic_read(&substream->mmap_count))
		return -EBADFD;
	if (substream->ops->hw_free)
		result = substream->ops->hw_free(substream);
	runtime->status->state = SNDRV_PCM_STATE_OPEN;
	remove_acceptable_latency(substream->latency_id);
	return result;
}

static int snd_pcm_sw_params(struct snd_pcm_substream *substream,
			     struct snd_pcm_sw_params *params)
{
	struct snd_pcm_runtime *runtime;

	snd_assert(substream != NULL, return -ENXIO);
	runtime = substream->runtime;
	snd_assert(runtime != NULL, return -ENXIO);
	snd_pcm_stream_lock_irq(substream);
	if (runtime->status->state == SNDRV_PCM_STATE_OPEN) {
		snd_pcm_stream_unlock_irq(substream);
		return -EBADFD;
	}
	snd_pcm_stream_unlock_irq(substream);

	if (params->tstamp_mode > SNDRV_PCM_TSTAMP_LAST)
		return -EINVAL;
	if (params->avail_min == 0)
		return -EINVAL;
	if (params->xfer_align == 0 ||
	    params->xfer_align % runtime->min_align != 0)
		return -EINVAL;
	if (params->silence_size >= runtime->boundary) {
		if (params->silence_threshold != 0)
			return -EINVAL;
	} else {
		if (params->silence_size > params->silence_threshold)
			return -EINVAL;
		if (params->silence_threshold > runtime->buffer_size)
			return -EINVAL;
	}
	snd_pcm_stream_lock_irq(substream);
	runtime->tstamp_mode = params->tstamp_mode;
	runtime->sleep_min = params->sleep_min;
	runtime->period_step = params->period_step;
	runtime->control->avail_min = params->avail_min;
	runtime->start_threshold = params->start_threshold;
	runtime->stop_threshold = params->stop_threshold;
	runtime->silence_threshold = params->silence_threshold;
	runtime->silence_size = params->silence_size;
	runtime->xfer_align = params->xfer_align;
        params->boundary = runtime->boundary;
	if (snd_pcm_running(substream)) {
		if (runtime->sleep_min)
			snd_pcm_tick_prepare(substream);
		else
			snd_pcm_tick_set(substream, 0);
		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
		    runtime->silence_size > 0)
			snd_pcm_playback_silence(substream, ULONG_MAX);
		wake_up(&runtime->sleep);
	}
	snd_pcm_stream_unlock_irq(substream);
	return 0;
}

static int snd_pcm_sw_params_user(struct snd_pcm_substream *substream,
				  struct snd_pcm_sw_params __user * _params)
{
	struct snd_pcm_sw_params params;
	int err;
	if (copy_from_user(&params, _params, sizeof(params)))
		return -EFAULT;
	err = snd_pcm_sw_params(substream, &params);
	if (copy_to_user(_params, &params, sizeof(params)))
		return -EFAULT;
	return err;
}

int snd_pcm_status(struct snd_pcm_substream *substream,
		   struct snd_pcm_status *status)
{
	struct snd_pcm_runtime *runtime = substream->runtime;

	snd_pcm_stream_lock_irq(substream);
	status->state = runtime->status->state;
	status->suspended_state = runtime->status->suspended_state;
	if (status->state == SNDRV_PCM_STATE_OPEN)
		goto _end;
	status->trigger_tstamp = runtime->trigger_tstamp;
	if (snd_pcm_running(substream)) {
		snd_pcm_update_hw_ptr(substream);
		if (runtime->tstamp_mode & SNDRV_PCM_TSTAMP_MMAP)
			status->tstamp = runtime->status->tstamp;
		else
			getnstimeofday(&status->tstamp);
	} else
		getnstimeofday(&status->tstamp);
	status->appl_ptr = runtime->control->appl_ptr;
	status->hw_ptr = runtime->status->hw_ptr;
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
		status->avail = snd_pcm_playback_avail(runtime);
		if (runtime->status->state == SNDRV_PCM_STATE_RUNNING ||
		    runtime->status->state == SNDRV_PCM_STATE_DRAINING)
			status->delay = runtime->buffer_size - status->avail;
		else
			status->delay = 0;
	} else {
		status->avail = snd_pcm_capture_avail(runtime);
		if (runtime->status->state == SNDRV_PCM_STATE_RUNNING)
			status->delay = status->avail;
		else
			status->delay = 0;
	}
	status->avail_max = runtime->avail_max;
	status->overrange = runtime->overrange;
	runtime->avail_max = 0;
	runtime->overrange = 0;
 _end:
 	snd_pcm_stream_unlock_irq(substream);
	return 0;
}

static int snd_pcm_status_user(struct snd_pcm_substream *substream,
			       struct snd_pcm_status __user * _status)
{
	struct snd_pcm_status status;
	struct snd_pcm_runtime *runtime;
	int res;
	
