[media] v4l: videobuf2: add DMA coherent allocator

Add an implementation of DMA coherent memory allocator and handling
routines for videobuf2, implemented on top of dma_alloc_coherent() call.

Signed-off-by: Pawel Osciak <p.osciak@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
CC: Pawel Osciak <pawel@osciak.com>
Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/include/media/videobuf2-dma-contig.h b/include/media/videobuf2-dma-contig.h
new file mode 100644
index 0000000..fb7ca84
--- /dev/null
+++ b/include/media/videobuf2-dma-contig.h
@@ -0,0 +1,29 @@
+/*
+ * videobuf2-dma-coherent.h - DMA coherent memory allocator for videobuf2
+ *
+ * Copyright (C) 2010 Samsung Electronics
+ *
+ * Author: Pawel Osciak <p.osciak@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.
+ */
+
+#ifndef _MEDIA_VIDEOBUF2_DMA_COHERENT_H
+#define _MEDIA_VIDEOBUF2_DMA_COHERENT_H
+
+#include <media/videobuf2-core.h>
+
+static inline unsigned long vb2_dma_contig_plane_paddr(
+		struct vb2_buffer *vb, unsigned int plane_no)
+{
+	return (unsigned long)vb2_plane_cookie(vb, plane_no);
+}
+
+void *vb2_dma_contig_init_ctx(struct device *dev);
+void vb2_dma_contig_cleanup_ctx(void *alloc_ctx);
+
+extern const struct vb2_mem_ops vb2_dma_contig_memops;
+
+#endif