net: dsa: sja1105: Rethink the PHYLINK callbacks

The first fact that needs to be stated is that the per-MAC settings in
SJA1105 called EGRESS and INGRESS do *not* disable egress and ingress on
the MAC. They only prevent non-link-local traffic from being
sent/received on this port.

So instead of having .phylink_mac_config essentially mess with the STP
state and force it to DISABLED/BLOCKING (which also brings useless
complications in sja1105_static_config_reload), simply add the
.phylink_mac_link_down and .phylink_mac_link_up callbacks which inhibit
TX at the MAC level, while leaving RX essentially enabled.

Also stop from trying to put the link down in .phylink_mac_config, which
is incorrect.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/sja1105/sja1105_main.c

@@ -695,18 +695,10 @@ static int sja1105_speed[] = {
 	[SJA1105_SPEED_1000MBPS]	= SPEED_1000,
 };
 
-/* Set link speed and enable/disable traffic I/O in the MAC configuration
- * for a specific port.
- *
- * @speed_mbps: If 0, leave the speed unchanged, else adapt MAC to PHY speed.
- * @enabled: Manage Rx and Tx settings for this port. If false, overrides the
- *	     settings from the STP state, but not persistently (does not
- *	     overwrite the static MAC info for this port).
- */
+/* Set link speed in the MAC configuration for a specific port. */
 static int sja1105_adjust_port_config(struct sja1105_private *priv, int port,
-				      int speed_mbps, bool enabled)
+				      int speed_mbps)
 {
-	struct sja1105_mac_config_entry dyn_mac;
 	struct sja1105_xmii_params_entry *mii;
 	struct sja1105_mac_config_entry *mac;
 	struct device *dev = priv->ds->dev;
@@ -714,8 +706,14 @@ static int sja1105_adjust_port_config(struct sja1105_private *priv, int port,
 	sja1105_speed_t speed;
 	int rc;
 
-	mii = priv->static_config.tables[BLK_IDX_XMII_PARAMS].entries;
+	/* On P/Q/R/S, one can read from the device via the MAC reconfiguration
+	 * tables. On E/T, MAC reconfig tables are not readable, only writable.
+	 * We have to *know* what the MAC looks like.  For the sake of keeping
+	 * the code common, we'll use the static configuration tables as a
+	 * reasonable approximation for both E/T and P/Q/R/S.
+	 */
 	mac = priv->static_config.tables[BLK_IDX_MAC_CONFIG].entries;
+	mii = priv->static_config.tables[BLK_IDX_XMII_PARAMS].entries;
 
 	switch (speed_mbps) {
 	case SPEED_UNKNOWN:
@@ -736,26 +734,16 @@ static int sja1105_adjust_port_config(struct sja1105_private *priv, int port,
 		return -EINVAL;
 	}
 
-	/* If requested, overwrite SJA1105_SPEED_AUTO from the static MAC
-	 * configuration table, since this will be used for the clocking setup,
-	 * and we no longer need to store it in the static config (already told
-	 * hardware we want auto during upload phase).
+	/* Overwrite SJA1105_SPEED_AUTO from the static MAC configuration
+	 * table, since this will be used for the clocking setup, and we no
+	 * longer need to store it in the static config (already told hardware
+	 * we want auto during upload phase).
 	 */
 	mac[port].speed = speed;
 
-	/* On P/Q/R/S, one can read from the device via the MAC reconfiguration
-	 * tables. On E/T, MAC reconfig tables are not readable, only writable.
-	 * We have to *know* what the MAC looks like.  For the sake of keeping
-	 * the code common, we'll use the static configuration tables as a
-	 * reasonable approximation for both E/T and P/Q/R/S.
-	 */
-	dyn_mac = mac[port];
-	dyn_mac.ingress = enabled && mac[port].ingress;
-	dyn_mac.egress  = enabled && mac[port].egress;
-
 	/* Write to the dynamic reconfiguration tables */
-	rc = sja1105_dynamic_config_write(priv, BLK_IDX_MAC_CONFIG,
-					  port, &dyn_mac, true);
+	rc = sja1105_dynamic_config_write(priv, BLK_IDX_MAC_CONFIG, port,
+					  &mac[port], true);
 	if (rc < 0) {
 		dev_err(dev, "Failed to write MAC config: %d\n", rc);
 		return rc;
@@ -767,9 +755,6 @@ static int sja1105_adjust_port_config(struct sja1105_private *priv, int port,
 	 * the clock setup does interrupt the clock signal for a certain time
 	 * which causes trouble for all PHYs relying on this signal.
 	 */
-	if (!enabled)
-		return 0;
-
 	phy_mode = mii->xmii_mode[port];
 	if (phy_mode != XMII_MODE_RGMII)
 		return 0;
@@ -784,9 +769,24 @@ static void sja1105_mac_config(struct dsa_switch *ds, int port,
 	struct sja1105_private *priv = ds->priv;
 
