linux/lib/iommu-helper.c
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   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
   9int 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
  19unsigned 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;
  28again:
  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}
  41EXPORT_SYMBOL(iommu_area_alloc);
  42
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