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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_NO_KERNEL_MAPPING,
19 DMA_ATTR_SKIP_CPU_SYNC,
20 DMA_ATTR_MAX,
21};
22
23#define __DMA_ATTRS_LONGS BITS_TO_LONGS(DMA_ATTR_MAX)
24
25/**
26 * struct dma_attrs - an opaque container for DMA attributes
27 * @flags - bitmask representing a collection of enum dma_attr
28 */
29struct dma_attrs {
30 unsigned long flags[__DMA_ATTRS_LONGS];
31};
32
33#define DEFINE_DMA_ATTRS(x) \
34 struct dma_attrs x = { \
35 .flags = { [0 ... __DMA_ATTRS_LONGS-1] = 0 }, \
36 }
37
38static inline void init_dma_attrs(struct dma_attrs *attrs)
39{
40 bitmap_zero(attrs->flags, __DMA_ATTRS_LONGS);
41}
42
43#ifdef CONFIG_HAVE_DMA_ATTRS
44/**
45 * dma_set_attr - set a specific attribute
46 * @attr: attribute to set
47 * @attrs: struct dma_attrs (may be NULL)
48 */
49static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
50{
51 if (attrs == NULL)
52 return;
53 BUG_ON(attr >= DMA_ATTR_MAX);
54 __set_bit(attr, attrs->flags);
55}
56
57/**
58 * dma_get_attr - check for a specific attribute
59 * @attr: attribute to set
60 * @attrs: struct dma_attrs (may be NULL)
61 */
62static inline int dma_get_attr(enum dma_attr attr, struct dma_attrs *attrs)
63{
64 if (attrs == NULL)
65 return 0;
66 BUG_ON(attr >= DMA_ATTR_MAX);
67 return test_bit(attr, attrs->flags);
68}
69#else /* !CONFIG_HAVE_DMA_ATTRS */
70static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
71{
72}
73
74static inline int dma_get_attr(enum dma_attr attr, struct dma_attrs *attrs)
75{
76 return 0;
77}
78#endif /* CONFIG_HAVE_DMA_ATTRS */
79#endif /* _DMA_ATTR_H */