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![Marek Szyprowski](/assets/img/avatar_default.png)
This patch adds dma_get_sgtable() function which is required to let drivers to share the buffers allocated by DMA-mapping subsystem. Right now the driver gets a dma address of the allocated buffer and the kernel virtual mapping for it. If it wants to share it with other device (= map into its dma address space) it usually hacks around kernel virtual addresses to get pointers to pages or assumes that both devices share the DMA address space. Both solutions are just hacks for the special cases, which should be avoided in the final version of buffer sharing. To solve this issue in a generic way, a new call to DMA mapping has been introduced - dma_get_sgtable(). It allocates a scatter-list which describes the allocated buffer and lets the driver(s) to use it with other device(s) by calling dma_map_sg() on it. This patch provides a generic implementation based on virt_to_page() call. Architectures which require more sophisticated translation might provide their own get_sgtable() methods. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
234 lines
7.4 KiB
C
234 lines
7.4 KiB
C
#ifndef _ASM_GENERIC_DMA_MAPPING_H
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#define _ASM_GENERIC_DMA_MAPPING_H
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#include <linux/kmemcheck.h>
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#include <linux/bug.h>
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#include <linux/scatterlist.h>
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#include <linux/dma-debug.h>
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#include <linux/dma-attrs.h>
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static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
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size_t size,
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enum dma_data_direction dir,
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struct dma_attrs *attrs)
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{
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struct dma_map_ops *ops = get_dma_ops(dev);
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dma_addr_t addr;
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kmemcheck_mark_initialized(ptr, size);
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BUG_ON(!valid_dma_direction(dir));
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addr = ops->map_page(dev, virt_to_page(ptr),
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(unsigned long)ptr & ~PAGE_MASK, size,
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dir, attrs);
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debug_dma_map_page(dev, virt_to_page(ptr),
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(unsigned long)ptr & ~PAGE_MASK, size,
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dir, addr, true);
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return addr;
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}
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static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr,
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size_t size,
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enum dma_data_direction dir,
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struct dma_attrs *attrs)
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{
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struct dma_map_ops *ops = get_dma_ops(dev);
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BUG_ON(!valid_dma_direction(dir));
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if (ops->unmap_page)
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ops->unmap_page(dev, addr, size, dir, attrs);
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debug_dma_unmap_page(dev, addr, size, dir, true);
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}
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static inline int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
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int nents, enum dma_data_direction dir,
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struct dma_attrs *attrs)
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{
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struct dma_map_ops *ops = get_dma_ops(dev);
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int i, ents;
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struct scatterlist *s;
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for_each_sg(sg, s, nents, i)
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kmemcheck_mark_initialized(sg_virt(s), s->length);
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BUG_ON(!valid_dma_direction(dir));
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ents = ops->map_sg(dev, sg, nents, dir, attrs);
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debug_dma_map_sg(dev, sg, nents, ents, dir);
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return ents;
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}
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static inline void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
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int nents, enum dma_data_direction dir,
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struct dma_attrs *attrs)
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{
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struct dma_map_ops *ops = get_dma_ops(dev);
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BUG_ON(!valid_dma_direction(dir));
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debug_dma_unmap_sg(dev, sg, nents, dir);
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if (ops->unmap_sg)
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ops->unmap_sg(dev, sg, nents, dir, attrs);
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}
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static inline dma_addr_t dma_map_page(struct device *dev, struct page *page,
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size_t offset, size_t size,
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enum dma_data_direction dir)
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{
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struct dma_map_ops *ops = get_dma_ops(dev);
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dma_addr_t addr;
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kmemcheck_mark_initialized(page_address(page) + offset, size);
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BUG_ON(!valid_dma_direction(dir));
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addr = ops->map_page(dev, page, offset, size, dir, NULL);
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debug_dma_map_page(dev, page, offset, size, dir, addr, false);
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return addr;
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}
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static inline void dma_unmap_page(struct device *dev, dma_addr_t addr,
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size_t size, enum dma_data_direction dir)
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{
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struct dma_map_ops *ops = get_dma_ops(dev);
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BUG_ON(!valid_dma_direction(dir));
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if (ops->unmap_page)
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ops->unmap_page(dev, addr, size, dir, NULL);
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debug_dma_unmap_page(dev, addr, size, dir, false);
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}
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static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
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size_t size,
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enum dma_data_direction dir)
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{
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struct dma_map_ops *ops = get_dma_ops(dev);
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BUG_ON(!valid_dma_direction(dir));
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if (ops->sync_single_for_cpu)
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ops->sync_single_for_cpu(dev, addr, size, dir);
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debug_dma_sync_single_for_cpu(dev, addr, size, dir);
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}
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static inline void dma_sync_single_for_device(struct device *dev,
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dma_addr_t addr, size_t size,
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enum dma_data_direction dir)
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{
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struct dma_map_ops *ops = get_dma_ops(dev);
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BUG_ON(!valid_dma_direction(dir));
