* [PATCH net 1/2] net: dsa: mt7530: use consistent egress tag for trapped link-local frames
[not found] <20260919065214.31604-1-gongtao0607@gmail.com>
@ 2026-09-19 6:52 ` Tao
2026-09-19 6:52 ` [PATCH net 2/2] net: dsa: mt7530: trap frames to conduit in MFC on EN7581 and AN7583 Tao
1 sibling, 0 replies; 3+ messages in thread
From: Tao @ 2026-09-19 6:52 UTC (permalink / raw)
To: netdev
Cc: Tao, Chester A. Unal, Daniel Golle, Andrew Lunn, Vladimir Oltean,
David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Matthias Brugger, AngeloGioacchino Del Regno, linux-kernel,
linux-arm-kernel, linux-mediatek
commit 3ac85bcfd404 ("net: dsa: mt7530: preserve VLAN tags on trapped
link-local frames") changed the egress VLAN tag attribute for trapped
link-local frames in BPC, RGAC1, and RGAC2 from MT7530_VLAN_EG_UNTAGGED
to MT7530_VLAN_EG_DISABLED, with the intention of passing frames
through without VLAN tag modification.
However, in MT7530 hardware, MT7530_VLAN_EG_DISABLED disables the
protocol-level egress tagging override, causing trapped frames to
fall back to the egress port's active VLAN table (VAWD2) rule. When a
bridge with VLAN filtering is active, the CPU port is configured with
stack mode, causing the switch to insert a VLAN tag into incoming
untagged BPDUs (01:80:C2:00:00:00) and other link-local frames before
delivering them to the CPU conduit.
Because BPDUs arrive at the CPU with a VLAN tag (EtherType 0x8100
at offset 12 instead of 802.3 length <= 1500), userspace STP daemons
(such as ustpd) and the kernel bridge drop or ignore them, breaking
STP convergence.
Use MT7530_VLAN_EG_CONSISTENT instead. This instructs the hardware to
keep egress tagging consistent with the ingress wire format: frames
received untagged on the wire remain untagged when forwarded to the
CPU, while VLAN-tagged frames preserve their original VLAN tag.
Fixes: 3ac85bcfd404 ("net: dsa: mt7530: preserve VLAN tags on trapped link-local frames")
Signed-off-by: Tao <gongtao0607@gmail.com>
---
drivers/net/dsa/mt7530.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 14692497e1a6..863f2079833f 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -1245,39 +1245,39 @@ static void
mt753x_trap_frames(struct mt7530_priv *priv)
{
/* Trap 802.1X PAE frames and BPDUs to the CPU port(s) and egress
- * them with the EG_TAG attribute set to disabled (system default)
- * so that any VLAN tags in the frame are not modified by the
- * switch egress VLAN tag processing. This preserves VLAN tags
- * for reception on VLAN sub-interfaces.
+ * them with the EG_TAG attribute set to consistent so that any
+ * VLAN tags in the frame are not modified by the switch egress
+ * VLAN tag processing. This preserves VLAN tags for reception
+ * on VLAN sub-interfaces.
*/
regmap_update_bits(priv->regmap, MT753X_BPC,
PAE_BPDU_FR | PAE_EG_TAG_MASK | PAE_PORT_FW_MASK |
BPDU_EG_TAG_MASK | BPDU_PORT_FW_MASK,
- PAE_BPDU_FR | PAE_EG_TAG(MT7530_VLAN_EG_DISABLED) |
+ PAE_BPDU_FR | PAE_EG_TAG(MT7530_VLAN_EG_CONSISTENT) |
PAE_PORT_FW(TO_CPU_FW_CPU_ONLY) |
- BPDU_EG_TAG(MT7530_VLAN_EG_DISABLED) |
+ BPDU_EG_TAG(MT7530_VLAN_EG_CONSISTENT) |
TO_CPU_FW_CPU_ONLY);
/* Trap frames with :01 and :02 MAC DAs to the CPU port(s) and
- * egress them with EG_TAG disabled.
+ * egress them with EG_TAG consistent.
