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dma: add dma_*map*_attrs() interfaces

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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>
This commit is contained in:
Arthur Kepner 2008-04-29 01:00:30 -07:00 committed by Linus Torvalds
parent d2ba7e2ae2
commit 74bc7ceebf
4 changed files with 95 additions and 0 deletions
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3
arch/Kconfig
View file

@ -36,3 +36,6 @@ config HAVE_KPROBES
config HAVE_KRETPROBES
def_bool n
config HAVE_DMA_ATTRS
def_bool n

1
arch/ia64/Kconfig
View file

@ -19,6 +19,7 @@ config IA64
select HAVE_OPROFILE
select HAVE_KPROBES
select HAVE_KRETPROBES
select HAVE_DMA_ATTRS
select HAVE_KVM
default y
help

74
include/linux/dma-attrs.h Normal file
View file

@ -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 */

17
include/linux/dma-mapping.h
View file

@ -146,4 +146,21 @@ static inline void dmam_release_declared_memory(struct device *dev)
}
#endif /* ARCH_HAS_DMA_DECLARE_COHERENT_MEMORY */
#ifndef CONFIG_HAVE_DMA_ATTRS
struct dma_attrs;
#define dma_map_single_attrs(dev, cpu_addr, size, dir, attrs) \
dma_map_single(dev, cpu_addr, size, dir)
#define dma_unmap_single_attrs(dev, dma_addr, size, dir, attrs) \
dma_unmap_single(dev, dma_addr, size, dir)
#define dma_map_sg_attrs(dev, sgl, nents, dir, attrs) \
dma_map_sg(dev, sgl, nents, dir)
#define dma_unmap_sg_attrs(dev, sgl, nents, dir, attrs) \
dma_unmap_sg(dev, sgl, nents, dir)
#endif /* CONFIG_HAVE_DMA_ATTRS */
#endif