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_NO_KERNEL_MAPPING,
19 DMA_ATTR_SKIP_CPU_SYNC,
20 DMA_ATTR_FORCE_CONTIGUOUS,
21 DMA_ATTR_MAX,
22 };
23
24 #define __DMA_ATTRS_LONGS BITS_TO_LONGS(DMA_ATTR_MAX)
25
26 /**
27 * struct dma_attrs - an opaque container for DMA attributes
28 * @flags - bitmask representing a collection of enum dma_attr
29 */
30 struct dma_attrs {
31 unsigned long flags[__DMA_ATTRS_LONGS];
32 };
33
34 #define DEFINE_DMA_ATTRS(x) \
35 struct dma_attrs x = { \
36 .flags = { [0 ... __DMA_ATTRS_LONGS-1] = 0 }, \
37 }
38
init_dma_attrs(struct dma_attrs * attrs)39 static inline void init_dma_attrs(struct dma_attrs *attrs)
40 {
41 bitmap_zero(attrs->flags, __DMA_ATTRS_LONGS);
42 }
43
44 #ifdef CONFIG_HAVE_DMA_ATTRS
45 /**
46 * dma_set_attr - set a specific attribute
47 * @attr: attribute to set
48 * @attrs: struct dma_attrs (may be NULL)
49 */
dma_set_attr(enum dma_attr attr,struct dma_attrs * attrs)50 static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
51 {
52 if (attrs == NULL)
53 return;
54 BUG_ON(attr >= DMA_ATTR_MAX);
55 __set_bit(attr, attrs->flags);
56 }
57
58 /**
59 * dma_get_attr - check for a specific attribute
60 * @attr: attribute to set
61 * @attrs: struct dma_attrs (may be NULL)
62 */
dma_get_attr(enum dma_attr attr,struct dma_attrs * attrs)63 static inline int dma_get_attr(enum dma_attr attr, struct dma_attrs *attrs)
64 {
65 if (attrs == NULL)
66 return 0;
67 BUG_ON(attr >= DMA_ATTR_MAX);
68 return test_bit(attr, attrs->flags);
69 }
70 #else /* !CONFIG_HAVE_DMA_ATTRS */
dma_set_attr(enum dma_attr attr,struct dma_attrs * attrs)71 static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
72 {
73 }
74
dma_get_attr(enum dma_attr attr,struct dma_attrs * attrs)75 static inline int dma_get_attr(enum dma_attr attr, struct dma_attrs *attrs)
76 {
77 return 0;
78 }
79 #endif /* CONFIG_HAVE_DMA_ATTRS */
80 #endif /* _DMA_ATTR_H */
81