dwmac1000 and dwmac4 both provide a hardware feature bit to indicate
when the PCS block is present. There is little point initialising the
PCS support when the hardware is not present.

Add a new callback which will be made after the hardware features have
been read, and heck whether the PCS is present.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 .../net/ethernet/stmicro/stmmac/dwmac1000_core.c    | 11 ++++++++++-
 drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c   | 13 ++++++++++++-
 drivers/net/ethernet/stmicro/stmmac/hwif.h          |  4 ++++
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c   |  4 ++++
 4 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
index b01c0fc822f9..571e48362444 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
@@ -22,6 +22,14 @@
 #include "stmmac_ptp.h"
 #include "dwmac1000.h"
 
+static int dwmac1000_pcs_init(struct stmmac_priv *priv)
+{
+	if (!priv->dma_cap.pcs)
+		return 0;
+
+	return stmmac_integrated_pcs_init(priv, GMAC_PCS_BASE);
+}
+
 static void dwmac1000_core_init(struct mac_device_info *hw,
 				struct net_device *dev)
 {
@@ -435,6 +443,7 @@ static void dwmac1000_set_mac_loopback(void __iomem *ioaddr, bool enable)
 }
 
 const struct stmmac_ops dwmac1000_ops = {
+	.pcs_init = dwmac1000_pcs_init,
 	.core_init = dwmac1000_core_init,
 	.set_mac = stmmac_set_mac,
 	.rx_ipc = dwmac1000_rx_ipc_enable,
@@ -484,7 +493,7 @@ int dwmac1000_setup(struct stmmac_priv *priv)
 	mac->mii.clk_csr_shift = 2;
 	mac->mii.clk_csr_mask = GENMASK(5, 2);
 
-	return stmmac_integrated_pcs_init(priv, GMAC_PCS_BASE);
+	return 0;
 }
 
 /* DWMAC 1000 HW Timestaming ops */
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
index 688e45b440dd..0b785389b7ef 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
@@ -22,6 +22,14 @@
 #include "dwmac4.h"
 #include "dwmac5.h"
 
+static int dwmac4_pcs_init(struct stmmac_priv *priv)
+{
+	if (!priv->dma_cap.pcs)
+		return 0;
+
+	return stmmac_integrated_pcs_init(priv, GMAC_PCS_BASE);
+}
+
 static void dwmac4_core_init(struct mac_device_info *hw,
 			     struct net_device *dev)
 {
@@ -875,6 +883,7 @@ static int dwmac4_config_l4_filter(struct mac_device_info *hw, u32 filter_no,
 }
 
 const struct stmmac_ops dwmac4_ops = {
+	.pcs_init = dwmac4_pcs_init,
 	.core_init = dwmac4_core_init,
 	.update_caps = dwmac4_update_caps,
 	.set_mac = stmmac_set_mac,
@@ -909,6 +918,7 @@ const struct stmmac_ops dwmac4_ops = {
 };
 
 const struct stmmac_ops dwmac410_ops = {
+	.pcs_init = dwmac4_pcs_init,
 	.core_init = dwmac4_core_init,
 	.update_caps = dwmac4_update_caps,
 	.set_mac = stmmac_dwmac4_set_mac,
@@ -945,6 +955,7 @@ const struct stmmac_ops dwmac410_ops = {
 };
 
 const struct stmmac_ops dwmac510_ops = {
+	.pcs_init = dwmac4_pcs_init,
 	.core_init = dwmac4_core_init,
 	.update_caps = dwmac4_update_caps,
 	.set_mac = stmmac_dwmac4_set_mac,
@@ -1017,5 +1028,5 @@ int dwmac4_setup(struct stmmac_priv *priv)
 	mac->mii.clk_csr_mask = GENMASK(11, 8);
 	mac->num_vlan = stmmac_get_num_vlan(priv->ioaddr);
 
-	return stmmac_integrated_pcs_init(priv, GMAC_PCS_BASE);
+	return 0;
 }
diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.h b/drivers/net/ethernet/stmicro/stmmac/hwif.h
index 7796f5f3c96f..82cfb6bec334 100644
--- a/drivers/net/ethernet/stmicro/stmmac/hwif.h
+++ b/drivers/net/ethernet/stmicro/stmmac/hwif.h
@@ -313,6 +313,8 @@ enum stmmac_lpi_mode {
 
 /* Helpers to program the MAC core */
 struct stmmac_ops {
+	/* Initialise any PCS instances */
+	int (*pcs_init)(struct stmmac_priv *priv);
 	/* MAC core initialization */
 	void (*core_init)(struct mac_device_info *hw, struct net_device *dev);
 	/* Update MAC capabilities */
@@ -413,6 +415,8 @@ struct stmmac_ops {
 					u32 pclass);
 };
 
+#define stmmac_mac_pcs_init(__priv) \
+	stmmac_do_callback(__priv, mac, pcs_init, __priv)
 #define stmmac_core_init(__priv, __args...) \
 	stmmac_do_void_callback(__priv, mac, core_init, __args)
 #define stmmac_mac_update_caps(__priv) \
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 2cf6e69f3303..0f243f207f99 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -7240,6 +7240,10 @@ static int stmmac_hw_init(struct stmmac_priv *priv)
 			 "Enable RX Mitigation via HW Watchdog Timer\n");
 	}
 
+	ret = stmmac_mac_pcs_init(priv);
+	if (ret != -EINVAL)
+		return ret;
+
 	return 0;
 }
 
-- 
2.47.3