Commit 486c2922 authored by Horatiu Vultur's avatar Horatiu Vultur Committed by Jakub Kicinski
Browse files

net: lan966x: Fix the MTU calculation 



When the MTU was changed, the lan966x didn't take in consideration
the L2 header and the FCS. So the HW was configured with a smaller
value than what was desired. Therefore the correct value to configure
the HW would be new_mtu + ETH_HLEN + ETH_FCS_LEN.
The vlan tag is not considered here, because at the time when the
blamed commit was added, there was no vlan filtering support. The
vlan fix will be part of the next patch.

Fixes: d28d6d2e ("net: lan966x: add port module support")
Signed-off-by: default avatarHoratiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 6c412da5

drivers/net/ethernet/microchip/lan966x/lan966x_main.c

+1 −1
Original line number Diff line number Diff line
@@ -386,7 +386,7 @@ static int lan966x_port_change_mtu(struct net_device *dev, int new_mtu) 
	int old_mtu = dev->mtu;

	int err;



	lan_wr(DEV_MAC_MAXLEN_CFG_MAX_LEN_SET(new_mtu),

	lan_wr(DEV_MAC_MAXLEN_CFG_MAX_LEN_SET(LAN966X_HW_MTU(new_mtu)),

	       lan966x, DEV_MAC_MAXLEN_CFG(port->chip_port));

	dev->mtu = new_mtu;

drivers/net/ethernet/microchip/lan966x/lan966x_main.h

+2 −0
Original line number Diff line number Diff line
@@ -26,6 +26,8 @@ 
#define LAN966X_BUFFER_MEMORY		(160 * 1024)

#define LAN966X_BUFFER_MIN_SZ		60



#define LAN966X_HW_MTU(mtu)		((mtu) + ETH_HLEN + ETH_FCS_LEN)



#define PGID_AGGR			64

#define PGID_SRC			80

#define PGID_ENTRIES			89