 	if (!state->link)
-		sja1105_adjust_port_config(priv, port, SPEED_UNKNOWN, false);
-	else
-		sja1105_adjust_port_config(priv, port, state->speed, true);
+		return;
+
+	sja1105_adjust_port_config(priv, port, state->speed);
+}
+
+static void sja1105_mac_link_down(struct dsa_switch *ds, int port,
+				  unsigned int mode,
+				  phy_interface_t interface)
+{
+	sja1105_inhibit_tx(ds->priv, BIT(port), true);
+}
+
+static void sja1105_mac_link_up(struct dsa_switch *ds, int port,
+				unsigned int mode,
+				phy_interface_t interface,
+				struct phy_device *phydev)
+{
+	sja1105_inhibit_tx(ds->priv, BIT(port), false);
 }
 
 static void sja1105_phylink_validate(struct dsa_switch *ds, int port,
@@ -1241,27 +1241,6 @@ static void sja1105_bridge_leave(struct dsa_switch *ds, int port,
 	sja1105_bridge_member(ds, port, br, false);
 }
 
-static u8 sja1105_stp_state_get(struct sja1105_private *priv, int port)
-{
-	struct sja1105_mac_config_entry *mac;
-
-	mac = priv->static_config.tables[BLK_IDX_MAC_CONFIG].entries;
-
-	if (!mac[port].ingress && !mac[port].egress && !mac[port].dyn_learn)
-		return BR_STATE_BLOCKING;
-	if (mac[port].ingress && !mac[port].egress && !mac[port].dyn_learn)
-		return BR_STATE_LISTENING;
-	if (mac[port].ingress && !mac[port].egress && mac[port].dyn_learn)
-		return BR_STATE_LEARNING;
-	if (mac[port].ingress && mac[port].egress && mac[port].dyn_learn)
-		return BR_STATE_FORWARDING;
-	/* This is really an error condition if the MAC was in none of the STP
-	 * states above. But treating the port as disabled does nothing, which
-	 * is adequate, and it also resets the MAC to a known state later on.
-	 */
-	return BR_STATE_DISABLED;
-}
-
 /* For situations where we need to change a setting at runtime that is only
  * available through the static configuration, resetting the switch in order
  * to upload the new static config is unavoidable. Back up the settings we
@@ -1272,27 +1251,18 @@ static int sja1105_static_config_reload(struct sja1105_private *priv)
 {
 	struct sja1105_mac_config_entry *mac;
 	int speed_mbps[SJA1105_NUM_PORTS];
-	u8 stp_state[SJA1105_NUM_PORTS];
 	int rc, i;
 
 	mac = priv->static_config.tables[BLK_IDX_MAC_CONFIG].entries;
 
-	/* Back up settings changed by sja1105_adjust_port_config and
-	 * sja1105_bridge_stp_state_set and restore their defaults.
+	/* Back up the dynamic link speed changed by sja1105_adjust_port_config
+	 * in order to temporarily restore it to SJA1105_SPEED_AUTO - which the
+	 * switch wants to see in the static config in order to allow us to
+	 * change it through the dynamic interface later.
 	 */
 	for (i = 0; i < SJA1105_NUM_PORTS; i++) {
 		speed_mbps[i] = sja1105_speed[mac[i].speed];
 		mac[i].speed = SJA1105_SPEED_AUTO;
-		if (i == dsa_upstream_port(priv->ds, i)) {
-			mac[i].ingress = true;
-			mac[i].egress = true;
-			mac[i].dyn_learn = true;
-		} else {
-			stp_state[i] = sja1105_stp_state_get(priv, i);
-			mac[i].ingress = false;
-			mac[i].egress = false;
-			mac[i].dyn_learn = false;
-		}
 	}
 
 	/* Reset switch and send updated static configuration */
@@ -1309,13 +1279,7 @@ static int sja1105_static_config_reload(struct sja1105_private *priv)
 		goto out;
 
 	for (i = 0; i < SJA1105_NUM_PORTS; i++) {
-		bool enabled = (speed_mbps[i] != SPEED_UNKNOWN);
-
-		if (i != dsa_upstream_port(priv->ds, i))
-			sja1105_bridge_stp_state_set(priv->ds, i, stp_state[i]);
-
-		rc = sja1105_adjust_port_config(priv, i, speed_mbps[i],
-						enabled);
+		rc = sja1105_adjust_port_config(priv, i, speed_mbps[i]);
 		if (rc < 0)
 			goto out;
 	}
@@ -1921,6 +1885,8 @@ static const struct dsa_switch_ops sja1105_switch_ops = {
 	.set_ageing_time	= sja1105_set_ageing_time,
 	.phylink_validate	= sja1105_phylink_validate,
 	.phylink_mac_config	= sja1105_mac_config,
+	.phylink_mac_link_up	= sja1105_mac_link_up,
+	.phylink_mac_link_down	= sja1105_mac_link_down,
 	.get_strings		= sja1105_get_strings,
 	.get_ethtool_stats	= sja1105_get_ethtool_stats,
 	.get_sset_count		= sja1105_get_sset_count,