[PATCH 06/18] ARM/dma-mapping: Support IOMMU default domains

Robin Murphy
2020-08-20T15:12:34Z

Now that iommu-dma is wired up, we can let it work as normal
without the dma_iommu_mapping hacks if the IOMMU driver already
supports default domains.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
arch/arm/mm/dma-mapping.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 0f69ede44cd7..2ef0afc17645 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1220,6 +1220,13 @@ static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
if (!iommu)
return false;

+ /* If a default domain exists, just let iommu-dma work normally */
+ if (iommu_get_domain_for_dev(dev)) {
+ iommu_setup_dma_ops(dev, dma_base, size);
+ return true;
+ }
+
+ /* Otherwise, use the workaround until the IOMMU driver is updated */
mapping = arm_iommu_create_mapping(dev->bus, dma_base, size);
if (IS_ERR(mapping)) {
pr_warn("Failed to create %llu-byte IOMMU mapping for device %s\n",
@@ -1234,6 +1241,7 @@ static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
return false;
}

+ set_dma_ops(dev, &iommu_dma_ops);
return true;
}

@@ -1263,8 +1271,6 @@ static void arm_teardown_iommu_dma_ops(struct device *dev) { }
void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
const struct iommu_ops *iommu, bool coherent)
{
- const struct dma_map_ops *dma_ops;
-
dev->archdata.dma_coherent = coherent;
#ifdef CONFIG_SWIOTLB
dev->dma_coherent = coherent;
@@ -1278,12 +1284,9 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
if (dev->dma_ops)
return;

- if (arm_setup_iommu_dma_ops(dev, dma_base, size, iommu))
- dma_ops = &iommu_dma_ops;
- else
- dma_ops = arm_get_dma_map_ops(coherent);
+ set_dma_ops(dev, arm_get_dma_map_ops(coherent));

- set_dma_ops(dev, dma_ops);
+ arm_setup_iommu_dma_ops(dev, dma_base, size, iommu);

#ifdef CONFIG_XEN
if (xen_initial_domain())
--
2.28.0.dirty