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net: lan966x: Fix the MTU calculation

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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: d28d6d2e37d1 ("net: lan966x: add port module support")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Horatiu Vultur 2022-10-30 22:36:34 +01:00 committed by Jakub Kicinski
parent 6c412da54c
commit 486c292230
2 changed files with 3 additions and 1 deletions
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2
drivers/net/ethernet/microchip/lan966x/lan966x_main.c
View File

@ -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;

2
drivers/net/ethernet/microchip/lan966x/lan966x_main.h
View File

@ -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