[PATCH net v1 1/1] net: dsa: microchip: Correct initialization order for KSZ88x3 ports

[Oleksij Rempel]

Adjust the initialization sequence of KSZ88x3 switches to enable
802.1p priority control on Port 2 before configuring Port 1. This
change ensures the apptrust functionality on Port 1 operates
correctly, as it depends on the priority settings of Port 2. The
prior initialization sequence incorrectly configured Port 1 first,
which could lead to functional discrepancies.

Fixes: a1ea57710c9d ("net: dsa: microchip: dcb: add special handling for KSZ88X3 family")
Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
 drivers/net/dsa/microchip/ksz_dcb.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/net/dsa/microchip/ksz_dcb.c b/drivers/net/dsa/microchip/ksz_dcb.c
index a971063275629..19b228b849247 100644
--- a/drivers/net/dsa/microchip/ksz_dcb.c
+++ b/drivers/net/dsa/microchip/ksz_dcb.c
@@ -805,5 +805,18 @@ int ksz_dcb_init(struct ksz_device *dev)
 	if (ret)
 		return ret;
 
+	/* Enable 802.1p priority control on Port 2 during switch initialization.
+	 * This setup is critical for the apptrust functionality on Port 1, which
+	 * relies on the priority settings of Port 2. Note: Port 1 is naturally
+	 * configured before Port 2, necessitating this configuration order.
+	 */
+	if (ksz_is_ksz88x3(dev)) {
+		ret = ksz_prmw8(dev, KSZ_PORT_2, KSZ8_REG_PORT_1_CTRL_0,
+				KSZ8_PORT_802_1P_ENABLE,
+				KSZ8_PORT_802_1P_ENABLE);
+		if (ret)
+			return ret;
+	}
+
 	return 0;
 }
-- 
2.39.2