Merge branch 'net-pcs-add-supported_interfaces-bitmap-for-pcs'

Russell King says:

====================
net: pcs: add supported_interfaces bitmap for PCS

This series adds supported_interfaces for PCS, which gives MAC code
a way to determine the interface modes that the PCS supports without
having to implement functions such as xpcs_get_interfaces(), or
workarounds such as in

 https://lore.kernel.org/20241213090526.71516-3-maxime.chevallier@bootlin.com

Patch 1 adds the new bitmask to struct phylink_pcs, and code within
phylink to validate that the PCS returned by the MAC driver supports
the interface mode - but only if this bitmask is non-empty.

Patch 2 through 4 fills in the interface modes for XPCS, Mediatek LynxI
and Lynx PCS.

Patch 5 adds support to stmmac to make use of this bitmask when filling
in phylink_config.supported_interfaces, eliminating the call to
xpcs_get_interfaces.

As xpcs_get_interfaces() is now unused outside of pcs-xpcs.c, patch 6
makes this function static and removes it from the header file.
====================

Link: https://patch.msgid.link/Z3fG9oTY9F9fCYHv@shell.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

7 files changed, 43 insertions, 5 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 99eaec8bac4a..2f518ec845ec 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1203,6 +1203,7 @@ static int stmmac_phy_setup(struct stmmac_priv *priv)
 	struct stmmac_mdio_bus_data *mdio_bus_data;
 	int mode = priv->plat->phy_interface;
 	struct fwnode_handle *fwnode;
+	struct phylink_pcs *pcs;
 	struct phylink *phylink;
 
 	priv->phylink_config.dev = &priv->dev->dev;
@@ -1224,8 +1225,14 @@ static int stmmac_phy_setup(struct stmmac_priv *priv)
 
 	/* If we have an xpcs, it defines which PHY interfaces are supported. */
 	if (priv->hw->xpcs)
-		xpcs_get_interfaces(priv->hw->xpcs,
-				    priv->phylink_config.supported_interfaces);
+		pcs = xpcs_to_phylink_pcs(priv->hw->xpcs);
+	else
+		pcs = priv->hw->phylink_pcs;
+
+	if (pcs)
+		phy_interface_or(priv->phylink_config.supported_interfaces,
+				 priv->phylink_config.supported_interfaces,
+				 pcs->supported_interfaces);
 
 	fwnode = priv->plat->port_node;
 	if (!fwnode)
diff --git a/drivers/net/pcs/pcs-lynx.c b/drivers/net/pcs/pcs-lynx.c
index 767a8c0714ac..6457190ec6e7 100644
--- a/drivers/net/pcs/pcs-lynx.c
+++ b/drivers/net/pcs/pcs-lynx.c
@@ -334,9 +334,19 @@ static const struct phylink_pcs_ops lynx_pcs_phylink_ops = {
 	.pcs_link_up = lynx_pcs_link_up,
 };
 
+static const phy_interface_t lynx_interfaces[] = {
+	PHY_INTERFACE_MODE_SGMII,
+	PHY_INTERFACE_MODE_QSGMII,
+	PHY_INTERFACE_MODE_1000BASEX,
+	PHY_INTERFACE_MODE_2500BASEX,
+	PHY_INTERFACE_MODE_10GBASER,
+	PHY_INTERFACE_MODE_USXGMII,
+};
+
 static struct phylink_pcs *lynx_pcs_create(struct mdio_device *mdio)
 {
 	struct lynx_pcs *lynx;
+	int i;
 
 	lynx = kzalloc(sizeof(*lynx), GFP_KERNEL);
 	if (!lynx)
@@ -348,6 +358,9 @@ static struct phylink_pcs *lynx_pcs_create(struct mdio_device *mdio)
 	lynx->pcs.neg_mode = true;
 	lynx->pcs.poll = true;
 
+	for (i = 0; i < ARRAY_SIZE(lynx_interfaces); i++)
+		__set_bit(lynx_interfaces[i], lynx->pcs.supported_interfaces);
+
 	return lynx_to_phylink_pcs(lynx);
 }
 
diff --git a/drivers/net/pcs/pcs-mtk-lynxi.c b/drivers/net/pcs/pcs-mtk-lynxi.c
index ed91cd7a406a..4fe0fb6d12a4 100644
--- a/drivers/net/pcs/pcs-mtk-lynxi.c
+++ b/drivers/net/pcs/pcs-mtk-lynxi.c
@@ -307,6 +307,10 @@ struct phylink_pcs *mtk_pcs_lynxi_create(struct device *dev,
 	mpcs->pcs.poll = true;
 	mpcs->interface = PHY_INTERFACE_MODE_NA;
 
