net: dsa: sja1105: Add support for FDB and MDB management
authorVladimir Oltean <olteanv@gmail.com>
Thu, 2 May 2019 20:23:31 +0000 (23:23 +0300)
committerDavid S. Miller <davem@davemloft.net>
Fri, 3 May 2019 14:49:17 +0000 (10:49 -0400)
Currently only the (more difficult) first generation E/T series is
supported. Here the TCAM is only 4-way associative, and to know where
the hardware will search for a FDB entry, we need to perform the same
hash algorithm in order to install the entry in the correct bin.

On P/Q/R/S, the TCAM should be fully associative. However the SPI
command interface is different, and because I don't have access to a
new-generation device at the moment, support for it is TODO.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/dsa/sja1105/sja1105.h
drivers/net/dsa/sja1105/sja1105_dynamic_config.c
drivers/net/dsa/sja1105/sja1105_main.c

index e01cb85..50ab928 100644 (file)
@@ -123,6 +123,8 @@ int sja1105_dynamic_config_write(struct sja1105_private *priv,
                                 enum sja1105_blk_idx blk_idx,
                                 int index, void *entry, bool keep);
 
+u8 sja1105_fdb_hash(struct sja1105_private *priv, const u8 *addr, u16 vid);
+
 /* Common implementations for the static and dynamic configs */
 size_t sja1105_l2_forwarding_entry_packing(void *buf, void *entry_ptr,
                                           enum packing_op op);
index d8f1454..e73ab28 100644 (file)
@@ -487,3 +487,46 @@ int sja1105_dynamic_config_write(struct sja1105_private *priv,
 
        return 0;
 }
+
+static u8 sja1105_crc8_add(u8 crc, u8 byte, u8 poly)
+{
+       int i;
+
+       for (i = 0; i < 8; i++) {
+               if ((crc ^ byte) & (1 << 7)) {
+                       crc <<= 1;
+                       crc ^= poly;
+               } else {
+                       crc <<= 1;
+               }
+               byte <<= 1;
+       }
+       return crc;
+}
+
+/* CRC8 algorithm with non-reversed input, non-reversed output,
+ * no input xor and no output xor. Code customized for receiving
+ * the SJA1105 E/T FDB keys (vlanid, macaddr) as input. CRC polynomial
+ * is also received as argument in the Koopman notation that the switch
+ * hardware stores it in.
+ */
+u8 sja1105_fdb_hash(struct sja1105_private *priv, const u8 *addr, u16 vid)
+{
+       struct sja1105_l2_lookup_params_entry *l2_lookup_params =
+               priv->static_config.tables[BLK_IDX_L2_LOOKUP_PARAMS].entries;
+       u64 poly_koopman = l2_lookup_params->poly;
+       /* Convert polynomial from Koopman to 'normal' notation */
+       u8 poly = (u8)(1 + (poly_koopman << 1));
+       u64 vlanid = l2_lookup_params->shared_learn ? 0 : vid;
+       u64 input = (vlanid << 48) | ether_addr_to_u64(addr);
+       u8 crc = 0; /* seed */
+       int i;
+
+       /* Mask the eight bytes starting from MSB one at a time */
+       for (i = 56; i >= 0; i -= 8) {
+               u8 byte = (input & (0xffull << i)) >> i;
+
+               crc = sja1105_crc8_add(crc, byte, poly);
+       }
+       return crc;
+}
index 7d2ad2d..ec8137e 100644 (file)
@@ -179,6 +179,9 @@ static int sja1105_init_static_fdb(struct sja1105_private *priv)
 
        table = &priv->static_config.tables[BLK_IDX_L2_LOOKUP];
 
+       /* We only populate the FDB table through dynamic
+        * L2 Address Lookup entries
+        */
        if (table->entry_count) {
                kfree(table->entries);
                table->entry_count = 0;
@@ -689,6 +692,191 @@ static void sja1105_adjust_link(struct dsa_switch *ds, int port,
                sja1105_adjust_port_config(priv, port, phydev->speed, true);
 }
 
