net: mtk_eth_soc: move restoration of SYSCFG0 to mac_finish()

The SGMIISYS configuration is performed while ETHSYS_SYSCFG0 is in a
disabled state. In order to preserve this when we switch to phylink_pcs
we need to move the restoration of this register to the mac_finish()
callback.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -400,8 +400,8 @@ static void mtk_mac_config(struct phylink_config *config, unsigned int mode,
 		if (err)
 			goto init_err;
 
-		regmap_update_bits(eth->ethsys, ETHSYS_SYSCFG0,
-				   SYSCFG0_SGMII_MASK, val);
+		/* Save the syscfg0 value for mac_finish */
+		mac->syscfg0 = val;
 	} else if (phylink_autoneg_inband(mode)) {
 		dev_err(eth->dev,
 			"In-band mode not supported in non SGMII mode!\n");
@@ -425,8 +425,15 @@ static int mtk_mac_finish(struct phylink_config *config, unsigned int mode,
 {
 	struct mtk_mac *mac = container_of(config, struct mtk_mac,
 					   phylink_config);
+	struct mtk_eth *eth = mac->hw;
 	u32 mcr_cur, mcr_new;
 
+	/* Enable SGMII */
+	if (interface == PHY_INTERFACE_MODE_SGMII ||
+	    phy_interface_mode_is_8023z(interface))
+		regmap_update_bits(eth->ethsys, ETHSYS_SYSCFG0,
+				   SYSCFG0_SGMII_MASK, mac->syscfg0);
+
 	/* Setup gmac */
 	mcr_cur = mtk_r32(mac->hw, MTK_MAC_MCR(mac->id));
 	mcr_new = mcr_cur;

drivers/net/ethernet/mediatek/mtk_eth_soc.h

@@ -1001,6 +1001,7 @@ struct mtk_mac {
 	struct mtk_hw_stats		*hw_stats;
 	__be32				hwlro_ip[MTK_MAX_LRO_IP_CNT];
 	int				hwlro_ip_cnt;
+	unsigned int			syscfg0;
 };
 
 /* the struct describing the SoC. these are declared in the soc_xyz.c files */