[media] v4l: vb2: add support for shared buffer (dma_buf)
This patch adds support for DMABUF memory type in videobuf2. It calls relevant
APIs of dma_buf for v4l reqbuf / qbuf / dqbuf operations.
For this version, the support is for videobuf2 as a user of the shared buffer;
so the allocation of the buffer is done outside of V4L2. [A sample allocator of
dma-buf shared buffer is given at [1]]
[1]: Rob Clark's DRM:
https://github.com/robclark/kernel-omap4/commits/drmplane-dmabuf
[original work in the PoC for buffer sharing]
Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Tested-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index e04252a..689ae4a 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -16,6 +16,7 @@
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/videodev2.h>
+#include <linux/dma-buf.h>
struct vb2_alloc_ctx;
struct vb2_fileio_data;
@@ -41,6 +42,20 @@
* argument to other ops in this structure
* @put_userptr: inform the allocator that a USERPTR buffer will no longer
* be used
+ * @attach_dmabuf: attach a shared struct dma_buf for a hardware operation;
+ * used for DMABUF memory types; alloc_ctx is the alloc context
+ * dbuf is the shared dma_buf; returns NULL on failure;
+ * allocator private per-buffer structure on success;
+ * this needs to be used for further accesses to the buffer
+ * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
+ * buffer is no longer used; the buf_priv argument is the
+ * allocator private per-buffer structure previously returned
+ * from the attach_dmabuf callback
+ * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
+ * of dmabuf is informed that this driver is going to use the
+ * dmabuf
+ * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
+ * that this driver is done using the dmabuf for now
* @vaddr: return a kernel virtual address to a given memory buffer
* associated with the passed private structure or NULL if no
* such mapping exists
@@ -56,6 +71,8 @@
* Required ops for USERPTR types: get_userptr, put_userptr.
* Required ops for MMAP types: alloc, put, num_users, mmap.
* Required ops for read/write access types: alloc, put, num_users, vaddr
+ * Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf,
+ * unmap_dmabuf.
*/
struct vb2_mem_ops {
void *(*alloc)(void *alloc_ctx, unsigned long size);
@@ -65,6 +82,12 @@
unsigned long size, int write);
void (*put_userptr)(void *buf_priv);
+ void *(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf,
+ unsigned long size, int write);
+ void (*detach_dmabuf)(void *buf_priv);
+ int (*map_dmabuf)(void *buf_priv);
+ void (*unmap_dmabuf)(void *buf_priv);
+
void *(*vaddr)(void *buf_priv);
void *(*cookie)(void *buf_priv);
@@ -75,6 +98,8 @@
struct vb2_plane {
void *mem_priv;
+ struct dma_buf *dbuf;
+ unsigned int dbuf_mapped;
};
/**
@@ -83,12 +108,14 @@
* @VB2_USERPTR: driver supports USERPTR with streaming API
* @VB2_READ: driver supports read() style access
* @VB2_WRITE: driver supports write() style access
+ * @VB2_DMABUF: driver supports DMABUF with streaming API
*/
enum vb2_io_modes {
VB2_MMAP = (1 << 0),
VB2_USERPTR = (1 << 1),
VB2_READ = (1 << 2),
VB2_WRITE = (1 << 3),
+ VB2_DMABUF = (1 << 4),
};
/**