From 429fdce9645b194eac02e6ed51751447fcc12b4e Mon Sep 17 00:00:00 2001 From: Kishon Vijay Abraham I Date: Tue, 11 Mar 2025 08:51:19 +0900 Subject: [PATCH] PCI: keystone: Add link up check to ks_pcie_other_map_bus() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit BugLink: https://bugs.launchpad.net/bugs/2101915 commit 9e9ec8d8692a6f64d81ef67d4fb6255af6be684b upstream. K2G forwards the error triggered by a link-down state (e.g., no connected endpoint device) on the system bus for PCI configuration transactions; these errors are reported as an SError at system level, which is fatal and hangs the system. So, apply fix similar to how it was done in the DesignWare Core driver commit 15b23906347c ("PCI: dwc: Add link up check in dw_child_pcie_ops.map_bus()"). Fixes: 10a797c6e54a ("PCI: dwc: keystone: Use pci_ops for config space accessors") Link: https://lore.kernel.org/r/20240524105714.191642-3-s-vadapalli@ti.com Signed-off-by: Kishon Vijay Abraham I Signed-off-by: Siddharth Vadapalli [kwilczynski: commit log, added tag for stable releases] Signed-off-by: Krzysztof Wilczyński Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- drivers/pci/controller/dwc/pci-keystone.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c index 311d3cb179c8..ed284a820ec9 100644 --- a/drivers/pci/controller/dwc/pci-keystone.c +++ b/drivers/pci/controller/dwc/pci-keystone.c @@ -462,6 +462,17 @@ static void __iomem *ks_pcie_other_map_bus(struct pci_bus *bus, struct keystone_pcie *ks_pcie = to_keystone_pcie(pci); u32 reg; + /* + * 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; + reg = CFG_BUS(bus->number) | CFG_DEVICE(PCI_SLOT(devfn)) | CFG_FUNC(PCI_FUNC(devfn)); if (!pci_is_root_bus(bus->parent))