Re: [PATCH v10 3/5] PCI: Disable Relaxed Ordering Attributes for AMD A1100

[Raj, Ashok]

On Mon, Aug 14, 2017 at 11:44:57PM +0800, Ding Tianhong wrote:
> Casey reported that the AMD ARM A1100 SoC has a bug in its PCIe
> Root Port where Upstream Transaction Layer Packets with the Relaxed
> Ordering Attribute clear are allowed to bypass earlier TLPs with
> Relaxed Ordering set, it would cause Data Corruption, so we need
> to disable Relaxed Ordering Attribute when Upstream TLPs to the
> Root Port.
> 
> Signed-off-by: Casey Leedom <leedom@xxxxxxxxxxx>
> Signed-off-by: Ding Tianhong <dingtianhong@xxxxxxxxxx>
> Acked-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
> Acked-by: Ashok Raj <ashok.raj@xxxxxxxxx>

I can't ack this patch :-).. must be someone from AMD. Please remove my
signature from this.

> ---
>  drivers/pci/quirks.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 1272f7e..1407604 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -4089,6 +4089,22 @@ static void quirk_relaxedordering_disable(struct pci_dev *dev)
>  			      quirk_relaxedordering_disable);
>  
>  /*
> + * The AMD ARM A1100 (AKA "SEATTLE") SoC has a bug in its PCIe Root Complex
> + * where Upstream Transaction Layer Packets with the Relaxed Ordering
> + * Attribute clear are allowed to bypass earlier TLPs with Relaxed Ordering
> + * set.  This is a violation of the PCIe 3.0 Transaction Ordering Rules
> + * outlined in Section 2.4.1 (PCI Express(r) Base Specification Revision 3.0
> + * November 10, 2010).  As a result, on this platform we can't use Relaxed
> + * Ordering for Upstream TLPs.
> + */
> +DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_AMD, 0x1a00, PCI_CLASS_NOT_DEFINED, 8,
> +			      quirk_relaxedordering_disable);
> +DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_AMD, 0x1a01, PCI_CLASS_NOT_DEFINED, 8,
> +			      quirk_relaxedordering_disable);
> +DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_AMD, 0x1a02, PCI_CLASS_NOT_DEFINED, 8,
> +			      quirk_relaxedordering_disable);
> +
> +/*
>   * Per PCIe r3.0, sec 2.2.9, "Completion headers must supply the same
>   * values for the Attribute as were supplied in the header of the
>   * corresponding Request, except as explicitly allowed when IDO is used."
> -- 
> 1.8.3.1
> 
>