net: mscc: ocelot: adjust MTU on the CPU port in NPI mode (ba551bc3) · Commits · 戴 / test

When using the NPI port, the DSA tag is passed through Ethernet, so the switch's MAC needs to accept it as it comes from the DSA master. Increase the MTU on the external CPU port to account for the length of the injection header. Without this patch, MTU-sized frames are dropped by the switch's CPU port on xmit, which is especially obvious in TCP sessions. Signed-off-by:

Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by:

Andrew Lunn <andrew@lunn.ch> Reviewed-by:

Florian Fainelli <f.fainelli@gmail.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mscc/ocelot.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -2230,9 +2230,18 @@ void ocelot_set_cpu_port(struct ocelot *ocelot, int cpu,
		* Only one port can be an NPI at the same time.
		*/
		if (cpu < ocelot->num_phys_ports) {
		int mtu = VLAN_ETH_FRAME_LEN + OCELOT_TAG_LEN;

		ocelot_write(ocelot, QSYS_EXT_CPU_CFG_EXT_CPUQ_MSK_M \|
		QSYS_EXT_CPU_CFG_EXT_CPU_PORT(cpu),
		QSYS_EXT_CPU_CFG);

		if (injection == OCELOT_TAG_PREFIX_SHORT)
		mtu += OCELOT_SHORT_PREFIX_LEN;
		else if (injection == OCELOT_TAG_PREFIX_LONG)
		mtu += OCELOT_LONG_PREFIX_LEN;

		ocelot_port_set_mtu(ocelot, cpu, mtu);
		}

		/* CPU port Injection/Extraction configuration */

drivers/net/ethernet/mscc/ocelot.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -65,6 +65,8 @@ struct frame_info {
		#define IFH_REW_OP_ORIGIN_PTP 0x5

		#define OCELOT_TAG_LEN 16
		#define OCELOT_SHORT_PREFIX_LEN 4
		#define OCELOT_LONG_PREFIX_LEN 16

		#define OCELOT_SPEED_2500 0
		#define OCELOT_SPEED_1000 1

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