Re: [PATCH v5] PCI: quirks: update Cavium ThunderX ACS quirk implementation

Vadim Lomovtsev
2017-09-26T15:23:36Z

Hi guys,

Could you please consider to review following patch?

For v5 changes:
- ACS mask comment has been updated.
- comment has been added for device id filtering mask at match
function to provide explantion of CN8xxx devid scheme.

WBR,
Vadim

On Mon, Sep 25, 2017 at 06:08:40AM -0700, Vadim Lomovtsev wrote:
> This commit makes Cavium PCI ACS quirk applicable only to Cavium
> ThunderX (CN8XXX) family PCIE Root Ports which has limited PCI capabilities
> in terms of no ACS support advertisement. However, the RTL internally
> implements similar protection as if ACS had completion/request redirection,
> upstream forwarding and validation features enabled.
>
> Current quirk implementation doesn't take into account PCIERCs which
> also needs to be quirked. So the pci device id check mask is updated
> and check of device ID moved into separate function.
>
> Signed-off-by: Vadim Lomovtsev <Vadim.Lomovtsev@caviumnetworks.com>
> ---
> drivers/pci/quirks.c | 29 +++++++++++++++++++++--------
> 1 file changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index a4d3361..0fd2e15 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -4211,20 +4211,33 @@ static int pci_quirk_amd_sb_acs(struct pci_dev *dev, u16 acs_flags)
> #endif
> }
>
> -static int pci_quirk_cavium_acs(struct pci_dev *dev, u16 acs_flags)
> +/*
> + * The Cavium downstream ports doesn't advertise their ACS capability registers.
> + * However, the RTL internally implements similar protection as if
> + * ACS had completion redirection, forwarding and validation features enabled.
> + * So by this flags we're asserting that the hardware implements and
> + * enables equivalent ACS functionality for these flags.
> + */
> +#define CAVIUM_CN8XXX_ACS_FLAGS (PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_SV | PCI_ACS_UF)
> +
> +static __inline__ bool pci_quirk_cavium_acs_match(struct pci_dev *dev)
> {
> /*
> - * Cavium devices matching this quirk do not perform peer-to-peer
> - * with other functions, allowing masking out these bits as if they
> - * were unimplemented in the ACS capability.
> + * Effectively selects all downstream ports for whole ThunderX 1 family
> + * by 0xa00 mask (which represents 8 SoCs), while the lower bits of device ID
> + * are used to indicate which subdevice is used within the SoC.
> */
> - acs_flags &= ~(PCI_ACS_SV | PCI_ACS_TB | PCI_ACS_RR |
> - PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_DT);
> + return (pci_is_pcie(dev) &&
> + (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) &&
> + ((dev->device & 0xf800) == 0xa000));
> +}
>
> - if (!((dev->device >= 0xa000) && (dev->device <= 0xa0ff)))
> +static int pci_quirk_cavium_acs(struct pci_dev *dev, u16 acs_flags)
> +{
> + if (!pci_quirk_cavium_acs_match(dev))
> return -ENOTTY;
>
> - return acs_flags ? 0 : 1;
> + return acs_flags & ~(CAVIUM_CN8XXX_ACS_FLAGS) ? 0 : 1;
> }
>
> static int pci_quirk_xgene_acs(struct pci_dev *dev, u16 acs_flags)
> --
> 2.9.5
>