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

[Will Deacon]

On Fri, Jul 12, 2024 at 12:48:31PM +0100, Robin Murphy wrote:
> On 2024-07-12 12:01 pm, Jon Hunter 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 :(

Ha, so it is!

> 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.

Jon -- any chance you could give this fix a go, please? I'm hesitant to
drop the whole branch just for this, but we've basically run out of time
for 6.11 and so knowing we have a working fix would be really helpful.

Cheers,

Will