arch/arm/include/asm/xen/page-coherent.h

   1 #ifndef _ASM_ARM_XEN_PAGE_COHERENT_H
   2 #define _ASM_ARM_XEN_PAGE_COHERENT_H
   3
   4 #include <asm/page.h>
   5 #include <linux/dma-attrs.h>
   6 #include <linux/dma-mapping.h>
   7
   8 void __xen_dma_map_page(struct device *hwdev, struct page *page,
   9              dma_addr_t dev_addr, unsigned long offset, size_t size,
  10              enum dma_data_direction dir, struct dma_attrs *attrs);
  11 void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
  12                 size_t size, enum dma_data_direction dir,
  13                 struct dma_attrs *attrs);
  14 void __xen_dma_sync_single_for_cpu(struct device *hwdev,
  15                 dma_addr_t handle, size_t size, enum dma_data_direction dir);
  16
  17 void __xen_dma_sync_single_for_device(struct device *hwdev,
  18                 dma_addr_t handle, size_t size, enum dma_data_direction dir);
  19
  20 static inline void *xen_alloc_coherent_pages(struct device *hwdev, size_t size,
  21                 dma_addr_t *dma_handle, gfp_t flags,
  22                 struct dma_attrs *attrs)
  23 {
  24         return __generic_dma_ops(hwdev)->alloc(hwdev, size, dma_handle, flags, attrs);
  25 }
  26
  27 static inline void xen_free_coherent_pages(struct device *hwdev, size_t size,
  28                 void *cpu_addr, dma_addr_t dma_handle,
  29                 struct dma_attrs *attrs)
  30 {
  31         __generic_dma_ops(hwdev)->free(hwdev, size, cpu_addr, dma_handle, attrs);
  32 }
  33
  34 static inline void xen_dma_map_page(struct device *hwdev, struct page *page,
  35              dma_addr_t dev_addr, unsigned long offset, size_t size,
  36              enum dma_data_direction dir, struct dma_attrs *attrs)
  37 {
  38         unsigned long page_pfn = page_to_xen_pfn(page);
  39         unsigned long dev_pfn = XEN_PFN_DOWN(dev_addr);
  40         unsigned long compound_pages =
  41                 (1<<compound_order(page)) * XEN_PFN_PER_PAGE;
  42         bool local = (page_pfn <= dev_pfn) &&
  43                 (dev_pfn - page_pfn < compound_pages);
  44
  45         /*
  46          * Dom0 is mapped 1:1, while the Linux page can span across
  47          * multiple Xen pages, it's not possible for it to contain a
  48          * mix of local and foreign Xen pages. So if the first xen_pfn
  49          * == mfn the page is local otherwise it's a foreign page
  50          * grant-mapped in dom0. If the page is local we can safely
  51          * call the native dma_ops function, otherwise we call the xen
  52          * specific function.
  53          */
  54         if (local)
  55                 __generic_dma_ops(hwdev)->map_page(hwdev, page, offset, size, dir, attrs);
  56         else
  57                 __xen_dma_map_page(hwdev, page, dev_addr, offset, size, dir, attrs);
  58 }
  59
  60 static inline void xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
  61                 size_t size, enum dma_data_direction dir,
  62                 struct dma_attrs *attrs)
  63 {
  64         unsigned long pfn = PFN_DOWN(handle);
  65         /*
  66          * Dom0 is mapped 1:1, while the Linux page can be spanned accross
  67          * multiple Xen page, it's not possible to have a mix of local and
  68          * foreign Xen page. Dom0 is mapped 1:1, so calling pfn_valid on a
  69          * foreign mfn will always return false. If the page is local we can
  70          * safely call the native dma_ops function, otherwise we call the xen
  71          * specific function.
  72          */
  73         if (pfn_valid(pfn)) {
  74                 if (__generic_dma_ops(hwdev)->unmap_page)
  75                         __generic_dma_ops(hwdev)->unmap_page(hwdev, handle, size, dir, attrs);
  76         } else
  77                 __xen_dma_unmap_page(hwdev, handle, size, dir, attrs);
  78 }
  79
  80 static inline void xen_dma_sync_single_for_cpu(struct device *hwdev,
  81                 dma_addr_t handle, size_t size, enum dma_data_direction dir)
  82 {
  83         unsigned long pfn = PFN_DOWN(handle);
  84         if (pfn_valid(pfn)) {
  85                 if (__generic_dma_ops(hwdev)->sync_single_for_cpu)
  86                         __generic_dma_ops(hwdev)->sync_single_for_cpu(hwdev, handle, size, dir);
  87         } else
  88                 __xen_dma_sync_single_for_cpu(hwdev, handle, size, dir);
  89 }
  90
  91 static inline void xen_dma_sync_single_for_device(struct device *hwdev,
  92                 dma_addr_t handle, size_t size, enum dma_data_direction dir)
  93 {
  94         unsigned long pfn = PFN_DOWN(handle);
  95         if (pfn_valid(pfn)) {
  96                 if (__generic_dma_ops(hwdev)->sync_single_for_device)
  97                         __generic_dma_ops(hwdev)->sync_single_for_device(hwdev, handle, size, dir);
  98         } else
  99                 __xen_dma_sync_single_for_device(hwdev, handle, size, dir);
 100 }
 101
 102 #endif /* _ASM_ARM_XEN_PAGE_COHERENT_H */