videobuf-core.c

来自「trident tm5600的linux驱动」· C语言 代码 · 共 1,138 行 · 第 1/2 页

	wake_up_interruptible_sync(&q->wait);

 done:
	mutex_unlock(&q->vb_lock);

	if (b->memory == V4L2_MEMORY_MMAP)
		up_read(&current->mm->mmap_sem);

	return retval;
}


/* Locking: Caller holds q->vb_lock */
static int stream_next_buffer_check_queue(struct videobuf_queue *q, int noblock)
{
	int retval;

checks:
	if (!q->streaming) {
		dprintk(1, "next_buffer: Not streaming\n");
		retval = -EINVAL;
		goto done;
	}

	if (list_empty(&q->stream)) {
		if (noblock) {
			retval = -EAGAIN;
			dprintk(2, "next_buffer: no buffers to dequeue\n");
			goto done;
		} else {
			dprintk(2, "next_buffer: waiting on buffer\n");

			/* Drop lock to avoid deadlock with qbuf */
			mutex_unlock(&q->vb_lock);

			/* Checking list_empty and streaming is safe without
			 * locks because we goto checks to validate while
			 * holding locks before proceeding */
			retval = wait_event_interruptible(q->wait,
				!list_empty(&q->stream) || !q->streaming);
			mutex_lock(&q->vb_lock);

			if (retval)
				goto done;

			goto checks;
		}
	}

	retval = 0;

done:
	return retval;
}


/* Locking: Caller holds q->vb_lock */
static int stream_next_buffer(struct videobuf_queue *q,
			struct videobuf_buffer **vb, int nonblocking)
{
	int retval;
	struct videobuf_buffer *buf = NULL;

	retval = stream_next_buffer_check_queue(q, nonblocking);
	if (retval)
		goto done;

	buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
	retval = videobuf_waiton(buf, nonblocking, 1);
	if (retval < 0)
		goto done;

	*vb = buf;
done:
	return retval;
}

int videobuf_dqbuf(struct videobuf_queue *q,
	       struct v4l2_buffer *b, int nonblocking)
{
	struct videobuf_buffer *buf = NULL;
	int retval;

	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);

	mutex_lock(&q->vb_lock);

	retval = stream_next_buffer(q, &buf, nonblocking);
	if (retval < 0) {
		dprintk(1, "dqbuf: next_buffer error: %i\n", retval);
		goto done;
	}

	switch (buf->state) {
	case VIDEOBUF_ERROR:
		dprintk(1, "dqbuf: state is error\n");
		retval = -EIO;
		CALL(q, sync, q, buf);
		buf->state = VIDEOBUF_IDLE;
		break;
	case VIDEOBUF_DONE:
		dprintk(1, "dqbuf: state is done\n");
		CALL(q, sync, q, buf);
		buf->state = VIDEOBUF_IDLE;
		break;
	default:
		dprintk(1, "dqbuf: state invalid\n");
		retval = -EINVAL;
		goto done;
	}
	list_del(&buf->stream);
	memset(b, 0, sizeof(*b));
	videobuf_status(q, b, buf, q->type);

 done:
	mutex_unlock(&q->vb_lock);
	return retval;
}

int videobuf_streamon(struct videobuf_queue *q)
{
	struct videobuf_buffer *buf;
	unsigned long flags = 0;
	int retval;

	mutex_lock(&q->vb_lock);
	retval = -EBUSY;
	if (q->reading)
		goto done;
	retval = 0;
	if (q->streaming)
		goto done;
	q->streaming = 1;
	spin_lock_irqsave(q->irqlock, flags);
	list_for_each_entry(buf, &q->stream, stream)
		if (buf->state == VIDEOBUF_PREPARED)
			q->ops->buf_queue(q, buf);
	spin_unlock_irqrestore(q->irqlock, flags);

	wake_up_interruptible_sync(&q->wait);
 done:
	mutex_unlock(&q->vb_lock);
	return retval;
}

