From 6ba99411b858bd70bae966633561e698cd6de38c Mon Sep 17 00:00:00 2001 From: Yoshihiro Shimoda Date: Wed, 28 Aug 2019 21:35:40 +0900 Subject: 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 Reviewed-by: Simon Horman Signed-off-by: Christoph Hellwig --- kernel/dma/mapping.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'kernel/dma') diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 1b96616c9f20..72c825c1788e 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -407,3 +407,14 @@ size_t dma_max_mapping_size(struct device *dev) return size; } EXPORT_SYMBOL_GPL(dma_max_mapping_size); + +unsigned long dma_get_merge_boundary(struct device *dev) +{ + const struct dma_map_ops *ops = get_dma_ops(dev); + + if (!ops || !ops->get_merge_boundary) + return 0; /* can't merge */ + + return ops->get_merge_boundary(dev); +} +EXPORT_SYMBOL_GPL(dma_get_merge_boundary); -- cgit v1.2.3