Re: [PATCH v7 2/4] mmc: sdhci-tegra: Add support to program MC stream ID

Thierry Reding
2022-10-17T14:11:35Z

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On Thu, Oct 13, 2022 at 03:43:18PM +0200, Ulf Hansson wrote:
> On Thu, 13 Oct 2022 at 08:33, Prathamesh Shete <pshete@nvidia.com> wrote:
> >
> > Hi Ulf,
> >
> > >> In that case, perhaps we can add a "depends on IOMMU_API" in the Kconfig
> > >> instead? Or is the tegra driver used on platforms where IOMMU_API could be
> > >> unset?
> > Yes it can/will work with IOMMU disabled so its not recommended to add a "depends on" condition in Kconfig.
>
> Alright, in that case it looks to me that there are two other options
> to move forward.
>
> 1) Add proper definitions of the struct iommu_fwspec in
> include/linux/iommu.h even when CONFIG_IOMMU_API is unset. In a way it
> seems a bit silly to me, to have the iommu stubs around, unless those
> can be used for cases like this, right!?

I recall that I had proposed a patch for this a long time ago:

https://lore.kernel.org/all/20191209120005.2254786-3-thierry.reding@gmail.com/

Given that Joerg had acked it at the time, I think the only reason why
it never ended up getting merged is because the rest of the series did
not get enough traction. I wonder if I should peel it out of the series
and propose it separately.

I agree it doesn't make any sense to have the stubs to allow compilation
and then break compilation because users of the stubs will end up
wanting to dereference the structure.

Thierry

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