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-rw-r--r--Documentation/DMA-API.txt33
1 files changed, 14 insertions, 19 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index 45ef3f279c3b..1d26eeb6b5f6 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -369,35 +369,32 @@ See also dma_map_single().
dma_addr_t
dma_map_single_attrs(struct device *dev, void *cpu_addr, size_t size,
enum dma_data_direction dir,
- struct dma_attrs *attrs)
+ unsigned long attrs)
void
dma_unmap_single_attrs(struct device *dev, dma_addr_t dma_addr,
size_t size, enum dma_data_direction dir,
- struct dma_attrs *attrs)
+ unsigned long attrs)
int
dma_map_sg_attrs(struct device *dev, struct scatterlist *sgl,
int nents, enum dma_data_direction dir,
- struct dma_attrs *attrs)
+ unsigned long attrs)
void
dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sgl,
int nents, enum dma_data_direction dir,
- struct dma_attrs *attrs)
+ unsigned long attrs)
The four functions above are just like the counterpart functions
without the _attrs suffixes, except that they pass an optional
-struct dma_attrs*.
-
-struct dma_attrs encapsulates a set of "DMA attributes". For the
-definition of struct dma_attrs see linux/dma-attrs.h.
+dma_attrs.
The interpretation of DMA attributes is architecture-specific, and
each attribute should be documented in Documentation/DMA-attributes.txt.
-If struct dma_attrs* is NULL, the semantics of each of these
-functions is identical to those of the corresponding function
+If dma_attrs are 0, the semantics of each of these functions
+is identical to those of the corresponding function
without the _attrs suffix. As a result dma_map_single_attrs()
can generally replace dma_map_single(), etc.
@@ -405,15 +402,15 @@ As an example of the use of the *_attrs functions, here's how
you could pass an attribute DMA_ATTR_FOO when mapping memory
for DMA:
-#include <linux/dma-attrs.h>
-/* DMA_ATTR_FOO should be defined in linux/dma-attrs.h and
+#include <linux/dma-mapping.h>
+/* DMA_ATTR_FOO should be defined in linux/dma-mapping.h and
* documented in Documentation/DMA-attributes.txt */
...
- DEFINE_DMA_ATTRS(attrs);
- dma_set_attr(DMA_ATTR_FOO, &attrs);
+ unsigned long attr;
+ attr |= DMA_ATTR_FOO;
....
- n = dma_map_sg_attrs(dev, sg, nents, DMA_TO_DEVICE, &attr);
+ n = dma_map_sg_attrs(dev, sg, nents, DMA_TO_DEVICE, attr);
....
Architectures that care about DMA_ATTR_FOO would check for its
@@ -422,12 +419,10 @@ routines, e.g.:
void whizco_dma_map_sg_attrs(struct device *dev, dma_addr_t dma_addr,
size_t size, enum dma_data_direction dir,
- struct dma_attrs *attrs)
+ unsigned long attrs)
{
....
- int foo = dma_get_attr(DMA_ATTR_FOO, attrs);
- ....
- if (foo)
+ if (attrs & DMA_ATTR_FOO)
/* twizzle the frobnozzle */
....