#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_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 */