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author | Arthur Kepner <akepner@sgi.com> | 2008-04-29 01:00:30 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-29 08:06:11 -0700 |
commit | 74bc7ceebfa1c84ddd3a843ebfb56df013bf7ef5 (patch) | |
tree | 548155250fbc7410273125019c70a7c5c085e895 /include/linux/dma-attrs.h | |
parent | d2ba7e2ae206e9ab24e8937d99d0d5513bfd08e5 (diff) | |
download | linux-stable-74bc7ceebfa1c84ddd3a843ebfb56df013bf7ef5.tar.gz linux-stable-74bc7ceebfa1c84ddd3a843ebfb56df013bf7ef5.tar.bz2 linux-stable-74bc7ceebfa1c84ddd3a843ebfb56df013bf7ef5.zip |
dma: add dma_*map*_attrs() interfaces
Introduce new interfaces, dma_*map*_attrs(), for passing architecture-specific
attributes when memory is mapped and unmapped for DMA. Give the interfaces
default implementations which ignore attributes. Also introduce the
dma_{set|get}_attr() interfaces for setting and retrieving individual
attributes. Define one attribute, DMA_ATTR_WRITE_BARRIER, in anticipation of
its use by ia64/sn. Select whether architectures implement arch-specific
versions of the dma_*map*_attrs() interfaces via HAVE_DMA_ATTRS in Kconfig.
[markn@au1.ibm.com: dma_{set,get}_attr() have to be static inline]
Signed-off-by: Arthur Kepner <akepner@sgi.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: David Miller <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Mark Nelson <markn@au1.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/dma-attrs.h')
-rw-r--r-- | include/linux/dma-attrs.h | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h new file mode 100644 index 000000000000..1677e2bfa00c --- /dev/null +++ b/include/linux/dma-attrs.h @@ -0,0 +1,74 @@ +#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_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 */ |