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_MAX,
17 };
18
19 #define __DMA_ATTRS_LONGS BITS_TO_LONGS(DMA_ATTR_MAX)
20
21 /**
22 * struct dma_attrs - an opaque container for DMA attributes
23 * @flags - bitmask representing a collection of enum dma_attr
24 */
25 struct dma_attrs {
26 unsigned long flags[__DMA_ATTRS_LONGS];
27 };
28
29 #define DEFINE_DMA_ATTRS(x) \
30 struct dma_attrs x = { \
31 .flags = { [0 ... __DMA_ATTRS_LONGS-1] = 0 }, \
32 }
33
init_dma_attrs(struct dma_attrs * attrs)34 static inline void init_dma_attrs(struct dma_attrs *attrs)
35 {
36 bitmap_zero(attrs->flags, __DMA_ATTRS_LONGS);
37 }
38
39 #ifdef CONFIG_HAVE_DMA_ATTRS
40 /**
41 * dma_set_attr - set a specific attribute
42 * @attr: attribute to set
43 * @attrs: struct dma_attrs (may be NULL)
44 */
dma_set_attr(enum dma_attr attr,struct dma_attrs * attrs)45 static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
46 {
47 if (attrs == NULL)
48 return;
49 BUG_ON(attr >= DMA_ATTR_MAX);
50 __set_bit(attr, attrs->flags);
51 }
52
53 /**
54 * dma_get_attr - check for a specific attribute
55 * @attr: attribute to set
56 * @attrs: struct dma_attrs (may be NULL)
57 */
dma_get_attr(enum dma_attr attr,struct dma_attrs * attrs)58 static inline int dma_get_attr(enum dma_attr attr, struct dma_attrs *attrs)
59 {
60 if (attrs == NULL)
61 return 0;
62 BUG_ON(attr >= DMA_ATTR_MAX);
63 return test_bit(attr, attrs->flags);
64 }
65 #else /* !CONFIG_HAVE_DMA_ATTRS */
dma_set_attr(enum dma_attr attr,struct dma_attrs * attrs)66 static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
67 {
68 }
69
dma_get_attr(enum dma_attr attr,struct dma_attrs * attrs)70 static inline int dma_get_attr(enum dma_attr attr, struct dma_attrs *attrs)
71 {
72 return 0;
73 }
74 #endif /* CONFIG_HAVE_DMA_ATTRS */
75 #endif /* _DMA_ATTR_H */
76