net: mvpp2: cls: Add Classification offload support

This commit introduces basic classification offloading support for the
PPv2 controller.

The PPv2 classifier has many classification engines, for now we only use
the C2 TCAM match engine.

This engine allows to perform ternary lookups on 64 bits keys (called
Header Extracted Key), that are built by extracting fields from the packet
header and concatenating them. At most 4 fields can be extracted for a
single lookup.

This basic implementation allows to build the HEK from the following
fields :
 - L4 source and destination ports (for UDP and TCP)

More fields are to be added in the future.

Classification flows are added through the ethtool interface, using the
newly introduced flow_rule infrastructure as an internal rule
representation, allowing to more easily implement tc flower rules if
need be.

The internal design for now allocates one range of 4 rules per port
due to the internal design of the flow table, which uses 22 sub-flows.

When inserting a classification rule, the rule is created in every
relevant sub-flow.

This low rule-count is a very simple design which reaches quickly the
limitations of the flow table ordering, but guarantees that the rule
ordering will always be respected.

This commit only introduces support for the "steer to rxq" action.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 316 insertions, 0 deletions

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_cls.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_cls.c
index 2bbd4c294fc9..f4dd59c00d80 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_cls.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_cls.c
@@ -448,6 +448,12 @@ static void mvpp2_cls_flow_port_add(struct mvpp2_cls_flow_entry *fe,
 	fe->data[0] |= MVPP2_CLS_FLOW_TBL0_PORT_ID(port);
 }
 
+static void mvpp2_cls_flow_port_remove(struct mvpp2_cls_flow_entry *fe,
+				       u32 port)
+{
+	fe->data[0] &= ~MVPP2_CLS_FLOW_TBL0_PORT_ID(port);
+}
+
 static void mvpp2_cls_flow_lu_type_set(struct mvpp2_cls_flow_entry *fe,
 				       u8 lu_type)
 {
@@ -559,6 +565,11 @@ static int mvpp2_cls_ethtool_flow_to_type(int flow_type)
 	}
 }
 
+static int mvpp2_cls_c2_port_flow_index(struct mvpp2_port *port, int loc)
+{
+	return MVPP22_CLS_C2_RFS_LOC(port->id, loc);
+}
+
 /* Initialize the flow table entries for the given flow */
 static void mvpp2_cls_flow_init(struct mvpp2 *priv,
 				const struct mvpp2_cls_flow *flow)
@@ -672,6 +683,26 @@ static int mvpp2_flow_set_hek_fields(struct mvpp2_cls_flow_entry *fe,
 	return 0;
 }
 
+/* Returns the size, in bits, of the corresponding HEK field */
+static int mvpp2_cls_hek_field_size(u32 field)
+{
+	switch (field) {
+	case MVPP22_CLS_HEK_OPT_MAC_DA:
+		return 48;
+	case MVPP22_CLS_HEK_OPT_IP4SA:
+	case MVPP22_CLS_HEK_OPT_IP4DA:
+		return 32;
+	case MVPP22_CLS_HEK_OPT_IP6SA:
+	case MVPP22_CLS_HEK_OPT_IP6DA:
+		return 128;
+	case MVPP22_CLS_HEK_OPT_L4SIP:
+	case MVPP22_CLS_HEK_OPT_L4DIP:
+		return 16;
+	default:
+		return -1;
+	}
+}
+
 const struct mvpp2_cls_flow *mvpp2_cls_flow_get(int flow)
 {
 	if (flow >= MVPP2_N_PRS_FLOWS)
@@ -964,6 +995,18 @@ void mvpp22_port_rss_disable(struct mvpp2_port *port)
 	mvpp2_rss_port_c2_disable(port);
 }
 
