iommu sg: add IOMMU helper functions for the free area management

extern 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);

extern void iommu_area_free(unsigned long *map, unsigned long start,

			    unsigned int nr);

obj-$(CONFIG_AUDIT_GENERIC) += audit.o

obj-$(CONFIG_SWIOTLB) += swiotlb.o

obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o

obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o

lib-$(CONFIG_GENERIC_BUG) += bug.o

/*

 * 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);