iommu/tegra-smmu: Implement an IDENTITY domain

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.

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/11-v8-81230027b2fa+9d-iommu_all_defdom_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index e445f80..80481e1 100644 (file)
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -511,23 +511,39 @@ disable:
        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) {