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Commit 74bc7cee authored by Arthur Kepner's avatar Arthur Kepner Committed by Linus Torvalds
Browse files

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: default avatarArthur 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: default avatarMark Nelson <markn@au1.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d2ba7e2a

arch/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -36,3 +36,6 @@ config HAVE_KPROBES 


config HAVE_KRETPROBES

	def_bool n



config HAVE_DMA_ATTRS

	def_bool n

arch/ia64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

include/linux/dma-attrs.h

0 → 100644
+74 −0
Original line number Diff line number Diff line 
#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 */

include/linux/dma-mapping.h

+17 −0
Original line number Diff line number Diff line
@@ -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