PCI: dwc: Disable outbound windows only for controllers using iATU

Some DWC-based controllers (e.g., pcie-al.c and pci-keystone.c, identified
by the fact that they override the default dw_child_pcie_ops) use their own
address translation approach instead of the DWC internal ATU (iATU).  For
those controllers, skip disabling the iATU outbound windows.

[bhelgaas: commit log, update multiple window comment]
Fixes: 458ad06c ("PCI: dwc: Ensure all outbound ATU windows are reset")
Link: https://lore.kernel.org/r/20220624143428.8334-4-Sergey.Semin@baikalelectronics.ruTested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>

drivers/pci/controller/dwc/pcie-designware-host.c

@@ -543,7 +543,6 @@ static struct pci_ops dw_pcie_ops = {
 
 void dw_pcie_setup_rc(struct pcie_port *pp)
 {
-	int i;
 	u32 val, ctrl, num_ctrls;
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
 
@@ -594,19 +593,22 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
 		PCI_COMMAND_MASTER | PCI_COMMAND_SERR;
 	dw_pcie_writel_dbi(pci, PCI_COMMAND, val);
 
-	/* Ensure all outbound windows are disabled so there are multiple matches */
-	for (i = 0; i < pci->num_ob_windows; i++)
-		dw_pcie_disable_atu(pci, i, DW_PCIE_REGION_OUTBOUND);
-
 	/*
 	 * If the platform provides its own child bus config accesses, it means
 	 * the platform uses its own address translation component rather than
 	 * ATU, so we should not program the ATU here.
 	 */
 	if (pp->bridge->child_ops == &dw_child_pcie_ops) {
-		int atu_idx = 0;
+		int i, atu_idx = 0;
 		struct resource_entry *entry;
 
+		/*
+		 * Disable all outbound windows to make sure a transaction
+		 * can't match multiple windows.
+		 */
+		for (i = 0; i < pci->num_ob_windows; i++)
+			dw_pcie_disable_atu(pci, i, DW_PCIE_REGION_OUTBOUND);
+
 		/* Get last memory resource entry */
 		resource_list_for_each_entry(entry, &pp->bridge->windows) {
 			if (resource_type(entry->res) != IORESOURCE_MEM)