net: stmmac: Set MAC's flow control register to reflect current settings

Currently, pause frame register GMAC_RX_FLOW_CTRL_RFE is not updated
correctly when 'ethtool -A <IFACE> autoneg off rx off tx off' command
is issued. This fix ensures the flow control change is reflected directly
in the GMAC_RX_FLOW_CTRL_RFE register.

Fixes: 46f69de ("net: stmmac: Use resolved link config in mac_link_up()")
Cc: <stable@vger.kernel.org> # 5.10.x
Signed-off-by: Goh, Wei Sheng <wei.sheng.goh@intel.com>
Signed-off-by: Noor Azura Ahmad Tarmizi <noor.azura.ahmad.tarmizi@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c

@@ -748,6 +748,8 @@ static void dwmac4_flow_ctrl(struct mac_device_info *hw, unsigned int duplex,
 	if (fc & FLOW_RX) {
 		pr_debug("\tReceive Flow-Control ON\n");
 		flow |= GMAC_RX_FLOW_CTRL_RFE;
+	} else {
+		pr_debug("\tReceive Flow-Control OFF\n");
 	}
 	writel(flow, ioaddr + GMAC_RX_FLOW_CTRL);
 

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

@@ -1061,8 +1061,16 @@ static void stmmac_mac_link_up(struct phylink_config *config,
 		ctrl |= priv->hw->link.duplex;
 
 	/* Flow Control operation */
-	if (tx_pause && rx_pause)
-		stmmac_mac_flow_ctrl(priv, duplex);
+	if (rx_pause && tx_pause)
+		priv->flow_ctrl = FLOW_AUTO;
+	else if (rx_pause && !tx_pause)
+		priv->flow_ctrl = FLOW_RX;
+	else if (!rx_pause && tx_pause)
+		priv->flow_ctrl = FLOW_TX;
+	else
+		priv->flow_ctrl = FLOW_OFF;
+
+	stmmac_mac_flow_ctrl(priv, duplex);
 
 	if (ctrl != old_ctrl)
 		writel(ctrl, priv->ioaddr + MAC_CTRL_REG);