From 26ace1c775e8862bb5403098a7d35803bcc6a143 Mon Sep 17 00:00:00 2001 From: Andrew Lunn Date: Sun, 26 Sep 2021 19:41:26 +0200 Subject: [PATCH] dsa: mv88e6xxx: Include tagger overhead when setting MTU for DSA and CPU ports MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Same members of the Marvell Ethernet switches impose MTU restrictions on ports used for connecting to the CPU or another switch for DSA. If the MTU is set too low, tagged frames will be discarded. Ensure the worst case tagger overhead is included in setting the MTU for DSA and CPU ports. Fixes: bf90e25f24c4 ("net: dsa: mv88e6xxx: Use chip-wide max frame size for MTU") Reported by: 曹煜 Signed-off-by: Andrew Lunn Signed-off-by: David S. Miller --- drivers/net/dsa/mv88e6xxx/chip.c | 9 ++++++--- drivers/net/dsa/mv88e6xxx/chip.h | 1 + 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c index ed4a6d18142b7..03744d1c43fc2 100644 --- a/drivers/net/dsa/mv88e6xxx/chip.c +++ b/drivers/net/dsa/mv88e6xxx/chip.c @@ -2944,10 +2944,10 @@ static int mv88e6xxx_get_max_mtu(struct dsa_switch *ds, int port) struct mv88e6xxx_chip *chip = ds->priv; if (chip->info->ops->port_set_jumbo_size) - return 10240 - VLAN_ETH_HLEN - ETH_FCS_LEN; + return 10240 - VLAN_ETH_HLEN - EDSA_HLEN - ETH_FCS_LEN; else if (chip->info->ops->set_max_frame_size) - return 1632 - VLAN_ETH_HLEN - ETH_FCS_LEN; - return 1522 - VLAN_ETH_HLEN - ETH_FCS_LEN; + return 1632 - VLAN_ETH_HLEN - EDSA_HLEN - ETH_FCS_LEN; + return 1522 - VLAN_ETH_HLEN - EDSA_HLEN - ETH_FCS_LEN; } static int mv88e6xxx_change_mtu(struct dsa_switch *ds, int port, int new_mtu) @@ -2955,6 +2955,9 @@ static int mv88e6xxx_change_mtu(struct dsa_switch *ds, int port, int new_mtu) struct mv88e6xxx_chip *chip = ds->priv; int ret = 0; + if (dsa_is_dsa_port(ds, port) || dsa_is_cpu_port(ds, port)) + new_mtu += EDSA_HLEN; + mv88e6xxx_reg_lock(chip); if (chip->info->ops->port_set_jumbo_size) ret = chip->info->ops->port_set_jumbo_size(chip, port, new_mtu); diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h index 675b1f3e43b7b..59f316cc8583e 100644 --- a/drivers/net/dsa/mv88e6xxx/chip.h +++ b/drivers/net/dsa/mv88e6xxx/chip.h @@ -18,6 +18,7 @@ #include #include +#define EDSA_HLEN 8 #define MV88E6XXX_N_FID 4096 /* PVT limits for 4-bit port and 5-bit switch */ -- 2.39.5