Root/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
8int 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
18unsigned 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
25    /* We don't want the last of the limit */
26    size -= 1;
27again:
28    index = bitmap_find_next_zero_area(map, size, start, nr, align_mask);
29    if (index < size) {
30        if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
31            /* we could do more effectively */
32            start = index + 1;
33            goto again;
34        }
35        bitmap_set(map, index, nr);
36        return index;
37    }
38    return -1;
39}
40EXPORT_SYMBOL(iommu_area_alloc);
41

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