/* Locking: Caller holds q->vb_lock */
static int __videobuf_streamoff(struct videobuf_queue *q)
{
	if (!q->streaming)
		return -EINVAL;

	videobuf_queue_cancel(q);

	return 0;
}

int videobuf_streamoff(struct videobuf_queue *q)
{
	int retval;

	mutex_lock(&q->vb_lock);
	retval = __videobuf_streamoff(q);
	mutex_unlock(&q->vb_lock);

	return retval;
}

/* Locking: Caller holds q->vb_lock */
static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
				      char __user *data,
				      size_t count, loff_t *ppos)
{
	enum v4l2_field field;
	unsigned long flags = 0;
	int retval;

	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);

	/* setup stuff */
	q->read_buf = videobuf_alloc(q);
	if (NULL == q->read_buf)
		return -ENOMEM;

	q->read_buf->memory = V4L2_MEMORY_USERPTR;
	q->read_buf->baddr  = (unsigned long)data;
	q->read_buf->bsize  = count;

	field = videobuf_next_field(q);
	retval = q->ops->buf_prepare(q, q->read_buf, field);
	if (0 != retval)
		goto done;

	/* start capture & wait */
	spin_lock_irqsave(q->irqlock, flags);
	q->ops->buf_queue(q, q->read_buf);
	spin_unlock_irqrestore(q->irqlock, flags);
	retval = videobuf_waiton(q->read_buf, 0, 0);
	if (0 == retval) {
		CALL(q, sync, q, q->read_buf);
		if (VIDEOBUF_ERROR == q->read_buf->state)
			retval = -EIO;
		else
			retval = q->read_buf->size;
	}

 done:
	/* cleanup */
	q->ops->buf_release(q, q->read_buf);
	kfree(q->read_buf);
	q->read_buf = NULL;
	return retval;
}

ssize_t videobuf_read_one(struct videobuf_queue *q,
			  char __user *data, size_t count, loff_t *ppos,
			  int nonblocking)
{
	enum v4l2_field field;
	unsigned long flags = 0;
	unsigned size = 0, nbufs = 1;
	int retval;

	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);

	mutex_lock(&q->vb_lock);

	q->ops->buf_setup(q, &nbufs, &size);

	if (NULL == q->read_buf  &&
	    count >= size        &&
	    !nonblocking) {
		retval = videobuf_read_zerocopy(q, data, count, ppos);
		if (retval >= 0  ||  retval == -EIO)
			/* ok, all done */
			goto done;
		/* fallback to kernel bounce buffer on failures */
	}

	if (NULL == q->read_buf) {
		/* need to capture a new frame */
		retval = -ENOMEM;
		q->read_buf = videobuf_alloc(q);

		dprintk(1, "video alloc=0x%p\n", q->read_buf);
		if (NULL == q->read_buf)
			goto done;
		q->read_buf->memory = V4L2_MEMORY_USERPTR;
		q->read_buf->bsize = count; /* preferred size */
		field = videobuf_next_field(q);
		retval = q->ops->buf_prepare(q, q->read_buf, field);

		if (0 != retval) {
			kfree(q->read_buf);
			q->read_buf = NULL;
			goto done;
		}

		spin_lock_irqsave(q->irqlock, flags);
		q->ops->buf_queue(q, q->read_buf);
		spin_unlock_irqrestore(q->irqlock, flags);

		q->read_off = 0;
	}

	/* wait until capture is done */
	retval = videobuf_waiton(q->read_buf, nonblocking, 1);
	if (0 != retval)
		goto done;

	CALL(q, sync, q, q->read_buf);

	if (VIDEOBUF_ERROR == q->read_buf->state) {
		/* catch I/O errors */
		q->ops->buf_release(q, q->read_buf);
		kfree(q->read_buf);
		q->read_buf = NULL;
		retval = -EIO;
		goto done;
	}

