1 /* 2 * IOMMU helper functions for the free area management 3 */ 4 5 #include <linux/module.h> 6 #include <linux/bitmap.h> 7 8 int 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 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) 22 { 23 unsigned long index; 24 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; 34 } 35 bitmap_set(map, index, nr); 36 return index; 37 } 38 return -1; 39 } 40 EXPORT_SYMBOL(iommu_area_alloc); 41