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.uh@xxxxxxxxxxx>
Reviewed-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
---
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,
};
/*
