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SubjectRe: [PATCH V4] pci: quirk: Apply APM ACS quirk to XGene devices
On Tue,  1 Aug 2017 16:08:13 -0700
Feng Kan <fkan@apm.com> 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 <fkan@apm.com>
> ---
> 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(+)


Reviewed-by: Alex Williamson <alex.williamson@redhat.com>


> 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 }
> };
>

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