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Commit b996444c authored by Robin Murphy's avatar Robin Murphy Committed by Will Deacon
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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: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 987068fc

drivers/iommu/of_iommu.c

+41 −5
Original line number Diff line number Diff line
@@ -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.