pcm_lib.c

linux 内核源代码

			return err;
	} else {
		char *hwbuf = runtime->dma_area + frames_to_bytes(runtime, hwoff);
		snd_assert(runtime->dma_area, return -EFAULT);
		if (copy_from_user(hwbuf, buf, frames_to_bytes(runtime, frames)))
			return -EFAULT;
	}
	return 0;
}
 
typedef int (*transfer_f)(struct snd_pcm_substream *substream, unsigned int hwoff,
			  unsigned long data, unsigned int off,
			  snd_pcm_uframes_t size);

static snd_pcm_sframes_t snd_pcm_lib_write1(struct snd_pcm_substream *substream, 
					    unsigned long data,
					    snd_pcm_uframes_t size,
					    int nonblock,
					    transfer_f transfer)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	snd_pcm_uframes_t xfer = 0;
	snd_pcm_uframes_t offset = 0;
	int err = 0;

	if (size == 0)
		return 0;
	if (size > runtime->xfer_align)
		size -= size % runtime->xfer_align;

	snd_pcm_stream_lock_irq(substream);
	switch (runtime->status->state) {
	case SNDRV_PCM_STATE_PREPARED:
	case SNDRV_PCM_STATE_RUNNING:
	case SNDRV_PCM_STATE_PAUSED:
		break;
	case SNDRV_PCM_STATE_XRUN:
		err = -EPIPE;
		goto _end_unlock;
	case SNDRV_PCM_STATE_SUSPENDED:
		err = -ESTRPIPE;
		goto _end_unlock;
	default:
		err = -EBADFD;
		goto _end_unlock;
	}

	while (size > 0) {
		snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
		snd_pcm_uframes_t avail;
		snd_pcm_uframes_t cont;
		if (runtime->sleep_min == 0 && runtime->status->state == SNDRV_PCM_STATE_RUNNING)
			snd_pcm_update_hw_ptr(substream);
		avail = snd_pcm_playback_avail(runtime);
		if (((avail < runtime->control->avail_min && size > avail) ||
		   (size >= runtime->xfer_align && avail < runtime->xfer_align))) {
			wait_queue_t wait;
			enum { READY, SIGNALED, ERROR, SUSPENDED, EXPIRED, DROPPED } state;
			long tout;

			if (nonblock) {
				err = -EAGAIN;
				goto _end_unlock;
			}

			init_waitqueue_entry(&wait, current);
			add_wait_queue(&runtime->sleep, &wait);
			while (1) {
				if (signal_pending(current)) {
					state = SIGNALED;
					break;
				}
				set_current_state(TASK_INTERRUPTIBLE);
				snd_pcm_stream_unlock_irq(substream);
				tout = schedule_timeout(10 * HZ);
				snd_pcm_stream_lock_irq(substream);
				if (tout == 0) {
					if (runtime->status->state != SNDRV_PCM_STATE_PREPARED &&
					    runtime->status->state != SNDRV_PCM_STATE_PAUSED) {
						state = runtime->status->state == SNDRV_PCM_STATE_SUSPENDED ? SUSPENDED : EXPIRED;
						break;
					}
				}
				switch (runtime->status->state) {
				case SNDRV_PCM_STATE_XRUN:
				case SNDRV_PCM_STATE_DRAINING:
					state = ERROR;
					goto _end_loop;
				case SNDRV_PCM_STATE_SUSPENDED:
					state = SUSPENDED;
					goto _end_loop;
				case SNDRV_PCM_STATE_SETUP:
					state = DROPPED;
					goto _end_loop;
				default:
					break;
				}
				avail = snd_pcm_playback_avail(runtime);
				if (avail >= runtime->control->avail_min) {
					state = READY;
					break;
				}
			}
		       _end_loop:
			remove_wait_queue(&runtime->sleep, &wait);

