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
iommu_is_span_boundary(unsigned int index,unsigned int nr,unsigned long shift,unsigned long boundary_size)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
iommu_area_alloc(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,unsigned long shift,unsigned long boundary_size,unsigned long align_mask)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 /* 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 }
41 EXPORT_SYMBOL(iommu_area_alloc);
42