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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 | ||
10 | int 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 | ||
20 | unsigned 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; | |
29 | again: | |
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 | } | |
41 | EXPORT_SYMBOL(iommu_area_alloc); |