+static void mvpp22_port_c2_lookup_disable(struct mvpp2_port *port, int entry)
+{
+	struct mvpp2_cls_c2_entry c2;
+
+	mvpp2_cls_c2_read(port->priv, entry, &c2);
+
+	/* Clear the port map so that the entry doesn't match anymore */
+	c2.tcam[4] &= ~(MVPP22_CLS_C2_PORT_ID(BIT(port->id)));
+
+	mvpp2_cls_c2_write(port->priv, &c2);
+}
+
 /* Set CPU queue number for oversize packets */
 void mvpp2_cls_oversize_rxq_set(struct mvpp2_port *port)
 {
@@ -980,6 +1023,279 @@ void mvpp2_cls_oversize_rxq_set(struct mvpp2_port *port)
 	mvpp2_write(port->priv, MVPP2_CLS_SWFWD_PCTRL_REG, val);
 }
 
+static int mvpp2_port_c2_tcam_rule_add(struct mvpp2_port *port,
+				       struct mvpp2_rfs_rule *rule)
+{
+	struct flow_action_entry *act;
+	struct mvpp2_cls_c2_entry c2;
+	u8 qh, ql, pmap;
+
+	memset(&c2, 0, sizeof(c2));
+
+	c2.index = mvpp2_cls_c2_port_flow_index(port, rule->loc);
+	if (c2.index < 0)
+		return -EINVAL;
+
+	act = &rule->flow->action.entries[0];
+
+	rule->c2_index = c2.index;
+
+	c2.tcam[0] = (rule->c2_tcam & 0xffff) |
+		     ((rule->c2_tcam_mask & 0xffff) << 16);
+	c2.tcam[1] = ((rule->c2_tcam >> 16) & 0xffff) |
+		     (((rule->c2_tcam_mask >> 16) & 0xffff) << 16);
+	c2.tcam[2] = ((rule->c2_tcam >> 32) & 0xffff) |
+		     (((rule->c2_tcam_mask >> 32) & 0xffff) << 16);
+	c2.tcam[3] = ((rule->c2_tcam >> 48) & 0xffff) |
+		     (((rule->c2_tcam_mask >> 48) & 0xffff) << 16);
+
+	pmap = BIT(port->id);
+	c2.tcam[4] = MVPP22_CLS_C2_PORT_ID(pmap);
+	c2.tcam[4] |= MVPP22_CLS_C2_TCAM_EN(MVPP22_CLS_C2_PORT_ID(pmap));
+
+	/* Match on Lookup Type */
+	c2.tcam[4] |= MVPP22_CLS_C2_TCAM_EN(MVPP22_CLS_C2_LU_TYPE(MVPP2_CLS_LU_TYPE_MASK));
+	c2.tcam[4] |= MVPP22_CLS_C2_LU_TYPE(rule->loc);
+
+	/* Mark packet as "forwarded to software", needed for RSS */
+	c2.act |= MVPP22_CLS_C2_ACT_FWD(MVPP22_C2_FWD_SW_LOCK);
+
+	c2.act |= MVPP22_CLS_C2_ACT_QHIGH(MVPP22_C2_UPD_LOCK) |
+		   MVPP22_CLS_C2_ACT_QLOW(MVPP22_C2_UPD_LOCK);
+
+	qh = ((act->queue.index + port->first_rxq) >> 3) & MVPP22_CLS_C2_ATTR0_QHIGH_MASK;
+	ql = (act->queue.index + port->first_rxq) & MVPP22_CLS_C2_ATTR0_QLOW_MASK;
+
+	c2.attr[0] = MVPP22_CLS_C2_ATTR0_QHIGH(qh) |
+		      MVPP22_CLS_C2_ATTR0_QLOW(ql);
+
+	c2.valid = true;
+
+	mvpp2_cls_c2_write(port->priv, &c2);
+
+	return 0;
+}
+
+static int mvpp2_port_c2_rfs_rule_insert(struct mvpp2_port *port,
+					 struct mvpp2_rfs_rule *rule)
+{
+	return mvpp2_port_c2_tcam_rule_add(port, rule);
+}
+
+static int mvpp2_port_cls_rfs_rule_remove(struct mvpp2_port *port,
+					  struct mvpp2_rfs_rule *rule)
+{
+	const struct mvpp2_cls_flow *flow;
+	struct mvpp2_cls_flow_entry fe;