+/* First-generation switches have a 4-way set associative TCAM that
+ * holds the FDB entries. An FDB index spans from 0 to 1023 and is comprised of
+ * a "bin" (grouping of 4 entries) and a "way" (an entry within a bin).
+ * For the placement of a newly learnt FDB entry, the switch selects the bin
+ * based on a hash function, and the way within that bin incrementally.
+ */
+static inline int sja1105et_fdb_index(int bin, int way)
+{
+       return bin * SJA1105ET_FDB_BIN_SIZE + way;
+}
+
+static int sja1105_is_fdb_entry_in_bin(struct sja1105_private *priv, int bin,
+                                      const u8 *addr, u16 vid,
+                                      struct sja1105_l2_lookup_entry *match,
+                                      int *last_unused)
+{
+       int way;
+
+       for (way = 0; way < SJA1105ET_FDB_BIN_SIZE; way++) {
+               struct sja1105_l2_lookup_entry l2_lookup = {0};
+               int index = sja1105et_fdb_index(bin, way);
+
+               /* Skip unused entries, optionally marking them
+                * into the return value
+                */
+               if (sja1105_dynamic_config_read(priv, BLK_IDX_L2_LOOKUP,
+                                               index, &l2_lookup)) {
+                       if (last_unused)
+                               *last_unused = way;
+                       continue;
+               }
+
+               if (l2_lookup.macaddr == ether_addr_to_u64(addr) &&
+                   l2_lookup.vlanid == vid) {
+                       if (match)
+                               *match = l2_lookup;
+                       return way;
+               }
+       }
+       /* Return an invalid entry index if not found */
+       return -1;
+}
+
+static int sja1105_fdb_add(struct dsa_switch *ds, int port,
+                          const unsigned char *addr, u16 vid)
+{
+       struct sja1105_l2_lookup_entry l2_lookup = {0};
+       struct sja1105_private *priv = ds->priv;
+       struct device *dev = ds->dev;
+       int last_unused = -1;
+       int bin, way;
+
+       bin = sja1105_fdb_hash(priv, addr, vid);
+
+       way = sja1105_is_fdb_entry_in_bin(priv, bin, addr, vid,
+                                         &l2_lookup, &last_unused);
+       if (way >= 0) {
+               /* We have an FDB entry. Is our port in the destination
+                * mask? If yes, we need to do nothing. If not, we need
+                * to rewrite the entry by adding this port to it.
+                */
+               if (l2_lookup.destports & BIT(port))
+                       return 0;
+               l2_lookup.destports |= BIT(port);
+       } else {
+               int index = sja1105et_fdb_index(bin, way);
+
+               /* We don't have an FDB entry. We construct a new one and
+                * try to find a place for it within the FDB table.
+                */
+               l2_lookup.macaddr = ether_addr_to_u64(addr);
+               l2_lookup.destports = BIT(port);
+               l2_lookup.vlanid = vid;
+
+               if (last_unused >= 0) {
+                       way = last_unused;
+               } else {
+                       /* Bin is full, need to evict somebody.
+                        * Choose victim at random. If you get these messages
+                        * often, you may need to consider changing the
+                        * distribution function:
+                        * static_config[BLK_IDX_L2_LOOKUP_PARAMS].entries->poly
+                        */
+                       get_random_bytes(&way, sizeof(u8));
+                       way %= SJA1105ET_FDB_BIN_SIZE;
+                       dev_warn(dev, "Warning, FDB bin %d full while adding entry for %pM. Evicting entry %u.\n",
+                                bin, addr, way);
+                       /* Evict entry */
+                       sja1105_dynamic_config_write(priv, BLK_IDX_L2_LOOKUP,
+                                                    index, NULL, false);
+               }
+       }
+       l2_lookup.index = sja1105et_fdb_index(bin, way);
+
+       return sja1105_dynamic_config_write(priv, BLK_IDX_L2_LOOKUP,
+                                           l2_lookup.index, &l2_lookup,
