net: ethernet: ti: am65-cpsw: Move mode specific config to mac_config()

Move the interface mode specific configuration to the mac_config()
callback am65_cpsw_nuss_mac_config().

Also, do not reset the MAC Control register on mac_link_down(). Only
clear those bits that can possibly be set in mac_link_up().

Let the MAC remain in IDLE state after mac_link_down(). Bring it out of
the IDLE state on mac_link_up().
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/ti/am65-cpsw-nuss.c

@@ -1506,9 +1506,13 @@ static void am65_cpsw_nuss_mac_config(struct phylink_config *config, unsigned in
 	struct am65_cpsw_common *common = port->common;
 
 	if (common->pdata.extra_modes & BIT(state->interface)) {
-		if (state->interface == PHY_INTERFACE_MODE_SGMII)
+		if (state->interface == PHY_INTERFACE_MODE_SGMII) {
 			writel(ADVERTISE_SGMII,
 			       port->sgmii_base + AM65_CPSW_SGMII_MR_ADV_ABILITY_REG);
+			cpsw_sl_ctl_set(port->slave.mac_sl, CPSW_SL_CTL_EXT_EN);
+		} else {
+			cpsw_sl_ctl_clr(port->slave.mac_sl, CPSW_SL_CTL_EXT_EN);
+		}
 
 		writel(AM65_CPSW_SGMII_CONTROL_MR_AN_ENABLE,
 		       port->sgmii_base + AM65_CPSW_SGMII_CONTROL_REG);
@@ -1523,6 +1527,7 @@ static void am65_cpsw_nuss_mac_link_down(struct phylink_config *config, unsigned
 	struct am65_cpsw_port *port = container_of(slave, struct am65_cpsw_port, slave);
 	struct am65_cpsw_common *common = port->common;
 	struct net_device *ndev = port->ndev;
+	u32 mac_control;
 	int tmo;
 
 	/* disable forwarding */
@@ -1534,7 +1539,14 @@ static void am65_cpsw_nuss_mac_link_down(struct phylink_config *config, unsigned
 	dev_dbg(common->dev, "down msc_sl %08x tmo %d\n",
 		cpsw_sl_reg_read(port->slave.mac_sl, CPSW_SL_MACSTATUS), tmo);
 
-	cpsw_sl_ctl_reset(port->slave.mac_sl);
+	/* All the bits that am65_cpsw_nuss_mac_link_up() can possibly set */
+	mac_control = CPSW_SL_CTL_GMII_EN | CPSW_SL_CTL_GIG | CPSW_SL_CTL_IFCTL_A |
+		      CPSW_SL_CTL_FULLDUPLEX | CPSW_SL_CTL_RX_FLOW_EN | CPSW_SL_CTL_TX_FLOW_EN;
+	/* If interface mode is RGMII, CPSW_SL_CTL_EXT_EN might have been set for 10 Mbps */
+	if (phy_interface_mode_is_rgmii(interface))
+		mac_control |= CPSW_SL_CTL_EXT_EN;
+	/* Only clear those bits that can be set by am65_cpsw_nuss_mac_link_up() */
+	cpsw_sl_ctl_clr(port->slave.mac_sl, mac_control);
 
 	am65_cpsw_qos_link_down(ndev);
 	netif_tx_stop_all_queues(ndev);
@@ -1551,10 +1563,12 @@ static void am65_cpsw_nuss_mac_link_up(struct phylink_config *config, struct phy
 	u32 mac_control = CPSW_SL_CTL_GMII_EN;
 	struct net_device *ndev = port->ndev;
 
+	/* Bring the port out of idle state */
+	cpsw_sl_ctl_clr(port->slave.mac_sl, CPSW_SL_CTL_CMD_IDLE);
+
 	if (speed == SPEED_1000)
 		mac_control |= CPSW_SL_CTL_GIG;
-	if (interface == PHY_INTERFACE_MODE_SGMII)
-		mac_control |= CPSW_SL_CTL_EXT_EN;
+	/* TODO: Verify whether in-band is necessary for 10 Mbps RGMII */
 	if (speed == SPEED_10 && phy_interface_mode_is_rgmii(interface))
 		/* Can be used with in band mode only */
 		mac_control |= CPSW_SL_CTL_EXT_EN;