LXR linux/lib/iommu-helper.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * IOMMU helper functions for the free area management
   4 */
   5
   6#include <linux/export.h>
   7#include <linux/bitmap.h>
   8#include <linux/bug.h>
   9
  10int iommu_is_span_boundary(unsigned int index, unsigned int nr,
  11                           unsigned long shift,
  12                           unsigned long boundary_size)
  13{
  14        BUG_ON(!is_power_of_2(boundary_size));
  15
  16        shift = (shift + index) & (boundary_size - 1);
  17        return shift + nr > boundary_size;
  18}
  19
  20unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
  21                               unsigned long start, unsigned int nr,
  22                               unsigned long shift, unsigned long boundary_size,
  23                               unsigned long align_mask)
  24{
  25        unsigned long index;
  26
  27        /* We don't want the last of the limit */
  28        size -= 1;
  29again:
  30        index = bitmap_find_next_zero_area(map, size, start, nr, align_mask);
  31        if (index < size) {
  32                if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
  33                        start = ALIGN(shift + index, boundary_size) - shift;
  34                        goto again;
  35                }
  36                bitmap_set(map, index, nr);
  37                return index;
  38        }
  39        return -1;
  40}
  41EXPORT_SYMBOL(iommu_area_alloc);
  42