diff options
Diffstat (limited to 'include/linux/dma-attrs.h')
-rw-r--r-- | include/linux/dma-attrs.h | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h new file mode 100644 index 000000000..c8e1831d7 --- /dev/null +++ b/include/linux/dma-attrs.h @@ -0,0 +1,80 @@ +#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 */ |