Re: [PATCH kernel] powerpc/powernv/npu: Remove dead iommu code

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, Feb 21, 2017 at 01:40:20PM +1100, Alexey Kardashevskiy wrote:
> PNV_IODA_PE_DEV is only used for NPU devices (emulated PCI bridges
> representing NVLink). These are added to IOMMU groups with corresponding
> NVIDIA devices after all non-NPU PEs are setup; a special helper -
> pnv_pci_ioda_setup_iommu_api() - handles this in pnv_pci_ioda_fixup().
> 
> The pnv_pci_ioda2_setup_dma_pe() helper sets up DMA for a PE. It is called
> for VFs (so it does not handle NPU case) and PCI bridges but only
> IODA1 and IODA2 types. An NPU bridge has its own type id (PNV_PHB_NPU)
> so pnv_pci_ioda2_setup_dma_pe() cannot be called on NPU and therefore
> (pe->flags & PNV_IODA_PE_DEV) is always "false".
> 
> This removes not used iommu_add_device(). This should not cause any
> behavioral change.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  arch/powerpc/platforms/powernv/pci-ioda.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 5fcae29107e1..51ec0dc1dfde 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -2724,9 +2724,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
>  	if (rc)
>  		return;
>  
> -	if (pe->flags & PNV_IODA_PE_DEV)
> -		iommu_add_device(&pe->pdev->dev);
> -	else if (pe->flags & (PNV_IODA_PE_BUS | PNV_IODA_PE_BUS_ALL))
> +	if (pe->flags & (PNV_IODA_PE_BUS | PNV_IODA_PE_BUS_ALL))
>  		pnv_ioda_setup_bus_dma(pe, pe->pbus);
>  }
>  

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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