[PATCH v6 12/25] iommu/tegra-smmu: Support DMA domains in tegra

Jason Gunthorpe
2023-08-03T00:10:09Z

All ARM64 iommu drivers should support IOMMU_DOMAIN_DMA to enable
dma-iommu.c.

tegra is blocking dma-iommu usage, and also default_domain's, because it
wants an identity translation. This is needed for some device quirk. The
correct way to do this is to support IDENTITY domains and use
ops->def_domain_type() to return IOMMU_DOMAIN_IDENTITY for only the quirky
devices.

Add support for IOMMU_DOMAIN_DMA and force IOMMU_DOMAIN_IDENTITY mode for
everything so no behavior changes.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
drivers/iommu/tegra-smmu.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index f63f1d4f0bd10f..6cba034905edbf 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -276,7 +276,7 @@ static struct iommu_domain *tegra_smmu_domain_alloc(unsigned type)
{
struct tegra_smmu_as *as;

- if (type != IOMMU_DOMAIN_UNMANAGED)
+ if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)
return NULL;

as = kzalloc(sizeof(*as), GFP_KERNEL);
@@ -989,6 +989,12 @@ static int tegra_smmu_def_domain_type(struct device *dev)
}

static const struct iommu_ops tegra_smmu_ops = {
+ /*
+ * FIXME: For now we want to run all translation in IDENTITY mode,
+ * better would be to have a def_domain_type op do this for just the
+ * quirky device.
+ */
+ .default_domain = &tegra_smmu_identity_domain,
.identity_domain = &tegra_smmu_identity_domain,
.def_domain_type = &tegra_smmu_def_domain_type,
.domain_alloc = tegra_smmu_domain_alloc,
--
2.41.0