From a1e4f4d11da3793774cdb28839e6362f6b5d3fa0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Sanju=C3=A1n=20Garc=C3=ADa=2C=20Jorge?= Date: Fri, 5 Jan 2024 08:55:43 +0000 Subject: [PATCH] net: ethernet: ti: am65-cpsw: Fix max mtu to fit ethernet frames [ Upstream commit 64e47d8afb5ca533b27efc006405e5bcae2c4a7b ] The value of AM65_CPSW_MAX_PACKET_SIZE represents the maximum length of a received frame. This value is written to the register AM65_CPSW_PORT_REG_RX_MAXLEN. The maximum MTU configured on the network device should then leave some room for the ethernet headers and frame check. Otherwise, if the network interface is configured to its maximum mtu possible, the frames will be larger than AM65_CPSW_MAX_PACKET_SIZE and will get dropped as oversized. The switch supports ethernet frame sizes between 64 and 2024 bytes (including VLAN) as stated in the technical reference manual, so define AM65_CPSW_MAX_PACKET_SIZE with that maximum size. Fixes: 93a76530316a ("net: ethernet: ti: introduce am65x/j721e gigabit eth subsystem driver") Signed-off-by: Jorge Sanjuan Garcia Reviewed-by: Horatiu Vultur Reviewed-by: Siddharth Vadapalli Link: https://lore.kernel.org/r/20240105085530.14070-2-jorge.sanjuangarcia@duagon.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/ti/am65-cpsw-nuss.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c index f14554ce7..3696ef851 100755 --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c @@ -51,7 +51,7 @@ #define AM65_CPSW_MAX_PORTS 8 #define AM65_CPSW_MIN_PACKET_SIZE VLAN_ETH_ZLEN -#define AM65_CPSW_MAX_PACKET_SIZE (VLAN_ETH_FRAME_LEN + ETH_FCS_LEN) +#define AM65_CPSW_MAX_PACKET_SIZE 2024 #define AM65_CPSW_REG_CTL 0x004 #define AM65_CPSW_REG_STAT_PORT_EN 0x014 @@ -1852,7 +1852,8 @@ static int am65_cpsw_nuss_init_ndev_2g(struct am65_cpsw_common *common) ether_addr_copy(port->ndev->dev_addr, port->slave.mac_addr); port->ndev->min_mtu = AM65_CPSW_MIN_PACKET_SIZE; - port->ndev->max_mtu = AM65_CPSW_MAX_PACKET_SIZE; + port->ndev->max_mtu = AM65_CPSW_MAX_PACKET_SIZE - + (VLAN_ETH_HLEN + ETH_FCS_LEN); port->ndev->hw_features = NETIF_F_SG | NETIF_F_RXCSUM | NETIF_F_HW_CSUM |