Re: [PATCH v4 2/3] iommu/tegra-smmu: Rework tegra_smmu_probe_device()

Dmitry Osipenko
2020-10-02T16:37:19Z

02.10.2020 19:00, Dmitry Osipenko пишет:
> 02.10.2020 18:23, Dmitry Osipenko пишет:
>> 02.10.2020 09:08, Nicolin Chen пишет:
>>> Then when a client gets probed, of_iommu_configure() in
>>> iommu core will search DTB for swgroup ID and call ->of_xlate()
>>> to prepare an fwspec, similar to tegra_smmu_probe_device() and
>>> tegra_smmu_configure(). Then it'll call tegra_smmu_probe_device()
>>> again, and this time we shall return smmu->iommu pointer properly.
>>
>> I don't quite see where IOMMU core calls of_xlate().
>>
>> Have tried to at least boot-test this patch?
>>
>
> I don't see how it ever could work because of_xlate() is only invoked from:
>
> fsl_mc_dma_configure()->of_dma_configure_id()->of_iommu_configure()
>
> Looks like the tegra_smmu_configure() is still needed.
>
> I don't know how sun50i driver could work to be honest. Seems IOMMU is
> broken on sun50i, but maybe I'm missing something.
>
> I added Maxime Ripard to this thread, who is the author of the
> sun50i-iommu driver.
>

Actually, I now see that the other IOMMU drivers (qcom, exynos, etc) do
the same. So obviously I'm missing something and it should work..