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    Subject[PATCH net-next 11/17] net: dsa: sja1105: Add support for FDB and MDB management
    Date
    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>
    ---
    drivers/net/dsa/sja1105/sja1105.h | 2 +
    .../net/dsa/sja1105/sja1105_dynamic_config.c | 40 ++++
    drivers/net/dsa/sja1105/sja1105_main.c | 193 ++++++++++++++++++
    3 files changed, 235 insertions(+)

    diff --git a/drivers/net/dsa/sja1105/sja1105.h b/drivers/net/dsa/sja1105/sja1105.h
    index 2874423a5cd0..26d93afa77a1 100644
    --- a/drivers/net/dsa/sja1105/sja1105.h
    +++ b/drivers/net/dsa/sja1105/sja1105.h
    @@ -118,6 +118,8 @@ int sja1105_dynamic_config_write(struct sja1105_private *priv,
    int index, void *entry, bool keep);
    void sja1105_dynamic_config_init(struct sja1105_private *priv);

    +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);
    diff --git a/drivers/net/dsa/sja1105/sja1105_dynamic_config.c b/drivers/net/dsa/sja1105/sja1105_dynamic_config.c
    index 4f3756e267ac..545988779fe5 100644
    --- a/drivers/net/dsa/sja1105/sja1105_dynamic_config.c
    +++ b/drivers/net/dsa/sja1105/sja1105_dynamic_config.c
    @@ -476,3 +476,43 @@ void sja1105_dynamic_config_init(struct sja1105_private *priv)

    priv->dyn_ops = ops;
    }
    +
    +static u8 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)
    + crc = crc8_add(crc, (input & (0xffull << i)) >> i, poly);
    + return crc;
    +}
    diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
    index 45c233d7fbba..93d1f607eeab 100644
    --- a/drivers/net/dsa/sja1105/sja1105_main.c
    +++ b/drivers/net/dsa/sja1105/sja1105_main.c
    @@ -187,6 +187,9 @@ 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;
    @@ -699,6 +702,190 @@ static void sja1105_adjust_link(struct dsa_switch *ds, int port,
    sja1105_adjust_port_config(priv, port, phydev->speed, true);
    }

    +#define fdb(bin, index) \
    + ((bin) * SJA1105ET_FDB_BIN_SIZE + (index))
    +#define is_bin_index_valid(i) \
    + ((i) >= 0 && (i) < SJA1105ET_FDB_BIN_SIZE)
    +
    +static int
    +sja1105_is_fdb_entry_in_bin(struct sja1105_private *priv, int bin,
    + const u8 *addr, u16 vid,
    + struct sja1105_l2_lookup_entry *fdb_match,
    + int *last_unused)
    +{
    + int index_in_bin;
    +
    + for (index_in_bin = 0; index_in_bin < SJA1105ET_FDB_BIN_SIZE;
    + index_in_bin++) {
    + struct sja1105_l2_lookup_entry l2_lookup = { 0 };
    +
    + /* Skip unused entries, optionally marking them
    + * into the return value
    + */
    + if (sja1105_dynamic_config_read(priv, BLK_IDX_L2_LOOKUP,
    + fdb(bin, index_in_bin),
    + &l2_lookup)) {
    + if (last_unused)
    + *last_unused = index_in_bin;
    + continue;
    + }
    +
    + if (l2_lookup.macaddr == ether_addr_to_u64(addr) &&
    + l2_lookup.vlanid == vid) {
    + if (fdb_match)
    + *fdb_match = l2_lookup;
    + return index_in_bin;
    + }
    + }
    + /* Return an invalid entry index if not found */
    + return SJA1105ET_FDB_BIN_SIZE;
    +}
    +
    +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 bin, index_in_bin;
    + int last_unused;
    +
    + bin = sja1105_fdb_hash(priv, addr, vid);
    +
    + index_in_bin = sja1105_is_fdb_entry_in_bin(priv, bin, addr, vid,
    + &l2_lookup, &last_unused);
    + if (is_bin_index_valid(index_in_bin)) {
    + /* 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 {
    + /* 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 (is_bin_index_valid(last_unused)) {
    + index_in_bin = 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(&index_in_bin, sizeof(u8));
    + index_in_bin %= SJA1105ET_FDB_BIN_SIZE;
    + dev_warn(dev, "Warning, FDB bin %d full while adding entry for %pM. Evicting entry %u.\n",
    + bin, addr, index_in_bin);
    + /* Evict entry */
    + sja1105_dynamic_config_write(priv, BLK_IDX_L2_LOOKUP,
    + fdb(bin, index_in_bin),
    + NULL, false);
    + }
    + }
    + l2_lookup.index = fdb(bin, index_in_bin);
    +
    + 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;
    + u8 bin, index_in_bin;
    + bool keep;
    +
    + bin = sja1105_fdb_hash(priv, addr, vid);
    +
    + index_in_bin = sja1105_is_fdb_entry_in_bin(priv, bin, addr, vid,
    + &l2_lookup, NULL);
    + if (!is_bin_index_valid(index_in_bin))
    + return 0;
    +
    + /* 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,
    + fdb(bin, index_in_bin),
    + &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 < MAX_L2_LOOKUP_COUNT; i++) {
    + struct sja1105_l2_lookup_entry l2_lookup;
    + u8 macaddr[ETH_ALEN];
    + int rc;
    +
    + memset(&l2_lookup, 0, sizeof(l2_lookup));
    + 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;
    +}
    +
    +#undef fdb
    +#undef is_bin_index_valid
    +
    +/* 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)
    {
    @@ -792,8 +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_probe(struct spi_device *spi)
    --
    2.17.1
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