On 14/06/16 15:45, Will Deacon wrote:
On Fri, Jun 03, 2016 at 06:15:39PM +0100, Robin Murphy wrote: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. CC: Rob Herring <robh+dt@xxxxxxxxxx> CC: Frank Rowand <frowand.list@xxxxxxxxx> Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx> --- v2: Skip disabled IOMMUs. drivers/iommu/of_iommu.c | 44 +++++++++++++++++++++++++++++++++++++------- 1 file changed, 37 insertions(+), 7 deletions(-) diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c index 662f9a600f4f..5716131199b3 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 @@ -134,20 +135,49 @@ 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; +} + const struct iommu_ops *of_iommu_configure(struct device *dev, struct device_node *master_np) { struct of_phandle_args iommu_spec; - struct device_node *np; + struct device_node *np = NULL; const struct iommu_ops *ops = NULL; int idx; - /* - * 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; + if (dev_is_pci(dev)) { + /* + * Start by tracing the RID alias down the PCI topology as + * far as the host bridge whose OF node we have... + */ + iommu_spec.np = master_np; + pci_for_each_dma_alias(to_pci_dev(dev), __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. + */ + if (of_pci_map_rid(master_np, "iommu-map", iommu_spec.args[0], + &np, iommu_spec.args) || + !of_device_is_available(np)) + return NULL;Hmm, do we need to of_node_put(np) in the case that it's not available?
Ah yes, now I see; I moved the put into the loop iteration for the non-PCI case so that a "continue" does the job, but I've not handled the equivalent here.
Robin.
Will
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