ACPI/IORT: Introduce iort_iommu_configure

DT based systems have a generic kernel API to configure IOMMUs
for devices (ie of_iommu_configure()).

On ARM based ACPI systems, the of_iommu_configure() equivalent can
be implemented atop ACPI IORT kernel API, with the corresponding
functions to map device identifiers to IOMMUs and retrieve the
corresponding IOMMU operations necessary for DMA operations set-up.

By relying on the iommu_fwspec generic kernel infrastructure,
implement the IORT based IOMMU configuration for ARM ACPI systems
and hook it up in the ACPI kernel layer that implements DMA
configuration for a device.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> [ACPI core]
Reviewed-by: Tomasz Nowicki <tn@semihalf.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Tomasz Nowicki <tn@semihalf.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Tomasz Nowicki <tn@semihalf.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 98 insertions, 0 deletions

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 6aae49c35a95..47bace8eafb6 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -28,6 +28,8 @@
 
 #define IORT_TYPE_MASK(type)    (1 << (type))
 #define IORT_MSI_TYPE           (1 << ACPI_IORT_NODE_ITS_GROUP)
+#define IORT_IOMMU_TYPE         ((1 << ACPI_IORT_NODE_SMMU) |   \
+                                (1 << ACPI_IORT_NODE_SMMU_V3))
 
 struct iort_its_msi_chip {
         struct list_head        list;
@@ -501,6 +503,102 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id)
         return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI);
 }
 
+static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
+{
+        u32 *rid = data;
+
+        *rid = alias;
+        return 0;
+}
+
+static int arm_smmu_iort_xlate(struct device *dev, u32 streamid,
+                               struct fwnode_handle *fwnode,
+                               const struct iommu_ops *ops)
+{
+        int ret = iommu_fwspec_init(dev, fwnode, ops);
+
+        if (!ret)
+                ret = iommu_fwspec_add_ids(dev, &streamid, 1);
+
+        return ret;
+}
+
+static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
+                                        struct acpi_iort_node *node,
+                                        u32 streamid)
+{
+        const struct iommu_ops *ops = NULL;
+        int ret = -ENODEV;
+        struct fwnode_handle *iort_fwnode;
+
+        if (node) {
+                iort_fwnode = iort_get_fwnode(node);
+                if (!iort_fwnode)
+                        return NULL;
+
+                ops = iommu_get_instance(iort_fwnode);
+                if (!ops)
+                        return NULL;
+
+                ret = arm_smmu_iort_xlate(dev, streamid, iort_fwnode, ops);
+        }
+
+        return ret ? NULL : ops;
+}
+
+/**
+ * iort_iommu_configure - Set-up IOMMU configuration for a device.
+ *
+ * @dev: device to configure
+ *
+ * Returns: iommu_ops pointer on configuration success
+ *          NULL on configuration failure
+ */
+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;
+
+        if (dev_is_pci(dev)) {
+                struct pci_bus *bus = to_pci_dev(dev)->bus;
+                u32 rid;
+
+                pci_for_each_dma_alias(to_pci_dev(dev), __get_pci_rid,
+                                       &rid);
+
+                node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
+                                      iort_match_node_callback, &bus->dev);
+                if (!node)
+                        return NULL;
+
+                parent = iort_node_map_rid(node, rid, &streamid,
+                                           IORT_IOMMU_TYPE);
+
+                ops = iort_iommu_xlate(dev, parent, streamid);
+
+        } else {
+                int i = 0;
+
+                node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
+                                      iort_match_node_callback, dev);
+                if (!node)
+                        return NULL;
+
+                parent = iort_node_get_id(node, &streamid,
+                                          IORT_IOMMU_TYPE, i++);
+
+                while (parent) {
+                        ops = iort_iommu_xlate(dev, parent, streamid);
+
+                        parent = iort_node_get_id(node, &streamid,
+                                                  IORT_IOMMU_TYPE, i++);
+                }
+        }
+
+        return ops;
+}
+
 static void __init acpi_iort_register_irq(int hwirq, const char *name,
                                           int trigger,
                                           struct resource *res)