PCI: layerscape: Change default error response behavior

By default, when the PCIe controller experiences an erroneous completion
from an external completer for its outbound non-posted request, it sends
an OKAY response to the device's internal AXI slave system interface.
However, this default system error response behavior cannot be used for
other types of outbound non-posted requests.  For example, the outbound
memory read transaction requires an actual ERROR response, like UR
completion or completion timeout.

Fix this by forwarding the error response of the non-posted request.

Signed-off-by: Minghuan Lian <Minghuan.Lian@nxp.com>
Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/dwc/pci-layerscape.c

@@ -33,6 +33,8 @@
 
 /* PEX Internal Configuration Registers */
 #define PCIE_STRFMR1		0x71c /* Symbol Timer & Filter Mask Register1 */
+#define PCIE_ABSERR		0x8d0 /* Bridge Slave Error Response Register */
+#define PCIE_ABSERR_SETTING	0x9401 /* Forward error of non-posted request */
 
 #define PCIE_IATU_NUM		6
 
@@ -124,6 +126,14 @@ static int ls_pcie_link_up(struct dw_pcie *pci)
 	return 1;
 }
 
+/* Forward error response of outbound non-posted requests */
+static void ls_pcie_fix_error_response(struct ls_pcie *pcie)
+{
+	struct dw_pcie *pci = pcie->pci;
+
+	iowrite32(PCIE_ABSERR_SETTING, pci->dbi_base + PCIE_ABSERR);
+}
+
 static int ls_pcie_host_init(struct pcie_port *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -135,6 +145,7 @@ static int ls_pcie_host_init(struct pcie_port *pp)
 	 * dw_pcie_setup_rc() will reconfigure the outbound windows.
 	 */
 	ls_pcie_disable_outbound_atus(pcie);
+	ls_pcie_fix_error_response(pcie);
 
 	dw_pcie_dbi_ro_wr_en(pci);
 	ls_pcie_clear_multifunction(pcie);