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iommu/arm-smmu: Make instance lookup robust

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Relying on the driver list was a cute idea for minimising the scope of
our SMMU device lookups, however it turns out to have a subtle flaw. The
SMMU device only gets added to that list after arm_smmu_device_probe()
returns success, so there's actually no way the iommu_device_register()
call from there could ever work as intended, even if it wasn't already
hampered by the fwspec setup not happening early enough.

Switch both arm_smmu_get_by_fwnode() implementations to use a platform
bus lookup instead, which *will* reliably work. Also make sure that we
don't register SMMUv2 instances until we've fully initialised them, to
avoid similar consequences of the lookup now finding a device with no
drvdata. Moving the error returns is also a perfect excuse to streamline
them with dev_err_probe() in the process.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/6d7ce1dc31873abdb75c895fb8bd2097cce098b4.1733406914.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Robin Murphy 2024-12-05 16:33:55 +00:00 committed by Will Deacon
parent 9b640ae7fb
commit 7d835134d4
2 changed files with 16 additions and 19 deletions
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4
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
View File

@ -3351,8 +3351,8 @@ static struct platform_driver arm_smmu_driver;
static
struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
{
struct device *dev = driver_find_device_by_fwnode(&arm_smmu_driver.driver,
fwnode);
struct device *dev = bus_find_device_by_fwnode(&platform_bus_type, fwnode);
put_device(dev);
return dev ? dev_get_drvdata(dev) : NULL;
}

31
drivers/iommu/arm/arm-smmu/arm-smmu.c
View File

@ -1411,8 +1411,8 @@ static bool arm_smmu_capable(struct device *dev, enum iommu_cap cap)
static
struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
{
struct device *dev = driver_find_device_by_fwnode(&arm_smmu_driver.driver,
fwnode);
struct device *dev = bus_find_device_by_fwnode(&platform_bus_type, fwnode);
put_device(dev);
return dev ? dev_get_drvdata(dev) : NULL;
}
@ -2227,21 +2227,6 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
i, irq);
}
err = iommu_device_sysfs_add(&smmu->iommu, smmu->dev, NULL,
"smmu.%pa", &smmu->ioaddr);
if (err) {
dev_err(dev, "Failed to register iommu in sysfs\n");
return err;
}
err = iommu_device_register(&smmu->iommu, &arm_smmu_ops,
using_legacy_binding ? NULL : dev);
if (err) {
dev_err(dev, "Failed to register iommu\n");
iommu_device_sysfs_remove(&smmu->iommu);
return err;
}
platform_set_drvdata(pdev, smmu);
/* Check for RMRs and install bypass SMRs if any */
@ -2250,6 +2235,18 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
arm_smmu_device_reset(smmu);
arm_smmu_test_smr_masks(smmu);
err = iommu_device_sysfs_add(&smmu->iommu, smmu->dev, NULL,
"smmu.%pa", &smmu->ioaddr);
if (err)
return dev_err_probe(dev, err, "Failed to register iommu in sysfs\n");
err = iommu_device_register(&smmu->iommu, &arm_smmu_ops,
using_legacy_binding ? NULL : dev);
if (err) {
iommu_device_sysfs_remove(&smmu->iommu);
return dev_err_probe(dev, err, "Failed to register iommu\n");
}
/*
* We want to avoid touching dev->power.lock in fastpaths unless
* it's really going to do something useful - pm_runtime_enabled()