mlxsw: spectrum_span: Add APIs to bind / unbind a SPAN agent

Currently, a SPAN agent can only be bound to a per-port trigger where
the trigger is either an incoming packet (INGRESS) or an outgoing packet
(EGRESS) to / from the port.

A follow-up patch set will introduce the concept of global triggers and
per-{port, TC} enablement. With global triggers, the trigger entry is
only keyed by a trigger and not by a port and a trigger. The trigger can
be, for example, a packet that was early dropped.

While the binding between the SPAN agent and the trigger is performed
only once, the trigger entry needs to be reference counted, as the
trigger can be enabled on multiple ports.

Add APIs to bind / unbind a SPAN agent to a trigger and reference count
the trigger entry in preparation for global triggers.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c

@@ -23,6 +23,7 @@ struct mlxsw_sp_span {
 	struct mlxsw_sp *mlxsw_sp;
 	struct list_head analyzed_ports_list;
 	struct mutex analyzed_ports_lock; /* Protects analyzed_ports_list */
+	struct list_head trigger_entries_list;
 	atomic_t active_entries_count;
 	int entries_count;
 	struct mlxsw_sp_span_entry entries[];
@@ -35,6 +36,14 @@ struct mlxsw_sp_span_analyzed_port {
 	bool ingress;
 };
 
+struct mlxsw_sp_span_trigger_entry {
+	struct list_head list; /* Member of trigger_entries_list */
+	refcount_t ref_count;
+	u8 local_port;
+	enum mlxsw_sp_span_trigger trigger;
+	struct mlxsw_sp_span_trigger_parms parms;
+};
+
 static void mlxsw_sp_span_respin_work(struct work_struct *work);
 
 static u64 mlxsw_sp_span_occ_get(void *priv)
@@ -61,6 +70,7 @@ int mlxsw_sp_span_init(struct mlxsw_sp *mlxsw_sp)
 	atomic_set(&span->active_entries_count, 0);
 	mutex_init(&span->analyzed_ports_lock);
 	INIT_LIST_HEAD(&span->analyzed_ports_list);
+	INIT_LIST_HEAD(&span->trigger_entries_list);
 	span->mlxsw_sp = mlxsw_sp;
 	mlxsw_sp->span = span;
 
@@ -91,6 +101,7 @@ void mlxsw_sp_span_fini(struct mlxsw_sp *mlxsw_sp)
 
