From 807e5eda2078327d1adaf213cf7d6b3862cad1f4 Mon Sep 17 00:00:00 2001 From: Rakesh Sankaranarayanan Date: Mon, 12 Sep 2022 10:42:28 +0530 Subject: net: dsa: microchip: lan937x: fix maximum frame length check Maximum frame length check is enabled in lan937x switch on POR, But it is found to be disabled on driver during port setup operation. Due to this, packets are not dropped when transmitted with greater than configured value. For testing, setup made for lan1->lan2 transmission and configured lan1 interface with a frame length (less than 1500 as mentioned in documentation) and transmitted packets with greater than configured value. Expected no packets at lan2 end, but packets observed at lan2. Based on the documentation, packets should get discarded if the actual packet length doesn't match the frame length configured. Frame length check should be disabled only for cascaded ports due to tailtags. This feature was disabled on ksz9477 series due to ptp issue, which is not in lan937x series. But since lan937x took ksz9477 as base, frame length check disabled here as well. Patch added to remove this portion from port setup so that maximum frame length check will be active for normal ports. Fixes: 55ab6ffaf378 ("net: dsa: microchip: add DSA support for microchip LAN937x") Signed-off-by: Rakesh Sankaranarayanan Link: https://lore.kernel.org/r/20220912051228.1306074-1-rakesh.sankaranarayanan@microchip.com Signed-off-by: Paolo Abeni --- drivers/net/dsa/microchip/lan937x_main.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'drivers/net/dsa') diff --git a/drivers/net/dsa/microchip/lan937x_main.c b/drivers/net/dsa/microchip/lan937x_main.c index daedd2bf20c1..5579644e8fde 100644 --- a/drivers/net/dsa/microchip/lan937x_main.c +++ b/drivers/net/dsa/microchip/lan937x_main.c @@ -244,10 +244,6 @@ void lan937x_port_setup(struct ksz_device *dev, int port, bool cpu_port) lan937x_port_cfg(dev, port, REG_PORT_CTRL_0, PORT_TAIL_TAG_ENABLE, true); - /* disable frame check length field */ - lan937x_port_cfg(dev, port, REG_PORT_MAC_CTRL_0, PORT_CHECK_LENGTH, - false); - /* set back pressure for half duplex */ lan937x_port_cfg(dev, port, REG_PORT_MAC_CTRL_1, PORT_BACK_PRESSURE, true); -- cgit v1.2.3-59-g8ed1b