	snd_assert(substream != NULL, return -ENXIO);
	runtime = substream->runtime;
	memset(&status, 0, sizeof(status));
	res = snd_pcm_status(substream, &status);
	if (res < 0)
		return res;
	if (copy_to_user(_status, &status, sizeof(status)))
		return -EFAULT;
	return 0;
}

static int snd_pcm_channel_info(struct snd_pcm_substream *substream,
				struct snd_pcm_channel_info * info)
{
	struct snd_pcm_runtime *runtime;
	unsigned int channel;
	
	snd_assert(substream != NULL, return -ENXIO);
	channel = info->channel;
	runtime = substream->runtime;
	snd_pcm_stream_lock_irq(substream);
	if (runtime->status->state == SNDRV_PCM_STATE_OPEN) {
		snd_pcm_stream_unlock_irq(substream);
		return -EBADFD;
	}
	snd_pcm_stream_unlock_irq(substream);
	if (channel >= runtime->channels)
		return -EINVAL;
	memset(info, 0, sizeof(*info));
	info->channel = channel;
	return substream->ops->ioctl(substream, SNDRV_PCM_IOCTL1_CHANNEL_INFO, info);
}

static int snd_pcm_channel_info_user(struct snd_pcm_substream *substream,
				     struct snd_pcm_channel_info __user * _info)
{
	struct snd_pcm_channel_info info;
	int res;
	
	if (copy_from_user(&info, _info, sizeof(info)))
		return -EFAULT;
	res = snd_pcm_channel_info(substream, &info);
	if (res < 0)
		return res;
	if (copy_to_user(_info, &info, sizeof(info)))
		return -EFAULT;
	return 0;
}

static void snd_pcm_trigger_tstamp(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	if (runtime->trigger_master == NULL)
		return;
	if (runtime->trigger_master == substream) {
		getnstimeofday(&runtime->trigger_tstamp);
	} else {
		snd_pcm_trigger_tstamp(runtime->trigger_master);
		runtime->trigger_tstamp = runtime->trigger_master->runtime->trigger_tstamp;
	}
	runtime->trigger_master = NULL;
}

struct action_ops {
	int (*pre_action)(struct snd_pcm_substream *substream, int state);
	int (*do_action)(struct snd_pcm_substream *substream, int state);
	void (*undo_action)(struct snd_pcm_substream *substream, int state);
	void (*post_action)(struct snd_pcm_substream *substream, int state);
};

/*
 *  this functions is core for handling of linked stream
 *  Note: the stream state might be changed also on failure
 *  Note2: call with calling stream lock + link lock
 */
static int snd_pcm_action_group(struct action_ops *ops,
				struct snd_pcm_substream *substream,
				int state, int do_lock)
{
	struct snd_pcm_substream *s = NULL;
	struct snd_pcm_substream *s1;
	int res = 0;

	snd_pcm_group_for_each_entry(s, substream) {
		if (do_lock && s != substream)
			spin_lock_nested(&s->self_group.lock,
					 SINGLE_DEPTH_NESTING);
		res = ops->pre_action(s, state);
		if (res < 0)
			goto _unlock;
	}
	snd_pcm_group_for_each_entry(s, substream) {
		res = ops->do_action(s, state);
		if (res < 0) {
			if (ops->undo_action) {
				snd_pcm_group_for_each_entry(s1, substream) {
					if (s1 == s) /* failed stream */
						break;
					ops->undo_action(s1, state);
				}
			}
			s = NULL; /* unlock all */
			goto _unlock;
		}
	}
	snd_pcm_group_for_each_entry(s, substream) {
		ops->post_action(s, state);
	}
 _unlock:
	if (do_lock) {
		/* unlock streams */
		snd_pcm_group_for_each_entry(s1, substream) {
			if (s1 != substream)
				spin_unlock(&s1->self_group.lock);
			if (s1 == s)	/* end */
				break;
		}
	}
	return res;
}

/*
 *  Note: call with stream lock
 */
static int snd_pcm_action_single(struct action_ops *ops,
				 struct snd_pcm_substream *substream,
				 int state)
{
	int res;
	
	res = ops->pre_action(substream, state);
	if (res < 0)
		return res;
	res = ops->do_action(substream, state);
	if (res == 0)
		ops->post_action(substream, state);
	else if (ops->undo_action)
		ops->undo_action(substream, state);
	return res;
}

/*
 *  Note: call with stream lock
 */
static int snd_pcm_action(struct action_ops *ops,
			  struct snd_pcm_substream *substream,
			  int state)
{
	int res;

	if (snd_pcm_stream_linked(substream)) {
		if (!spin_trylock(&substream->group->lock)) {
			spin_unlock(&substream->self_group.lock);
			spin_lock(&substream->group->lock);
			spin_lock(&substream->self_group.lock);
		}
		res = snd_pcm_action_group(ops, substream, state, 1);
		spin_unlock(&substream->group->lock);
	} else {
		res = snd_pcm_action_single(ops, substream, state);
	}
	return res;
}

