[+cc Tanmay]

On Tue, Aug 01, 2017 at 04:08:13PM -0700, Feng Kan wrote:
> The APM X-Gene PCIe root port does not support ACS at this point.
> However, the hw provides isolation and source validation through
> the SMMU. The stream ID generated by the PCIe ports contain both
> the BDF as well as the port ID in its 3 most significant bits.
> Turn on ACS but disable all the peer to peer features.
> 
> Signed-off-by: Feng Kan <f...@apm.com>

This should really have Tanmay's ack (cc'd).

Provisionally applied to pci/host-xgene for v4.14.

> ---
>       V4 Change: Remove TB & TD flags from ACS mask
>         V3 Change: Add comment regarding unique port id in stream ID
>         V2 Change: Move XGene ACS quirk to unique XGene function
> 
>  drivers/pci/quirks.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 085fb78..22343b3 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -4120,6 +4120,18 @@ static int pci_quirk_cavium_acs(struct pci_dev *dev, 
> u16 acs_flags)
>       return acs_flags ? 0 : 1;
>  }
>  
> +static int pci_quirk_xgene_acs(struct pci_dev *dev, u16 acs_flags)
> +{
> +     /*
> +      * XGene root matching this quirk do not allow peer-to-peer
> +      * transactions with others, allowing masking out these bits as if they
> +      * were unimplemented in the ACS capability.
> +      */
> +     acs_flags &= ~(PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF);
> +
> +     return acs_flags ? 0 : 1;
> +}
> +
>  /*
>   * Many Intel PCH root ports do provide ACS-like features to disable peer
>   * transactions and validate bus numbers in requests, but do not provide an
> @@ -4368,6 +4380,8 @@ static int pci_quirk_mf_endpoint_acs(struct pci_dev 
> *dev, u16 acs_flags)
>       { 0x10df, 0x720, pci_quirk_mf_endpoint_acs }, /* Emulex Skyhawk-R */
>       /* Cavium ThunderX */
>       { PCI_VENDOR_ID_CAVIUM, PCI_ANY_ID, pci_quirk_cavium_acs },
> +     /* APM XGene */
> +     { PCI_VENDOR_ID_AMCC, 0xE004, pci_quirk_xgene_acs },
>       { 0 }
>  };
>  
> -- 
> 1.8.3.1
> 

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