From b996444cf35e736621855e73f9d0762bd49f41f2 Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Mon, 12 Sep 2016 17:13:41 +0100 Subject: [PATCH] iommu/of: Handle iommu-map property for PCI 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 Signed-off-by: Robin Murphy Signed-off-by: Will Deacon --- 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 #include #include +#include #include 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. -- 2.20.1