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1#ifndef _DMA_ATTR_H
2#define _DMA_ATTR_H
3
4#include <linux/bitmap.h>
5#include <linux/bitops.h>
6#include <linux/bug.h>
7
8/**
9 * an enum dma_attr represents an attribute associated with a DMA
10 * mapping. The semantics of each attribute should be defined in
11 * Documentation/DMA-attributes.txt.
12 */
13enum dma_attr {
14 DMA_ATTR_WRITE_BARRIER,
15 DMA_ATTR_WEAK_ORDERING,
16 DMA_ATTR_WRITE_COMBINE,
17 DMA_ATTR_NON_CONSISTENT,
18 DMA_ATTR_MAX,
19};
20
21#define __DMA_ATTRS_LONGS BITS_TO_LONGS(DMA_ATTR_MAX)
22
23/**
24 * struct dma_attrs - an opaque container for DMA attributes
25 * @flags - bitmask representing a collection of enum dma_attr
26 */
27struct dma_attrs {
28 unsigned long flags[__DMA_ATTRS_LONGS];
29};
30
31#define DEFINE_DMA_ATTRS(x) \
32 struct dma_attrs x = { \
33 .flags = { [0 ... __DMA_ATTRS_LONGS-1] = 0 }, \
34 }
35
36static inline void init_dma_attrs(struct dma_attrs *attrs)
37{
38 bitmap_zero(attrs->flags, __DMA_ATTRS_LONGS);
39}
40
41#ifdef CONFIG_HAVE_DMA_ATTRS
42/**
43 * dma_set_attr - set a specific attribute
44 * @attr: attribute to set
45 * @attrs: struct dma_attrs (may be NULL)
46 */
47static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
48{
49 if (attrs == NULL)
50 return;
51 BUG_ON(attr >= DMA_ATTR_MAX);
52 __set_bit(attr, attrs->flags);
53}
54
55/**
56 * dma_get_attr - check for a specific attribute
57 * @attr: attribute to set
58 * @attrs: struct dma_attrs (may be NULL)
59 */
60static inline int dma_get_attr(enum dma_attr attr, struct dma_attrs *attrs)
61{
62 if (attrs == NULL)
63 return 0;
64 BUG_ON(attr >= DMA_ATTR_MAX);
65 return test_bit(attr, attrs->flags);
66}
67#else /* !CONFIG_HAVE_DMA_ATTRS */
68static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
69{
70}
71
72static inline int dma_get_attr(enum dma_attr attr, struct dma_attrs *attrs)
73{
74 return 0;
75}
76#endif /* CONFIG_HAVE_DMA_ATTRS */
77#endif /* _DMA_ATTR_H */