+	int index, i;
+
+	for_each_cls_flow_id_containing_type(i, rule->flow_type) {
+		flow = mvpp2_cls_flow_get(i);
+		if (!flow)
+			return 0;
+
+		index = MVPP2_CLS_FLT_C2_RFS(port->id, flow->flow_id, rule->loc);
+
+		mvpp2_cls_flow_read(port->priv, index, &fe);
+		mvpp2_cls_flow_port_remove(&fe, BIT(port->id));
+		mvpp2_cls_flow_write(port->priv, &fe);
+	}
+
+	if (rule->c2_index >= 0)
+		mvpp22_port_c2_lookup_disable(port, rule->c2_index);
+
+	return 0;
+}
+
+static int mvpp2_port_flt_rfs_rule_insert(struct mvpp2_port *port,
+					  struct mvpp2_rfs_rule *rule)
+{
+	const struct mvpp2_cls_flow *flow;
+	struct mvpp2 *priv = port->priv;
+	struct mvpp2_cls_flow_entry fe;
+	int index, ret, i;
+
+	if (rule->engine != MVPP22_CLS_ENGINE_C2)
+		return -EOPNOTSUPP;
+
+	ret = mvpp2_port_c2_rfs_rule_insert(port, rule);
+	if (ret)
+		return ret;
+
+	for_each_cls_flow_id_containing_type(i, rule->flow_type) {
+		flow = mvpp2_cls_flow_get(i);
+		if (!flow)
+			return 0;
+
+		index = MVPP2_CLS_FLT_C2_RFS(port->id, flow->flow_id, rule->loc);
+
+		mvpp2_cls_flow_read(priv, index, &fe);
+		mvpp2_cls_flow_eng_set(&fe, rule->engine);
+		mvpp2_cls_flow_port_id_sel(&fe, true);
+		mvpp2_flow_set_hek_fields(&fe, rule->hek_fields);
+		mvpp2_cls_flow_lu_type_set(&fe, rule->loc);
+		mvpp2_cls_flow_port_add(&fe, 0xf);
+
+		mvpp2_cls_flow_write(priv, &fe);
+	}
+
+	return 0;
+}
+
+static int mvpp2_cls_c2_build_match(struct mvpp2_rfs_rule *rule)
+{
+	struct flow_rule *flow = rule->flow;
+	struct flow_action_entry *act;
+	int offs = 64;
+
+	act = &flow->action.entries[0];
+
+	if (flow_rule_match_key(flow, FLOW_DISSECTOR_KEY_PORTS)) {
+		struct flow_match_ports match;
+
+		flow_rule_match_ports(flow, &match);
+		if (match.mask->src) {
+			rule->hek_fields |= MVPP22_CLS_HEK_OPT_L4SIP;
+			offs -= mvpp2_cls_hek_field_size(MVPP22_CLS_HEK_OPT_L4SIP);
+
+			rule->c2_tcam |= ((u64)ntohs(match.key->src)) << offs;
+			rule->c2_tcam_mask |= ((u64)ntohs(match.mask->src)) << offs;
+		}
+
+		if (match.mask->dst) {
+			rule->hek_fields |= MVPP22_CLS_HEK_OPT_L4DIP;
+			offs -= mvpp2_cls_hek_field_size(MVPP22_CLS_HEK_OPT_L4DIP);
+
+			rule->c2_tcam |= ((u64)ntohs(match.key->dst)) << offs;
+			rule->c2_tcam_mask |= ((u64)ntohs(match.mask->dst)) << offs;
+		}
+	}
+
+	if (hweight16(rule->hek_fields) > MVPP2_FLOW_N_FIELDS)
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
+static int mvpp2_cls_rfs_parse_rule(struct mvpp2_rfs_rule *rule)
+{
+	struct flow_rule *flow = rule->flow;
+	struct flow_action_entry *act;
+
+	act = &flow->action.entries[0];
+	if (act->id != FLOW_ACTION_QUEUE)
