[linux.git] / lib / iommu-helper.c

/*
 * 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);
Commit	Line	Data
0291df8c FT	1	/*
	2	* IOMMU helper functions for the free area management
	3	*/
	4
	5	#include <linux/module.h>
a66022c4	6	#include <linux/bitmap.h>
0291df8c	7
3715863a FT	8	int iommu_is_span_boundary(unsigned int index, unsigned int nr,
	9	unsigned long shift,
	10	unsigned long boundary_size)
0291df8c	11	{
3715863a FT	12	BUG_ON(!is_power_of_2(boundary_size));
3715863a FT	13
0291df8c FT	14	shift = (shift + index) & (boundary_size - 1);
	15	return shift + nr > boundary_size;
	16	}
	17
	18	unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
	19	unsigned long start, unsigned int nr,
	20	unsigned long shift, unsigned long boundary_size,
	21	unsigned long align_mask)
	22	{
	23	unsigned long index;
a66022c4 AM	24
	25	/* We don't want the last of the limit */
	26	size -= 1;
0291df8c	27	again:
a66022c4 AM	28	index = bitmap_find_next_zero_area(map, size, start, nr, align_mask);
a66022c4 AM	29	if (index < size) {
3715863a	30	if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
0291df8c FT	31	/* we could do more effectively */
	32	start = index + 1;
	33	goto again;
	34	}
a66022c4 AM	35	bitmap_set(map, index, nr);
a66022c4 AM	36	return index;
0291df8c	37	}
a66022c4	38	return -1;
0291df8c FT	39	}
0291df8c FT	40	EXPORT_SYMBOL(iommu_area_alloc);