PCI: rockchip: Mark RC as common clock architecture

The default value of common clock configuration is zero indicating
Rockchip's RC is using asynchronous clock architecture but actually we are
using common clock.  This will confuse some EP drivers if they need some
different settings referring to this value.

Set the Common Clock Configuration bit in the Link Control Register.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/host/pcie-rockchip.c

@@ -141,6 +141,7 @@
 #define   PCIE_RC_CONFIG_DCR_CPLS_SHIFT		26
 #define PCIE_RC_CONFIG_LCS		(PCIE_RC_CONFIG_BASE + 0xd0)
 #define   PCIE_RC_CONFIG_LCS_RETRAIN_LINK	BIT(5)
+#define   PCIE_RC_CONFIG_LCS_CCC		BIT(6)
 #define   PCIE_RC_CONFIG_LCS_LBMIE		BIT(10)
 #define   PCIE_RC_CONFIG_LCS_LABIE		BIT(11)
 #define   PCIE_RC_CONFIG_LCS_LBMS		BIT(30)
@@ -577,6 +578,11 @@ static int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
 
 	rockchip_pcie_set_power_limit(rockchip);
 
+	/* Set RC's clock architecture as common clock */
+	status = rockchip_pcie_read(rockchip, PCIE_RC_CONFIG_LCS);
+	status |= PCIE_RC_CONFIG_LCS_CCC;
+	rockchip_pcie_write(rockchip, status, PCIE_RC_CONFIG_LCS);
+
 	/* Enable Gen1 training */
 	rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE,
 			    PCIE_CLIENT_CONFIG);