arch/arm/xen/mm32.c

   1 #include <linux/cpu.h>
   2 #include <linux/dma-mapping.h>
   3 #include <linux/gfp.h>
   4 #include <linux/highmem.h>
   5
   6 #include <xen/features.h>
   7 enum dma_cache_op {
   8        DMA_UNMAP,
   9        DMA_MAP,
  10 };
  11
  12 /* functions called by SWIOTLB */
  13
  14 static void dma_cache_maint(dma_addr_t handle, unsigned long offset,
  15         size_t size, enum dma_data_direction dir, enum dma_cache_op op)
  16 {
  17         unsigned long pfn;
  18         size_t left = size;
  19
  20         pfn = (handle >> PAGE_SHIFT) + offset / PAGE_SIZE;
  21         offset %= PAGE_SIZE;
  22
  23         do {
  24                 size_t len = left;
  25
  26                 /* TODO: cache flush */
  27
  28                 offset = 0;
  29                 pfn++;
  30                 left -= len;
  31         } while (left);
  32 }
  33
  34 static void __xen_dma_page_dev_to_cpu(struct device *hwdev, dma_addr_t handle,
  35                 size_t size, enum dma_data_direction dir)
  36 {
  37         dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_UNMAP);
  38 }
  39
  40 static void __xen_dma_page_cpu_to_dev(struct device *hwdev, dma_addr_t handle,
  41                 size_t size, enum dma_data_direction dir)
  42 {
  43         dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_MAP);
  44 }
  45
  46 void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
  47                 size_t size, enum dma_data_direction dir,
  48                 struct dma_attrs *attrs)
  49
  50 {
  51         if (is_device_dma_coherent(hwdev))
  52                 return;
  53         if (dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
  54                 return;
  55
  56         __xen_dma_page_dev_to_cpu(hwdev, handle, size, dir);
  57 }
  58
  59 void __xen_dma_sync_single_for_cpu(struct device *hwdev,
  60                 dma_addr_t handle, size_t size, enum dma_data_direction dir)
  61 {
  62         if (is_device_dma_coherent(hwdev))
  63                 return;
  64         __xen_dma_page_dev_to_cpu(hwdev, handle, size, dir);
  65 }
  66
  67 void __xen_dma_sync_single_for_device(struct device *hwdev,
  68                 dma_addr_t handle, size_t size, enum dma_data_direction dir)
  69 {
  70         if (is_device_dma_coherent(hwdev))
  71                 return;
  72         __xen_dma_page_cpu_to_dev(hwdev, handle, size, dir);
  73 }
  74
  75 int __init xen_mm32_init(void)
  76 {
  77         if (!xen_initial_domain())
  78                 return 0;
  79
  80         return 0;
  81 }
  82 arch_initcall(xen_mm32_init);