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Documentation: DMA API: Be more explicit that nents is always the same

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The nents argument to the DMA API functions operating on scatterlists is
always the same. The documentation used different argument names and the
matter was not mentioned in Documentation/DMA-API-HOWTO.txt at all. Fix
these.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Sakari Ailus 2015-09-23 14:41:09 +03:00 committed by Jonathan Corbet
parent c604503192
commit 7bc590b2fc
2 changed files with 8 additions and 3 deletions
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5
Documentation/DMA-API-HOWTO.txt
View File

@ -681,6 +681,11 @@ or:
as appropriate.
PLEASE NOTE: The 'nents' argument to dma_sync_sg_for_cpu() and
dma_sync_sg_for_device() must be the same passed to
dma_map_sg(). It is _NOT_ the count returned by
dma_map_sg().
After the last DMA transfer call one of the DMA unmap routines
dma_unmap_{single,sg}(). If you don't touch the data from the first
dma_map_*() call till dma_unmap_*(), then you don't have to call the

6
Documentation/DMA-API.txt
View File

@ -340,7 +340,7 @@ accessed sg->address and sg->length as shown above.
void
dma_unmap_sg(struct device *dev, struct scatterlist *sg,
int nhwentries, enum dma_data_direction direction)
int nents, enum dma_data_direction direction)
Unmap the previously mapped scatter/gather list. All the parameters
must be the same as those and passed in to the scatter/gather mapping
@ -356,10 +356,10 @@ void
dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle, size_t size,
enum dma_data_direction direction)
void
dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nelems,
dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents,
enum dma_data_direction direction)
void
dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nelems,
dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents,
enum dma_data_direction direction)
Synchronise a single contiguous or scatter/gather mapping for the CPU