[PATCH v6 06/25] iommu/tegra-gart: Remove tegra-gart

[Baolu Lu]

On 2023/8/3 8:07, 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>
> Signed-off-by: Jason Gunthorpe<jgg at nvidia.com>
> ---
>   arch/arm/configs/multi_v7_defconfig |   1 -
>   arch/arm/configs/tegra_defconfig    |   1 -
>   drivers/iommu/Kconfig               |  11 -
>   drivers/iommu/Makefile              |   1 -
>   drivers/iommu/tegra-gart.c          | 371 ----------------------------
>   drivers/memory/tegra/mc.c           |  34 ---
>   drivers/memory/tegra/tegra20.c      |  28 ---
>   include/soc/tegra/mc.h              |  26 --
>   8 files changed, 473 deletions(-)
>   delete mode 100644 drivers/iommu/tegra-gart.c

Reviewed-by: Lu Baolu <baolu.lu at linux.intel.com>

Best regards,
baolu