*/
regmap_update_bits(priv->regmap, MT753X_RGAC1,
R02_BPDU_FR | R02_EG_TAG_MASK | R02_PORT_FW_MASK |
R01_BPDU_FR | R01_EG_TAG_MASK | R01_PORT_FW_MASK,
- R02_BPDU_FR | R02_EG_TAG(MT7530_VLAN_EG_DISABLED) |
+ R02_BPDU_FR | R02_EG_TAG(MT7530_VLAN_EG_CONSISTENT) |
R02_PORT_FW(TO_CPU_FW_CPU_ONLY) | R01_BPDU_FR |
- R01_EG_TAG(MT7530_VLAN_EG_DISABLED) |
+ R01_EG_TAG(MT7530_VLAN_EG_CONSISTENT) |
TO_CPU_FW_CPU_ONLY);
/* Trap frames with :03 and :0E MAC DAs to the CPU port(s) and
- * egress them with EG_TAG disabled.
+ * egress them with EG_TAG consistent.
*/
regmap_update_bits(priv->regmap, MT753X_RGAC2,
R0E_BPDU_FR | R0E_EG_TAG_MASK | R0E_PORT_FW_MASK |
R03_BPDU_FR | R03_EG_TAG_MASK | R03_PORT_FW_MASK,
- R0E_BPDU_FR | R0E_EG_TAG(MT7530_VLAN_EG_DISABLED) |
+ R0E_BPDU_FR | R0E_EG_TAG(MT7530_VLAN_EG_CONSISTENT) |
R0E_PORT_FW(TO_CPU_FW_CPU_ONLY) | R03_BPDU_FR |
- R03_EG_TAG(MT7530_VLAN_EG_DISABLED) |
+ R03_EG_TAG(MT7530_VLAN_EG_CONSISTENT) |
TO_CPU_FW_CPU_ONLY);
}
--
2.55.0
^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH net 2/2] net: dsa: mt7530: trap frames to conduit in MFC on EN7581 and AN7583
[not found] <20260919065214.31604-1-gongtao0607@gmail.com>
2026-09-19 6:52 ` [PATCH net 1/2] net: dsa: mt7530: use consistent egress tag for trapped link-local frames Tao
@ 2026-09-19 6:52 ` Tao
2026-09-19 17:32 ` Lorenzo Bianconi
1 sibling, 1 reply; 3+ messages in thread
From: Tao @ 2026-09-19 6:52 UTC (permalink / raw)
To: netdev
Cc: Tao, Chester A. Unal, Daniel Golle, Andrew Lunn, Vladimir Oltean,
David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Matthias Brugger, AngeloGioacchino Del Regno, Florian Fainelli,
Arınç ÜNAL, Lorenzo Bianconi, linux-kernel,
linux-arm-kernel, linux-mediatek
On MT7531 and MT7988 switches, trapped frames forwarding is directed to
CPU ports specified in the MT7531_CFC (0x04) CPU_PMAP bitmap. When support
for EN7581 was introduced, it was assumed to follow the MT7531 model.
However, on Airoha EN7581 and AN7583 switch IP, setting MT7531_CFC alone
is not sufficient for trapped control frames (such as STP BPDUs) to exit
towards the CPU port. The switch forwarding hardware also requires the
MT7530_CPU_EN bit and MT7530_CPU_PORT field to be enabled in MT753X_MFC
(0x10). Without this, trapped frames are dropped by the switch forwarding
logic and never reach the CPU conduit.
Include ID_EN7581 and ID_AN7583 in mt753x_conduit_state_change() to set
MT7530_CPU_EN and MT7530_CPU_PORT in MT753X_MFC when the conduit becomes
operational, matching the handling for MT7530, MT7621, and EN7528.
Fixes: 2b0229f67932 ("net: dsa: mt7530: Add EN7581 support")
Signed-off-by: Tao <gongtao0607@gmail.com>
---
drivers/net/dsa/mt7530.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 863f2079833f..9693a55f553e 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -3309,7 +3309,8 @@ mt753x_conduit_state_change(struct dsa_switch *ds,
* interface is up.
*/
if (priv->id != ID_MT7530 && priv->id != ID_MT7621 &&
- priv->id != ID_EN7528)
+ priv->id != ID_EN7528 &&
+ priv->id != ID_EN7581 && priv->id != ID_AN7583)
return;
mask = BIT(cpu_dp->index);
--
2.55.0
^ permalink raw reply [flat|nested] 3+ messages in thread