diff options
Diffstat (limited to 'lib/iommu-helper.c')
-rw-r--r-- | lib/iommu-helper.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c new file mode 100644 index 00000000..da053313 --- /dev/null +++ b/lib/iommu-helper.c @@ -0,0 +1,40 @@ +/* + * IOMMU helper functions for the free area management + */ + +#include <linux/module.h> +#include <linux/bitmap.h> + +int iommu_is_span_boundary(unsigned int index, unsigned int nr, + unsigned long shift, + unsigned long boundary_size) +{ + BUG_ON(!is_power_of_2(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; + + /* We don't want the last of the limit */ + size -= 1; +again: + index = bitmap_find_next_zero_area(map, size, start, nr, align_mask); + if (index < size) { + if (iommu_is_span_boundary(index, nr, shift, boundary_size)) { + /* we could do more effectively */ + start = index + 1; + goto again; + } + bitmap_set(map, index, nr); + return index; + } + return -1; +} +EXPORT_SYMBOL(iommu_area_alloc); |