+	__set_bit(PHY_INTERFACE_MODE_SGMII, mpcs->pcs.supported_interfaces);
+	__set_bit(PHY_INTERFACE_MODE_1000BASEX, mpcs->pcs.supported_interfaces);
+	__set_bit(PHY_INTERFACE_MODE_2500BASEX, mpcs->pcs.supported_interfaces);
+
 	return &mpcs->pcs;
 }
 EXPORT_SYMBOL(mtk_pcs_lynxi_create);
diff --git a/drivers/net/pcs/pcs-xpcs.c b/drivers/net/pcs/pcs-xpcs.c
index f70ca39f0905..c06b66f40022 100644
--- a/drivers/net/pcs/pcs-xpcs.c
+++ b/drivers/net/pcs/pcs-xpcs.c
@@ -594,14 +594,13 @@ static unsigned int xpcs_inband_caps(struct phylink_pcs *pcs,
 	}
 }
 
-void xpcs_get_interfaces(struct dw_xpcs *xpcs, unsigned long *interfaces)
+static void xpcs_get_interfaces(struct dw_xpcs *xpcs, unsigned long *interfaces)
 {
 	const struct dw_xpcs_compat *compat;
 
 	for (compat = xpcs->desc->compat; compat->supported; compat++)
 		__set_bit(compat->interface, interfaces);
 }
-EXPORT_SYMBOL_GPL(xpcs_get_interfaces);
 
 int xpcs_config_eee(struct dw_xpcs *xpcs, int mult_fact_100ns, int enable)
 {
@@ -1446,6 +1445,8 @@ static struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev)
 	if (ret)
 		goto out_clear_clks;
 
+	xpcs_get_interfaces(xpcs, xpcs->pcs.supported_interfaces);
+
 	if (xpcs->info.pma == WX_TXGBE_XPCS_PMA_10G_ID)
 		xpcs->pcs.poll = false;
 	else
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 6d50c2fdb190..31754d5fd659 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -691,6 +691,17 @@ static int phylink_validate_mac_and_pcs(struct phylink *pl,
 			return -EINVAL;
 		}
 
+		/* Ensure that this PCS supports the interface which the MAC
+		 * returned it for. It is an error for the MAC to return a PCS
+		 * that does not support the interface mode.
+		 */
+		if (!phy_interface_empty(pcs->supported_interfaces) &&
+		    !test_bit(state->interface, pcs->supported_interfaces)) {
+			phylink_err(pl, "MAC returned PCS which does not support %s\n",
+				    phy_modes(state->interface));
+			return -EINVAL;
+		}
+
 		/* Validate the link parameters with the PCS */
 		if (pcs->ops->pcs_validate) {
 			ret = pcs->ops->pcs_validate(pcs, supported, state);
diff --git a/include/linux/pcs/pcs-xpcs.h b/include/linux/pcs/pcs-xpcs.h
index b5b5d17998b8..733f4ddd2ef1 100644
--- a/include/linux/pcs/pcs-xpcs.h
+++ b/include/linux/pcs/pcs-xpcs.h
@@ -50,7 +50,6 @@ struct dw_xpcs;
 
 struct phylink_pcs *xpcs_to_phylink_pcs(struct dw_xpcs *xpcs);
 int xpcs_get_an_mode(struct dw_xpcs *xpcs, phy_interface_t interface);
-void xpcs_get_interfaces(struct dw_xpcs *xpcs, unsigned long *interfaces);
 int xpcs_config_eee(struct dw_xpcs *xpcs, int mult_fact_100ns,
 		    int enable);
 struct dw_xpcs *xpcs_create_mdiodev(struct mii_bus *bus, int addr);
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index 5462cc6a37dc..4b7a20620b49 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -393,6 +393,8 @@ struct phylink_pcs_ops;
 
 /**
  * struct phylink_pcs - PHYLINK PCS instance
+ * @supported_interfaces: describing which PHY_INTERFACE_MODE_xxx
+ *                        are supported by this PCS.
  * @ops: a pointer to the &struct phylink_pcs_ops structure
  * @phylink: pointer to &struct phylink_config
  * @neg_mode: provide PCS neg mode via "mode" argument
@@ -409,6 +411,7 @@ struct phylink_pcs_ops;
  * the PCS driver.
  */
 struct phylink_pcs {
+	DECLARE_PHY_INTERFACE_MASK(supported_interfaces);
 	const struct phylink_pcs_ops *ops;
 	struct phylink *phylink;
 	bool neg_mode;