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| author |   Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> | 2019-08-28 21:35:40 +0900 |
|---|---|---|
| committer |   Christoph Hellwig <hch@lst.de> | 2019-09-03 08:33:01 +0200 |
| commit | 6ba99411b858bd70bae966633561e698cd6de38c (patch) | |
| tree | 5679bf75e3c4fc1a8bba626da01c2d0ce42f556f /Documentation/DMA-API.txt | |
| parent | mmc: queue: use bigger segments if DMA MAP layer can merge the segments (diff) | |
| download | linux-dev-6ba99411b858bd70bae966633561e698cd6de38c.tar.xz linux-dev-6ba99411b858bd70bae966633561e698cd6de38c.zip | |
dma-mapping: introduce dma_get_merge_boundary()
This patch adds a new DMA API "dma_get_merge_boundary". This function
returns the DMA merge boundary if the DMA layer can merge the segments.
This patch also adds the implementation for a new dma_map_ops pointer.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'Documentation/DMA-API.txt')
| -rw-r--r-- | Documentation/DMA-API.txt | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index e47c63bd4887..9c4dd3d779ed 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -204,6 +204,14 @@ Returns the maximum size of a mapping for the device. The size parameter of the mapping functions like dma_map_single(), dma_map_page() and others should not be larger than the returned value. +:: + + unsigned long + dma_get_merge_boundary(struct device *dev); + +Returns the DMA merge boundary. If the device cannot merge any the DMA address +segments, the function returns 0. + Part Id - Streaming DMA mappings -------------------------------- |