blob: a816f3a806258c8ea08ac787c8eee9841d3204bc
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 | |
9 | int 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 | |
19 | unsigned 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; |
28 | again: |
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 | start = ALIGN(shift + index, boundary_size) - shift; |
33 | goto again; |
34 | } |
35 | bitmap_set(map, index, nr); |
36 | return index; |
37 | } |
38 | return -1; |
39 | } |
40 | EXPORT_SYMBOL(iommu_area_alloc); |
41 |