Re: [PATCH v2 10/12] cxl/pci: Unconditionally unmask 256B Flit errors

[Dave Jiang <dave.jiang@intel.com>]

On 6/14/23 18:30, Dan Williams wrote:
> The current check for 256B Flit mode is incomplete and unnecessary. It
> is incomplete because it fails to consider the link speed, or check for
> CXL link capabilities. It is unnecessary because unconditionally
> unmasking 256B Flit errors is a nop when 256B Flit operation is not
> available.
> 
> Remove this check in preparation for creating a cxl_probe_link() helper
> to centralize this detection.
> 
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> ---
>   drivers/cxl/pci.c |   18 ++----------------
>   1 file changed, 2 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index 4e2845b7331a..3f78082014cc 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -368,19 +368,6 @@ static bool is_cxl_restricted(struct pci_dev *pdev)
>   	return pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END;
>   }
>   
> -/*
> - * CXL v3.0 6.2.3 Table 6-4
> - * The table indicates that if PCIe Flit Mode is set, then CXL is in 256B flits
> - * mode, otherwise it's 68B flits mode.
> - */
> -static bool cxl_pci_flit_256(struct pci_dev *pdev)
> -{
> -	u16 lnksta2;
> -
> -	pcie_capability_read_word(pdev, PCI_EXP_LNKSTA2, &lnksta2);
> -	return lnksta2 & PCI_EXP_LNKSTA2_FLIT;
> -}
> -
>   static int cxl_pci_ras_unmask(struct pci_dev *pdev)
>   {
>   	struct pci_host_bridge *host_bridge = pci_find_host_bridge(pdev->bus);
> @@ -407,9 +394,8 @@ static int cxl_pci_ras_unmask(struct pci_dev *pdev)
>   		addr = cxlds->regs.ras + CXL_RAS_UNCORRECTABLE_MASK_OFFSET;
>   		orig_val = readl(addr);
>   
> -		mask = CXL_RAS_UNCORRECTABLE_MASK_MASK;
> -		if (!cxl_pci_flit_256(pdev))
> -			mask &= ~CXL_RAS_UNCORRECTABLE_MASK_F256B_MASK;
> +		mask = CXL_RAS_UNCORRECTABLE_MASK_MASK |
> +		       CXL_RAS_UNCORRECTABLE_MASK_F256B_MASK;
>   		val = orig_val & ~mask;
>   		writel(val, addr);
>   		dev_dbg(&pdev->dev,
>