Now that we have a way to pick up the RID translation and target IOMMU,
hook up of_iommu_configure() to bring PCI devices into the of_xlate
mechanism and allow them IOMMU-backed DMA ops without the need for
driver-specific handling.
Reviewed-by: Will Deacon <will.dea...@arm.com>
Signed-off-by: Robin Murphy <robin.mur...@arm.com>
---
- Split PCI handling into a separate function
---
drivers/iommu/of_iommu.c | 46 +++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 41 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 57f23eaaa2f9..19e1e8f2f871 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -22,6 +22,7 @@
#include <linux/limits.h>
#include <linux/of.h>
#include <linux/of_iommu.h>
+#include <linux/of_pci.h>
#include <linux/slab.h>
static const struct of_device_id __iommu_of_table_sentinel
@@ -134,6 +135,45 @@ const struct iommu_ops *of_iommu_get_ops(struct
device_node *np)
return ops;
}
+static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
+{
+ struct of_phandle_args *iommu_spec = data;
+
+ iommu_spec->args[0] = alias;
+ return iommu_spec->np == pdev->bus->dev.of_node;
+}
+
+static const struct iommu_ops
+*of_pci_iommu_configure(struct pci_dev *pdev, struct device_node *bridge_np)
+{
+ const struct iommu_ops *ops;
+ struct of_phandle_args iommu_spec;
+
+ /*
+ * Start by tracing the RID alias down the PCI topology as
+ * far as the host bridge whose OF node we have...
+ * (we're not even attempting to handle multi-alias devices yet)
+ */
+ iommu_spec.args_count = 1;
+ iommu_spec.np = bridge_np;
+ pci_for_each_dma_alias(pdev, __get_pci_rid, &iommu_spec);
+ /*
+ * ...then find out what that becomes once it escapes the PCI
+ * bus into the system beyond, and which IOMMU it ends up at.
+ */
+ iommu_spec.np = NULL;
+ if (of_pci_map_rid(bridge_np, iommu_spec.args[0], "iommu-map",
+ "iommu-map-mask", &iommu_spec.np, iommu_spec.args))
+ return NULL;
+
+ ops = of_iommu_get_ops(iommu_spec.np);
+ if (!ops || !ops->of_xlate || ops->of_xlate(&pdev->dev, &iommu_spec))
+ ops = NULL;
+
+ of_node_put(iommu_spec.np);
+ return ops;
+}
+
const struct iommu_ops *of_iommu_configure(struct device *dev,
struct device_node *master_np)
{
@@ -142,12 +182,8 @@ const struct iommu_ops *of_iommu_configure(struct device
*dev,
const struct iommu_ops *ops = NULL;
int idx = 0;
- /*
- * We can't do much for PCI devices without knowing how
- * device IDs are wired up from the PCI bus to the IOMMU.
- */
if (dev_is_pci(dev))
- return NULL;
+ return of_pci_iommu_configure(to_pci_dev(dev), master_np);
/*
* We don't currently walk up the tree looking for a parent IOMMU.
--
2.8.1.dirty
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