RE: [PATCH V3 0/8] IOMMU probe deferral support

Sricharan
2016-10-17T06:58:01Z

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>From: Sricharan [mailto:sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org]
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>To: 'Marek Szyprowski' <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>; 'will.deacon-5wv7dgnIgG8@public.gmane.org' <will.deacon-5wv7dgnIgG8@public.gmane.org>; 'robin.murphy-5wv7dgnIgG8@public.gmane.org'
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>Subject: RE: [PATCH V3 0/8] IOMMU probe deferral support
>
>Hi Marek,
>
>>Hi Sricharan,
>>
>>
>>On 2016-10-04 19:03, Sricharan R wrote:
>>> Initial post from Laurent Pinchart[1]. This is
>>> series calls the dma ops configuration for the devices
>>> at a generic place so that it works for all busses.
>>> The dma_configure_ops for a device is now called during
>>> the device_attach callback just before the probe of the
>>> bus/driver is called. Similarly dma_deconfigure is called during
>>> device/driver_detach path.
>>>
>>>
>>> pci_bus_add_devices (platform/amba)(_device_create/driver_register)
>>> | |
>>> pci_bus_add_device (device_add/driver_register)
>>> | |
>>> device_attach device_initial_probe
>>> | |
>>> __device_attach_driver __device_attach_driver
>>> |
>>> driver_probe_device
>>> |
>>> really_probe
>>> |
>>> dma_configure
>>>
>>> Similarly on the device/driver_unregister path __device_release_driver is
>>> called which inturn calls dma_deconfigure.
>>>
>>> If the ACPI bus code follows the same, we can add acpi_dma_configure
>>> at the same place as of_dma_configure.
>>>
>>> This series is based on the recently merged Generic DT bindings for
>>> PCI IOMMUs and ARM SMMU from Robin Murphy robin.murphy-5wv7dgnIgG8@public.gmane.org [2]
>>>
>>> This time tested this with platform and pci device for probe deferral
>>> and reprobe on arm64 based platform. There is an issue on the cleanup
>>> path for arm64 though, where there is WARN_ON if the dma_ops is reset while
>>> device is attached to an domain in arch_teardown_dma_ops.
>>> But with iommu_groups created from the iommu driver, the device is always
>>> attached to a domain/default_domain. So so the WARN has to be removed/handled
>>> probably.
>>
>>Thanks for continuing work on this feature! Your can add my:
>>
>>Tested-by: Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
>>
Hi Will,Robin,Joerg,

I have tested the probe deferral for platform/pcie bus devices based on latest Generic bindings
series merged [1], for pci/arm-smmu.
It will good to know from you on whats the right way to take this forward ?

Regards,
Sricharan