[PATCH net-next v3 2/3] net: ethernet: ti: am65-cpsw: enable bc/mc storm prevention support

[Grygorii Strashko]

This patch enables support for ingress broadcast(BC)/multicast(MC) packets
rate limiting in TI AM65x CPSW driver (the corresponding ALE support was
added in previous patch) by implementing HW offload for simple tc-flower
with policer action with matches on dst_mac/mask:
 - ff:ff:ff:ff:ff:ff/ff:ff:ff:ff:ff:ff has to be used for BC packets rate
limiting (exact match)
 - 01:00:00:00:00:00/01:00:00:00:00:00 fixed value has to be used for MC
packets rate limiting

The CPSW supports MC/BC packets rate limiting in packets/sec and affects
all ingress MC/BC packets and serves as BC/MC storm prevention feature.

Examples:
- BC rate limit to 1000pps:
  tc qdisc add dev eth0 clsact
  tc filter add dev eth0 ingress flower skip_sw dst_mac ff:ff:ff:ff:ff:ff \
  action police pkts_rate 1000 pkts_burst 1 drop

- MC rate limit to 20000pps:
  tc qdisc add dev eth0 clsact
  tc filter add dev eth0 ingress flower skip_sw dst_mac 01:00:00:00:00:00/01:00:00:00:00:00 \
  action police rate pkts_rate 20000 pkts_burst 1 drop

  pkts_burst - not used.

Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
---
 drivers/net/ethernet/ti/am65-cpsw-qos.c | 180 ++++++++++++++++++++++++
 drivers/net/ethernet/ti/am65-cpsw-qos.h |   8 ++
 2 files changed, 188 insertions(+)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-qos.c b/drivers/net/ethernet/ti/am65-cpsw-qos.c
index ebcc6386cc34..aa32dd905e2b 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-qos.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-qos.c
@@ -8,10 +8,12 @@
 
 #include <linux/pm_runtime.h>
 #include <linux/time.h>
+#include <net/pkt_cls.h>
 
 #include "am65-cpsw-nuss.h"
 #include "am65-cpsw-qos.h"
 #include "am65-cpts.h"
+#include "cpsw_ale.h"
 
 #define AM65_CPSW_REG_CTL			0x004
 #define AM65_CPSW_PN_REG_CTL			0x004
@@ -588,12 +590,190 @@ static int am65_cpsw_setup_taprio(struct net_device *ndev, void *type_data)
 	return am65_cpsw_set_taprio(ndev, type_data);
 }
 
