net: dsa: felix: support changing the MTU

Changing the MTU for this switch means altering the
DEV_GMII:MAC_CFG_STATUS:MAC_MAXLEN_CFG field MAX_LEN, which in turn
limits the size of frames that can be received.

Special accounting needs to be done for the DSA CPU port (NPI port in
hardware terms). The NPI port configuration needs to be held inside the
private ocelot structure, since it is now accessed from multiple places.

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/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
index 69546383a382393adafd467b9a6c2bfce12c8eb7..e2effeaa685e978207a857890ff34bceec9a16d0 100644 (file)
--- a/drivers/net/dsa/ocelot/felix.c
+++ b/drivers/net/dsa/ocelot/felix.c
@@ -532,6 +532,7 @@ static int felix_setup(struct dsa_switch *ds)
                         ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)),
                         ANA_PGID_PGID, PGID_UC);
 
+       ds->mtu_enforcement_ingress = true;
        /* It looks like the MAC/PCS interrupt register - PM0_IEVENT (0x8040)
         * isn't instantiated for the Felix PF.
         * In-band AN may take a few ms to complete, so we need to poll.
@@ -609,6 +610,22 @@ static bool felix_txtstamp(struct dsa_switch *ds, int port,
        return false;
 }
 
+static int felix_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
+{
+       struct ocelot *ocelot = ds->priv;
+
+       ocelot_port_set_maxlen(ocelot, port, new_mtu);
+
+       return 0;
+}
+
+static int felix_get_max_mtu(struct dsa_switch *ds, int port)
+{
+       struct ocelot *ocelot = ds->priv;
+
+       return ocelot_get_max_mtu(ocelot, port);
+}
+
 static int felix_cls_flower_add(struct dsa_switch *ds, int port,
                                struct flow_cls_offload *cls, bool ingress)
 {
@@ -664,6 +681,8 @@ static const struct dsa_switch_ops felix_switch_ops = {
        .port_hwtstamp_set      = felix_hwtstamp_set,
        .port_rxtstamp          = felix_rxtstamp,
        .port_txtstamp          = felix_txtstamp,
+       .port_change_mtu        = felix_change_mtu,
+       .port_max_mtu           = felix_get_max_mtu,
        .cls_flower_add         = felix_cls_flower_add,
        .cls_flower_del         = felix_cls_flower_del,
        .cls_flower_stats       = felix_cls_flower_stats,

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index dc0e273286617d955ed24092de2aeaed7ca5c0bb..b4731df186f497a3b7a58e53ec6e0b7cd81e3761 100644 (file)
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -2185,13 +2185,25 @@ static int ocelot_init_timestamp(struct ocelot *ocelot)
 
 /* Configure the maximum SDU (L2 payload) on RX to the value specified in @sdu.
  * The length of VLAN tags is accounted for automatically via DEV_MAC_TAGS_CFG.
+ * In the special case that it's the NPI port that we're configuring, the
+ * length of the tag and optional prefix needs to be accounted for privately,
+ * in order to be able to sustain communication at the requested @sdu.
  */
-static void ocelot_port_set_maxlen(struct ocelot *ocelot, int port, size_t sdu)
+void ocelot_port_set_maxlen(struct ocelot *ocelot, int port, size_t sdu)
 {
        struct ocelot_port *ocelot_port = ocelot->ports[port];
        int maxlen = sdu + ETH_HLEN + ETH_FCS_LEN;
        int atop_wm;
 
+       if (port == ocelot->npi) {
+               maxlen += OCELOT_TAG_LEN;
+
+               if (ocelot->inj_prefix == OCELOT_TAG_PREFIX_SHORT)
+                       maxlen += OCELOT_SHORT_PREFIX_LEN;
+               else if (ocelot->inj_prefix == OCELOT_TAG_PREFIX_LONG)
+                       maxlen += OCELOT_LONG_PREFIX_LEN;
+       }
+
        ocelot_port_writel(ocelot_port, maxlen, DEV_MAC_MAXLEN_CFG);
 
