Re: [PATCH v3 2/5] iommu: Resolve fwspec ops automatically

[Jon Hunter]

On 12/07/2024 12:48, Robin Murphy wrote:

...

> > I am seeing some failures on -next with some of our devices. Bisect is 
> > pointing to this commit. Looks like the host1x device is no longer 
> > probing successfully. I see the following ...
> >
> >   tegra-host1x 50000000.host1x: failed to initialize fwspec: -517
> >   nouveau 57000000.gpu: failed to initialize fwspec: -517
> >
> > The probe seems to be deferred forever. The above is seen on Tegra210 
> > but Tegra30 and Tegra194 are also having the same problem. 
> > Interestingly it is not all devices and so make me wonder if we are 
> > missing something on these devices? Let me know if you have any thoughts.
>
> Ugh, tegra-smmu has been doing a complete nonsense this whole time - on 
> closer inspection, it's passing the fwnode of the *client device* where 
> it should be that of the IOMMU device :(
>
> I *think* it should probably just be a case of:
>
> -    err = iommu_fwspec_init(dev, of_fwnode_handle(dev->of_node));
> +    err = iommu_fwspec_init(dev, of_fwnode_handle(smmu->dev->of_node));
>
> since smmu->dev appears to be the same one initially passed to 
> iommu_device_register(), so it at least ought to match and work, but the 
> SMMU device vs. MC device thing leaves me mildly wary of how correct it 
> might be overall.
>
> (Also now I'm wondering why I didn't just use dev_fwnode() there...)


Yes making that change in the tegra-smmu driver does fix it.

Thanks!
Jon

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