dma-attrs.h
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#ifndef _DMA_ATTR_H
#define _DMA_ATTR_H
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/bug.h>
/**
* an enum dma_attr represents an attribute associated with a DMA
* mapping. The semantics of each attribute should be defined in
* Documentation/DMA-attributes.txt.
*/
enum dma_attr {
DMA_ATTR_WRITE_BARRIER,
DMA_ATTR_WEAK_ORDERING,
DMA_ATTR_WRITE_COMBINE,
DMA_ATTR_NON_CONSISTENT,
DMA_ATTR_NO_KERNEL_MAPPING,
DMA_ATTR_SKIP_CPU_SYNC,
DMA_ATTR_FORCE_CONTIGUOUS,
DMA_ATTR_MAX,
};
#define __DMA_ATTRS_LONGS BITS_TO_LONGS(DMA_ATTR_MAX)
/**
* struct dma_attrs - an opaque container for DMA attributes
* @flags - bitmask representing a collection of enum dma_attr
*/
struct dma_attrs {
unsigned long flags[__DMA_ATTRS_LONGS];
};
#define DEFINE_DMA_ATTRS(x) \
struct dma_attrs x = { \
.flags = { [0 ... __DMA_ATTRS_LONGS-1] = 0 }, \
}
static inline void init_dma_attrs(struct dma_attrs *attrs)
{
bitmap_zero(attrs->flags, __DMA_ATTRS_LONGS);
}
#ifdef CONFIG_HAVE_DMA_ATTRS
/**
* dma_set_attr - set a specific attribute
* @attr: attribute to set
* @attrs: struct dma_attrs (may be NULL)
*/
static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
{
if (attrs == NULL)
return;
BUG_ON(attr >= DMA_ATTR_MAX);
__set_bit(attr, attrs->flags);
}
/**
* dma_get_attr - check for a specific attribute
* @attr: attribute to set
* @attrs: struct dma_attrs (may be NULL)
*/
static inline int dma_get_attr(enum dma_attr attr, struct dma_attrs *attrs)
{
if (attrs == NULL)
return 0;
BUG_ON(attr >= DMA_ATTR_MAX);
return test_bit(attr, attrs->flags);
}
#else /* !CONFIG_HAVE_DMA_ATTRS */
static inline void dma_set_attr(enum dma_attr attr, struct dma_attrs *attrs)
{
}
static inline int dma_get_attr(enum dma_attr attr, struct dma_attrs *attrs)
{
return 0;
}
#endif /* CONFIG_HAVE_DMA_ATTRS */
#endif /* _DMA_ATTR_H */