[PATCH net-next v13 06/10] net: stmmac: qcom-ethqos: update phy_mode to the resolved interface in mac_finish()

[Bartosz Golaszewski]

ethqos->phy_mode is read by serdes_powerup() and
qcom_ethqos_set_sgmii_loopback() to configure the SerDes and its
wrapper for the correct interface. It is set once at probe from the DT
phy-mode property and never updated.

phylink resolves the actual runtime interface and passes it to the
mac_finish() callback. On platforms that only ever operate at one speed
these two values are always the same, but when the interface changes
at runtime - for example switching between SGMII and 2500BASE-X — the
stored value becomes stale. The next serdes_powerup() call, on
a subsequent link cycle, then reinitialises the SerDes to the wrong mode.

Update ethqos->phy_mode from the interface argument in
ethqos_mac_finish_serdes() so that it always reflects the last
resolved interface.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski at oss.qualcomm.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
index 47b70b5e706f221c01f1c0ae3b1acafae6641165..9d19203ae4bd7dc17aca068f5eb88ff830e4e906 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
@@ -632,6 +632,12 @@ static int ethqos_mac_finish_serdes(struct net_device *ndev, void *priv,
 	struct qcom_ethqos *ethqos = priv;
 	int ret = 0;
 
+	/* The interface mode is only known once phylink has resolved it and
+	 * may change at runtime, so keep it in sync for later
+	 * serdes_powerup()/serdes_powerdown() calls.
+	 */
+	ethqos->phy_mode = interface;
+
 	qcom_ethqos_set_sgmii_loopback(ethqos, false);
 
 	if (interface == PHY_INTERFACE_MODE_SGMII ||

-- 
2.47.3