[PATCH 5.15 311/317] net: dsa: mt7530: fix handling of LLDP frames

[Sasha Levin]

From: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>

[ Upstream commit 8332cf6fd7c7087dbc2067115b33979c9851bbc4 ]

LLDP frames are link-local frames, therefore they must be trapped to the
CPU port. Currently, the MT753X switches treat LLDP frames as regular
multicast frames, therefore flooding them to user ports. To fix this, set
LLDP frames to be trapped to the CPU port(s).

Fixes: b8f126a8d543 ("net-next: dsa: add dsa support for Mediatek MT7530 switch")
Signed-off-by: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>
Reviewed-by: Vladimir Oltean <olteanv@xxxxxxxxx>
Reviewed-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
Reviewed-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Stable-dep-of: e8bf353577f3 ("net: dsa: mt7530: fix link-local frames that ingress vlan filtering ports")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/dsa/mt7530.c | 4 ++++
 drivers/net/dsa/mt7530.h | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 636943035c292..252e8eaa92767 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -999,6 +999,10 @@ mt753x_trap_frames(struct mt7530_priv *priv)
 	/* Trap BPDUs to the CPU port(s) */
 	mt7530_rmw(priv, MT753X_BPC, MT753X_BPDU_PORT_FW_MASK,
 		   MT753X_BPDU_CPU_ONLY);
+
+	/* Trap LLDP frames with :0E MAC DA to the CPU port(s) */
+	mt7530_rmw(priv, MT753X_RGAC2, MT753X_R0E_PORT_FW_MASK,
+		   MT753X_R0E_PORT_FW(MT753X_BPDU_CPU_ONLY));
 }
 
 static int
diff --git a/drivers/net/dsa/mt7530.h b/drivers/net/dsa/mt7530.h
index 91508e2feef95..8cee462d5f1cb 100644
--- a/drivers/net/dsa/mt7530.h
+++ b/drivers/net/dsa/mt7530.h
@@ -66,6 +66,11 @@ enum mt753x_id {
 #define MT753X_BPC			0x24
 #define  MT753X_BPDU_PORT_FW_MASK	GENMASK(2, 0)
 
+/* Register for :03 and :0E MAC DA frame control */
+#define MT753X_RGAC2			0x2c
+#define  MT753X_R0E_PORT_FW_MASK	GENMASK(18, 16)
+#define  MT753X_R0E_PORT_FW(x)		FIELD_PREP(MT753X_R0E_PORT_FW_MASK, x)
+
 enum mt753x_bpdu_port_fw {
 	MT753X_BPDU_FOLLOW_MFC,
 	MT753X_BPDU_CPU_EXCLUDE = 4,
-- 
2.43.0