1/*
2 * IOMMU helper functions for the free area management
3 */
4
5#include <linux/module.h>
6#include <linux/bitmap.h>
7
8int 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
18unsigned 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;
27again:
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}
40EXPORT_SYMBOL(iommu_area_alloc);
41