[PATCH v6 11/25] iommu/tegra-smmu: Implement an IDENTITY domain

Jason Gunthorpe
2023-08-03T00:09:23Z

What tegra-smmu does during tegra_smmu_set_platform_dma() is actually
putting the iommu into identity mode.

Move to the new core support for ARM_DMA_USE_IOMMU by defining
ops->identity_domain.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
drivers/iommu/tegra-smmu.c | 37 ++++++++++++++++++++++++++++++++-----
1 file changed, 32 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 1cbf063ccf147a..f63f1d4f0bd10f 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -511,23 +511,39 @@ static int tegra_smmu_attach_dev(struct iommu_domain *domain,
return err;
}

-static void tegra_smmu_set_platform_dma(struct device *dev)
+static int tegra_smmu_identity_attach(struct iommu_domain *identity_domain,
+ struct device *dev)
{
struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
- struct tegra_smmu_as *as = to_smmu_as(domain);
- struct tegra_smmu *smmu = as->smmu;
+ struct tegra_smmu_as *as;
+ struct tegra_smmu *smmu;
unsigned int index;

if (!fwspec)
- return;
+ return -ENODEV;

+ if (domain == identity_domain || !domain)
+ return 0;
+
+ as = to_smmu_as(domain);
+ smmu = as->smmu;
for (index = 0; index < fwspec->num_ids; index++) {
tegra_smmu_disable(smmu, fwspec->ids[index], as->id);
tegra_smmu_as_unprepare(smmu, as);
}
+ return 0;
}

+static struct iommu_domain_ops tegra_smmu_identity_ops = {
+ .attach_dev = tegra_smmu_identity_attach,
+};
+
+static struct iommu_domain tegra_smmu_identity_domain = {
+ .type = IOMMU_DOMAIN_IDENTITY,
+ .ops = &tegra_smmu_identity_ops,
+};
+
static void tegra_smmu_set_pde(struct tegra_smmu_as *as, unsigned long iova,
u32 value)
{
@@ -962,11 +978,22 @@ static int tegra_smmu_of_xlate(struct device *dev,
return iommu_fwspec_add_ids(dev, &id, 1);
}

+static int tegra_smmu_def_domain_type(struct device *dev)
+{
+ /*
+ * FIXME: For now we want to run all translation in IDENTITY mode, due
+ * to some device quirks. Better would be to just quirk the troubled
+ * devices.
+ */
+ return IOMMU_DOMAIN_IDENTITY;
+}
+
static const struct iommu_ops tegra_smmu_ops = {
+ .identity_domain = &tegra_smmu_identity_domain,
+ .def_domain_type = &tegra_smmu_def_domain_type,
.domain_alloc = tegra_smmu_domain_alloc,
.probe_device = tegra_smmu_probe_device,
.device_group = tegra_smmu_device_group,
- .set_platform_dma_ops = tegra_smmu_set_platform_dma,
.of_xlate = tegra_smmu_of_xlate,
.pgsize_bitmap = SZ_4K,
.default_domain_ops = &(const struct iommu_domain_ops) {
--
2.41.0