        /* Set Pause WM hysteresis
@@ -2209,6 +2221,24 @@ static void ocelot_port_set_maxlen(struct ocelot *ocelot, int port, size_t sdu)
                         SYS_ATOP, port);
        ocelot_write(ocelot, ocelot_wm_enc(atop_wm), SYS_ATOP_TOT_CFG);
 }
+EXPORT_SYMBOL(ocelot_port_set_maxlen);
+
+int ocelot_get_max_mtu(struct ocelot *ocelot, int port)
+{
+       int max_mtu = 65535 - ETH_HLEN - ETH_FCS_LEN;
+
+       if (port == ocelot->npi) {
+               max_mtu -= OCELOT_TAG_LEN;
+
+               if (ocelot->inj_prefix == OCELOT_TAG_PREFIX_SHORT)
+                       max_mtu -= OCELOT_SHORT_PREFIX_LEN;
+               else if (ocelot->inj_prefix == OCELOT_TAG_PREFIX_LONG)
+                       max_mtu -= OCELOT_LONG_PREFIX_LEN;
+       }
+
+       return max_mtu;
+}
+EXPORT_SYMBOL(ocelot_get_max_mtu);
 
 void ocelot_init_port(struct ocelot *ocelot, int port)
 {
@@ -2318,6 +2348,10 @@ void ocelot_configure_cpu(struct ocelot *ocelot, int npi,
 {
        int cpu = ocelot->num_phys_ports;
 
+       ocelot->npi = npi;
+       ocelot->inj_prefix = injection;
+       ocelot->xtr_prefix = extraction;
+
        /* The unicast destination PGID for the CPU port module is unused */
        ocelot_write_rix(ocelot, 0, ANA_PGID_PGID, cpu);
        /* Instead set up a multicast destination PGID for traffic copied to
@@ -2330,19 +2364,10 @@ void ocelot_configure_cpu(struct ocelot *ocelot, int npi,
                         ANA_PORT_PORT_CFG, cpu);
 
        if (npi >= 0 && npi < ocelot->num_phys_ports) {
-               int sdu = ETH_DATA_LEN + OCELOT_TAG_LEN;
-
                ocelot_write(ocelot, QSYS_EXT_CPU_CFG_EXT_CPUQ_MSK_M |
                             QSYS_EXT_CPU_CFG_EXT_CPU_PORT(npi),
                             QSYS_EXT_CPU_CFG);
 
-               if (injection == OCELOT_TAG_PREFIX_SHORT)
-                       sdu += OCELOT_SHORT_PREFIX_LEN;
-               else if (injection == OCELOT_TAG_PREFIX_LONG)
-                       sdu += OCELOT_LONG_PREFIX_LEN;
-
-               ocelot_port_set_maxlen(ocelot, npi, sdu);
-
                /* Enable NPI port */
                ocelot_write_rix(ocelot,
                                 QSYS_SWITCH_PORT_MODE_INGRESS_DROP_MODE |

diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index 007b584cc431cad5703f73a8cc49bc898aaeade2..eadbc2ddfcb5cc5385bcf7b102633d5aa7cc9ade 100644 (file)
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -517,6 +517,11 @@ struct ocelot {
         */
        u8                              num_phys_ports;
 
+       int                             npi;
+
+       enum ocelot_tag_prefix          inj_prefix;
+       enum ocelot_tag_prefix          xtr_prefix;
+
        u32                             *lags;
 
        struct list_head                multicast;
@@ -611,6 +616,8 @@ int ocelot_ptp_gettime64(struct ptp_clock_info *ptp, struct timespec64 *ts);
 int ocelot_port_add_txtstamp_skb(struct ocelot_port *ocelot_port,
                                 struct sk_buff *skb);
 void ocelot_get_txtstamp(struct ocelot *ocelot);
+void ocelot_port_set_maxlen(struct ocelot *ocelot, int port, size_t sdu);
+int ocelot_get_max_mtu(struct ocelot *ocelot, int port);
 int ocelot_cls_flower_replace(struct ocelot *ocelot, int port,
                              struct flow_cls_offload *f, bool ingress);
 int ocelot_cls_flower_destroy(struct ocelot *ocelot, int port,