1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * IOMMU helper functions for the free area management 4 */ 5 6 #include <linux/export.h> 7 #include <linux/bitmap.h> 8 #include <linux/bug.h> 9 10 int iommu_is_span_boundary(unsigned int index, unsigned int nr, 11 unsigned long shift, 12 unsigned long boundary_size) 13 { 14 BUG_ON(!is_power_of_2(boundary_size)); 15 16 shift = (shift + index) & (boundary_size - 1); 17 return shift + nr > boundary_size; 18 } 19 20 unsigned long iommu_area_alloc(unsigned long *map, unsigned long size, 21 unsigned long start, unsigned int nr, 22 unsigned long shift, unsigned long boundary_size, 23 unsigned long align_mask) 24 { 25 unsigned long index; 26 27 /* We don't want the last of the limit */ 28 size -= 1; 29 again: 30 index = bitmap_find_next_zero_area(map, size, start, nr, align_mask); 31 if (index < size) { 32 if (iommu_is_span_boundary(index, nr, shift, boundary_size)) { 33 start = ALIGN(shift + index, boundary_size) - shift; 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