Merge tag 'docs-4.12-2' of git://git.lwn.net/linux

[sfrench/cifs-2.6.git] / drivers / acpi / arm64 / iort.c

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 22e08d272db7f66969d37744bcc56cb70b10f4f2..c5fecf97ee2f52bd11188a0cd2295bd82d5d02db 100644 (file)
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -618,6 +618,46 @@ static int arm_smmu_iort_xlate(struct device *dev, u32 streamid,
        return ret;
 }
 
+static inline bool iort_iommu_driver_enabled(u8 type)
+{
+       switch (type) {
+       case ACPI_IORT_NODE_SMMU_V3:
+               return IS_BUILTIN(CONFIG_ARM_SMMU_V3);
+       case ACPI_IORT_NODE_SMMU:
+               return IS_BUILTIN(CONFIG_ARM_SMMU);
+       default:
+               pr_warn("IORT node type %u does not describe an SMMU\n", type);
+               return false;
+       }
+}
+
+#ifdef CONFIG_IOMMU_API
+static inline
+const struct iommu_ops *iort_fwspec_iommu_ops(struct iommu_fwspec *fwspec)
+{
+       return (fwspec && fwspec->ops) ? fwspec->ops : NULL;
+}
+
+static inline
+int iort_add_device_replay(const struct iommu_ops *ops, struct device *dev)
+{
+       int err = 0;
+
+       if (!IS_ERR_OR_NULL(ops) && ops->add_device && dev->bus &&
+           !dev->iommu_group)
+               err = ops->add_device(dev);
+
+       return err;
+}
+#else
+static inline
+const struct iommu_ops *iort_fwspec_iommu_ops(struct iommu_fwspec *fwspec)
+{ return NULL; }
+static inline
+int iort_add_device_replay(const struct iommu_ops *ops, struct device *dev)
+{ return 0; }
+#endif
+
 static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
                                        struct acpi_iort_node *node,
                                        u32 streamid)
@@ -626,14 +666,31 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
        int ret = -ENODEV;
        struct fwnode_handle *iort_fwnode;
 
+       /*
+        * If we already translated the fwspec there
+        * is nothing left to do, return the iommu_ops.
+        */
+       ops = iort_fwspec_iommu_ops(dev->iommu_fwspec);
+       if (ops)
+               return ops;
+
        if (node) {
                iort_fwnode = iort_get_fwnode(node);
                if (!iort_fwnode)
                        return NULL;
 
                ops = iommu_ops_from_fwnode(iort_fwnode);
+               /*
+                * If the ops look-up fails, this means that either
+                * the SMMU drivers have not been probed yet or that
+                * the SMMU drivers are not built in the kernel;
+                * Depending on whether the SMMU drivers are built-in
+                * in the kernel or not, defer the IOMMU configuration
+                * or just abort it.
+                */
                if (!ops)
-                       return NULL;
+                       return iort_iommu_driver_enabled(node->type) ?
+                              ERR_PTR(-EPROBE_DEFER) : NULL;
 
                ret = arm_smmu_iort_xlate(dev, streamid, iort_fwnode, ops);
        }
@@ -676,6 +733,7 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev)
        struct acpi_iort_node *node, *parent;
        const struct iommu_ops *ops = NULL;
        u32 streamid = 0;
+       int err;
 
        if (dev_is_pci(dev)) {
                struct pci_bus *bus = to_pci_dev(dev)->bus;
@@ -707,6 +765,8 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev)
 
                while (parent) {
                        ops = iort_iommu_xlate(dev, parent, streamid);
+                       if (IS_ERR_OR_NULL(ops))
+                               return ops;
 
                        parent = iort_node_map_platform_id(node, &streamid,
                                                           IORT_IOMMU_TYPE,
@@ -714,6 +774,14 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev)
                }
        }
 
+       /*
+        * If we have reason to believe the IOMMU driver missed the initial
+        * add_device callback for dev, replay it to get things in order.
+        */
+       err = iort_add_device_replay(ops, dev);
+       if (err)
+               ops = ERR_PTR(err);
+
        return ops;
 }
 
@@ -1052,6 +1120,4 @@ void __init acpi_iort_init(void)
        }
 
        iort_init_platform_devices();
-
-       acpi_probe_device_table(iort);
 }