	/* Copy to userspace */
	retval = CALL(q, video_copy_to_user, q, data, count, nonblocking);
	if (retval < 0)
		goto done;

	q->read_off += retval;
	if (q->read_off == q->read_buf->size) {
		/* all data copied, cleanup */
		q->ops->buf_release(q, q->read_buf);
		kfree(q->read_buf);
		q->read_buf = NULL;
	}

 done:
	mutex_unlock(&q->vb_lock);
	return retval;
}

/* Locking: Caller holds q->vb_lock */
static int __videobuf_read_start(struct videobuf_queue *q)
{
	enum v4l2_field field;
	unsigned long flags = 0;
	unsigned int count = 0, size = 0;
	int err, i;

	q->ops->buf_setup(q, &count, &size);
	if (count < 2)
		count = 2;
	if (count > VIDEO_MAX_FRAME)
		count = VIDEO_MAX_FRAME;
	size = PAGE_ALIGN(size);

	err = __videobuf_mmap_setup(q, count, size, V4L2_MEMORY_USERPTR);
	if (err < 0)
		return err;

	count = err;

	for (i = 0; i < count; i++) {
		field = videobuf_next_field(q);
		err = q->ops->buf_prepare(q, q->bufs[i], field);
		if (err)
			return err;
		list_add_tail(&q->bufs[i]->stream, &q->stream);
	}
	spin_lock_irqsave(q->irqlock, flags);
	for (i = 0; i < count; i++)
		q->ops->buf_queue(q, q->bufs[i]);
	spin_unlock_irqrestore(q->irqlock, flags);
	q->reading = 1;
	return 0;
}

static void __videobuf_read_stop(struct videobuf_queue *q)
{
	int i;

	videobuf_queue_cancel(q);
	__videobuf_mmap_free(q);
	INIT_LIST_HEAD(&q->stream);
	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
		if (NULL == q->bufs[i])
			continue;
		kfree(q->bufs[i]);
		q->bufs[i] = NULL;
	}
	q->read_buf = NULL;

}

int videobuf_read_start(struct videobuf_queue *q)
{
	int rc;

	mutex_lock(&q->vb_lock);
	rc = __videobuf_read_start(q);
	mutex_unlock(&q->vb_lock);

	return rc;
}

void videobuf_read_stop(struct videobuf_queue *q)
{
	mutex_lock(&q->vb_lock);
	__videobuf_read_stop(q);
	mutex_unlock(&q->vb_lock);
}

void videobuf_stop(struct videobuf_queue *q)
{
	mutex_lock(&q->vb_lock);

	if (q->streaming)
		__videobuf_streamoff(q);

	if (q->reading)
		__videobuf_read_stop(q);

	mutex_unlock(&q->vb_lock);
}


ssize_t videobuf_read_stream(struct videobuf_queue *q,
			     char __user *data, size_t count, loff_t *ppos,
			     int vbihack, int nonblocking)
{
	int rc, retval;
	unsigned long flags = 0;

	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);

	dprintk(2, "%s\n", __func__);
	mutex_lock(&q->vb_lock);
	retval = -EBUSY;
	if (q->streaming)
		goto done;
	if (!q->reading) {
		retval = __videobuf_read_start(q);
		if (retval < 0)
			goto done;
	}

	retval = 0;
	while (count > 0) {
		/* get / wait for data */
		if (NULL == q->read_buf) {
			q->read_buf = list_entry(q->stream.next,
						 struct videobuf_buffer,
						 stream);
			list_del(&q->read_buf->stream);
			q->read_off = 0;
		}
		rc = videobuf_waiton(q->read_buf, nonblocking, 1);
		if (rc < 0) {
			if (0 == retval)
				retval = rc;
			break;
		}

		if (q->read_buf->state == VIDEOBUF_DONE) {
			rc = CALL(q, copy_stream, q, data + retval, count,
					retval, vbihack, nonblocking);
			if (rc < 0) {
				retval = rc;
				break;
			}
			retval      += rc;
			count       -= rc;
			q->read_off += rc;
		} else {
			/* some error */
			q->read_off = q->read_buf->size;
			if (0 == retval)
				retval = -EIO;
		}

