um: arch_hweight.h is needed only on uml-x86
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / lib / iommu-helper.c
blobda053313ee5c089e099d02c9a368eb4f4aacaf56
1 /*
2 * IOMMU helper functions for the free area management
3 */
5 #include <linux/module.h>
6 #include <linux/bitmap.h>
8 int iommu_is_span_boundary(unsigned int index, unsigned int nr,
9 unsigned long shift,
10 unsigned long boundary_size)
12 BUG_ON(!is_power_of_2(boundary_size));
14 shift = (shift + index) & (boundary_size - 1);
15 return shift + nr > boundary_size;
18 unsigned 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)
23 unsigned long index;
25 /* We don't want the last of the limit */
26 size -= 1;
27 again:
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;
35 bitmap_set(map, index, nr);
36 return index;
38 return -1;
40 EXPORT_SYMBOL(iommu_area_alloc);