[PATCH] PCI: xilinx-nwl: Avoid crashing if configuring when the link is down

[Stefan Roese]

Hi Sean,

On 1/6/26 23:08, Sean Anderson wrote:
> The ECAM will return a slave error if we access non-root devices while
> the link is down. Add a check for this like Linux does so we don't
> crash.
> 
> Fixes: 2f5ad77cfea ("PCI: zynqmp: Add ZynqMP NWL PCIe root port driver")
> Signed-off-by: Sean Anderson <sean.anderson at linux.dev>

Reviewed-by: Stefan Roese <stefan.roese at mailbox.org>

Thanks,
Stefan

> ---
> 
>   drivers/pci/pcie-xilinx-nwl.c | 17 ++++++++++-------
>   1 file changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/pci/pcie-xilinx-nwl.c b/drivers/pci/pcie-xilinx-nwl.c
> index e03ab3be912..ab597c83e47 100644
> --- a/drivers/pci/pcie-xilinx-nwl.c
> +++ b/drivers/pci/pcie-xilinx-nwl.c
> @@ -135,6 +135,13 @@ struct nwl_pcie {
>   	u32 ecam_value;
>   };
>   
> +static bool nwl_pcie_link_up(struct nwl_pcie *pcie)
> +{
> +	if (readl(pcie->pcireg_base + PS_LINKUP_OFFSET) & PCIE_PHY_LINKUP_BIT)
> +		return true;
> +	return false;
> +}
> +
>   static int nwl_pcie_config_address(const struct udevice *bus,
>   				   pci_dev_t bdf, uint offset,
>   				   void **paddress)
> @@ -142,6 +149,9 @@ static int nwl_pcie_config_address(const struct udevice *bus,
>   	struct nwl_pcie *pcie = dev_get_priv(bus);
>   	void *addr;
>   
> +	if (PCI_BUS(bdf) != dev_seq(bus) && !nwl_pcie_link_up(pcie))
> +		return -EIO;
> +
>   	addr = pcie->ecam_base;
>   	addr += PCIE_ECAM_OFFSET(PCI_BUS(bdf) - dev_seq(bus),
>   				 PCI_DEV(bdf), PCI_FUNC(bdf), offset);
> @@ -181,13 +191,6 @@ static inline void nwl_bridge_writel(struct nwl_pcie *pcie, u32 val, u32 off)
>   	writel(val, pcie->breg_base + off);
>   }
>   
> -static bool nwl_pcie_link_up(struct nwl_pcie *pcie)
> -{
> -	if (readl(pcie->pcireg_base + PS_LINKUP_OFFSET) & PCIE_PHY_LINKUP_BIT)
> -		return true;
> -	return false;
> -}
> -
>   static bool nwl_phy_link_up(struct nwl_pcie *pcie)
>   {
>   	if (readl(pcie->pcireg_base + PS_LINKUP_OFFSET) & PHY_RDY_LINKUP_BIT)