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kernel/linux-rt-4.4.41/arch/arm/include/asm/xen/page-coherent.h 3.75 KB
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  #ifndef _ASM_ARM_XEN_PAGE_COHERENT_H
  #define _ASM_ARM_XEN_PAGE_COHERENT_H
  
  #include <asm/page.h>
  #include <linux/dma-attrs.h>
  #include <linux/dma-mapping.h>
  
  void __xen_dma_map_page(struct device *hwdev, struct page *page,
  	     dma_addr_t dev_addr, unsigned long offset, size_t size,
  	     enum dma_data_direction dir, struct dma_attrs *attrs);
  void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
  		size_t size, enum dma_data_direction dir,
  		struct dma_attrs *attrs);
  void __xen_dma_sync_single_for_cpu(struct device *hwdev,
  		dma_addr_t handle, size_t size, enum dma_data_direction dir);
  
  void __xen_dma_sync_single_for_device(struct device *hwdev,
  		dma_addr_t handle, size_t size, enum dma_data_direction dir);
  
  static inline void *xen_alloc_coherent_pages(struct device *hwdev, size_t size,
  		dma_addr_t *dma_handle, gfp_t flags,
  		struct dma_attrs *attrs)
  {
  	return __generic_dma_ops(hwdev)->alloc(hwdev, size, dma_handle, flags, attrs);
  }
  
  static inline void xen_free_coherent_pages(struct device *hwdev, size_t size,
  		void *cpu_addr, dma_addr_t dma_handle,
  		struct dma_attrs *attrs)
  {
  	__generic_dma_ops(hwdev)->free(hwdev, size, cpu_addr, dma_handle, attrs);
  }
  
  static inline void xen_dma_map_page(struct device *hwdev, struct page *page,
  	     dma_addr_t dev_addr, unsigned long offset, size_t size,
  	     enum dma_data_direction dir, struct dma_attrs *attrs)
  {
  	unsigned long page_pfn = page_to_xen_pfn(page);
  	unsigned long dev_pfn = XEN_PFN_DOWN(dev_addr);
  	unsigned long compound_pages =
  		(1<<compound_order(page)) * XEN_PFN_PER_PAGE;
  	bool local = (page_pfn <= dev_pfn) &&
  		(dev_pfn - page_pfn < compound_pages);
  
  	/*
  	 * Dom0 is mapped 1:1, while the Linux page can span across
  	 * multiple Xen pages, it's not possible for it to contain a
  	 * mix of local and foreign Xen pages. So if the first xen_pfn
  	 * == mfn the page is local otherwise it's a foreign page
  	 * grant-mapped in dom0. If the page is local we can safely
  	 * call the native dma_ops function, otherwise we call the xen
  	 * specific function.
  	 */
  	if (local)
  		__generic_dma_ops(hwdev)->map_page(hwdev, page, offset, size, dir, attrs);
  	else
  		__xen_dma_map_page(hwdev, page, dev_addr, offset, size, dir, attrs);
  }
  
  static inline void xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
  		size_t size, enum dma_data_direction dir,
  		struct dma_attrs *attrs)
  {
  	unsigned long pfn = PFN_DOWN(handle);
  	/*
  	 * Dom0 is mapped 1:1, while the Linux page can be spanned accross
  	 * multiple Xen page, it's not possible to have a mix of local and
  	 * foreign Xen page. Dom0 is mapped 1:1, so calling pfn_valid on a
  	 * foreign mfn will always return false. If the page is local we can
  	 * safely call the native dma_ops function, otherwise we call the xen
  	 * specific function.
  	 */
  	if (pfn_valid(pfn)) {
  		if (__generic_dma_ops(hwdev)->unmap_page)
  			__generic_dma_ops(hwdev)->unmap_page(hwdev, handle, size, dir, attrs);
  	} else
  		__xen_dma_unmap_page(hwdev, handle, size, dir, attrs);
  }
  
  static inline void xen_dma_sync_single_for_cpu(struct device *hwdev,
  		dma_addr_t handle, size_t size, enum dma_data_direction dir)
  {
  	unsigned long pfn = PFN_DOWN(handle);
  	if (pfn_valid(pfn)) {
  		if (__generic_dma_ops(hwdev)->sync_single_for_cpu)
  			__generic_dma_ops(hwdev)->sync_single_for_cpu(hwdev, handle, size, dir);
  	} else
  		__xen_dma_sync_single_for_cpu(hwdev, handle, size, dir);
  }
  
  static inline void xen_dma_sync_single_for_device(struct device *hwdev,
  		dma_addr_t handle, size_t size, enum dma_data_direction dir)
  {
  	unsigned long pfn = PFN_DOWN(handle);
  	if (pfn_valid(pfn)) {
  		if (__generic_dma_ops(hwdev)->sync_single_for_device)
  			__generic_dma_ops(hwdev)->sync_single_for_device(hwdev, handle, size, dir);
  	} else
  		__xen_dma_sync_single_for_device(hwdev, handle, size, dir);
  }
  
  #endif /* _ASM_ARM_XEN_PAGE_COHERENT_H */