v4.19.13 snapshot.
diff --git a/include/linux/iommu-helper.h b/include/linux/iommu-helper.h
new file mode 100644
index 0000000..70d01ed
--- /dev/null
+++ b/include/linux/iommu-helper.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_IOMMU_HELPER_H
+#define _LINUX_IOMMU_HELPER_H
+
+#include <linux/bug.h>
+#include <linux/kernel.h>
+
+static inline unsigned long iommu_device_max_index(unsigned long size,
+ unsigned long offset,
+ u64 dma_mask)
+{
+ if (size + offset > dma_mask)
+ return dma_mask - offset + 1;
+ else
+ return size;
+}
+
+static inline 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;
+}
+
+extern 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);
+
+static inline 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);
+}
+
+#endif