/*
 *  Note: don't use any locks before
 */
static int snd_pcm_action_lock_irq(struct action_ops *ops,
				   struct snd_pcm_substream *substream,
				   int state)
{
	int res;

	read_lock_irq(&snd_pcm_link_rwlock);
	if (snd_pcm_stream_linked(substream)) {
		spin_lock(&substream->group->lock);
		spin_lock(&substream->self_group.lock);
		res = snd_pcm_action_group(ops, substream, state, 1);
		spin_unlock(&substream->self_group.lock);
		spin_unlock(&substream->group->lock);
	} else {
		spin_lock(&substream->self_group.lock);
		res = snd_pcm_action_single(ops, substream, state);
		spin_unlock(&substream->self_group.lock);
	}
	read_unlock_irq(&snd_pcm_link_rwlock);
	return res;
}

/*
 */
static int snd_pcm_action_nonatomic(struct action_ops *ops,
				    struct snd_pcm_substream *substream,
				    int state)
{
	int res;

	down_read(&snd_pcm_link_rwsem);
	if (snd_pcm_stream_linked(substream))
		res = snd_pcm_action_group(ops, substream, state, 0);
	else
		res = snd_pcm_action_single(ops, substream, state);
	up_read(&snd_pcm_link_rwsem);
	return res;
}

/*
 * start callbacks
 */
static int snd_pcm_pre_start(struct snd_pcm_substream *substream, int state)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	if (runtime->status->state != SNDRV_PCM_STATE_PREPARED)
		return -EBADFD;
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
	    !snd_pcm_playback_data(substream))
		return -EPIPE;
	runtime->trigger_master = substream;
	return 0;
}

static int snd_pcm_do_start(struct snd_pcm_substream *substream, int state)
{
	if (substream->runtime->trigger_master != substream)
		return 0;
	return substream->ops->trigger(substream, SNDRV_PCM_TRIGGER_START);
}

static void snd_pcm_undo_start(struct snd_pcm_substream *substream, int state)
{
	if (substream->runtime->trigger_master == substream)
		substream->ops->trigger(substream, SNDRV_PCM_TRIGGER_STOP);
}

static void snd_pcm_post_start(struct snd_pcm_substream *substream, int state)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	snd_pcm_trigger_tstamp(substream);
	runtime->status->state = state;
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
	    runtime->silence_size > 0)
		snd_pcm_playback_silence(substream, ULONG_MAX);
	if (runtime->sleep_min)
		snd_pcm_tick_prepare(substream);
	if (substream->timer)
		snd_timer_notify(substream->timer, SNDRV_TIMER_EVENT_MSTART,
				 &runtime->trigger_tstamp);
}

static struct action_ops snd_pcm_action_start = {
	.pre_action = snd_pcm_pre_start,
	.do_action = snd_pcm_do_start,
	.undo_action = snd_pcm_undo_start,
	.post_action = snd_pcm_post_start
};

/**
 * snd_pcm_start
 * @substream: the PCM substream instance
 *
 * Start all linked streams.
 */
int snd_pcm_start(struct snd_pcm_substream *substream)
{
	return snd_pcm_action(&snd_pcm_action_start, substream,
			      SNDRV_PCM_STATE_RUNNING);
}

/*
 * stop callbacks
 */
static int snd_pcm_pre_stop(struct snd_pcm_substream *substream, int state)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
		return -EBADFD;
	runtime->trigger_master = substream;
	return 0;
}

static int snd_pcm_do_stop(struct snd_pcm_substream *substream, int state)
{
	if (substream->runtime->trigger_master == substream &&
	    snd_pcm_running(substream))
		substream->ops->trigger(substream, SNDRV_PCM_TRIGGER_STOP);
	return 0; /* unconditonally stop all substreams */
}

static void snd_pcm_post_stop(struct snd_pcm_substream *substream, int state)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	if (runtime->status->state != state) {
		snd_pcm_trigger_tstamp(substream);
		if (substream->timer)
			snd_timer_notify(substream->timer, SNDRV_TIMER_EVENT_MSTOP,
					 &runtime->trigger_tstamp);
		runtime->status->state = state;
		snd_pcm_tick_set(substream, 0);
	}
	wake_up(&runtime->sleep);
}

static struct action_ops snd_pcm_action_stop = {
	.pre_action = snd_pcm_pre_stop,
	.do_action = snd_pcm_do_stop,
	.post_action = snd_pcm_post_stop
};

/**
 * snd_pcm_stop
 * @substream: the PCM substream instance