This is a note to let you know that I've just added the patch titled
net: ethernet: ti: am65-cpsw: Fix max mtu to fit ethernet frames
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-ethernet-ti-am65-cpsw-fix-max-mtu-to-fit-etherne.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0b8903a6fd15648cd4e543b6b3c50b3239d9948a
Author: Sanjuán García, Jorge <Jorge.SanjuanGarcia@xxxxxxxxxx>
Date: Fri Jan 5 08:55:43 2024 +0000
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 <jorge.sanjuangarcia@xxxxxxxxxx>
Reviewed-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
Reviewed-by: Siddharth Vadapalli <s-vadapalli@xxxxxx>
Link: https://lore.kernel.org/r/20240105085530.14070-2-jorge.sanjuangarcia@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 24120605502f..c62b0f99f2bc 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -56,7 +56,7 @@
#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
@@ -2167,7 +2167,8 @@ am65_cpsw_nuss_init_port_ndev(struct am65_cpsw_common *common, u32 port_idx)
eth_hw_addr_set(port->ndev, 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 |
