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 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 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 start = ALIGN(shift + index, boundary_size) - shift; 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