/* * IOMMU helper functions for the free area management */ #include <linux/module.h> #include <linux/bitops.h> static unsigned long find_next_zero_area(unsigned long *map, unsigned long size, unsigned long start, unsigned int nr, unsigned long align_mask) { unsigned long index, end, i; again: index = find_next_zero_bit(map, size, start); /* Align allocation */ index = (index + align_mask) & ~align_mask; end = index + nr; if (end >= size) return -1; for (i = index; i < end; i++) { if (test_bit(i, map)) { start = i+1; goto again; } } return index; } static inline void set_bit_area(unsigned long *map, unsigned long i, int len) { unsigned long end = i + len; while (i < end) { __set_bit(i, map); i++; } } static inline int is_span_boundary(unsigned int index, unsigned int nr, unsigned long shift, unsigned long boundary_size) { shift = (shift + index) & (boundary_size - 1); return shift + nr > boundary_size; } unsigned long iommu_area_alloc(unsigned long *map, unsigned long size, unsigned long start, unsigned int nr, unsigned long shift, unsigned long boundary_size, unsigned long align_mask) { unsigned long index; again: index = find_next_zero_area(map, size, start, nr, align_mask); if (index != -1) { if (is_span_boundary(index, nr, shift, boundary_size)) { /* we could do more effectively */ start = index + 1; goto again; } set_bit_area(map, index, nr); } return index; } EXPORT_SYMBOL(iommu_area_alloc); void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr) { unsigned long end = start + nr; while (start < end) { __clear_bit(start, map); start++; } } EXPORT_SYMBOL(iommu_area_free);