[PATCH v7 06/24] iommu/tegra-gart: Remove tegra-gart

[Jerry Snitselaar]

On Wed, Aug 23, 2023 at 01:47:20PM -0300, Jason Gunthorpe wrote:
> Thierry says this is not used anymore, and doesn't think it makes sense as
> an iommu driver. The HW it supports is about 10 years old now and newer HW
> uses different IOMMU drivers.
> 
> As this is the only driver with a GART approach, and it doesn't really
> meet the driver expectations from the IOMMU core, let's just remove it
> so we don't have to think about how to make it fit in.
> 
> It has a number of identified problems:
>  - The assignment of iommu_groups doesn't match the HW behavior
> 
>  - It claims to have an UNMANAGED domain but it is really an IDENTITY
>    domain with a translation aperture. This is inconsistent with the core
>    expectation for security sensitive operations
> 
>  - It doesn't implement a SW page table under struct iommu_domain so
>    * It can't accept a map until the domain is attached
>    * It forgets about all maps after the domain is detached
>    * It doesn't clear the HW of maps once the domain is detached
>      (made worse by having the wrong groups)
> 
> Cc: Thierry Reding <treding at nvidia.com>
> Cc: Dmitry Osipenko <digetx at gmail.com>
> Acked-by: Thierry Reding <treding at nvidia.com>
> Reviewed-by: Lu Baolu <baolu.lu at linux.intel.com>
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>

Reviewed-by: Jerry Snitselaar <jsnitsel at redhat.com>