42 lines
1.0 KiB
C
42 lines
1.0 KiB
C
|
/*
|
||
|
|
* IOMMU helper functions for the free area management
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <linux/export.h>
|
||
|
|
#include <linux/bitmap.h>
|
||
|
|
#include <linux/bug.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);
|