Re: [PATCH] iommu/arm: Allow disabling Qualcomm support in arm_smmu_v3

[Aaron Kling]

On Tue, Mar 11, 2025 at 12:55 PM Daniel Mentz <danielmentz@xxxxxxxxxx> wrote:
>
> On Mon, Mar 10, 2025 at 9:51 AM Aaron Kling <webgeek1234@xxxxxxxxx> wrote:
> > I am working with the android kernel. The more recent setup enables a
> > minimal setup of configs in a core kernel that works across all
> > supported arch's, then requires further support to all be modules. I
> > specifically am working with tegra devices. But as ARCH_QCOM is
> > enabled in the core defconfig, when I build smmuv3 as a module, I end
> > up with a dependency on qcom-scm which gets built as an additional
> > module. And it would be preferable to not require qcom modules to boot
> > a tegra device.
>
> If you want to build arm_smmu_v3.ko, you'd have
>
> # CONFIG_ARM_SMMU is not set
> CONFIG_ARM_SMMU_V3=m
>
> in your .config. I don't see how this would enable ARM_SMMU_QCOM or QCOM_SCM.

I went and double checked my defconfig snippet and I have to
apologize. I put the wrong thing in the commit message and caused
confusion to myself and the entire discussion. This is what I've got:

# MMU
CONFIG_ARM_SMMU=m
# CONFIG_ARM_SMMU_QCOM is not set

Tegra186, tegra194, and tegra234 are supported by arm-smmu, not by
arm-smmu-v3. And these are the relevant archs I'm trying to work on.

Having the extra dep doesn't break anything, so worst case I continue
to carry the extra dep or this as a downstream patch. But I had to at
least try to decouple unnecessary dep.

Sincerely,
Aaron