[PATCHv2 2/6] PCI: designware: enable write permission before updating class code

[Zhiqiang Hou <Zhiqiang.Hou@nxp.com>]

From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>

The existing fix doesn't actually work because the Class register is
read-only, so it must enable the write permission before write the
correct value to this register.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
---
V2:
 - None

 drivers/pci/dwc/pcie-designware-host.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
index d29c020..6e10cda 100644
--- a/drivers/pci/dwc/pcie-designware-host.c
+++ b/drivers/pci/dwc/pcie-designware-host.c
@@ -634,8 +634,12 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
 
 	dw_pcie_wr_own_conf(pp, PCI_BASE_ADDRESS_0, 4, 0);
 
+	/* Enable write permission for the DBI read-only register */
+	dw_pcie_dbi_ro_wr_en(pci);
 	/* program correct class for RC */
 	dw_pcie_wr_own_conf(pp, PCI_CLASS_DEVICE, 2, PCI_CLASS_BRIDGE_PCI);
+	/* Better disable write permission right after the update */
+	dw_pcie_dbi_ro_wr_dis(pci);
 
 	dw_pcie_rd_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, &val);
 	val |= PORT_LOGIC_SPEED_CHANGE;
-- 
2.1.0.27.g96db324