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

From: Wong Vee Khee
Date: Mon Aug 09 2021 - 06:17:30 EST


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

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@xxxxxxx>
Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit@xxxxxxxxx>
Signed-off-by: Wong Vee Khee <vee.khee.wong@xxxxxxxxxxxxxxx>
---
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