Root/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
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

Archive Download this file



interactive