+		return -EOPNOTSUPP;
+
+	/* For now, only use the C2 engine which has a HEK size limited to 64
+	 * bits for TCAM matching.
+	 */
+	rule->engine = MVPP22_CLS_ENGINE_C2;
+
+	if (mvpp2_cls_c2_build_match(rule))
+		return -EINVAL;
+
+	return 0;
+}
+
+int mvpp2_ethtool_cls_rule_get(struct mvpp2_port *port,
+			       struct ethtool_rxnfc *rxnfc)
+{
+	struct mvpp2_ethtool_fs *efs;
+
+	if (rxnfc->fs.location >= MVPP2_N_RFS_RULES)
+		return -EINVAL;
+
+	efs = port->rfs_rules[rxnfc->fs.location];
+	if (!efs)
+		return -ENOENT;
+
+	memcpy(rxnfc, &efs->rxnfc, sizeof(efs->rxnfc));
+
+	return 0;
+}
+
+int mvpp2_ethtool_cls_rule_ins(struct mvpp2_port *port,
+			       struct ethtool_rxnfc *info)
+{
+	struct ethtool_rx_flow_spec_input input = {};
+	struct ethtool_rx_flow_rule *ethtool_rule;
+	struct mvpp2_ethtool_fs *efs, *old_efs;
+	int ret = 0;
+
+	if (info->fs.location >= 4 ||
+	    info->fs.location < 0)
+		return -EINVAL;
+
+	efs = kzalloc(sizeof(*efs), GFP_KERNEL);
+	if (!efs)
+		return -ENOMEM;
+
+	input.fs = &info->fs;
+
+	ethtool_rule = ethtool_rx_flow_rule_create(&input);
+	if (IS_ERR(ethtool_rule)) {
+		ret = PTR_ERR(ethtool_rule);
+		goto clean_rule;
+	}
+
+	efs->rule.flow = ethtool_rule->rule;
+	efs->rule.flow_type = mvpp2_cls_ethtool_flow_to_type(info->fs.flow_type);
+
+	ret = mvpp2_cls_rfs_parse_rule(&efs->rule);
+	if (ret)
+		goto clean_eth_rule;
+
+	efs->rule.loc = info->fs.location;
+
+	/* Replace an already existing rule */
+	if (port->rfs_rules[efs->rule.loc]) {
+		old_efs = port->rfs_rules[efs->rule.loc];
+		ret = mvpp2_port_cls_rfs_rule_remove(port, &old_efs->rule);
+		if (ret)
+			goto clean_eth_rule;
+		kfree(old_efs);
+		port->n_rfs_rules--;
+	}
+
+	ret = mvpp2_port_flt_rfs_rule_insert(port, &efs->rule);
+	if (ret)
+		goto clean_eth_rule;
+
+	memcpy(&efs->rxnfc, info, sizeof(*info));
+	port->rfs_rules[efs->rule.loc] = efs;
+	port->n_rfs_rules++;
+
+	return ret;
+
+clean_eth_rule:
+	ethtool_rx_flow_rule_destroy(ethtool_rule);
+clean_rule:
+	kfree(efs);
+	return ret;
+}
+
+int mvpp2_ethtool_cls_rule_del(struct mvpp2_port *port,
+			       struct ethtool_rxnfc *info)
+{
+	struct mvpp2_ethtool_fs *efs;
+	int ret;
+
+	efs = port->rfs_rules[info->fs.location];
+	if (!efs)
+		return -EINVAL;
+
+	/* Remove the rule from the engines. */
+	ret = mvpp2_port_cls_rfs_rule_remove(port, &efs->rule);
+	if (ret)
+		return ret;
+
+	port->n_rfs_rules--;
+	port->rfs_rules[info->fs.location] = NULL;
+	kfree(efs);
+
+	return 0;
+}
+
 static inline u32 mvpp22_rxfh_indir(struct mvpp2_port *port, u32 rxq)
 {
 	int nrxqs, cpu, cpus = num_possible_cpus();