Merge branch 'for-next/iommu/tegra-smmu' into for-next/iommu/core

Tegra SMMU updates for 5.11: a complete redesign of the probing logic,
support for PCI devices and cleanup work.

* for-next/iommu/tegra-smmu:
  iommu/tegra-smmu: Add PCI support
  iommu/tegra-smmu: Rework tegra_smmu_probe_device()
  iommu/tegra-smmu: Use fwspec in tegra_smmu_(de)attach_dev
  iommu/tegra-smmu: Expand mutex protection range
  iommu/tegra-smmu: Unwrap tegra_smmu_group_get

1 files changed, 88 insertions, 152 deletions

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 0becdbfea306..4a3f095a1c26 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/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>
@@ -256,26 +257,19 @@ static int tegra_smmu_alloc_asid(struct tegra_smmu *smmu, unsigned int *idp)
 {
 	unsigned long id;
 
-	mutex_lock(&smmu->lock);
-
 	id = find_first_zero_bit(smmu->asids, smmu->soc->num_asids);
-	if (id >= smmu->soc->num_asids) {
-		mutex_unlock(&smmu->lock);
+	if (id >= smmu->soc->num_asids)
 		return -ENOSPC;
-	}
 
 	set_bit(id, smmu->asids);
 	*idp = id;
 
-	mutex_unlock(&smmu->lock);
 	return 0;
 }
 
 static void tegra_smmu_free_asid(struct tegra_smmu *smmu, unsigned int id)
 {
-	mutex_lock(&smmu->lock);
 	clear_bit(id, smmu->asids);
-	mutex_unlock(&smmu->lock);
 }
 
 static bool tegra_smmu_capable(enum iommu_cap cap)
@@ -420,17 +414,21 @@ static int tegra_smmu_as_prepare(struct tegra_smmu *smmu,
 				 struct tegra_smmu_as *as)
 {
 	u32 value;
-	int err;
+	int err = 0;
+
+	mutex_lock(&smmu->lock);
 
 	if (as->use_count > 0) {
 		as->use_count++;
-		return 0;
+		goto unlock;
 	}
 
 	as->pd_dma = dma_map_page(smmu->dev, as->pd, 0, SMMU_SIZE_PD,
 				  DMA_TO_DEVICE);
-	if (dma_mapping_error(smmu->dev, as->pd_dma))
-		return -ENOMEM;
+	if (dma_mapping_error(smmu->dev, as->pd_dma)) {
+		err = -ENOMEM;
+		goto unlock;
+	}
 
 	/* We can't handle 64-bit DMA addresses */
 	if (!smmu_dma_addr_valid(smmu, as->pd_dma)) {
@@ -453,83 +451,84 @@ static int tegra_smmu_as_prepare(struct tegra_smmu *smmu,
 	as->smmu = smmu;
 	as->use_count++;
 
+	mutex_unlock(&smmu->lock);
+
 	return 0;
 
 err_unmap:
 	dma_unmap_page(smmu->dev, as->pd_dma, SMMU_SIZE_PD, DMA_TO_DEVICE);
+unlock:
+	mutex_unlock(&smmu->lock);
+
 	return err;
 }
 
 static void tegra_smmu_as_unprepare(struct tegra_smmu *smmu,
 				    struct tegra_smmu_as *as)
 {
-	if (--as->use_count > 0)
+	mutex_lock(&smmu->lock);
+
+	if (--as->use_count > 0) {
+		mutex_unlock(&smmu->lock);
 		return;
+	}
 
 	tegra_smmu_free_asid(smmu, as->id);
 
 	dma_unmap_page(smmu->dev, as->pd_dma, SMMU_SIZE_PD, DMA_TO_DEVICE);
 
 	as->smmu = NULL;
+
+	mutex_unlock(&smmu->lock);
 }
 
 static int tegra_smmu_attach_dev(struct iommu_domain *domain,
 				 struct device *dev)
 {
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
 	struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
 	struct tegra_smmu_as *as = to_smmu_as(domain);
-	struct device_node *np = dev->of_node;
-	struct of_phandle_args args;
-	unsigned int index = 0;
-	int err = 0;
-
-	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
-					   &args)) {
-		unsigned int swgroup = args.args[0];
-
-		if (args.np != smmu->dev->of_node) {
-			of_node_put(args.np);
-			continue;
-		}
+	unsigned int index;
+	int err;
 
