From 90b940c249e4624b36534572482ec06d4e23c195 Mon Sep 17 00:00:00 2001

From: Jan Hoffmann <jan@3e8.eu>

Date: Wed, 1 Sep 2021 20:49:33 +0200

Subject: [PATCH] net: dsa: lantiq_gswip: fix maximum frame length

Git-commit: 552799f8b3b0074d2617f53a63a088f9514a66e3

Patch-mainline: v5.15-rc1

References: stable-5.14.6

commit 552799f8b3b0074d2617f53a63a088f9514a66e3 upstream.

Currently, outgoing packets larger than 1496 bytes are dropped when

tagged VLAN is used on a switch port.

Add the frame check sequence length to the value of the register

GSWIP_MAC_FLEN to fix this. This matches the lantiq_ppa vendor driver,

which uses a value consisting of 1518 bytes for the MAC frame, plus the

lengths of special tag and VLAN tags.

Fixes: 14fceff4771e ("net: dsa: Add Lantiq / Intel DSA driver for vrx200")

Cc: stable@vger.kernel.org

Signed-off-by: Jan Hoffmann <jan@3e8.eu>

Acked-by: Hauke Mehrtens <hauke@hauke-m.de>

Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/net/dsa/lantiq_gswip.c | 3 ++-

 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/lantiq_gswip.c b/drivers/net/dsa/lantiq_gswip.c

index e78026ef6d8c..64d6dfa83122 100644

--- a/drivers/net/dsa/lantiq_gswip.c

+++ b/drivers/net/dsa/lantiq_gswip.c

@@ -843,7 +843,8 @@ static int gswip_setup(struct dsa_switch *ds)

 	gswip_switch_mask(priv, 0, GSWIP_MAC_CTRL_2_MLEN,

 			  GSWIP_MAC_CTRL_2p(cpu_port));

-	gswip_switch_w(priv, VLAN_ETH_FRAME_LEN + 8, GSWIP_MAC_FLEN);

+	gswip_switch_w(priv, VLAN_ETH_FRAME_LEN + 8 + ETH_FCS_LEN,

+		       GSWIP_MAC_FLEN);

 	gswip_switch_mask(priv, 0, GSWIP_BM_QUEUE_GCTRL_GL_MOD,

 			  GSWIP_BM_QUEUE_GCTRL);

-- 

2.26.2