			switch (state) {
			case ERROR:
				err = -EPIPE;
				goto _end_unlock;
			case SUSPENDED:
				err = -ESTRPIPE;
				goto _end_unlock;
			case SIGNALED:
				err = -ERESTARTSYS;
				goto _end_unlock;
			case EXPIRED:
				snd_printd("playback write error (DMA or IRQ trouble?)\n");
				err = -EIO;
				goto _end_unlock;
			case DROPPED:
				err = -EBADFD;
				goto _end_unlock;
			default:
				break;
			}
		}
		if (avail > runtime->xfer_align)
			avail -= avail % runtime->xfer_align;
		frames = size > avail ? avail : size;
		cont = runtime->buffer_size - runtime->control->appl_ptr % runtime->buffer_size;
		if (frames > cont)
			frames = cont;
		snd_assert(frames != 0, snd_pcm_stream_unlock_irq(substream); return -EINVAL);
		appl_ptr = runtime->control->appl_ptr;
		appl_ofs = appl_ptr % runtime->buffer_size;
		snd_pcm_stream_unlock_irq(substream);
		if ((err = transfer(substream, appl_ofs, data, offset, frames)) < 0)
			goto _end;
		snd_pcm_stream_lock_irq(substream);
		switch (runtime->status->state) {
		case SNDRV_PCM_STATE_XRUN:
			err = -EPIPE;
			goto _end_unlock;
		case SNDRV_PCM_STATE_SUSPENDED:
			err = -ESTRPIPE;
			goto _end_unlock;
		default:
			break;
		}
		appl_ptr += frames;
		if (appl_ptr >= runtime->boundary)
			appl_ptr -= runtime->boundary;
		runtime->control->appl_ptr = appl_ptr;
		if (substream->ops->ack)
			substream->ops->ack(substream);

		offset += frames;
		size -= frames;
		xfer += frames;
		if (runtime->status->state == SNDRV_PCM_STATE_PREPARED &&
		    snd_pcm_playback_hw_avail(runtime) >= (snd_pcm_sframes_t)runtime->start_threshold) {
			err = snd_pcm_start(substream);
			if (err < 0)
				goto _end_unlock;
		}
		if (runtime->sleep_min &&
		    runtime->status->state == SNDRV_PCM_STATE_RUNNING)
			snd_pcm_tick_prepare(substream);
	}
 _end_unlock:
	snd_pcm_stream_unlock_irq(substream);
 _end:
	return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}

snd_pcm_sframes_t snd_pcm_lib_write(struct snd_pcm_substream *substream, const void __user *buf, snd_pcm_uframes_t size)
{
	struct snd_pcm_runtime *runtime;
	int nonblock;

	snd_assert(substream != NULL, return -ENXIO);
	runtime = substream->runtime;
	snd_assert(runtime != NULL, return -ENXIO);
	snd_assert(substream->ops->copy != NULL || runtime->dma_area != NULL, return -EINVAL);
	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
		return -EBADFD;

	nonblock = !!(substream->f_flags & O_NONBLOCK);

	if (runtime->access != SNDRV_PCM_ACCESS_RW_INTERLEAVED &&
	    runtime->channels > 1)
		return -EINVAL;
	return snd_pcm_lib_write1(substream, (unsigned long)buf, size, nonblock,
				  snd_pcm_lib_write_transfer);
}

EXPORT_SYMBOL(snd_pcm_lib_write);