		/* requeue buffer when done with copying */
		if (q->read_off == q->read_buf->size) {
			list_add_tail(&q->read_buf->stream,
				      &q->stream);
			spin_lock_irqsave(q->irqlock, flags);
			q->ops->buf_queue(q, q->read_buf);
			spin_unlock_irqrestore(q->irqlock, flags);
			q->read_buf = NULL;
		}
		if (retval < 0)
			break;
	}

 done:
	mutex_unlock(&q->vb_lock);
	return retval;
}

unsigned int videobuf_poll_stream(struct file *file,
				  struct videobuf_queue *q,
				  poll_table *wait)
{
	struct videobuf_buffer *buf = NULL;
	unsigned int rc = 0;

	mutex_lock(&q->vb_lock);
	if (q->streaming) {
		if (!list_empty(&q->stream))
			buf = list_entry(q->stream.next,
					 struct videobuf_buffer, stream);
	} else {
		if (!q->reading)
			__videobuf_read_start(q);
		if (!q->reading) {
			rc = POLLERR;
		} else if (NULL == q->read_buf) {
			q->read_buf = list_entry(q->stream.next,
						 struct videobuf_buffer,
						 stream);
			list_del(&q->read_buf->stream);
			q->read_off = 0;
		}
		buf = q->read_buf;
	}
	if (!buf)
		rc = POLLERR;

	if (0 == rc) {
		poll_wait(file, &buf->done, wait);
		if (buf->state == VIDEOBUF_DONE ||
		    buf->state == VIDEOBUF_ERROR)
			rc = POLLIN|POLLRDNORM;
	}
	mutex_unlock(&q->vb_lock);
	return rc;
}

int videobuf_mmap_mapper(struct videobuf_queue *q,
			 struct vm_area_struct *vma)
{
	int retval;

	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);

	mutex_lock(&q->vb_lock);
	retval = CALL(q, mmap_mapper, q, vma);
	q->is_mmapped = 1;
	mutex_unlock(&q->vb_lock);

	return retval;
}

#ifdef CONFIG_VIDEO_V4L1_COMPAT
int videobuf_cgmbuf(struct videobuf_queue *q,
		    struct video_mbuf *mbuf, int count)
{
	struct v4l2_requestbuffers req;
	int rc, i;

	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);

	memset(&req, 0, sizeof(req));
	req.type   = q->type;
	req.count  = count;
	req.memory = V4L2_MEMORY_MMAP;
	rc = videobuf_reqbufs(q, &req);
	if (rc < 0)
		return rc;

	mbuf->frames = req.count;
	mbuf->size   = 0;
	for (i = 0; i < mbuf->frames; i++) {
		mbuf->offsets[i]  = q->bufs[i]->boff;
		mbuf->size       += q->bufs[i]->bsize;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(videobuf_cgmbuf);
#endif

/* --------------------------------------------------------------------- */

EXPORT_SYMBOL_GPL(videobuf_waiton);
EXPORT_SYMBOL_GPL(videobuf_iolock);

EXPORT_SYMBOL_GPL(videobuf_alloc);

EXPORT_SYMBOL_GPL(videobuf_queue_core_init);
EXPORT_SYMBOL_GPL(videobuf_queue_cancel);
EXPORT_SYMBOL_GPL(videobuf_queue_is_busy);

EXPORT_SYMBOL_GPL(videobuf_next_field);
EXPORT_SYMBOL_GPL(videobuf_reqbufs);
EXPORT_SYMBOL_GPL(videobuf_querybuf);
EXPORT_SYMBOL_GPL(videobuf_qbuf);
EXPORT_SYMBOL_GPL(videobuf_dqbuf);
EXPORT_SYMBOL_GPL(videobuf_streamon);
EXPORT_SYMBOL_GPL(videobuf_streamoff);

EXPORT_SYMBOL_GPL(videobuf_read_start);
EXPORT_SYMBOL_GPL(videobuf_read_stop);
EXPORT_SYMBOL_GPL(videobuf_stop);
EXPORT_SYMBOL_GPL(videobuf_read_stream);
EXPORT_SYMBOL_GPL(videobuf_read_one);
EXPORT_SYMBOL_GPL(videobuf_poll_stream);

EXPORT_SYMBOL_GPL(__videobuf_mmap_setup);
EXPORT_SYMBOL_GPL(videobuf_mmap_setup);
EXPORT_SYMBOL_GPL(videobuf_mmap_free);
EXPORT_SYMBOL_GPL(videobuf_mmap_mapper);