net: dsa: qca8k: set internal delay also for sgmii

QCA original code report port instability and sa that SGMII also require
to set internal delay. Generalize the rgmii delay function and apply the
advised value if they are not defined in DT.

Signed-off-by: Ansuel Smith <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/dsa/qca8k.c

···
 		case PHY_INTERFACE_MODE_RGMII_ID:
 		case PHY_INTERFACE_MODE_RGMII_TXID:
 		case PHY_INTERFACE_MODE_RGMII_RXID:
+		case PHY_INTERFACE_MODE_SGMII:
 			delay = 0;
 
 			if (!of_property_read_u32(port_dn, "tx-internal-delay-ps", &delay))
···
 
 			priv->rgmii_rx_delay[cpu_port_index] = delay;
 
-			break;
-		case PHY_INTERFACE_MODE_SGMII:
+			/* Skip sgmii parsing for rgmii* mode */
+			if (mode == PHY_INTERFACE_MODE_RGMII ||
+			    mode == PHY_INTERFACE_MODE_RGMII_ID ||
+			    mode == PHY_INTERFACE_MODE_RGMII_TXID ||
+			    mode == PHY_INTERFACE_MODE_RGMII_RXID)
+				break;
+
 			if (of_property_read_bool(port_dn, "qca,sgmii-txclk-falling-edge"))
 				priv->sgmii_tx_clk_falling_edge = true;
 
···
 }
 
 static void
+qca8k_mac_config_setup_internal_delay(struct qca8k_priv *priv, int cpu_port_index,
+				      u32 reg)
+{
+	u32 delay, val = 0;
+	int ret;
+
+	/* Delay can be declared in 3 different way.
+	 * Mode to rgmii and internal-delay standard binding defined
+	 * rgmii-id or rgmii-tx/rx phy mode set.
+	 * The parse logic set a delay different than 0 only when one
+	 * of the 3 different way is used. In all other case delay is
+	 * not enabled. With ID or TX/RXID delay is enabled and set
+	 * to the default and recommended value.
+	 */
+	if (priv->rgmii_tx_delay[cpu_port_index]) {
+		delay = priv->rgmii_tx_delay[cpu_port_index];
+
+		val |= QCA8K_PORT_PAD_RGMII_TX_DELAY(delay) |
+			QCA8K_PORT_PAD_RGMII_TX_DELAY_EN;
+	}
+
+	if (priv->rgmii_rx_delay[cpu_port_index]) {
+		delay = priv->rgmii_rx_delay[cpu_port_index];
+
+		val |= QCA8K_PORT_PAD_RGMII_RX_DELAY(delay) |
+			QCA8K_PORT_PAD_RGMII_RX_DELAY_EN;
+	}
+
+	/* Set RGMII delay based on the selected values */
+	ret = qca8k_rmw(priv, reg,
+			QCA8K_PORT_PAD_RGMII_TX_DELAY_MASK |
+			QCA8K_PORT_PAD_RGMII_RX_DELAY_MASK |
+			QCA8K_PORT_PAD_RGMII_TX_DELAY_EN |
+			QCA8K_PORT_PAD_RGMII_RX_DELAY_EN,
+			val);
+	if (ret)
+		dev_err(priv->dev, "Failed to set internal delay for CPU port%d",
+			cpu_port_index == QCA8K_CPU_PORT0 ? 0 : 6);
+}
+
+static void
 qca8k_phylink_mac_config(struct dsa_switch *ds, int port, unsigned int mode,
 			 const struct phylink_link_state *state)
 {
 	struct qca8k_priv *priv = ds->priv;
 	int cpu_port_index, ret;
-	u32 reg, val, delay;
+	u32 reg, val;
 
 	switch (port) {
 	case 0: /* 1st CPU port */
···
 	case PHY_INTERFACE_MODE_RGMII_ID:
 	case PHY_INTERFACE_MODE_RGMII_TXID:
 	case PHY_INTERFACE_MODE_RGMII_RXID:
-		val = QCA8K_PORT_PAD_RGMII_EN;
+		qca8k_write(priv, reg, QCA8K_PORT_PAD_RGMII_EN);
 
-		/* Delay can be declared in 3 different way.
-		 * Mode to rgmii and internal-delay standard binding defined
-		 * rgmii-id or rgmii-tx/rx phy mode set.
-		 * The parse logic set a delay different than 0 only when one
-		 * of the 3 different way is used. In all other case delay is
-		 * not enabled. With ID or TX/RXID delay is enabled and set
-		 * to the default and recommended value.
-		 */
-		if (priv->rgmii_tx_delay[cpu_port_index]) {
-			delay = priv->rgmii_tx_delay[cpu_port_index];
-
-			val |= QCA8K_PORT_PAD_RGMII_TX_DELAY(delay) |
-			       QCA8K_PORT_PAD_RGMII_TX_DELAY_EN;
-		}
-
-		if (priv->rgmii_rx_delay[cpu_port_index]) {
-			delay = priv->rgmii_rx_delay[cpu_port_index];
-
-			val |= QCA8K_PORT_PAD_RGMII_RX_DELAY(delay) |
-			       QCA8K_PORT_PAD_RGMII_RX_DELAY_EN;
-		}
-
-		/* Set RGMII delay based on the selected values */
-		qca8k_write(priv, reg, val);
+		/* Configure rgmii delay */
+		qca8k_mac_config_setup_internal_delay(priv, cpu_port_index, reg);
 
 		/* QCA8337 requires to set rgmii rx delay for all ports.
 		 * This is enabled through PORT5_PAD_CTRL for all ports,
···
 					QCA8K_PORT0_PAD_SGMII_RXCLK_FALLING_EDGE |
 					QCA8K_PORT0_PAD_SGMII_TXCLK_FALLING_EDGE,
 					val);
+
+		/* From original code is reported port instability as SGMII also
+		 * require delay set. Apply advised values here or take them from DT.
+		 */
+		if (state->interface == PHY_INTERFACE_MODE_SGMII)
+			qca8k_mac_config_setup_internal_delay(priv, cpu_port_index, reg);
+
 		break;
 	default:
 		dev_err(ds->dev, "xMII mode %s not supported for port %d\n",

drivers/net/dsa/qca8k.h

···
 #define QCA8K_REG_PORT5_PAD_CTRL			0x008
 #define QCA8K_REG_PORT6_PAD_CTRL			0x00c
 #define   QCA8K_PORT_PAD_RGMII_EN			BIT(26)
+#define   QCA8K_PORT_PAD_RGMII_TX_DELAY_MASK		GENMASK(23, 22)
 #define   QCA8K_PORT_PAD_RGMII_TX_DELAY(x)		((x) << 22)
+#define   QCA8K_PORT_PAD_RGMII_RX_DELAY_MASK		GENMASK(21, 20)
 #define   QCA8K_PORT_PAD_RGMII_RX_DELAY(x)		((x) << 20)
 #define	  QCA8K_PORT_PAD_RGMII_TX_DELAY_EN		BIT(25)
 #define   QCA8K_PORT_PAD_RGMII_RX_DELAY_EN		BIT(24)