| 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_ALLOC_SINGLE_PAGES, |
| 22 | DMA_ATTR_MAX, |
| 23 | }; |
| 24 | |
| 25 | #define __DMA_ATTRS_LONGS BITS_TO_LONGS(DMA_ATTR_MAX) |
| 26 | |
| 27 | /** |
| 28 | * struct dma_attrs - an opaque container for DMA attributes |
| 29 | * @flags - bitmask representing a collection of enum dma_attr |
| 30 | */ |
| 31 | struct dma_attrs { |
| 32 | unsigned long flags[__DMA_ATTRS_LONGS]; |
| 33 | }; |
| 34 | |
| 35 | #define DEFINE_DMA_ATTRS(x) \ |
| 36 | struct dma_attrs x = { \ |
| 37 | .flags = { [0 ... __DMA_ATTRS_LONGS-1] = 0 }, \ |
| 38 | } |
| 39 | |
| 40 | static inline void init_dma_attrs(struct dma_attrs *attrs) |
| 41 | { |
| 42 | bitmap_zero(attrs->flags, __DMA_ATTRS_LONGS); |
| 43 | } |
| 44 | |
| 45 | /** |
| 46 | * dma_set_attr - set a specific attribute |
| 47 | * @attr: attribute to set |
| 48 | * @attrs: struct dma_attrs (may be NULL) |
| 49 | */ |
| 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 | */ |
| 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 | |
| 71 | #endif /* _DMA_ATTR_H */ |