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-rw-r--r--lib/iommu-helper.c80
1 files changed, 80 insertions, 0 deletions
diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c
new file mode 100644
index 000000000000..495575a59ca6
--- /dev/null
+++ b/lib/iommu-helper.c
@@ -0,0 +1,80 @@
+/*
+ * 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);