+static int am65_cpsw_qos_clsflower_add_policer(struct am65_cpsw_port *port,
+					       struct netlink_ext_ack *extack,
+					       struct flow_cls_offload *cls,
+					       u64 rate_pkt_ps)
+{
+	struct flow_rule *rule = flow_cls_offload_flow_rule(cls);
+	struct flow_dissector *dissector = rule->match.dissector;
+	static const u8 mc_mac[] = {0x01, 0x00, 0x00, 0x00, 0x00, 0x00};
+	struct am65_cpsw_qos *qos = &port->qos;
+	struct flow_match_eth_addrs match;
+	int ret;
+
+	if (dissector->used_keys &
+	    ~(BIT(FLOW_DISSECTOR_KEY_BASIC) |
+	      BIT(FLOW_DISSECTOR_KEY_CONTROL) |
+	      BIT(FLOW_DISSECTOR_KEY_ETH_ADDRS))) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Unsupported keys used");
+		return -EOPNOTSUPP;
+	}
+
+	if (!flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
+		NL_SET_ERR_MSG_MOD(extack, "Not matching on eth address");
+		return -EOPNOTSUPP;
+	}
+
+	flow_rule_match_eth_addrs(rule, &match);
+
+	if (!is_zero_ether_addr(match.mask->src)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Matching on source MAC not supported");
+		return -EOPNOTSUPP;
+	}
+
+	if (is_broadcast_ether_addr(match.key->dst) &&
+	    is_broadcast_ether_addr(match.mask->dst)) {
+		ret = cpsw_ale_rx_ratelimit_bc(port->common->ale, port->port_id, rate_pkt_ps);
+		if (ret)
+			return ret;
+
+		qos->ale_bc_ratelimit.cookie = cls->cookie;
+		qos->ale_bc_ratelimit.rate_packet_ps = rate_pkt_ps;
+	} else if (ether_addr_equal_unaligned(match.key->dst, mc_mac) &&
+		   ether_addr_equal_unaligned(match.mask->dst, mc_mac)) {
+		ret = cpsw_ale_rx_ratelimit_mc(port->common->ale, port->port_id, rate_pkt_ps);
+		if (ret)
+			return ret;
+
+		qos->ale_mc_ratelimit.cookie = cls->cookie;
+		qos->ale_mc_ratelimit.rate_packet_ps = rate_pkt_ps;
+	} else {
+		NL_SET_ERR_MSG_MOD(extack, "Not supported matching key");
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int am65_cpsw_qos_clsflower_policer_validate(const struct flow_action *action,
+						    const struct flow_action_entry *act,
+						    struct netlink_ext_ack *extack)
+{
+	if (act->police.exceed.act_id != FLOW_ACTION_DROP) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Offload not supported when exceed action is not drop");
+		return -EOPNOTSUPP;
+	}
+
+	if (act->police.notexceed.act_id != FLOW_ACTION_PIPE &&
+	    act->police.notexceed.act_id != FLOW_ACTION_ACCEPT) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Offload not supported when conform action is not pipe or ok");
+		return -EOPNOTSUPP;
+	}
+
+	if (act->police.notexceed.act_id == FLOW_ACTION_ACCEPT &&
+	    !flow_action_is_last_entry(action, act)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Offload not supported when conform action is ok, but action is not last");
+		return -EOPNOTSUPP;
+	}
+
+	if (act->police.rate_bytes_ps || act->police.peakrate_bytes_ps ||
+	    act->police.avrate || act->police.overhead) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Offload not supported when bytes per second/peakrate/avrate/overhead is configured");
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int am65_cpsw_qos_configure_clsflower(struct am65_cpsw_port *port,
+					     struct flow_cls_offload *cls)
+{
+	struct flow_rule *rule = flow_cls_offload_flow_rule(cls);
+	struct netlink_ext_ack *extack = cls->common.extack;
+	const struct flow_action_entry *act;
+	int i, ret;
+
+	flow_action_for_each(i, act, &rule->action) {
+		switch (act->id) {
+		case FLOW_ACTION_POLICE:
+			ret = am65_cpsw_qos_clsflower_policer_validate(&rule->action, act, extack);
+			if (ret)
+				return ret;
+
+			return am65_cpsw_qos_clsflower_add_policer(port, extack, cls,
+								   act->police.rate_pkt_ps);
+		default:
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Action not supported");
+			return -EOPNOTSUPP;
+		}
+	}
+	return -EOPNOTSUPP;
+}
+
+static int am65_cpsw_qos_delete_clsflower(struct am65_cpsw_port *port, struct flow_cls_offload *cls)
+{
+	struct am65_cpsw_qos *qos = &port->qos;
+
+	if (cls->cookie == qos->ale_bc_ratelimit.cookie) {
+		qos->ale_bc_ratelimit.cookie = 0;
+		qos->ale_bc_ratelimit.rate_packet_ps = 0;
+		cpsw_ale_rx_ratelimit_bc(port->common->ale, port->port_id, 0);
+	}
+
+	if (cls->cookie == qos->ale_mc_ratelimit.cookie) {
+		qos->ale_mc_ratelimit.cookie = 0;
+		qos->ale_mc_ratelimit.rate_packet_ps = 0;
+		cpsw_ale_rx_ratelimit_mc(port->common->ale, port->port_id, 0);
+	}
+
+	return 0;
+}
+
+static int am65_cpsw_qos_setup_tc_clsflower(struct am65_cpsw_port *port,
+					    struct flow_cls_offload *cls_flower)
+{
+	switch (cls_flower->command) {
+	case FLOW_CLS_REPLACE:
+		return am65_cpsw_qos_configure_clsflower(port, cls_flower);
+	case FLOW_CLS_DESTROY:
+		return am65_cpsw_qos_delete_clsflower(port, cls_flower);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int am65_cpsw_qos_setup_tc_block_cb(enum tc_setup_type type, void *type_data, void *cb_priv)
+{
+	struct am65_cpsw_port *port = cb_priv;
+
+	if (!tc_cls_can_offload_and_chain0(port->ndev, type_data))
+		return -EOPNOTSUPP;
+
+	switch (type) {
+	case TC_SETUP_CLSFLOWER:
+		return am65_cpsw_qos_setup_tc_clsflower(port, type_data);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static LIST_HEAD(am65_cpsw_qos_block_cb_list);
+
+static int am65_cpsw_qos_setup_tc_block(struct net_device *ndev, struct flow_block_offload *f)
+{
+	struct am65_cpsw_port *port = am65_ndev_to_port(ndev);
+
+	return flow_block_cb_setup_simple(f, &am65_cpsw_qos_block_cb_list,
+					  am65_cpsw_qos_setup_tc_block_cb,
+					  port, port, true);
+}
+
 int am65_cpsw_qos_ndo_setup_tc(struct net_device *ndev, enum tc_setup_type type,
 			       void *type_data)
 {
 	switch (type) {
 	case TC_SETUP_QDISC_TAPRIO:
 		return am65_cpsw_setup_taprio(ndev, type_data);
+	case TC_SETUP_BLOCK:
+		return am65_cpsw_qos_setup_tc_block(ndev, type_data);
 	default:
 		return -EOPNOTSUPP;
 	}
diff --git a/drivers/net/ethernet/ti/am65-cpsw-qos.h b/drivers/net/ethernet/ti/am65-cpsw-qos.h
index e8f1b6b59e93..fb223b43b196 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-qos.h
+++ b/drivers/net/ethernet/ti/am65-cpsw-qos.h
@@ -14,11 +14,19 @@ struct am65_cpsw_est {
 	struct tc_taprio_qopt_offload taprio;
 };
 
+struct am65_cpsw_ale_ratelimit {
+	unsigned long cookie;
+	u64 rate_packet_ps;
+};
+
 struct am65_cpsw_qos {
 	struct am65_cpsw_est *est_admin;
 	struct am65_cpsw_est *est_oper;
 	ktime_t link_down_time;
 	int link_speed;
+
+	struct am65_cpsw_ale_ratelimit ale_bc_ratelimit;
+	struct am65_cpsw_ale_ratelimit ale_mc_ratelimit;
 };
 
 int am65_cpsw_qos_ndo_setup_tc(struct net_device *ndev, enum tc_setup_type type,
-- 
2.17.1