LXR linux/lib/iommu-helper.c

   1/*
   2 * IOMMU helper functions for the free area management
   3 */
   4
   5#include <linux/module.h>
   6#include <linux/bitops.h>
   7
   8static unsigned long find_next_zero_area(unsigned long *map,
   9                                         unsigned long size,
  10                                         unsigned long start,
  11                                         unsigned int nr,
  12                                         unsigned long align_mask)
  13{
  14        unsigned long index, end, i;
  15again:
  16        index = find_next_zero_bit(map, size, start);
  17
  18        /* Align allocation */
  19        index = (index + align_mask) & ~align_mask;
  20
  21        end = index + nr;
  22        if (end >= size)
  23                return -1;
  24        for (i = index; i < end; i++) {
  25                if (test_bit(i, map)) {
  26                        start = i+1;
  27                        goto again;
  28                }
  29        }
  30        return index;
  31}
  32
  33void iommu_area_reserve(unsigned long *map, unsigned long i, int len)
  34{
  35        unsigned long end = i + len;
  36        while (i < end) {
  37                __set_bit(i, map);
  38                i++;
  39        }
  40}
  41
  42int iommu_is_span_boundary(unsigned int index, unsigned int nr,
  43                           unsigned long shift,
  44                           unsigned long boundary_size)
  45{
  46        BUG_ON(!is_power_of_2(boundary_size));
  47
  48        shift = (shift + index) & (boundary_size - 1);
  49        return shift + nr > boundary_size;
  50}
  51
  52unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
  53                               unsigned long start, unsigned int nr,
  54                               unsigned long shift, unsigned long boundary_size,
  55                               unsigned long align_mask)
  56{
  57        unsigned long index;
  58again:
  59        index = find_next_zero_area(map, size, start, nr, align_mask);
  60        if (index != -1) {
  61                if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
  62                        /* we could do more effectively */
  63                        start = index + 1;
  64                        goto again;
  65                }
  66                iommu_area_reserve(map, index, nr);
  67        }
  68        return index;
  69}
  70EXPORT_SYMBOL(iommu_area_alloc);
  71
  72void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr)
  73{
  74        unsigned long end = start + nr;
  75
  76        while (start < end) {
  77                __clear_bit(start, map);
  78                start++;
  79        }
  80}
  81EXPORT_SYMBOL(iommu_area_free);
  82
  83unsigned long iommu_num_pages(unsigned long addr, unsigned long len,
  84                              unsigned long io_page_size)
  85{
  86        unsigned long size = (addr & (io_page_size - 1)) + len;
  87
  88        return DIV_ROUND_UP(size, io_page_size);
  89}
  90EXPORT_SYMBOL(iommu_num_pages);
  91