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3f03396918
Add a helper function for device drivers to set DMA's max_seg_size. Setting it to largest possible value lets DMA-mapping API always create contiguous mappings in DMA address space. This is essential for all devices, which use dma-contig videobuf2 memory allocator and shared buffers. Till now, the only case when vb2-dma-contig really 'worked' was a case where userspace provided USERPTR buffer, which was in fact mmaped contiguous buffer from the other v4l2/drm device. Also DMABUF made of contiguous buffer worked only when its exporter did not split it into several chunks in the scatter-list. Any other buffer failed, regardless of the arch/platform used and the presence of the IOMMU of the device bus. This patch provides interface to fix this issue. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
44 lines
1.1 KiB
C
44 lines
1.1 KiB
C
/*
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* videobuf2-dma-contig.h - DMA contig memory allocator for videobuf2
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*
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* Copyright (C) 2010 Samsung Electronics
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*
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* Author: Pawel Osciak <pawel@osciak.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation.
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*/
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#ifndef _MEDIA_VIDEOBUF2_DMA_CONTIG_H
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#define _MEDIA_VIDEOBUF2_DMA_CONTIG_H
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#include <media/videobuf2-v4l2.h>
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#include <linux/dma-mapping.h>
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struct dma_attrs;
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static inline dma_addr_t
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vb2_dma_contig_plane_dma_addr(struct vb2_buffer *vb, unsigned int plane_no)
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{
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dma_addr_t *addr = vb2_plane_cookie(vb, plane_no);
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return *addr;
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}
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void *vb2_dma_contig_init_ctx_attrs(struct device *dev,
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struct dma_attrs *attrs);
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static inline void *vb2_dma_contig_init_ctx(struct device *dev)
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{
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return vb2_dma_contig_init_ctx_attrs(dev, NULL);
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}
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void vb2_dma_contig_cleanup_ctx(void *alloc_ctx);
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int vb2_dma_contig_set_max_seg_size(struct device *dev, unsigned int size);
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void vb2_dma_contig_clear_max_seg_size(struct device *dev);
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extern const struct vb2_mem_ops vb2_dma_contig_memops;
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#endif
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