diff options
Diffstat (limited to 'lib/iommu-helper.c')
-rw-r--r-- | lib/iommu-helper.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c new file mode 100644 index 0000000..75dbda0 --- /dev/null +++ b/lib/iommu-helper.c @@ -0,0 +1,90 @@ +/* + * 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; +} + +void iommu_area_reserve(unsigned long *map, unsigned long i, int len) +{ + unsigned long end = i + len; + while (i < end) { + __set_bit(i, map); + i++; + } +} + +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; +again: + index = find_next_zero_area(map, size, start, nr, align_mask); + if (index != -1) { + if (iommu_is_span_boundary(index, nr, shift, boundary_size)) { + /* we could do more effectively */ + start = index + 1; + goto again; + } + iommu_area_reserve(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); + +unsigned long iommu_num_pages(unsigned long addr, unsigned long len, + unsigned long io_page_size) +{ + unsigned long size = (addr & (io_page_size - 1)) + len; + + return DIV_ROUND_UP(size, io_page_size); +} +EXPORT_SYMBOL(iommu_num_pages); |