video-buf.c

LINUX 2.6.17.4的源码

			dprintk(1,"busy: buffer #%d queued\n",i);
			return 1;
		}
		if (q->bufs[i]->state == STATE_ACTIVE) {
			dprintk(1,"busy: buffer #%d avtive\n",i);
			return 1;
		}
	}
	return 0;
}

void
videobuf_queue_cancel(struct videobuf_queue *q)
{
	unsigned long flags=0;
	int i;

	/* remove queued buffers from list */
	if (q->irqlock)
		spin_lock_irqsave(q->irqlock,flags);
	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
		if (NULL == q->bufs[i])
			continue;
		if (q->bufs[i]->state == STATE_QUEUED) {
			list_del(&q->bufs[i]->queue);
			q->bufs[i]->state = STATE_ERROR;
		}
	}
	if (q->irqlock)
		spin_unlock_irqrestore(q->irqlock,flags);

	/* free all buffers + clear queue */
	for (i = 0; i < VIDEO_MAX_FRAME; i++) {
		if (NULL == q->bufs[i])
			continue;
		q->ops->buf_release(q,q->bufs[i]);
	}
	INIT_LIST_HEAD(&q->stream);
}

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

enum v4l2_field
videobuf_next_field(struct videobuf_queue *q)
{
	enum v4l2_field field = q->field;

	BUG_ON(V4L2_FIELD_ANY == field);

	if (V4L2_FIELD_ALTERNATE == field) {
		if (V4L2_FIELD_TOP == q->last) {
			field   = V4L2_FIELD_BOTTOM;
			q->last = V4L2_FIELD_BOTTOM;
		} else {
			field   = V4L2_FIELD_TOP;
			q->last = V4L2_FIELD_TOP;
		}
	}
	return field;
}

void
videobuf_status(struct v4l2_buffer *b, struct videobuf_buffer *vb,
		enum v4l2_buf_type type)
{
	MAGIC_CHECK(vb->magic,MAGIC_BUFFER);

	b->index    = vb->i;
	b->type     = type;

	b->memory   = vb->memory;
	switch (b->memory) {
	case V4L2_MEMORY_MMAP:
		b->m.offset  = vb->boff;
		b->length    = vb->bsize;
		break;
	case V4L2_MEMORY_USERPTR:
		b->m.userptr = vb->baddr;
		b->length    = vb->bsize;
		break;
	case V4L2_MEMORY_OVERLAY:
		b->m.offset  = vb->boff;
		break;
	}

	b->flags    = 0;
	if (vb->map)
		b->flags |= V4L2_BUF_FLAG_MAPPED;

	switch (vb->state) {
	case STATE_PREPARED:
	case STATE_QUEUED:
	case STATE_ACTIVE:
		b->flags |= V4L2_BUF_FLAG_QUEUED;
		break;
	case STATE_DONE:
	case STATE_ERROR:
		b->flags |= V4L2_BUF_FLAG_DONE;
		break;
	case STATE_NEEDS_INIT:
	case STATE_IDLE:
		/* nothing */
		break;
	}

	if (vb->input != UNSET) {
		b->flags |= V4L2_BUF_FLAG_INPUT;
		b->input  = vb->input;
	}

	b->field     = vb->field;
	b->timestamp = vb->ts;
	b->bytesused = vb->size;
	b->sequence  = vb->field_count >> 1;
}

int
videobuf_reqbufs(struct videobuf_queue *q,
		 struct v4l2_requestbuffers *req)
{
	unsigned int size,count;
	int retval;

	if (req->type != q->type) {
		dprintk(1,"reqbufs: queue type invalid\n");
		return -EINVAL;
	}
	if (req->count < 1) {
		dprintk(1,"reqbufs: count invalid (%d)\n",req->count);
		return -EINVAL;
	}
	if (req->memory != V4L2_MEMORY_MMAP     &&
	    req->memory != V4L2_MEMORY_USERPTR  &&
	    req->memory != V4L2_MEMORY_OVERLAY) {
		dprintk(1,"reqbufs: memory type invalid\n");
		return -EINVAL;
	}

	if (q->streaming) {
		dprintk(1,"reqbufs: streaming already exists\n");
		return -EBUSY;
	}
	if (!list_empty(&q->stream)) {
		dprintk(1,"reqbufs: stream running\n");
		return -EBUSY;
	}

	mutex_lock(&q->lock);
	count = req->count;
	if (count > VIDEO_MAX_FRAME)
		count = VIDEO_MAX_FRAME;
	size = 0;
	q->ops->buf_setup(q,&count,&size);
	size = PAGE_ALIGN(size);
	dprintk(1,"reqbufs: bufs=%d, size=0x%x [%d pages total]\n",
		count, size, (count*size)>>PAGE_SHIFT);

	retval = videobuf_mmap_setup(q,count,size,req->memory);
	if (retval < 0) {
		dprintk(1,"reqbufs: mmap setup returned %d\n",retval);
		goto done;
	}

	req->count = count;

