1 files changed, 74 insertions, 0 deletions

diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h
new file mode 100644
index 000000000000..1677e2bfa00c
--- /dev/null
+++ b/include/linux/dma-attrs.h
@@ -0,0 +1,74 @@
+#ifndef _DMA_ATTR_H
+#define _DMA_ATTR_H
+
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/bug.h>
+
+/**
+ * an enum dma_attr represents an attribute associated with a DMA
+ * mapping. The semantics of each attribute should be defined in
+ * Documentation/DMA-attributes.txt.
+ */
+enum dma_attr {
+        DMA_ATTR_WRITE_BARRIER,
+        DMA_ATTR_MAX,
+};
+
+#define __DMA_ATTRS_LONGS BITS_TO_LONGS(DMA_ATTR_MAX)
+
+/**
+ * struct dma_attrs - an opaque container for DMA attributes
+ * @flags - bitmask representing a collection of enum dma_attr
+ */
+struct dma_attrs {
+        unsigned long flags[__DMA_ATTRS_LONGS];
+};
+
+#define DEFINE_DMA_ATTRS(x)                                     \
+        struct dma_attrs x = {                                  \
+                .flags = { [0 ... __DMA_ATTRS_LONGS-1] = 0 },   \
+        }
+
+static inline void init_dma_attrs(struct dma_attrs *attrs)
+{
+        bitmap_zero(attrs->flags, __DMA_ATTRS_LONGS);
+}
+
+#ifdef CONFIG_HAVE_DMA_ATTRS
+/**
+ * dma_set_attr - set a specific attribute
+ * @attr: attribute to set
+ * @attrs: struct dma_attrs (may be NULL)
+ */
+static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
+{
+        if (attrs == NULL)
+                return;
+        BUG_ON(attr >= DMA_ATTR_MAX);
+        __set_bit(attr, attrs->flags);
+}
+
+/**
+ * dma_get_attr - check for a specific attribute
+ * @attr: attribute to set
+ * @attrs: struct dma_attrs (may be NULL)
+ */
+static inline int dma_get_attr(enum dma_attr attr, struct dma_attrs *attrs)
+{
+        if (attrs == NULL)
+                return 0;
+        BUG_ON(attr >= DMA_ATTR_MAX);
+        return test_bit(attr, attrs->flags);
+}
+#else /* !CONFIG_HAVE_DMA_ATTRS */
+static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
+{
+}
+
+static inline int dma_get_attr(enum dma_attr attr, struct dma_attrs *attrs)
+{
+        return 0;
+}
+#endif /* CONFIG_HAVE_DMA_ATTRS */
+#endif /* _DMA_ATTR_H */