+                                           true);
+}
+
+static int sja1105_fdb_del(struct dsa_switch *ds, int port,
+                          const unsigned char *addr, u16 vid)
+{
+       struct sja1105_l2_lookup_entry l2_lookup = {0};
+       struct sja1105_private *priv = ds->priv;
+       int index, bin, way;
+       bool keep;
+
+       bin = sja1105_fdb_hash(priv, addr, vid);
+       way = sja1105_is_fdb_entry_in_bin(priv, bin, addr, vid,
+                                         &l2_lookup, NULL);
+       if (way < 0)
+               return 0;
+       index = sja1105et_fdb_index(bin, way);
+
+       /* We have an FDB entry. Is our port in the destination mask? If yes,
+        * we need to remove it. If the resulting port mask becomes empty, we
+        * need to completely evict the FDB entry.
+        * Otherwise we just write it back.
+        */
+       if (l2_lookup.destports & BIT(port))
+               l2_lookup.destports &= ~BIT(port);
+       if (l2_lookup.destports)
+               keep = true;
+       else
+               keep = false;
+
+       return sja1105_dynamic_config_write(priv, BLK_IDX_L2_LOOKUP,
+                                           index, &l2_lookup, keep);
+}
+
+static int sja1105_fdb_dump(struct dsa_switch *ds, int port,
+                           dsa_fdb_dump_cb_t *cb, void *data)
+{
+       struct sja1105_private *priv = ds->priv;
+       struct device *dev = ds->dev;
+       int i;
+
+       for (i = 0; i < SJA1105_MAX_L2_LOOKUP_COUNT; i++) {
+               struct sja1105_l2_lookup_entry l2_lookup = {0};
+               u8 macaddr[ETH_ALEN];
+               int rc;
+
+               rc = sja1105_dynamic_config_read(priv, BLK_IDX_L2_LOOKUP,
+                                                i, &l2_lookup);
+               /* No fdb entry at i, not an issue */
+               if (rc == -EINVAL)
+                       continue;
+               if (rc) {
+                       dev_err(dev, "Failed to dump FDB: %d\n", rc);
+                       return rc;
+               }
+
+               /* FDB dump callback is per port. This means we have to
+                * disregard a valid entry if it's not for this port, even if
+                * only to revisit it later. This is inefficient because the
+                * 1024-sized FDB table needs to be traversed 4 times through
+                * SPI during a 'bridge fdb show' command.
+                */
+               if (!(l2_lookup.destports & BIT(port)))
+                       continue;
+               u64_to_ether_addr(l2_lookup.macaddr, macaddr);
+               cb(macaddr, l2_lookup.vlanid, false, data);
+       }
+       return 0;
+}
+
+/* This callback needs to be present */
+static int sja1105_mdb_prepare(struct dsa_switch *ds, int port,
+                              const struct switchdev_obj_port_mdb *mdb)
+{
+       return 0;
+}
+
+static void sja1105_mdb_add(struct dsa_switch *ds, int port,
+                           const struct switchdev_obj_port_mdb *mdb)
+{
+       sja1105_fdb_add(ds, port, mdb->addr, mdb->vid);
+}
+
+static int sja1105_mdb_del(struct dsa_switch *ds, int port,
+                          const struct switchdev_obj_port_mdb *mdb)
+{
+       return sja1105_fdb_del(ds, port, mdb->addr, mdb->vid);
+}
+
 static int sja1105_bridge_member(struct dsa_switch *ds, int port,
                                 struct net_device *br, bool member)
 {
@@ -791,8 +979,14 @@ static const struct dsa_switch_ops sja1105_switch_ops = {
        .get_tag_protocol       = sja1105_get_tag_protocol,
        .setup                  = sja1105_setup,
        .adjust_link            = sja1105_adjust_link,
+       .port_fdb_dump          = sja1105_fdb_dump,
+       .port_fdb_add           = sja1105_fdb_add,
+       .port_fdb_del           = sja1105_fdb_del,
        .port_bridge_join       = sja1105_bridge_join,
        .port_bridge_leave      = sja1105_bridge_leave,
+       .port_mdb_prepare       = sja1105_mdb_prepare,
+       .port_mdb_add           = sja1105_mdb_add,
+       .port_mdb_del           = sja1105_mdb_del,
 };
 
 static int sja1105_check_device_id(struct sja1105_private *priv)