Re: [PATCH 1/3] iommu/dma: Clean up Kconfig

[Jason Gunthorpe <jgg@nvidia.com>]

On Tue, Aug 16, 2022 at 06:28:03PM +0100, Robin Murphy wrote:
> Although iommu-dma is a per-architecture chonce, that is currently
> implemented in a rather haphazard way. Selecting from the arch Kconfig
> was the original logical approach, but is complicated by having to
> manage dependencies; conversely, selecting from drivers ends up hiding
> the architecture dependency *too* well. Instead, let's just have it
> enable itself automatically when IOMMU API support is enabled for the
> relevant architectures. It can't get much clearer than that.
> 
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
>  arch/arm64/Kconfig          | 1 -
>  drivers/iommu/Kconfig       | 3 +--
>  drivers/iommu/amd/Kconfig   | 1 -
>  drivers/iommu/intel/Kconfig | 1 -
>  4 files changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 571cc234d0b3..59af600445c2 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -209,7 +209,6 @@ config ARM64
>  	select HAVE_KPROBES
>  	select HAVE_KRETPROBES
>  	select HAVE_GENERIC_VDSO
> -	select IOMMU_DMA if IOMMU_SUPPORT
>  	select IRQ_DOMAIN
>  	select IRQ_FORCED_THREADING
>  	select KASAN_VMALLOC if KASAN
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index 5c5cb5bee8b6..1d99c2d984fb 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -137,7 +137,7 @@ config OF_IOMMU
>  
>  # IOMMU-agnostic DMA-mapping layer
>  config IOMMU_DMA
> -	bool
> +	def_bool ARM64 || IA64 || X86

Robin, do you remember why you added IA64 here? What is the Itanimum
IOMMU driver?

Thanks,
Jason