PCI: designware-ep: Make dw_pcie_ep_reset_bar() handle 64-bit BARs properly

Since a 64-bit BAR consists of a BAR pair, we need to write to both
BARs in the BAR pair to clear the BAR properly.

Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/pci/dwc/pcie-designware-ep.c

@@ -28,6 +28,10 @@ static void __dw_pcie_ep_reset_bar(struct dw_pcie *pci, enum pci_barno bar,
 	dw_pcie_dbi_ro_wr_en(pci);
 	dw_pcie_writel_dbi2(pci, reg, 0x0);
 	dw_pcie_writel_dbi(pci, reg, 0x0);
+	if (flags & PCI_BASE_ADDRESS_MEM_TYPE_64) {
+		dw_pcie_writel_dbi2(pci, reg + 4, 0x0);
+		dw_pcie_writel_dbi(pci, reg + 4, 0x0);
+	}
 	dw_pcie_dbi_ro_wr_dis(pci);
 }