target/linux/layerscape/patches-5.4/701-net-0258-net-mscc-ocelot-adjust-MTU-on-the-CPU-port-in-NPI-mo.patch

   1 From b2f7c18c351737c2a053c39c09ef50870fd78c06 Mon Sep 17 00:00:00 2001
   2 From: Vladimir Oltean <vladimir.oltean@nxp.com>
   3 Date: Thu, 14 Nov 2019 17:03:25 +0200
   4 Subject: [PATCH] net: mscc: ocelot: adjust MTU on the CPU port in NPI mode
   5
   6 When using the NPI port, the DSA tag is passed through Ethernet, so the
   7 switch's MAC needs to accept it as it comes from the DSA master. Increase
   8 the MTU on the external CPU port to account for the length of the
   9 injection header.
  10
  11 Without this patch, MTU-sized frames are dropped by the switch's CPU
  12 port on xmit, which is especially obvious in TCP sessions.
  13
  14 Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
  15 Reviewed-by: Andrew Lunn <andrew@lunn.ch>
  16 Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
  17 Signed-off-by: David S. Miller <davem@davemloft.net>
  18 ---
  19  drivers/net/ethernet/mscc/ocelot.c | 9 +++++++++
  20  drivers/net/ethernet/mscc/ocelot.h | 2 ++
  21  2 files changed, 11 insertions(+)
  22
  23 --- a/drivers/net/ethernet/mscc/ocelot.c
  24 +++ b/drivers/net/ethernet/mscc/ocelot.c
  25 @@ -2229,9 +2229,18 @@ void ocelot_set_cpu_port(struct ocelot *
  26          * Only one port can be an NPI at the same time.
  27          */
  28         if (cpu < ocelot->num_phys_ports) {
  29 +               int mtu = VLAN_ETH_FRAME_LEN + OCELOT_TAG_LEN;
  30 +
  31                 ocelot_write(ocelot, QSYS_EXT_CPU_CFG_EXT_CPUQ_MSK_M |
  32                              QSYS_EXT_CPU_CFG_EXT_CPU_PORT(cpu),
  33                              QSYS_EXT_CPU_CFG);
  34 +
  35 +               if (injection == OCELOT_TAG_PREFIX_SHORT)
  36 +                       mtu += OCELOT_SHORT_PREFIX_LEN;
  37 +               else if (injection == OCELOT_TAG_PREFIX_LONG)
  38 +                       mtu += OCELOT_LONG_PREFIX_LEN;
  39 +
  40 +               ocelot_port_set_mtu(ocelot, cpu, mtu);
  41         }
  42
  43         /* CPU port Injection/Extraction configuration */
  44 --- a/drivers/net/ethernet/mscc/ocelot.h
  45 +++ b/drivers/net/ethernet/mscc/ocelot.h
  46 @@ -65,6 +65,8 @@ struct frame_info {
  47  #define IFH_REW_OP_ORIGIN_PTP          0x5
  48
  49  #define OCELOT_TAG_LEN                 16
  50 +#define OCELOT_SHORT_PREFIX_LEN                4
  51 +#define OCELOT_LONG_PREFIX_LEN         16
  52
  53  #define OCELOT_SPEED_2500 0
  54  #define OCELOT_SPEED_1000 1