static int snd_pcm_lib_writev_transfer(struct snd_pcm_substream *substream,
				       unsigned int hwoff,
				       unsigned long data, unsigned int off,
				       snd_pcm_uframes_t frames)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	int err;
	void __user **bufs = (void __user **)data;
	int channels = runtime->channels;
	int c;
	if (substream->ops->copy) {
		snd_assert(substream->ops->silence != NULL, return -EINVAL);
		for (c = 0; c < channels; ++c, ++bufs) {
			if (*bufs == NULL) {
				if ((err = substream->ops->silence(substream, c, hwoff, frames)) < 0)
					return err;
			} else {
				char __user *buf = *bufs + samples_to_bytes(runtime, off);
				if ((err = substream->ops->copy(substream, c, hwoff, buf, frames)) < 0)
					return err;
			}
		}
	} else {
		/* default transfer behaviour */
		size_t dma_csize = runtime->dma_bytes / channels;
		snd_assert(runtime->dma_area, return -EFAULT);
		for (c = 0; c < channels; ++c, ++bufs) {
			char *hwbuf = runtime->dma_area + (c * dma_csize) + samples_to_bytes(runtime, hwoff);
			if (*bufs == NULL) {
				snd_pcm_format_set_silence(runtime->format, hwbuf, frames);
			} else {
				char __user *buf = *bufs + samples_to_bytes(runtime, off);
				if (copy_from_user(hwbuf, buf, samples_to_bytes(runtime, frames)))
					return -EFAULT;
			}
		}
	}
	return 0;
}
 
snd_pcm_sframes_t snd_pcm_lib_writev(struct snd_pcm_substream *substream,
				     void __user **bufs,
				     snd_pcm_uframes_t frames)
{
	struct snd_pcm_runtime *runtime;
	int nonblock;

	snd_assert(substream != NULL, return -ENXIO);
	runtime = substream->runtime;
	snd_assert(runtime != NULL, return -ENXIO);
	snd_assert(substream->ops->copy != NULL || runtime->dma_area != NULL, return -EINVAL);
	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
		return -EBADFD;

	nonblock = !!(substream->f_flags & O_NONBLOCK);

	if (runtime->access != SNDRV_PCM_ACCESS_RW_NONINTERLEAVED)
		return -EINVAL;
	return snd_pcm_lib_write1(substream, (unsigned long)bufs, frames,
				  nonblock, snd_pcm_lib_writev_transfer);
}

EXPORT_SYMBOL(snd_pcm_lib_writev);

static int snd_pcm_lib_read_transfer(struct snd_pcm_substream *substream, 
				     unsigned int hwoff,
				     unsigned long data, unsigned int off,
				     snd_pcm_uframes_t frames)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	int err;
	char __user *buf = (char __user *) data + frames_to_bytes(runtime, off);
	if (substream->ops->copy) {
		if ((err = substream->ops->copy(substream, -1, hwoff, buf, frames)) < 0)
			return err;
	} else {
		char *hwbuf = runtime->dma_area + frames_to_bytes(runtime, hwoff);
		snd_assert(runtime->dma_area, return -EFAULT);
		if (copy_to_user(buf, hwbuf, frames_to_bytes(runtime, frames)))
			return -EFAULT;
	}
	return 0;
}

static snd_pcm_sframes_t snd_pcm_lib_read1(struct snd_pcm_substream *substream,
					   unsigned long data,
					   snd_pcm_uframes_t size,
					   int nonblock,
					   transfer_f transfer)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	snd_pcm_uframes_t xfer = 0;
	snd_pcm_uframes_t offset = 0;
	int err = 0;

	if (size == 0)
		return 0;
	if (size > runtime->xfer_align)
		size -= size % runtime->xfer_align;

	snd_pcm_stream_lock_irq(substream);
	switch (runtime->status->state) {
	case SNDRV_PCM_STATE_PREPARED:
		if (size >= runtime->start_threshold) {
			err = snd_pcm_start(substream);
			if (err < 0)
				goto _end_unlock;
		}
		break;
	case SNDRV_PCM_STATE_DRAINING:
	case SNDRV_PCM_STATE_RUNNING:
	case SNDRV_PCM_STATE_PAUSED:
		break;
	case SNDRV_PCM_STATE_XRUN:
		err = -EPIPE;
		goto _end_unlock;
	case SNDRV_PCM_STATE_SUSPENDED:
		err = -ESTRPIPE;
		goto _end_unlock;
	default:
		err = -EBADFD;
		goto _end_unlock;
	}

