83 lines
1.8 KiB
C
83 lines
1.8 KiB
C
/*
|
|
* 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++;
|
|
}
|
|
}
|
|
|
|
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;
|
|
}
|
|
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);
|