net: ethernet: stmmac: Fix altr_tse_pcs SGMII Initialization

Fix NETDEV WATCHDOG timeout on startup by adding missing register
writes that properly setup SGMII.
Signed-off-by: NThor Thayer <thor.thayer@linux.intel.com>
Acked-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/altr_tse_pcs.c

@@ -37,6 +37,7 @@
 #define TSE_PCS_CONTROL_AN_EN_MASK			BIT(12)
 #define TSE_PCS_CONTROL_REG				0x00
 #define TSE_PCS_CONTROL_RESTART_AN_MASK			BIT(9)
+#define TSE_PCS_CTRL_AUTONEG_SGMII			0x1140
 #define TSE_PCS_IF_MODE_REG				0x28
 #define TSE_PCS_LINK_TIMER_0_REG			0x24
 #define TSE_PCS_LINK_TIMER_1_REG			0x26
@@ -65,6 +66,7 @@
 #define TSE_PCS_SW_RESET_TIMEOUT			100
 #define TSE_PCS_USE_SGMII_AN_MASK			BIT(1)
 #define TSE_PCS_USE_SGMII_ENA				BIT(0)
+#define TSE_PCS_IF_USE_SGMII				0x03
 
 #define SGMII_ADAPTER_CTRL_REG				0x00
 #define SGMII_ADAPTER_DISABLE				0x0001
@@ -101,7 +103,9 @@ int tse_pcs_init(void __iomem *base, struct tse_pcs *pcs)
 {
 	int ret = 0;
 
-	writew(TSE_PCS_USE_SGMII_ENA, base + TSE_PCS_IF_MODE_REG);
+	writew(TSE_PCS_IF_USE_SGMII, base + TSE_PCS_IF_MODE_REG);
+
+	writew(TSE_PCS_CTRL_AUTONEG_SGMII, base + TSE_PCS_CONTROL_REG);
 
 	writew(TSE_PCS_SGMII_LINK_TIMER_0, base + TSE_PCS_LINK_TIMER_0_REG);
 	writew(TSE_PCS_SGMII_LINK_TIMER_1, base + TSE_PCS_LINK_TIMER_1_REG);