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Commit | Line | Data |
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1 | /* | |
2 | * IOMMU helper functions for the free area management | |
3 | */ | |
4 | ||
5 | #include <linux/module.h> | |
6 | #include <linux/bitmap.h> | |
7 | ||
8 | int 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 | ||
18 | unsigned 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; | |
27 | again: | |
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 | } | |
40 | EXPORT_SYMBOL(iommu_area_alloc); |