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-rw-r--r--lib/iommu-helper.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c
new file mode 100644
index 000000000..92a9f243c
--- /dev/null
+++ b/lib/iommu-helper.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * IOMMU helper functions for the free area management
+ */
+
+#include <linux/bitmap.h>
+#include <linux/iommu-helper.h>
+
+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)) {
+ start = ALIGN(shift + index, boundary_size) - shift;
+ goto again;
+ }
+ bitmap_set(map, index, nr);
+ return index;
+ }
+ return -1;
+}