lib/iommu-helper.c

   1 /*
   2  * IOMMU helper functions for the free area management
   3  */
   4
   5 #include <linux/module.h>
   6 #include <linux/bitmap.h>
   7
   8 int iommu_is_span_boundary(unsigned int index, unsigned int nr,
   9                            unsigned long shift,
  10                            unsigned long boundary_size)
  11 {
  12         BUG_ON(!is_power_of_2(boundary_size));
  13
  14         shift = (shift + index) & (boundary_size - 1);
  15         return shift + nr > boundary_size;
  16 }
  17
  18 unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
  19                                unsigned long start, unsigned int nr,
  20                                unsigned long shift, unsigned long boundary_size,
  21                                unsigned long align_mask)
  22 {
  23         unsigned long index;
  24 again:
  25         index = bitmap_find_next_zero_area(map, size, start, nr, align_mask);
  26         if (index < size) {
  27                 if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
  28                         /* we could do more effectively */
  29                         start = index + 1;
  30                         goto again;
  31                 }
  32                 bitmap_set(map, index, nr);
  33                 return index;
  34         }
  35         return -1;
  36 }
  37 EXPORT_SYMBOL(iommu_area_alloc);
  38
  39 unsigned long iommu_num_pages(unsigned long addr, unsigned long len,
  40                               unsigned long io_page_size)
  41 {
  42         unsigned long size = (addr & (io_page_size - 1)) + len;
  43
  44         return DIV_ROUND_UP(size, io_page_size);
  45 }
  46 EXPORT_SYMBOL(iommu_num_pages);