	while (size > 0) {
		snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
		snd_pcm_uframes_t avail;
		snd_pcm_uframes_t cont;
		if (runtime->sleep_min == 0 && runtime->status->state == SNDRV_PCM_STATE_RUNNING)
			snd_pcm_update_hw_ptr(substream);
	      __draining:
		avail = snd_pcm_capture_avail(runtime);
		if (runtime->status->state == SNDRV_PCM_STATE_DRAINING) {
			if (avail < runtime->xfer_align) {
				err = -EPIPE;
				goto _end_unlock;
			}
		} else if ((avail < runtime->control->avail_min && size > avail) ||
			   (size >= runtime->xfer_align && avail < runtime->xfer_align)) {
			wait_queue_t wait;
			enum { READY, SIGNALED, ERROR, SUSPENDED, EXPIRED, DROPPED } state;
			long tout;

			if (nonblock) {
				err = -EAGAIN;
				goto _end_unlock;
			}

			init_waitqueue_entry(&wait, current);
			add_wait_queue(&runtime->sleep, &wait);
			while (1) {
				if (signal_pending(current)) {
					state = SIGNALED;
					break;
				}
				set_current_state(TASK_INTERRUPTIBLE);
				snd_pcm_stream_unlock_irq(substream);
				tout = schedule_timeout(10 * HZ);
				snd_pcm_stream_lock_irq(substream);
				if (tout == 0) {
					if (runtime->status->state != SNDRV_PCM_STATE_PREPARED &&
					    runtime->status->state != SNDRV_PCM_STATE_PAUSED) {
						state = runtime->status->state == SNDRV_PCM_STATE_SUSPENDED ? SUSPENDED : EXPIRED;
						break;
					}
				}
				switch (runtime->status->state) {
				case SNDRV_PCM_STATE_XRUN:
					state = ERROR;
					goto _end_loop;
				case SNDRV_PCM_STATE_SUSPENDED:
					state = SUSPENDED;
					goto _end_loop;
				case SNDRV_PCM_STATE_DRAINING:
					goto __draining;
				case SNDRV_PCM_STATE_SETUP:
					state = DROPPED;
					goto _end_loop;
				default:
					break;
				}
				avail = snd_pcm_capture_avail(runtime);
				if (avail >= runtime->control->avail_min) {
					state = READY;
					break;
				}
			}
		       _end_loop:
			remove_wait_queue(&runtime->sleep, &wait);

			switch (state) {
			case ERROR:
				err = -EPIPE;
				goto _end_unlock;
			case SUSPENDED:
				err = -ESTRPIPE;
				goto _end_unlock;
			case SIGNALED:
				err = -ERESTARTSYS;
				goto _end_unlock;
			case EXPIRED:
				snd_printd("capture read error (DMA or IRQ trouble?)\n");
				err = -EIO;
				goto _end_unlock;
			case DROPPED:
				err = -EBADFD;
				goto _end_unlock;
			default:
				break;
			}
		}
		if (avail > runtime->xfer_align)
			avail -= avail % runtime->xfer_align;
		frames = size > avail ? avail : size;
		cont = runtime->buffer_size - runtime->control->appl_ptr % runtime->buffer_size;
		if (frames > cont)
			frames = cont;
		snd_assert(frames != 0, snd_pcm_stream_unlock_irq(substream); return -EINVAL);
		appl_ptr = runtime->control->appl_ptr;
		appl_ofs = appl_ptr % runtime->buffer_size;
		snd_pcm_stream_unlock_irq(substream);
		if ((err = transfer(substream, appl_ofs, data, offset, frames)) < 0)
			goto _end;
		snd_pcm_stream_lock_irq(substream);
		switch (runtime->status->state) {
		case SNDRV_PCM_STATE_XRUN:
			err = -EPIPE;
			goto _end_unlock;
		case SNDRV_PCM_STATE_SUSPENDED:
			err = -ESTRPIPE;
			goto _end_unlock;
		default:
			break;
		}
		appl_ptr += frames;
		if (appl_ptr >= runtime->boundary)
			appl_ptr -= runtime->boundary;
		runtime->control->appl_ptr = appl_ptr;
		if (substream->ops->ack)
			substream->ops->ack(substream);

