[PATCH net-next 1/2] net: pcs: xpcs: enable skip xPCS soft reset

[Wong Vee Khee <vee.khee.wong@linux.intel.com>]

From: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>

Unlike any other platforms, Intel AlderLake-S uses Synopsys SerDes where
all the SerDes PLL configurations are controlled by the xPCS at the BIOS
level. If the driver perform a xPCS soft reset on initialization, these
settings will be switched back to the power on reset values.

This changes the xpcs_create function to take in an additional argument
to check if the platform request to skip xPCS soft reset during device
initialization.

Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
---
 drivers/net/dsa/sja1105/sja1105_mdio.c           |  2 +-
 .../net/ethernet/stmicro/stmmac/stmmac_mdio.c    |  4 +++-
 drivers/net/pcs/pcs-xpcs.c                       | 16 ++++++++++++----
 include/linux/pcs/pcs-xpcs.h                     |  3 ++-
 include/linux/stmmac.h                           |  1 +
 5 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/net/dsa/sja1105/sja1105_mdio.c b/drivers/net/dsa/sja1105/sja1105_mdio.c
index 19aea8fb76f6..73b43a5da68a 100644
--- a/drivers/net/dsa/sja1105/sja1105_mdio.c
+++ b/drivers/net/dsa/sja1105/sja1105_mdio.c
@@ -437,7 +437,7 @@ static int sja1105_mdiobus_pcs_register(struct sja1105_private *priv)
 			goto out_pcs_free;
 		}
 
-		xpcs = xpcs_create(mdiodev, priv->phy_mode[port]);
+		xpcs = xpcs_create(mdiodev, priv->phy_mode[port], false);
 		if (IS_ERR(xpcs)) {
 			rc = PTR_ERR(xpcs);
 			goto out_pcs_free;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
index a5d150c5f3d8..803a4e61105b 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
@@ -401,12 +401,14 @@ int stmmac_xpcs_setup(struct mii_bus *bus)
 {
 	struct net_device *ndev = bus->priv;
 	struct mdio_device *mdiodev;
+	bool skip_xpcs_soft_reset;
 	struct stmmac_priv *priv;
 	struct dw_xpcs *xpcs;
 	int mode, addr;
 
 	priv = netdev_priv(ndev);
 	mode = priv->plat->phy_interface;
+	skip_xpcs_soft_reset = priv->plat->skip_xpcs_soft_reset;
 
 	/* Try to probe the XPCS by scanning all addresses. */
 	for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
@@ -414,7 +416,7 @@ int stmmac_xpcs_setup(struct mii_bus *bus)
 		if (IS_ERR(mdiodev))
 			continue;
 
-		xpcs = xpcs_create(mdiodev, mode);
+		xpcs = xpcs_create(mdiodev, mode, skip_xpcs_soft_reset);
 		if (IS_ERR_OR_NULL(xpcs)) {
 			mdio_device_free(mdiodev);
 			continue;
diff --git a/drivers/net/pcs/pcs-xpcs.c b/drivers/net/pcs/pcs-xpcs.c
index 63fda3fc40aa..c7a3aa862079 100644
--- a/drivers/net/pcs/pcs-xpcs.c
+++ b/drivers/net/pcs/pcs-xpcs.c
@@ -1081,7 +1081,8 @@ static const struct phylink_pcs_ops xpcs_phylink_ops = {
 };
 
 struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
-			    phy_interface_t interface)
+			    phy_interface_t interface,
+			    bool skip_reset)
 {
 	struct dw_xpcs *xpcs;
 	u32 xpcs_id;
@@ -1113,9 +1114,16 @@ struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
 		xpcs->pcs.ops = &xpcs_phylink_ops;
 		xpcs->pcs.poll = true;
 
-		ret = xpcs_soft_reset(xpcs, compat);
-		if (ret)
-			goto out;
+		if (!skip_reset) {
+			dev_info(&xpcs->mdiodev->dev, "%s: xPCS soft reset\n",
+				 __func__);
+			ret = xpcs_soft_reset(xpcs, compat);
+			if (ret)
+				goto out;
+		} else {
+			dev_info(&xpcs->mdiodev->dev,
+				 "%s: skip xpcs soft reset\n", __func__);
+		}
 
 		return xpcs;
 	}
diff --git a/include/linux/pcs/pcs-xpcs.h b/include/linux/pcs/pcs-xpcs.h
index add077a81b21..0c05a63f3446 100644
--- a/include/linux/pcs/pcs-xpcs.h
+++ b/include/linux/pcs/pcs-xpcs.h
@@ -36,7 +36,8 @@ void xpcs_validate(struct dw_xpcs *xpcs, unsigned long *supported,
 int xpcs_config_eee(struct dw_xpcs *xpcs, int mult_fact_100ns,
 		    int enable);
 struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
-			    phy_interface_t interface);
+			    phy_interface_t interface,
+			    bool xpcs_reset);
 void xpcs_destroy(struct dw_xpcs *xpcs);
 
 #endif /* __LINUX_PCS_XPCS_H */
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index a6f03b36fc4f..0f901773c5e4 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -268,5 +268,6 @@ struct plat_stmmacenet_data {
 	int msi_rx_base_vec;
 	int msi_tx_base_vec;
 	bool use_phy_wol;
+	bool skip_xpcs_soft_reset;
 };
 #endif
-- 
2.25.1