When the IOMMU is PCI-based, IORT doesn't know the fwnode until the
driver has had a chance to register it. In addition to deferring the
probe until the IOMMU ops are set, also defer the probe until the fwspec
is available.

Signed-off-by: Jean-Philippe Brucker <jean-phili...@linaro.org>
---
 drivers/acpi/iort.c | 54 ++++++++++++++++++++++++++-------------------
 1 file changed, 31 insertions(+), 23 deletions(-)

diff --git a/drivers/acpi/iort.c b/drivers/acpi/iort.c
index b517aa4e83ba..f08f72d8af78 100644
--- a/drivers/acpi/iort.c
+++ b/drivers/acpi/iort.c
@@ -61,6 +61,22 @@ static bool iort_type_matches(u8 type, enum 
iort_node_category category)
        }
 }
 
+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);
+       case ACPI_VIOT_IORT_NODE_VIRTIO_MMIO_IOMMU:
+       case ACPI_VIOT_IORT_NODE_VIRTIO_PCI_IOMMU:
+               return IS_ENABLED(CONFIG_VIRTIO_IOMMU);
+       default:
+               pr_warn("IORT node type %u does not describe an IOMMU\n", type);
+               return false;
+       }
+}
+
 /**
  * iort_set_fwnode() - Create iort_fwnode and use it to register
  *                    iommu data in the iort_fwnode_list
@@ -102,9 +118,9 @@ static inline int iort_set_fwnode(struct acpi_iort_node 
*iort_node,
  *
  * Returns: fwnode_handle pointer on success, NULL on failure
  */
-static inline struct fwnode_handle *iort_get_fwnode(
-                       struct acpi_iort_node *node)
+static inline struct fwnode_handle *iort_get_fwnode(struct acpi_iort_node 
*node)
 {
+       int err = -ENODEV;
        struct iort_fwnode *curr;
        struct fwnode_handle *fwnode = NULL;
 
@@ -112,12 +128,20 @@ static inline struct fwnode_handle *iort_get_fwnode(
        list_for_each_entry(curr, &iort_fwnode_list, list) {
                if (curr->iort_node == node) {
                        fwnode = curr->fwnode;
+                       if (!fwnode && curr->pci_devid) {
+                               /*
+                                * Postpone probe until virtio-iommu has
+                                * registered its fwnode.
+                                */
+                               err = iort_iommu_driver_enabled(node->type) ?
+                                       -EPROBE_DEFER : -ENODEV;
+                       }
                        break;
                }
        }
        spin_unlock(&iort_fwnode_lock);
 
-       return fwnode;
+       return fwnode ?: ERR_PTR(err);
 }
 
 /**
@@ -874,22 +898,6 @@ int iort_iommu_msi_get_resv_regions(struct device *dev, 
struct list_head *head)
        return (resv == its->its_count) ? resv : -ENODEV;
 }
 
-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);
-       case ACPI_VIOT_IORT_NODE_VIRTIO_MMIO_IOMMU:
-       case ACPI_VIOT_IORT_NODE_VIRTIO_PCI_IOMMU:
-               return IS_ENABLED(CONFIG_VIRTIO_IOMMU);
-       default:
-               pr_warn("IORT node type %u does not describe an IOMMU\n", type);
-               return false;
-       }
-}
-
 static int arm_smmu_iort_xlate(struct device *dev, u32 streamid,
                               struct fwnode_handle *fwnode,
                               const struct iommu_ops *ops)
@@ -920,8 +928,8 @@ static int iort_iommu_xlate(struct device *dev, struct 
acpi_iort_node *node,
                return -ENODEV;
 
        iort_fwnode = iort_get_fwnode(node);
-       if (!iort_fwnode)
-               return -ENODEV;
+       if (IS_ERR(iort_fwnode))
+               return PTR_ERR(iort_fwnode);
 
        /*
         * If the ops look-up fails, this means that either
@@ -1618,8 +1626,8 @@ static int __init iort_add_platform_device(struct 
acpi_iort_node *node,
 
        fwnode = iort_get_fwnode(node);
 
-       if (!fwnode) {
-               ret = -ENODEV;
+       if (IS_ERR(fwnode)) {
+               ret = PTR_ERR(fwnode);
                goto dev_put;
        }
 
-- 
2.24.0

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