Thread (29 messages) flat view 29 messages, 5 authors, 2026-03-19

Re: [net-next,11/14] net: dsa: netc: add phylink MAC operations

From: Simon Horman <horms@kernel.org>
Date: 2026-03-18 14:47:11
Also in: imx, linux-arm-kernel, linux-devicetree, lkml, netdev

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---
net: dsa: netc: add phylink MAC operations

This commit adds phylink MAC operations to the NETC DSA switch driver,
including support for different PHY interface modes (RGMII, RMII, MII,
REVMII, SGMII, 2500BASE-X).
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/dsa/netc/netc_main.c b/drivers/net/dsa/netc/netc_main.c
index bc7d48b99610..884ee899fc89 100644
--- a/drivers/net/dsa/netc/netc_main.c
+++ b/drivers/net/dsa/netc/netc_main.c
[ ... ]
quoted hunk ↗ jump to hunk
@@ -595,10 +595,221 @@ static void netc_switch_get_ip_revision(struct netc_switch *priv)
 	priv->revision = val & IPBRR0_IP_REV;
 }

+static void netc_phylink_get_caps(struct dsa_switch *ds, int port,
+				  struct phylink_config *config)
+{
+	struct netc_switch *priv = ds->priv;
+
+	priv->info->phylink_get_caps(port, config);
+}
+
+static void netc_port_set_mac_mode(struct netc_port *np,
+				   unsigned int mode,
+				   phy_interface_t phy_mode)
+{
+	u32 mask = PM_IF_MODE_IFMODE | PM_IF_MODE_ENA;
+	u32 val = 0;
+
+	switch (phy_mode) {
+	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		val |= IFMODE_RGMII;
+		/* Enable auto-negotiation for the MAC if its
+		 * RGMII interface supports In-Band status.
+		 */
+		if (phylink_autoneg_inband(mode))
+			val |= PM_IF_MODE_ENA;
+		break;
+	case PHY_INTERFACE_MODE_RMII:
+		val |= IFMODE_RMII;
+		break;
+	case PHY_INTERFACE_MODE_REVMII:
+		val |= PM_IF_MODE_REVMII;
+		fallthrough;
+	case PHY_INTERFACE_MODE_MII:
+		val |= IFMODE_MII;
+		break;
Does the mask need to include PM_IF_MODE_REVMII? Looking at
netc_port_set_mac_mode(), the mask is set to:

    u32 mask = PM_IF_MODE_IFMODE | PM_IF_MODE_ENA;

which expands to GENMASK(2,0) | BIT(15) = 0x8007. When the REVMII
case sets val |= PM_IF_MODE_REVMII (BIT(3)), this makes val = 0x9.

In netc_mac_port_rmw(), there's a check:

    WARN_ON((mask | val) != mask)

This check would fire on every REVMII configuration since 0x800F != 0x8007.

Additionally, REVMII is reachable because imx94_switch_phylink_get_caps()
advertises PHY_INTERFACE_MODE_REVMII as supported for port 2. When
transitioning FROM REVMII to another mode, PM_IF_MODE_REVMII (BIT(3))
won't be cleared since it's not in the mask, leaving stale configuration.

Should the mask be:

