Commit | Line | Data |
---|---|---|
0291df8c FT |
1 | /* |
2 | * IOMMU helper functions for the free area management | |
3 | */ | |
4 | ||
5 | #include <linux/module.h> | |
6 | #include <linux/bitops.h> | |
7 | ||
8 | static unsigned long find_next_zero_area(unsigned long *map, | |
9 | unsigned long size, | |
10 | unsigned long start, | |
11 | unsigned int nr, | |
12 | unsigned long align_mask) | |
13 | { | |
14 | unsigned long index, end, i; | |
15 | again: | |
16 | index = find_next_zero_bit(map, size, start); | |
17 | ||
18 | /* Align allocation */ | |
19 | index = (index + align_mask) & ~align_mask; | |
20 | ||
21 | end = index + nr; | |
22 | if (end >= size) | |
23 | return -1; | |
24 | for (i = index; i < end; i++) { | |
25 | if (test_bit(i, map)) { | |
26 | start = i+1; | |
27 | goto again; | |
28 | } | |
29 | } | |
30 | return index; | |
31 | } | |
32 | ||
33 | static inline void set_bit_area(unsigned long *map, unsigned long i, | |
34 | int len) | |
35 | { | |
36 | unsigned long end = i + len; | |
37 | while (i < end) { | |
38 | __set_bit(i, map); | |
39 | i++; | |
40 | } | |
41 | } | |
42 | ||
43 | static inline int is_span_boundary(unsigned int index, unsigned int nr, | |
44 | unsigned long shift, | |
45 | unsigned long boundary_size) | |
46 | { | |
47 | shift = (shift + index) & (boundary_size - 1); | |
48 | return shift + nr > boundary_size; | |
49 | } | |
50 | ||
51 | unsigned long iommu_area_alloc(unsigned long *map, unsigned long size, | |
52 | unsigned long start, unsigned int nr, | |
53 | unsigned long shift, unsigned long boundary_size, | |
54 | unsigned long align_mask) | |
55 | { | |
56 | unsigned long index; | |
57 | again: | |
58 | index = find_next_zero_area(map, size, start, nr, align_mask); | |
59 | if (index != -1) { | |
60 | if (is_span_boundary(index, nr, shift, boundary_size)) { | |
61 | /* we could do more effectively */ | |
62 | start = index + 1; | |
63 | goto again; | |
64 | } | |
65 | set_bit_area(map, index, nr); | |
66 | } | |
67 | return index; | |
68 | } | |
69 | EXPORT_SYMBOL(iommu_area_alloc); | |
70 | ||
71 | void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr) | |
72 | { | |
73 | unsigned long end = start + nr; | |
74 | ||
75 | while (start < end) { | |
76 | __clear_bit(start, map); | |
77 | start++; | |
78 | } | |
79 | } | |
80 | EXPORT_SYMBOL(iommu_area_free); |