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 */
13 enum 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 */
27 struct 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
init_dma_attrs(struct dma_attrs * attrs)36 static 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 */
dma_set_attr(enum dma_attr attr,struct dma_attrs * attrs)47 static 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 */
dma_get_attr(enum dma_attr attr,struct dma_attrs * attrs)60 static 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 */
dma_set_attr(enum dma_attr attr,struct dma_attrs * attrs)68 static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
69 {
70 }
71
dma_get_attr(enum dma_attr attr,struct dma_attrs * attrs)72 static 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 */
78