lib/iommu-helper.c

   1 /*
   2  * IOMMU helper functions for the free area management
   3  */
   4
   5 #include <linux/export.h>
   6 #include <linux/bitmap.h>
   7 #include <linux/bug.h>
   8
   9 int iommu_is_span_boundary(unsigned int index, unsigned int nr,
  10                            unsigned long shift,
  11                            unsigned long boundary_size)
  12 {
  13         BUG_ON(!is_power_of_2(boundary_size));
  14
  15         shift = (shift + index) & (boundary_size - 1);
  16         return shift + nr > boundary_size;
  17 }
  18
  19 unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
  20                                unsigned long start, unsigned int nr,
  21                                unsigned long shift, unsigned long boundary_size,
  22                                unsigned long align_mask)
  23 {
  24         unsigned long index;
  25
  26         /* We don't want the last of the limit */
  27         size -= 1;
  28 again:
  29         index = bitmap_find_next_zero_area(map, size, start, nr, align_mask);
  30         if (index < size) {
  31                 if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
  32                         /* we could do more effectively */
  33                         start = index + 1;
  34                         goto again;
  35                 }
  36                 bitmap_set(map, index, nr);
  37                 return index;
  38         }
  39         return -1;
  40 }
  41 EXPORT_SYMBOL(iommu_area_alloc);