iommu/tegra-smmu: Add PCI support

This patch simply adds support for PCI devices.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20201125101013.14953-6-nicoleotsuka@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/tegra-smmu.c

@@ -10,6 +10,7 @@
 #include <linux/kernel.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -865,7 +866,11 @@ static struct iommu_group *tegra_smmu_device_group(struct device *dev)
 	group->smmu = smmu;
 	group->soc = soc;
 
-	group->group = iommu_group_alloc();
+	if (dev_is_pci(dev))
+		group->group = pci_device_group(dev);
+	else
+		group->group = generic_device_group(dev);
+
 	if (IS_ERR(group->group)) {
 		devm_kfree(smmu->dev, group);
 		mutex_unlock(&smmu->lock);
@@ -1075,22 +1080,32 @@ struct tegra_smmu *tegra_smmu_probe(struct device *dev,
 	iommu_device_set_fwnode(&smmu->iommu, dev->fwnode);
 
 	err = iommu_device_register(&smmu->iommu);
-	if (err) {
-		iommu_device_sysfs_remove(&smmu->iommu);
-		return ERR_PTR(err);
-	}
+	if (err)
+		goto remove_sysfs;
 
 	err = bus_set_iommu(&platform_bus_type, &tegra_smmu_ops);
-	if (err < 0) {
-		iommu_device_unregister(&smmu->iommu);
-		iommu_device_sysfs_remove(&smmu->iommu);
-		return ERR_PTR(err);
-	}
+	if (err < 0)
+		goto unregister;
+
+#ifdef CONFIG_PCI
+	err = bus_set_iommu(&pci_bus_type, &tegra_smmu_ops);
+	if (err < 0)
+		goto unset_platform_bus;
+#endif
 
 	if (IS_ENABLED(CONFIG_DEBUG_FS))
 		tegra_smmu_debugfs_init(smmu);
 
 	return smmu;
+
+unset_platform_bus: __maybe_unused;
+	bus_set_iommu(&platform_bus_type, NULL);
+unregister:
+	iommu_device_unregister(&smmu->iommu);
+remove_sysfs:
+	iommu_device_sysfs_remove(&smmu->iommu);
+
+	return ERR_PTR(err);
 }
 
 void tegra_smmu_remove(struct tegra_smmu *smmu)