This patch adds extension to videobuf2-core. It allow to export a mmap buffer
as a file descriptor.
Signed-off-by: Tomasz Stanislawski <t.stanisl...@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.p...@samsung.com>
---
drivers/media/video/videobuf2-core.c | 64 ++++++++++++++++++++++++++++++++++
include/media/videobuf2-core.h | 2 +
2 files changed, 66 insertions(+), 0 deletions(-)
diff --git a/drivers/media/video/videobuf2-core.c
b/drivers/media/video/videobuf2-core.c
index e7df560..41c4bf8 100644
--- a/drivers/media/video/videobuf2-core.c
+++ b/drivers/media/video/videobuf2-core.c
@@ -1553,6 +1553,70 @@ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer
*b, bool nonblocking)
}
EXPORT_SYMBOL_GPL(vb2_dqbuf);
+static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off,
+ unsigned int *_buffer, unsigned int *_plane);
+
+/**
+ * vb2_expbuf() - Export a buffer as a file descriptor
+ * @q: videobuf2 queue
+ * @b: export buffer structure passed from userspace to vidioc_expbuf
+ * handler in driver
+ *
+ * The return values from this function are intended to be directly returned
+ * from vidioc_expbuf handler in driver.
+ */
+int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb)
+{
+ struct vb2_buffer *vb = NULL;
+ struct vb2_plane *vb_plane;
+ unsigned int buffer, plane;
+ int ret;
+ struct dma_buf *dbuf;
+
+ if (q->memory != V4L2_MEMORY_MMAP) {
+ dprintk(1, "Queue is not currently set up for mmap\n");
+ return -EINVAL;
+ }
+
+ if (!q->mem_ops->get_dmabuf) {
+ dprintk(1, "Queue does not support DMA buffer exporting\n");
+ return -EINVAL;
+ }
+
+ /*
+ * Find the plane corresponding to the offset passed by userspace.
+ */
+ ret = __find_plane_by_offset(q, eb->mem_offset, &buffer, &plane);
+ if (ret) {
+ dprintk(1, "invalid offset %u\n", eb->mem_offset);
+ return ret;
+ }
+
+ vb = q->bufs[buffer];
+ vb_plane = &vb->planes[plane];
+
+ dbuf = call_memop(q, get_dmabuf, vb_plane->mem_priv);
+ if (IS_ERR_OR_NULL(dbuf)) {
+ dprintk(1, "Failed to export buffer %d, plane %d\n",
+ buffer, plane);
+ return -EINVAL;
+ }
+
+ ret = dma_buf_fd(dbuf);
+ if (ret < 0) {
+ dprintk(3, "buffer %d, plane %d failed to export (%d)\n",
+ buffer, plane, ret);
+ return ret;
+ }
+
+ dprintk(3, "buffer %d, plane %d exported as %d descriptor\n",
+ buffer, plane, ret);
+ eb->fd = ret;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_expbuf);
+
/**
* __vb2_queue_cancel() - cancel and stop (pause) streaming
*
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 412c6a4..548252b 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -79,6 +79,7 @@ struct vb2_mem_ops {
void (*prepare)(void *buf_priv);
void (*finish)(void *buf_priv);
void (*put)(void *buf_priv);
+ struct dma_buf *(*get_dmabuf)(void *buf_priv);
void *(*get_userptr)(void *alloc_ctx, unsigned long vaddr,
unsigned long size, int write);
@@ -348,6 +349,7 @@ int vb2_queue_init(struct vb2_queue *q);
void vb2_queue_release(struct vb2_queue *q);
int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b);
+int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);
int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
--
1.7.5.4
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