linux/lib/iommu-helper.c
Joerg Roedel 56d9366074 introduce generic iommu_num_pages function
This patch introduces the generic iommu_num_pages function. It can be used by
a given memory area.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 11:21:33 -07:00

91 lines
2.0 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;
}
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);