net: dsa: sja1105: implement the port MTU callbacks

On this switch, the frame length enforcements are performed by the
ingress policers. There are 2 types of those: regular L2 (also called
best-effort) and Virtual Link policers (an ARINC664/AFDX concept for
defining L2 streams with certain QoS abilities). To avoid future
confusion, I prefer to call the reset reason "Best-effort policers",
even though the VL policers are not yet supported.

We also need to change the setup of the initial static config, such that
DSA calls to .change_mtu (which are expensive) become no-ops and don't
reset the switch 5 times.

A driver-level decision is to unconditionally allow single VLAN-tagged
traffic on all ports. The CPU port must accept an additional VLAN header
for the DSA tag, which is again a driver-level decision.

The policers actually count bytes not only from the SDU, but also from
the Ethernet header and FCS, so those need to be accounted for as well.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/sja1105/sja1105.h b/drivers/net/dsa/sja1105/sja1105.h
index a358fc89a6db6faa176050a649dca244e9d6fc6d..0e5b739b2fe8e363737974a697e23554f6eeb319 100644 (file)
--- a/drivers/net/dsa/sja1105/sja1105.h
+++ b/drivers/net/dsa/sja1105/sja1105.h
@@ -126,6 +126,7 @@ enum sja1105_reset_reason {
        SJA1105_RX_HWTSTAMPING,
        SJA1105_AGEING_TIME,
        SJA1105_SCHEDULING,
+       SJA1105_BEST_EFFORT_POLICING,
 };
 
 int sja1105_static_config_reload(struct sja1105_private *priv,

diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
index e0c99bb63cdfd76ef42d04f2072bfeea9f55fb53..763ae1d3bca80b1a1b0be04ec8d61a58c1c22ef0 100644 (file)
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -519,12 +519,12 @@ static int sja1105_init_avb_params(struct sja1105_private *priv)
 #define SJA1105_RATE_MBPS(speed) (((speed) * 64000) / 1000)
 
 static void sja1105_setup_policer(struct sja1105_l2_policing_entry *policing,
-                                 int index)
+                                 int index, int mtu)
 {
        policing[index].sharindx = index;
        policing[index].smax = 65535; /* Burst size in bytes */
        policing[index].rate = SJA1105_RATE_MBPS(1000);
-       policing[index].maxlen = ETH_FRAME_LEN + VLAN_HLEN + ETH_FCS_LEN;
+       policing[index].maxlen = mtu;
        policing[index].partition = 0;
 }
 
@@ -556,12 +556,16 @@ static int sja1105_init_l2_policing(struct sja1105_private *priv)
         */
        for (i = 0, k = 0; i < SJA1105_NUM_PORTS; i++) {
                int bcast = (SJA1105_NUM_PORTS * SJA1105_NUM_TC) + i;
+               int mtu = VLAN_ETH_FRAME_LEN + ETH_FCS_LEN;
+
+               if (dsa_is_cpu_port(priv->ds, i))
+                       mtu += VLAN_HLEN;
 
                for (j = 0; j < SJA1105_NUM_TC; j++, k++)
-                       sja1105_setup_policer(policing, k);
+                       sja1105_setup_policer(policing, k, mtu);
 
                /* Set up this port's policer for broadcast traffic */
-               sja1105_setup_policer(policing, bcast);
+               sja1105_setup_policer(policing, bcast, mtu);
        }
        return 0;
 }
@@ -1544,6 +1548,7 @@ static const char * const sja1105_reset_reasons[] = {
        [SJA1105_RX_HWTSTAMPING] = "RX timestamping",
        [SJA1105_AGEING_TIME] = "Ageing time",
        [SJA1105_SCHEDULING] = "Time-aware scheduling",
+       [SJA1105_BEST_EFFORT_POLICING] = "Best-effort policing",
 };
 
 /* For situations where we need to change a setting at runtime that is only
@@ -1952,6 +1957,8 @@ static int sja1105_setup(struct dsa_switch *ds)
        /* Advertise the 8 egress queues */
        ds->num_tx_queues = SJA1105_NUM_TC;
 
+       ds->mtu_enforcement_ingress = true;
+
        /* The DSA/switchdev model brings up switch ports in standalone mode by
         * default, and that means vlan_filtering is 0 since they're not under
         * a bridge, so it's safe to set up switch tagging at this time.
@@ -2120,6 +2127,39 @@ static int sja1105_set_ageing_time(struct dsa_switch *ds,
        return sja1105_static_config_reload(priv, SJA1105_AGEING_TIME);
 }
 
+static int sja1105_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
+{
+       int bcast = (SJA1105_NUM_PORTS * SJA1105_NUM_TC) + port;
+       struct sja1105_l2_policing_entry *policing;
+       struct sja1105_private *priv = ds->priv;
+       int tc;
+
+       new_mtu += VLAN_ETH_HLEN + ETH_FCS_LEN;
+
+       if (dsa_is_cpu_port(ds, port))
+               new_mtu += VLAN_HLEN;
+
+       policing = priv->static_config.tables[BLK_IDX_L2_POLICING].entries;
+
+       /* We set all 9 port policers to the same value, so just checking the
+        * broadcast one is fine.
+        */
+       if (policing[bcast].maxlen == new_mtu)
+               return 0;
+
+       for (tc = 0; tc < SJA1105_NUM_TC; tc++)
+               policing[port * SJA1105_NUM_TC + tc].maxlen = new_mtu;
+
+       policing[bcast].maxlen = new_mtu;
+
+       return sja1105_static_config_reload(priv, SJA1105_BEST_EFFORT_POLICING);
+}
+
+static int sja1105_get_max_mtu(struct dsa_switch *ds, int port)
+{
+       return 2043 - VLAN_ETH_HLEN - ETH_FCS_LEN;
+}
+
 static int sja1105_port_setup_tc(struct dsa_switch *ds, int port,
                                 enum tc_setup_type type,
                                 void *type_data)
@@ -2215,6 +2255,8 @@ static const struct dsa_switch_ops sja1105_switch_ops = {
        .setup                  = sja1105_setup,
        .teardown               = sja1105_teardown,
        .set_ageing_time        = sja1105_set_ageing_time,
+       .port_change_mtu        = sja1105_change_mtu,
+       .port_max_mtu           = sja1105_get_max_mtu,
        .phylink_validate       = sja1105_phylink_validate,
        .phylink_mac_link_state = sja1105_mac_pcs_get_state,
        .phylink_mac_config     = sja1105_mac_config,