    u32 mask = PM_IF_MODE_IFMODE | PM_IF_MODE_REVMII | PM_IF_MODE_ENA;
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_2500BASEX:
+		val |= IFMODE_SGMII;
+		break;
+	default:
+		break;
+	}
+
+	netc_mac_port_rmw(np, NETC_PM_IF_MODE(0), mask, val);
+}
[ ... ]
+static void netc_port_force_set_rgmii_mac(struct netc_port *np,
+					  int speed, int duplex)
+{
+	u32 mask, val;
+
+	mask = PM_IF_MODE_ENA | PM_IF_MODE_SSP | PM_IF_MODE_HD |
+	       PM_IF_MODE_M10 | PM_IF_MODE_REVMII;
+
+	switch (speed) {
+	default:
+	case SPEED_1000:
+		val = FIELD_PREP(PM_IF_MODE_SSP, SSP_1G);
+		break;
+	case SPEED_100:
+		val = FIELD_PREP(PM_IF_MODE_SSP, SSP_100M);
+		break;
+	case SPEED_10:
+		val = FIELD_PREP(PM_IF_MODE_SSP, SSP_10M);
+		break;
+	}
+
+	if (duplex != DUPLEX_FULL)
+		val |= PM_IF_MODE_HD;
+
+	netc_mac_port_rmw(np, NETC_PM_IF_MODE(0), mask, val);
+}
+
+static void net_port_set_rmii_mii_mac(struct netc_port *np,
This isn't a bug, but should this function be named
netc_port_set_rmii_mii_mac() instead of net_port_set_rmii_mii_mac()?
All other functions in this driver use the netc_ prefix
(netc_port_set_speed, netc_port_force_set_rgmii_mac,
netc_port_set_mac_mode, etc.).
+				      int speed, int duplex)
+{
+	u32 mask, val = 0;
+
+	mask = PM_IF_MODE_ENA | PM_IF_MODE_SSP | PM_IF_MODE_HD |
+	       PM_IF_MODE_M10;
+
+	if (speed == SPEED_10)
+		val |= PM_IF_MODE_M10;
+
+	if (duplex != DUPLEX_FULL)
+		val |= PM_IF_MODE_HD;
+
+	netc_mac_port_rmw(np, NETC_PM_IF_MODE(0), mask, val);
+}
[ ... ]
quoted hunk ↗ jump to hunk
+static void netc_mac_link_up(struct phylink_config *config,
+			     struct phy_device *phy, unsigned int mode,
+			     phy_interface_t interface, int speed,
+			     int duplex, bool tx_pause, bool rx_pause)
+{
+	struct dsa_port *dp = dsa_phylink_to_port(config);
+	struct netc_port *np;
+
+	np = NETC_PORT(dp->ds, dp->index);
+	netc_port_set_speed(np, speed);
+
+	if (phy_interface_mode_is_rgmii(interface) &&
+	    !phylink_autoneg_inband(mode)) {
+		netc_port_force_set_rgmii_mac(np, speed, duplex);
+	}
+
+	if (interface == PHY_INTERFACE_MODE_RMII ||
+	    interface == PHY_INTERFACE_MODE_REVMII ||
+	    interface == PHY_INTERFACE_MODE_MII) {
+		net_port_set_rmii_mii_mac(np, speed, duplex);
+	}
+
+	netc_port_set_hd_flow_control(np, duplex == DUPLEX_HALF);
+	netc_port_mac_rx_enable(np);
+}
+
+static void netc_mac_link_down(struct phylink_config *config,
+			       unsigned int mode,
+			       phy_interface_t interface)
+{
+	struct dsa_port *dp = dsa_phylink_to_port(config);
+
+	netc_port_mac_rx_graceful_stop(NETC_PORT(dp->ds, dp->index));
+}
+
+static const struct phylink_mac_ops netc_phylink_mac_ops = {
+	.mac_config		= netc_mac_config,
+	.mac_link_up		= netc_mac_link_up,
+	.mac_link_down		= netc_mac_link_down,
+};
+
 static const struct dsa_switch_ops netc_switch_ops = {
 	.get_tag_protocol		= netc_get_tag_protocol,
 	.setup				= netc_setup,
 	.teardown			= netc_teardown,
+	.phylink_get_caps		= netc_phylink_get_caps,
 };

 static int netc_switch_probe(struct pci_dev *pdev,
@@ -639,6 +850,7 @@ static int netc_switch_probe(struct pci_dev *pdev,
 	ds->num_ports = priv->info->num_ports;
 	ds->num_tx_queues = NETC_TC_NUM;
 	ds->ops = &netc_switch_ops;
+	ds->phylink_mac_ops = &netc_phylink_mac_ops;
 	ds->priv = priv;

 	priv->ds = ds;
[ ... ]
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