-		of_node_put(args.np);
+	if (!fwspec)
+		return -ENOENT;
 
+	for (index = 0; index < fwspec->num_ids; index++) {
 		err = tegra_smmu_as_prepare(smmu, as);
-		if (err < 0)
-			return err;
+		if (err)
+			goto disable;
 
-		tegra_smmu_enable(smmu, swgroup, as->id);
-		index++;
+		tegra_smmu_enable(smmu, fwspec->ids[index], as->id);
 	}
 
 	if (index == 0)
 		return -ENODEV;
 
 	return 0;
+
+disable:
+	while (index--) {
+		tegra_smmu_disable(smmu, fwspec->ids[index], as->id);
+		tegra_smmu_as_unprepare(smmu, as);
+	}
+
+	return err;
 }
 
 static void tegra_smmu_detach_dev(struct iommu_domain *domain, struct device *dev)
 {
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
 	struct tegra_smmu_as *as = to_smmu_as(domain);
-	struct device_node *np = dev->of_node;
 	struct tegra_smmu *smmu = as->smmu;
-	struct of_phandle_args args;
-	unsigned int index = 0;
-
-	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
-					   &args)) {
-		unsigned int swgroup = args.args[0];
-
-		if (args.np != smmu->dev->of_node) {
-			of_node_put(args.np);
-			continue;
-		}
+	unsigned int index;
 
-		of_node_put(args.np);
+	if (!fwspec)
+		return;
 
-		tegra_smmu_disable(smmu, swgroup, as->id);
+	for (index = 0; index < fwspec->num_ids; index++) {
+		tegra_smmu_disable(smmu, fwspec->ids[index], as->id);
 		tegra_smmu_as_unprepare(smmu, as);
-		index++;
 	}
 }
 
@@ -799,75 +798,9 @@ static phys_addr_t tegra_smmu_iova_to_phys(struct iommu_domain *domain,
 	return SMMU_PFN_PHYS(pfn) + SMMU_OFFSET_IN_PAGE(iova);
 }
 
-static struct tegra_smmu *tegra_smmu_find(struct device_node *np)
-{
-	struct platform_device *pdev;
-	struct tegra_mc *mc;
-
-	pdev = of_find_device_by_node(np);
-	if (!pdev)
-		return NULL;
-
-	mc = platform_get_drvdata(pdev);
-	if (!mc)
-		return NULL;
-
-	return mc->smmu;
-}
-
-static int tegra_smmu_configure(struct tegra_smmu *smmu, struct device *dev,
-				struct of_phandle_args *args)
-{
-	const struct iommu_ops *ops = smmu->iommu.ops;
-	int err;
-
-	err = iommu_fwspec_init(dev, &dev->of_node->fwnode, ops);
-	if (err < 0) {
-		dev_err(dev, "failed to initialize fwspec: %d\n", err);
-		return err;
-	}
-
-	err = ops->of_xlate(dev, args);
-	if (err < 0) {
-		dev_err(dev, "failed to parse SW group ID: %d\n", err);
-		iommu_fwspec_free(dev);
-		return err;
-	}
-
-	return 0;
-}
-
 static struct iommu_device *tegra_smmu_probe_device(struct device *dev)
 {
-	struct device_node *np = dev->of_node;
-	struct tegra_smmu *smmu = NULL;
-	struct of_phandle_args args;
-	unsigned int index = 0;
-	int err;
-
-	while (of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
-					  &args) == 0) {
-		smmu = tegra_smmu_find(args.np);
-		if (smmu) {
-			err = tegra_smmu_configure(smmu, dev, &args);
-			of_node_put(args.np);
-
-			if (err < 0)
-				return ERR_PTR(err);
-
-			/*
-			 * Only a single IOMMU master interface is currently
-			 * supported by the Linux kernel, so abort after the
-			 * first match.
-			 */
-			dev_iommu_priv_set(dev, smmu);
-
-			break;
-		}
-
-		of_node_put(args.np);
-		index++;
-	}
+	struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
 
