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_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 */
30struct 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
39static 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 */
50static 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 */
63static 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 */
71static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
72{
73}
74
75static 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