IOMMU_FWSPEC_PCI_RC_ATS for SMMUv3 with DT configuration?

[Nicolin Chen]

Hi all.

Currently, the SMMUv3 driver relies on IOMMU_FWSPEC_PCI_RC_ATS
in arm_smmu_ats_supported(). This flag seems to be only set in
the drivers/acpi/arm64/iort.c file, which does not work for DT
configuration.

We have a need to enable ATS on a system using Device Tree. Is
there a suggested way or name of DT binding to add?

Thanks
Nicolin