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if (ops->sync_single_for_device)
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ops->sync_single_for_device(dev, addr, size, dir);
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debug_dma_sync_single_for_device(dev, addr, size, dir);
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}
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static inline void dma_sync_single_range_for_cpu(struct device *dev,
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dma_addr_t addr,
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unsigned long offset,
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size_t size,
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enum dma_data_direction dir)
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{
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const struct dma_map_ops *ops = get_dma_ops(dev);
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BUG_ON(!valid_dma_direction(dir));
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if (ops->sync_single_for_cpu)
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ops->sync_single_for_cpu(dev, addr + offset, size, dir);
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debug_dma_sync_single_range_for_cpu(dev, addr, offset, size, dir);
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}
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static inline void dma_sync_single_range_for_device(struct device *dev,
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dma_addr_t addr,
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unsigned long offset,
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size_t size,
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enum dma_data_direction dir)
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{
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const struct dma_map_ops *ops = get_dma_ops(dev);
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BUG_ON(!valid_dma_direction(dir));
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if (ops->sync_single_for_device)
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ops->sync_single_for_device(dev, addr + offset, size, dir);
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debug_dma_sync_single_range_for_device(dev, addr, offset, size, dir);
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}
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static inline void
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dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
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int nelems, enum dma_data_direction dir)
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{
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struct dma_map_ops *ops = get_dma_ops(dev);
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BUG_ON(!valid_dma_direction(dir));
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if (ops->sync_sg_for_cpu)
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ops->sync_sg_for_cpu(dev, sg, nelems, dir);
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debug_dma_sync_sg_for_cpu(dev, sg, nelems, dir);
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}
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static inline void
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dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
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int nelems, enum dma_data_direction dir)
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{
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struct dma_map_ops *ops = get_dma_ops(dev);
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BUG_ON(!valid_dma_direction(dir));
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if (ops->sync_sg_for_device)
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ops->sync_sg_for_device(dev, sg, nelems, dir);
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debug_dma_sync_sg_for_device(dev, sg, nelems, dir);
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}
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#define dma_map_single(d, a, s, r) dma_map_single_attrs(d, a, s, r, NULL)
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#define dma_unmap_single(d, a, s, r) dma_unmap_single_attrs(d, a, s, r, NULL)
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#define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, NULL)
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#define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, NULL)
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extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
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void *cpu_addr, dma_addr_t dma_addr, size_t size);
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/**
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* dma_mmap_attrs - map a coherent DMA allocation into user space
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* @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
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* @vma: vm_area_struct describing requested user mapping
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* @cpu_addr: kernel CPU-view address returned from dma_alloc_attrs
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* @handle: device-view address returned from dma_alloc_attrs
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* @size: size of memory originally requested in dma_alloc_attrs
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* @attrs: attributes of mapping properties requested in dma_alloc_attrs
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*
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* Map a coherent DMA buffer previously allocated by dma_alloc_attrs
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* into user space. The coherent DMA buffer must not be freed by the
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* driver until the user space mapping has been released.
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*/
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static inline int
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dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void *cpu_addr,
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dma_addr_t dma_addr, size_t size, struct dma_attrs *attrs)
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{
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struct dma_map_ops *ops = get_dma_ops(dev);
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BUG_ON(!ops);
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if (ops->mmap)
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return ops->mmap(dev, vma, cpu_addr, dma_addr, size, attrs);
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return dma_common_mmap(dev, vma, cpu_addr, dma_addr, size);
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}
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#define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, NULL)
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static inline int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
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void *cpu_addr, dma_addr_t dma_addr, size_t size)
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{
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DEFINE_DMA_ATTRS(attrs);
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dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
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return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, &attrs);
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}
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int
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dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
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void *cpu_addr, dma_addr_t dma_addr, size_t size);
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static inline int
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dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr,
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dma_addr_t dma_addr, size_t size, struct dma_attrs *attrs)
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{
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struct dma_map_ops *ops = get_dma_ops(dev);
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BUG_ON(!ops);
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if (ops->get_sgtable)
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return ops->get_sgtable(dev, sgt, cpu_addr, dma_addr, size,
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attrs);
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return dma_common_get_sgtable(dev, sgt, cpu_addr, dma_addr, size);
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}
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#define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, NULL)
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#endif
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