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iommu/arm-smmu: Don't inadvertently reject multiple SMMUv3s

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We now delay installing our per-bus iommu_ops until we know an SMMU has
successfully probed, as they don't serve much purpose beforehand, and
doing so also avoids fights between multiple IOMMU drivers in a single
kernel. However, the upshot of passing the return value of bus_set_iommu()
back from our probe function is that if there happens to be more than
one SMMUv3 device in a system, the second and subsequent probes will
wind up returning -EBUSY to the driver core and getting torn down again.

Avoid re-setting ops if ours are already installed, so that any genuine
failures stand out.

Fixes: 08d4ca2a67 ("iommu/arm-smmu: Support non-PCI devices with SMMUv3")
CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
CC: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Robin Murphy 2016-11-03 17:39:07 +00:00 committed by Joerg Roedel
parent fba4f8e5c4
commit ec615f43d3
1 changed files with 17 additions and 8 deletions
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25
drivers/iommu/arm-smmu-v3.c
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@ -2636,17 +2636,26 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
/* And we're up. Go go go! */
of_iommu_set_ops(dev->of_node, &arm_smmu_ops);
#ifdef CONFIG_PCI
pci_request_acs();
ret = bus_set_iommu(&pci_bus_type, &arm_smmu_ops);
if (ret)
return ret;
if (pci_bus_type.iommu_ops != &arm_smmu_ops) {
pci_request_acs();
ret = bus_set_iommu(&pci_bus_type, &arm_smmu_ops);
if (ret)
return ret;
}
#endif
#ifdef CONFIG_ARM_AMBA
ret = bus_set_iommu(&amba_bustype, &arm_smmu_ops);
if (ret)
return ret;
if (amba_bustype.iommu_ops != &arm_smmu_ops) {
ret = bus_set_iommu(&amba_bustype, &arm_smmu_ops);
if (ret)
return ret;
}
#endif
return bus_set_iommu(&platform_bus_type, &arm_smmu_ops);
if (platform_bus_type.iommu_ops != &arm_smmu_ops) {
ret = bus_set_iommu(&platform_bus_type, &arm_smmu_ops);
if (ret)
return ret;
}
return 0;
}
static int arm_smmu_device_remove(struct platform_device *pdev)