On 26/07/2019 09:31, Yoshihiro Shimoda wrote:
This patch adds a new dma_map_ops of get_merge_boundary() to expose the DMA merge boundary if the domain type is IOMMU_DOMAIN_DMA.Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda...@renesas.com> Reviewed-by: Simon Horman <horms+rene...@verge.net.au> --- drivers/iommu/dma-iommu.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index a7f9c3e..2992ce4 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1085,6 +1085,16 @@ static int iommu_dma_get_sgtable(struct device *dev, struct sg_table *sgt, return ret; }+static unsigned long iommu_dma_get_merge_boundary(struct device *dev)+{ + struct iommu_domain *domain = iommu_get_dma_domain(dev); + + if (domain->type != IOMMU_DOMAIN_DMA)
Did you actually need this check? In principle, if the default domain is not of type IOMMU_DOMAIN_DMA then the device should be assigned dma_direct_ops rather than iommu_dma_ops, thus it shouldn't be possible to get here. If you did manage to hit a case where the domain type didn't match the ops it would be interesting to figure out how.
Robin.
+ return 0; /* can't merge */ + + return (1UL << __ffs(domain->pgsize_bitmap)) - 1; +} + static const struct dma_map_ops iommu_dma_ops = { .alloc = iommu_dma_alloc, .free = iommu_dma_free, @@ -1100,6 +1110,7 @@ static const struct dma_map_ops iommu_dma_ops = { .sync_sg_for_device = iommu_dma_sync_sg_for_device, .map_resource = iommu_dma_map_resource, .unmap_resource = iommu_dma_unmap_resource, + .get_merge_boundary = iommu_dma_get_merge_boundary, };/*
