diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
index de5e809a537d..d0c643996476 100644
--- a/drivers/pci/controller/pci-loongson.c
+++ b/drivers/pci/controller/pci-loongson.c
@@ -177,6 +177,42 @@ static void loongson_pci_msi_quirk(struct pci_dev *dev)
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON, DEV_LS7A_PCIE_PORT5, loongson_pci_msi_quirk);
 
+/*
+ * Older steppings of the Loongson-3C6000 series incorrectly report the
+ * supported link speeds on their PCIe bridges (device IDs 0x3c19,
+ * 0x3c29) as only 2.5 GT/s, despite the upstream bus supporting speeds
+ * from 2.5 GT/s up to 16 GT/s.
+ */
+static void loongson_pci_bridge_speed_quirk(struct pci_dev *pdev)
+{
+	u8 old_supported_speeds = pdev->supported_speeds;
+
+	switch (pdev->bus->max_bus_speed) {
+	case PCIE_SPEED_16_0GT:
+		pdev->supported_speeds |= PCI_EXP_LNKCAP2_SLS_16_0GB;
+		fallthrough;
+	case PCIE_SPEED_8_0GT:
+		pdev->supported_speeds |= PCI_EXP_LNKCAP2_SLS_8_0GB;
+		fallthrough;
+	case PCIE_SPEED_5_0GT:
+		pdev->supported_speeds |= PCI_EXP_LNKCAP2_SLS_5_0GB;
+		fallthrough;
+	case PCIE_SPEED_2_5GT:
+		pdev->supported_speeds |= PCI_EXP_LNKCAP2_SLS_2_5GB;
+		break;
+	default:
+		pci_warn(pdev, "unexpected max bus speed");
+
+		return;
+	}
+
+	if (pdev->supported_speeds != old_supported_speeds)
+		pci_info(pdev, "fixed up supported link speeds: 0x%x => 0x%x",
+			 old_supported_speeds, pdev->supported_speeds);
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LOONGSON, 0x3c19, loongson_pci_bridge_speed_quirk);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LOONGSON, 0x3c29, loongson_pci_bridge_speed_quirk);
+
 static struct loongson_pci *pci_bus_to_loongson_pci(struct pci_bus *bus)
 {
 	struct pci_config_window *cfg;