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Lorenzo Pieralisi authored
Current bus notifier in ARM64 (__iommu_attach_notifier) attempts to attach dma_ops to a device on BUS_NOTIFY_ADD_DEVICE action notification. This will cause issues on ACPI based systems, where PCI devices can be added before the IOMMUs the devices are attached to had a chance to be probed, causing failures on attempts to attach dma_ops in that the domain for the respective IOMMU may not be set-up yet by the time the bus notifier is run. Devices dma_ops do not require to be set-up till the matching device drivers are probed. This means that instead of running the notifier attaching dma_ops to devices (__iommu_attach_notifier) on BUS_NOTIFY_ADD_DEVICE action, it can be run just before the device driver is bound to the device in question (on action BUS_NOTIFY_BIND_DRIVER) so that it is certain that its IOMMU group and domain are set-up accordingly at the time the notifier is triggered. This patch changes the notifier action upon which dma_ops are attached to devices and defer it to driver binding time, so that IOMMU devices have a chance to be probed and to register their bus notifiers before the dma_ops attach sequence for a device is actually carried out. As a result we also no longer need worry about racing with iommu_bus_notifier(), or about retrying the queue in case devices were added too early on DT-based systems, so clean up the notifier itself plus the additional workaround from 722ec35f ("arm64: dma-mapping: fix handling of devices registered before arch_initcall") Acked-by:
Will Deacon <will.deacon@arm.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by:
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> [rm: get rid of other now-redundant bits] Signed-off-by:
Robin Murphy <robin.murphy@arm.com> Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com>
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