1 /* 2 * IOMMU helper functions for the free area management 3 */ 4 5 #include <linux/module.h> 6 #include <linux/bitops.h> 7 8 static unsigned long find_next_zero_area(unsigned long *map, 9 unsigned long size, 10 unsigned long start, 11 unsigned int nr, 12 unsigned long align_mask) 13 { 14 unsigned long index, end, i; 15 again: 16 index = find_next_zero_bit(map, size, start); 17 18 /* Align allocation */ 19 index = (index + align_mask) & ~align_mask; 20 21 end = index + nr; 22 if (end >= size) 23 return -1; 24 for (i = index; i < end; i++) { 25 if (test_bit(i, map)) { 26 start = i+1; 27 goto again; 28 } 29 } 30 return index; 31 } 32 33 void iommu_area_reserve(unsigned long *map, unsigned long i, int len) 34 { 35 unsigned long end = i + len; 36 while (i < end) { 37 __set_bit(i, map); 38 i++; 39 } 40 } 41 42 int iommu_is_span_boundary(unsigned int index, unsigned int nr, 43 unsigned long shift, 44 unsigned long boundary_size) 45 { 46 BUG_ON(!is_power_of_2(boundary_size)); 47 48 shift = (shift + index) & (boundary_size - 1); 49 return shift + nr > boundary_size; 50 } 51 52 unsigned long iommu_area_alloc(unsigned long *map, unsigned long size, 53 unsigned long start, unsigned int nr, 54 unsigned long shift, unsigned long boundary_size, 55 unsigned long align_mask) 56 { 57 unsigned long index; 58 again: 59 index = find_next_zero_area(map, size, start, nr, align_mask); 60 if (index != -1) { 61 if (iommu_is_span_boundary(index, nr, shift, boundary_size)) { 62 /* we could do more effectively */ 63 start = index + 1; 64 goto again; 65 } 66 iommu_area_reserve(map, index, nr); 67 } 68 return index; 69 } 70 EXPORT_SYMBOL(iommu_area_alloc); 71 72 void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr) 73 { 74 unsigned long end = start + nr; 75 76 while (start < end) { 77 __clear_bit(start, map); 78 start++; 79 } 80 } 81 EXPORT_SYMBOL(iommu_area_free); 82 83 unsigned long iommu_num_pages(unsigned long addr, unsigned long len, 84 unsigned long io_page_size) 85 { 86 unsigned long size = (addr & (io_page_size - 1)) + len; 87 88 return DIV_ROUND_UP(size, io_page_size); 89 } 90 EXPORT_SYMBOL(iommu_num_pages); 91