 	if (!smmu)
 		return ERR_PTR(-ENODEV);
@@ -875,10 +808,7 @@ static struct iommu_device *tegra_smmu_probe_device(struct device *dev)
 	return &smmu->iommu;
 }
 
-static void tegra_smmu_release_device(struct device *dev)
-{
-	dev_iommu_priv_set(dev, NULL);
-}
+static void tegra_smmu_release_device(struct device *dev) {}
 
 static const struct tegra_smmu_group_soc *
 tegra_smmu_find_group(struct tegra_smmu *smmu, unsigned int swgroup)
@@ -903,10 +833,12 @@ static void tegra_smmu_group_release(void *iommu_data)
 	mutex_unlock(&smmu->lock);
 }
 
-static struct iommu_group *tegra_smmu_group_get(struct tegra_smmu *smmu,
-						unsigned int swgroup)
+static struct iommu_group *tegra_smmu_device_group(struct device *dev)
 {
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+	struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
 	const struct tegra_smmu_group_soc *soc;
+	unsigned int swgroup = fwspec->ids[0];
 	struct tegra_smmu_group *group;
 	struct iommu_group *grp;
 
@@ -934,7 +866,11 @@ static struct iommu_group *tegra_smmu_group_get(struct tegra_smmu *smmu,
 	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);
@@ -950,24 +886,24 @@ static struct iommu_group *tegra_smmu_group_get(struct tegra_smmu *smmu,
 	return group->group;
 }
 
-static struct iommu_group *tegra_smmu_device_group(struct device *dev)
-{
-	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
-	struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
-	struct iommu_group *group;
-
-	group = tegra_smmu_group_get(smmu, fwspec->ids[0]);
-	if (!group)
-		group = generic_device_group(dev);
-
-	return group;
-}
-
 static int tegra_smmu_of_xlate(struct device *dev,
 			       struct of_phandle_args *args)
 {
+	struct platform_device *iommu_pdev = of_find_device_by_node(args->np);
+	struct tegra_mc *mc = platform_get_drvdata(iommu_pdev);
 	u32 id = args->args[0];
 
+	/*
+	 * Note: we are here releasing the reference of &iommu_pdev->dev, which
+	 * is mc->dev. Although some functions in tegra_smmu_ops may keep using
+	 * its private data beyond this point, it's still safe to do so because
+	 * the SMMU parent device is the same as the MC, so the reference count
+	 * isn't strictly necessary.
+	 */
+	put_device(&iommu_pdev->dev);
+
+	dev_iommu_priv_set(dev, mc->smmu);
+
 	return iommu_fwspec_add_ids(dev, &id, 1);
 }
 
@@ -1092,16 +1028,6 @@ struct tegra_smmu *tegra_smmu_probe(struct device *dev,
 	if (!smmu)
 		return ERR_PTR(-ENOMEM);
 
-	/*
-	 * This is a bit of a hack. Ideally we'd want to simply return this
-	 * value. However the IOMMU registration process will attempt to add
-	 * all devices to the IOMMU when bus_set_iommu() is called. In order
-	 * not to rely on global variables to track the IOMMU instance, we
-	 * set it here so that it can be looked up from the .probe_device()
-	 * callback via the IOMMU device's .drvdata field.
-	 */
-	mc->smmu = smmu;
-
 	size = BITS_TO_LONGS(soc->num_asids) * sizeof(long);
 
 	smmu->asids = devm_kzalloc(dev, size, GFP_KERNEL);
@@ -1154,22 +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)