net: dsa: rtl8366rb: Implement setting up link on CPU port

We auto-negotiate most ports in the RTL8366RB driver, but
the CPU port is hard-coded to 1Gbit, full duplex, tx and
rx pause.

This isn't very nice. People may configure speed and
duplex differently in the device tree.

Actually respect the arguments passed to the function for
the CPU port, which get passed properly after Russell's
patch "net: dsa: realtek: add phylink_get_caps implementation"

After this the link is still set up properly.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/realtek/rtl8366rb.c

@@ -95,12 +95,6 @@
 #define RTL8366RB_PAACR_RX_PAUSE	BIT(6)
 #define RTL8366RB_PAACR_AN		BIT(7)
 
-#define RTL8366RB_PAACR_CPU_PORT	(RTL8366RB_PAACR_SPEED_1000M | \
-					 RTL8366RB_PAACR_FULL_DUPLEX | \
-					 RTL8366RB_PAACR_LINK_UP | \
-					 RTL8366RB_PAACR_TX_PAUSE | \
-					 RTL8366RB_PAACR_RX_PAUSE)
-
 /* bits 0..7 = port 0, bits 8..15 = port 1 */
 #define RTL8366RB_PSTAT0		0x0014
 /* bits 0..7 = port 2, bits 8..15 = port 3 */
@@ -1081,29 +1075,61 @@ rtl8366rb_mac_link_up(struct dsa_switch *ds, int port, unsigned int mode,
 		      int speed, int duplex, bool tx_pause, bool rx_pause)
 {
 	struct realtek_priv *priv = ds->priv;
+	unsigned int val;
 	int ret;
 
+	/* Allow forcing the mode on the fixed CPU port, no autonegotiation.
+	 * We assume autonegotiation works on the PHY-facing ports.
+	 */
 	if (port != priv->cpu_port)
 		return;
 
 	dev_dbg(priv->dev, "MAC link up on CPU port (%d)\n", port);
 
-	/* Force the fixed CPU port into 1Gbit mode, no autonegotiation */
 	ret = regmap_update_bits(priv->map, RTL8366RB_MAC_FORCE_CTRL_REG,
 				 BIT(port), BIT(port));
 	if (ret) {
-		dev_err(priv->dev, "failed to force 1Gbit on CPU port\n");
+		dev_err(priv->dev, "failed to force CPU port\n");
 		return;
 	}
 
+	/* Conjure port config */
+	switch (speed) {
+	case SPEED_10:
+		val = RTL8366RB_PAACR_SPEED_10M;
+		break;
+	case SPEED_100:
+		val = RTL8366RB_PAACR_SPEED_100M;
+		break;
+	case SPEED_1000:
+		val = RTL8366RB_PAACR_SPEED_1000M;
+		break;
+	default:
+		val = RTL8366RB_PAACR_SPEED_1000M;
+		break;
+	}
+
+	if (duplex == DUPLEX_FULL)
+		val |= RTL8366RB_PAACR_FULL_DUPLEX;
+
+	if (tx_pause)
+		val |=  RTL8366RB_PAACR_TX_PAUSE;
+
+	if (rx_pause)
+		val |= RTL8366RB_PAACR_RX_PAUSE;
+
+	val |= RTL8366RB_PAACR_LINK_UP;
+
 	ret = regmap_update_bits(priv->map, RTL8366RB_PAACR2,
 				 0xFF00U,
-				 RTL8366RB_PAACR_CPU_PORT << 8);
+				 val << 8);
 	if (ret) {
 		dev_err(priv->dev, "failed to set PAACR on CPU port\n");
 		return;
 	}
 
+	dev_dbg(priv->dev, "set PAACR to %04x\n", val);
+
 	/* Enable the CPU port */
 	ret = regmap_update_bits(priv->map, RTL8366RB_PECR, BIT(port),
 				 0);