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

int
videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b)
{
	if (unlikely(b->type != q->type)) {
		dprintk(1,"querybuf: Wrong type.\n");
		return -EINVAL;
	}
	if (unlikely(b->index < 0 || b->index >= VIDEO_MAX_FRAME)) {
		dprintk(1,"querybuf: index out of range.\n");
		return -EINVAL;
	}
	if (unlikely(NULL == q->bufs[b->index])) {
		dprintk(1,"querybuf: buffer is null.\n");
		return -EINVAL;
	}
	videobuf_status(b,q->bufs[b->index],q->type);
	return 0;
}

int
videobuf_qbuf(struct videobuf_queue *q,
	      struct v4l2_buffer *b)
{
	struct videobuf_buffer *buf;
	enum v4l2_field field;
	unsigned long flags=0;
	int retval;

	mutex_lock(&q->lock);
	retval = -EBUSY;
	if (q->reading) {
		dprintk(1,"qbuf: Reading running...\n");
		goto done;
	}
	retval = -EINVAL;
	if (b->type != q->type) {
		dprintk(1,"qbuf: Wrong type.\n");
		goto done;
	}
	if (b->index < 0 || b->index >= VIDEO_MAX_FRAME) {
		dprintk(1,"qbuf: index out of range.\n");
		goto done;
	}
	buf = q->bufs[b->index];
	if (NULL == buf) {
		dprintk(1,"qbuf: buffer is null.\n");
		goto done;
	}
	MAGIC_CHECK(buf->magic,MAGIC_BUFFER);
	if (buf->memory != b->memory) {
		dprintk(1,"qbuf: memory type is wrong.\n");
		goto done;
	}
	if (buf->state == STATE_QUEUED ||
	    buf->state == STATE_ACTIVE) {
		dprintk(1,"qbuf: buffer is already queued or active.\n");
		goto done;
	}

	if (b->flags & V4L2_BUF_FLAG_INPUT) {
		if (b->input >= q->inputs) {
			dprintk(1,"qbuf: wrong input.\n");
			goto done;
		}
		buf->input = b->input;
	} else {
		buf->input = UNSET;
	}

	switch (b->memory) {
	case V4L2_MEMORY_MMAP:
		if (0 == buf->baddr) {
			dprintk(1,"qbuf: mmap requested but buffer addr is zero!\n");
			goto done;
		}
		break;
	case V4L2_MEMORY_USERPTR:
		if (b->length < buf->bsize) {
			dprintk(1,"qbuf: buffer length is not enough\n");
			goto done;
		}
		if (STATE_NEEDS_INIT != buf->state && buf->baddr != b->m.userptr)
			q->ops->buf_release(q,buf);
		buf->baddr = b->m.userptr;
		break;
	case V4L2_MEMORY_OVERLAY:
		buf->boff = b->m.offset;
		break;
	default:
		dprintk(1,"qbuf: wrong memory type\n");
		goto done;
	}

	dprintk(1,"qbuf: requesting next field\n");
	field = videobuf_next_field(q);
	retval = q->ops->buf_prepare(q,buf,field);
	if (0 != retval) {
		dprintk(1,"qbuf: buffer_prepare returned %d\n",retval);
		goto done;
	}

	list_add_tail(&buf->stream,&q->stream);
	if (q->streaming) {
		if (q->irqlock)
			spin_lock_irqsave(q->irqlock,flags);
		q->ops->buf_queue(q,buf);
		if (q->irqlock)
			spin_unlock_irqrestore(q->irqlock,flags);
	}
	dprintk(1,"qbuf: succeded\n");
	retval = 0;

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

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

	mutex_lock(&q->lock);
	retval = -EBUSY;
	if (q->reading) {
		dprintk(1,"dqbuf: Reading running...\n");
		goto done;
	}
	retval = -EINVAL;
	if (b->type != q->type) {
		dprintk(1,"dqbuf: Wrong type.\n");
		goto done;
	}
	if (list_empty(&q->stream)) {
		dprintk(1,"dqbuf: stream running\n");
		goto done;
	}
	buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
	retval = videobuf_waiton(buf, nonblocking, 1);
	if (retval < 0) {
		dprintk(1,"dqbuf: waiton returned %d\n",retval);
		goto done;
	}
	switch (buf->state) {
	case STATE_ERROR:
		dprintk(1,"dqbuf: state is error\n");
		retval = -EIO;
		videobuf_dma_sync(q,&buf->dma);
		buf->state = STATE_IDLE;
		break;
	case STATE_DONE:
		dprintk(1,"dqbuf: state is done\n");
		videobuf_dma_sync(q,&buf->dma);
		buf->state = STATE_IDLE;
		break;
	default:
		dprintk(1,"dqbuf: state invalid\n");
		retval = -EINVAL;
		goto done;
	}
	list_del(&buf->stream);
	memset(b,0,sizeof(*b));
	videobuf_status(b,buf,q->type);

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

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

	mutex_lock(&q->lock);
	retval = -EBUSY;
	if (q->reading)
		goto done;
	retval = 0;
	if (q->streaming)
		goto done;
	q->streaming = 1;
	if (q->irqlock)
		spin_lock_irqsave(q->irqlock,flags);
	list_for_each(list,&q->stream) {
		buf = list_entry(list, struct videobuf_buffer, stream);
		if (buf->state == STATE_PREPARED)
			q->ops->buf_queue(q,buf);
	}
	if (q->irqlock)
		spin_unlock_irqrestore(q->irqlock,flags);

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

int videobuf_streamoff(struct videobuf_queue *q)
{
	int retval = -EINVAL;

	mutex_lock(&q->lock);
	if (!q->streaming)
		goto done;
	videobuf_queue_cancel(q);
	q->streaming = 0;
	retval = 0;

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

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;

	/* setup stuff */
	q->read_buf = videobuf_alloc(q->msize);
	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 */
	if (q->irqlock)
		spin_lock_irqsave(q->irqlock,flags);
	q->ops->buf_queue(q,q->read_buf);
	if (q->irqlock)
		spin_unlock_irqrestore(q->irqlock,flags);
	retval = videobuf_waiton(q->read_buf,0,0);
	if (0 == retval) {
		videobuf_dma_sync(q,&q->read_buf->dma);
		if (STATE_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, nbufs, bytes;
	int retval;

	mutex_lock(&q->lock);

	nbufs = 1; size = 0;
	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->msize);
		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;
		}
		if (q->irqlock)
			spin_lock_irqsave(q->irqlock,flags);
		q->ops->buf_queue(q,q->read_buf);