iommu/of: Fix of_iommu_configure() for disabled IOMMUs

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Sudeep reports that the logic got slightly broken when a PCI iommu-map
entry targets an IOMMU marked as disabled in DT, since of_pci_map_rid()
succeeds in following a phandle, and of_iommu_xlate() doesn't return an
error value, but we miss checking whether ops was actually non-NULL.
Whilst this could be solved with a point fix in of_pci_iommu_init(), it
suggests that all the juggling of ERR_PTR values through the ops pointer
is proving rather too complicated for its own good, so let's instead
simplify the whole flow (with a side-effect of eliminating the cause of
the bug).

The fact that we now rely on iommu_fwspec means that we no longer need
to pass around an iommu_ops pointer at all - we can simply propagate a
regular int return value until we know whether we have a viable IOMMU,
then retrieve the ops from the fwspec if and when we actually need them.
This makes everything a bit more uniform and certainly easier to follow.

Fixes: d87beb7492 ("iommu/of: Handle PCI aliases properly")
Reported-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

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Robin Murphy 2017-08-04 17:29:06 +01:00 • committed by Joerg Roedel

parent 05f80300dc

commit da4b02750a

1 changed files with 29 additions and 30 deletions

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drivers/iommu/of_iommu.c

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