diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c index d02c7e74738d7..674f32db85ca4 100644 --- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c @@ -444,6 +444,17 @@ static void __iomem *dw_pcie_other_conf_map_bus(struct pci_bus *bus, struct pcie_port *pp = bus->sysdata; struct dw_pcie *pci = to_dw_pcie_from_pp(pp); + /* + * Checking whether the link is up here is a last line of defense + * against platforms that forward errors on the system bus as + * SError upon PCI configuration transactions issued when the link + * is down. This check is racy by definition and does not stop + * the system from triggering an SError if the link goes down + * after this check is performed. + */ + if (!dw_pcie_link_up(pci)) + return NULL; + busdev = PCIE_ATU_BUS(bus->number) | PCIE_ATU_DEV(PCI_SLOT(devfn)) | PCIE_ATU_FUNC(PCI_FUNC(devfn));