Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / lib / iommu-helper.c

diff --git a/kernel/lib/iommu-helper.c b/kernel/lib/iommu-helper.c
new file mode 100644 (file)
index 0000000..c27e269
--- /dev/null
+++ b/kernel/lib/iommu-helper.c
@@ -0,0 +1,41 @@
+/*
+ * IOMMU helper functions for the free area management
+ */
+
+#include <linux/export.h>
+#include <linux/bitmap.h>
+#include <linux/bug.h>
+
+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;
+
+       /* 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)) {
+                       /* we could do more effectively */
+                       start = index + 1;
+                       goto again;
+               }
+               bitmap_set(map, index, nr);
+               return index;
+       }
+       return -1;
+}
+EXPORT_SYMBOL(iommu_area_alloc);