From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
This flag helps drivers that need to reprogram their DMA engine whenever
a plane cookie (== DMA address or DMA scatter-gather list) changes.
Otherwise they would have to reprogram the DMA engine for every frame.
Note that it is not possible to do this in buf_init() since dma_map_sg has
to be done first, which happens just before buf_prepare() in the prepare()
memop. It is dma_map_sg that sets up the dma addresses that are needed to
configure the DMA engine.
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
drivers/media/v4l2-core/videobuf2-core.c | 5 +++++
include/media/videobuf2-core.h | 14 ++++++++++++--
2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 01bab25..7217eb1 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -391,6 +391,7 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory,
kfree(vb);
break;
}
+ vb->new_cookies = 1;
}
q->bufs[q->num_buffers + buffer] = vb;
@@ -1373,6 +1374,8 @@ static int __buf_memory_prepare(struct vb2_buffer *vb)
for (plane = 0; plane < vb->num_planes; ++plane)
call_void_memop(vb, finish, vb->planes[plane].mem_priv);
call_void_vb_qop(vb, buf_finish_for_cpu, vb);
+ } else {
+ vb->new_cookies = 0;
}
return ret;
}
@@ -1467,6 +1470,7 @@ static int __qbuf_userptr(struct vb2_buffer *vb, const struct v4l2_buffer *b)
dprintk(1, "buffer initialization failed\n");
goto err;
}
+ vb->new_cookies = 1;
}
ret = __buf_memory_prepare(vb);
@@ -1591,6 +1595,7 @@ static int __qbuf_dmabuf(struct vb2_buffer *vb, const struct v4l2_buffer *b)
dprintk(1, "buffer initialization failed\n");
goto err;
}
+ vb->new_cookies = 1;
}
ret = __buf_memory_prepare(vb);
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index bf8bde2..9304718 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -186,6 +186,11 @@ struct vb2_queue;
* @vb2_queue: the queue to which this driver belongs
* @num_planes: number of planes in the buffer
* on an internal driver queue
+ * @new_cookies: the planes of the buffer have new cookie values.
+ * This happens if a new userptr or dmabuf is used for one
+ * or more of the buffer planes. This will change the cookie
+ * value of those planes and you may need to reprogram the DMA
+ * engine when buf_prepare is called.
* @state: current buffer state; do not change
* @queued_entry: entry on the queued buffers list, which holds all
* buffers queued from userspace
@@ -200,6 +205,7 @@ struct vb2_buffer {
struct vb2_queue *vb2_queue;
unsigned int num_planes;
+ unsigned int new_cookies:1;
/* Private: internal use only */
enum vb2_buffer_state state;
@@ -290,8 +296,12 @@ struct vb2_buffer {
* hardware operation in this callback; drivers that
* support VIDIOC_CREATE_BUFS must also validate the
* buffer size, if they haven't done that yet in
- * @buf_prepare_for_cpu. If an error is returned, the
- * buffer will not be queued in the driver; optional.
+ * @buf_prepare_for_cpu. If one or more of the plane
+ * cookies (see vb2_plane_cookie) are updated, then
+ * vb->new_cookies is set to 1. If buf_prepare returns
+ * 0 (success), then new_cookies is cleared automatically.
+ * If an error is returned, then the buffer will not be
+ * queued in the driver; optional.
* @buf_finish: called before every dequeue of the buffer back to
* userspace; the contents of the buffer cannot be
* accessed by the cpu at this stage as it is still setup
--
2.1.0
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