		offset += frames;
		size -= frames;
		xfer += frames;
		if (runtime->sleep_min &&
		    runtime->status->state == SNDRV_PCM_STATE_RUNNING)
			snd_pcm_tick_prepare(substream);
	}
 _end_unlock:
	snd_pcm_stream_unlock_irq(substream);
 _end:
	return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}

snd_pcm_sframes_t snd_pcm_lib_read(struct snd_pcm_substream *substream, void __user *buf, snd_pcm_uframes_t size)
{
	struct snd_pcm_runtime *runtime;
	int nonblock;
	
	snd_assert(substream != NULL, return -ENXIO);
	runtime = substream->runtime;
	snd_assert(runtime != NULL, return -ENXIO);
	snd_assert(substream->ops->copy != NULL || runtime->dma_area != NULL, return -EINVAL);
	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
		return -EBADFD;

	nonblock = !!(substream->f_flags & O_NONBLOCK);
	if (runtime->access != SNDRV_PCM_ACCESS_RW_INTERLEAVED)
		return -EINVAL;
	return snd_pcm_lib_read1(substream, (unsigned long)buf, size, nonblock, snd_pcm_lib_read_transfer);
}

EXPORT_SYMBOL(snd_pcm_lib_read);

static int snd_pcm_lib_readv_transfer(struct snd_pcm_substream *substream,
				      unsigned int hwoff,
				      unsigned long data, unsigned int off,
				      snd_pcm_uframes_t frames)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	int err;
	void __user **bufs = (void __user **)data;
	int channels = runtime->channels;
	int c;
	if (substream->ops->copy) {
		for (c = 0; c < channels; ++c, ++bufs) {
			char __user *buf;
			if (*bufs == NULL)
				continue;
			buf = *bufs + samples_to_bytes(runtime, off);
			if ((err = substream->ops->copy(substream, c, hwoff, buf, frames)) < 0)
				return err;
		}
	} else {
		snd_pcm_uframes_t dma_csize = runtime->dma_bytes / channels;
		snd_assert(runtime->dma_area, return -EFAULT);
		for (c = 0; c < channels; ++c, ++bufs) {
			char *hwbuf;
			char __user *buf;
			if (*bufs == NULL)
				continue;

			hwbuf = runtime->dma_area + (c * dma_csize) + samples_to_bytes(runtime, hwoff);
			buf = *bufs + samples_to_bytes(runtime, off);
			if (copy_to_user(buf, hwbuf, samples_to_bytes(runtime, frames)))
				return -EFAULT;
		}
	}
	return 0;
}
 
snd_pcm_sframes_t snd_pcm_lib_readv(struct snd_pcm_substream *substream,
				    void __user **bufs,
				    snd_pcm_uframes_t frames)
{
	struct snd_pcm_runtime *runtime;
	int nonblock;

	snd_assert(substream != NULL, return -ENXIO);
	runtime = substream->runtime;
	snd_assert(runtime != NULL, return -ENXIO);
	snd_assert(substream->ops->copy != NULL || runtime->dma_area != NULL, return -EINVAL);
	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
		return -EBADFD;

	nonblock = !!(substream->f_flags & O_NONBLOCK);
	if (runtime->access != SNDRV_PCM_ACCESS_RW_NONINTERLEAVED)
		return -EINVAL;
	return snd_pcm_lib_read1(substream, (unsigned long)bufs, frames, nonblock, snd_pcm_lib_readv_transfer);
}

EXPORT_SYMBOL(snd_pcm_lib_readv);