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Subject[PATCH v2 net-next 13/22] 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>
---
Changes from v2:
None

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 ef555dd385a3..4c9df44a4478 100644
--- a/drivers/net/dsa/sja1105/sja1105.h
+++ b/drivers/net/dsa/sja1105/sja1105.h
@@ -129,6 +129,8 @@ 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);
diff --git a/drivers/net/dsa/sja1105/sja1105_dynamic_config.c b/drivers/net/dsa/sja1105/sja1105_dynamic_config.c
index 74c3a00d453c..0aeda6868c27 100644
--- a/drivers/net/dsa/sja1105/sja1105_dynamic_config.c
+++ b/drivers/net/dsa/sja1105/sja1105_dynamic_config.c
@@ -462,3 +462,43 @@ int sja1105_dynamic_config_write(struct sja1105_private *priv,

return 0;
}
+
+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 c3e4fff11101..e37181bd2a6a 100644
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -188,6 +188,9 @@ 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;
@@ -705,6 +708,190 @@ 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)
{
@@ -807,8 +994,14 @@ 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)
--
2.17.1
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