 		WARN_ON_ONCE(!list_empty(&curr->bound_ports_list));
 	}
+	WARN_ON_ONCE(!list_empty(&mlxsw_sp->span->trigger_entries_list));
 	WARN_ON_ONCE(!list_empty(&mlxsw_sp->span->analyzed_ports_list));
 	mutex_destroy(&mlxsw_sp->span->analyzed_ports_lock);
 	kfree(mlxsw_sp->span);
@@ -1225,3 +1236,161 @@ void mlxsw_sp_span_analyzed_port_put(struct mlxsw_sp_port *mlxsw_sp_port,
 out_unlock:
 	mutex_unlock(&mlxsw_sp->span->analyzed_ports_lock);
 }
+
+static int
+__mlxsw_sp_span_trigger_entry_bind(struct mlxsw_sp_span *span,
+				   struct mlxsw_sp_span_trigger_entry *
+				   trigger_entry, bool enable)
+{
+	char mpar_pl[MLXSW_REG_MPAR_LEN];
+	enum mlxsw_reg_mpar_i_e i_e;
+
+	switch (trigger_entry->trigger) {
+	case MLXSW_SP_SPAN_TRIGGER_INGRESS:
+		i_e = MLXSW_REG_MPAR_TYPE_INGRESS;
+		break;
+	case MLXSW_SP_SPAN_TRIGGER_EGRESS:
+		i_e = MLXSW_REG_MPAR_TYPE_EGRESS;
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		return -EINVAL;
+	}
+
+	mlxsw_reg_mpar_pack(mpar_pl, trigger_entry->local_port, i_e, enable,
+			    trigger_entry->parms.span_id);
+	return mlxsw_reg_write(span->mlxsw_sp->core, MLXSW_REG(mpar), mpar_pl);
+}
+
+static int
+mlxsw_sp_span_trigger_entry_bind(struct mlxsw_sp_span *span,
+				 struct mlxsw_sp_span_trigger_entry *
+				 trigger_entry)
+{
+	return __mlxsw_sp_span_trigger_entry_bind(span, trigger_entry, true);
+}
+
+static void
+mlxsw_sp_span_trigger_entry_unbind(struct mlxsw_sp_span *span,
+				   struct mlxsw_sp_span_trigger_entry *
+				   trigger_entry)
+{
+	__mlxsw_sp_span_trigger_entry_bind(span, trigger_entry, false);
+}
+
+static struct mlxsw_sp_span_trigger_entry *
+mlxsw_sp_span_trigger_entry_create(struct mlxsw_sp_span *span,
+				   enum mlxsw_sp_span_trigger trigger,
+				   struct mlxsw_sp_port *mlxsw_sp_port,
+				   const struct mlxsw_sp_span_trigger_parms
+				   *parms)
+{
+	struct mlxsw_sp_span_trigger_entry *trigger_entry;
+	int err;
+
+	trigger_entry = kzalloc(sizeof(*trigger_entry), GFP_KERNEL);
+	if (!trigger_entry)
+		return ERR_PTR(-ENOMEM);
+
+	refcount_set(&trigger_entry->ref_count, 1);
+	trigger_entry->local_port = mlxsw_sp_port->local_port;
+	trigger_entry->trigger = trigger;
+	memcpy(&trigger_entry->parms, parms, sizeof(trigger_entry->parms));
+	list_add_tail(&trigger_entry->list, &span->trigger_entries_list);
+
+	err = mlxsw_sp_span_trigger_entry_bind(span, trigger_entry);
+	if (err)
+		goto err_trigger_entry_bind;
+
+	return trigger_entry;
+
+err_trigger_entry_bind:
+	list_del(&trigger_entry->list);
+	kfree(trigger_entry);
+	return ERR_PTR(err);
+}
+
+static void
+mlxsw_sp_span_trigger_entry_destroy(struct mlxsw_sp_span *span,
+				    struct mlxsw_sp_span_trigger_entry *
+				    trigger_entry)
+{
+	mlxsw_sp_span_trigger_entry_unbind(span, trigger_entry);
+	list_del(&trigger_entry->list);
+	kfree(trigger_entry);
+}
+
+static struct mlxsw_sp_span_trigger_entry *
+mlxsw_sp_span_trigger_entry_find(struct mlxsw_sp_span *span,
+				 enum mlxsw_sp_span_trigger trigger,
+				 struct mlxsw_sp_port *mlxsw_sp_port)
+{
+	struct mlxsw_sp_span_trigger_entry *trigger_entry;
+
+	list_for_each_entry(trigger_entry, &span->trigger_entries_list, list) {
+		if (trigger_entry->trigger == trigger &&
+		    trigger_entry->local_port == mlxsw_sp_port->local_port)
+			return trigger_entry;
+	}
+
+	return NULL;
+}
+
+int mlxsw_sp_span_agent_bind(struct mlxsw_sp *mlxsw_sp,
+			     enum mlxsw_sp_span_trigger trigger,
+			     struct mlxsw_sp_port *mlxsw_sp_port,
+			     const struct mlxsw_sp_span_trigger_parms *parms)
+{
+	struct mlxsw_sp_span_trigger_entry *trigger_entry;
+	int err = 0;
+
+	ASSERT_RTNL();
+
+	if (!mlxsw_sp_span_entry_find_by_id(mlxsw_sp, parms->span_id))
+		return -EINVAL;
+
+	trigger_entry = mlxsw_sp_span_trigger_entry_find(mlxsw_sp->span,
+							 trigger,
+							 mlxsw_sp_port);
+	if (trigger_entry) {
+		if (trigger_entry->parms.span_id != parms->span_id)
+			return -EINVAL;
+		refcount_inc(&trigger_entry->ref_count);
+		goto out;
+	}
+
+	trigger_entry = mlxsw_sp_span_trigger_entry_create(mlxsw_sp->span,
+							   trigger,
+							   mlxsw_sp_port,
+							   parms);
+	if (IS_ERR(trigger_entry))
+		err = PTR_ERR(trigger_entry);
+
+out:
+	return err;
+}
+
+void mlxsw_sp_span_agent_unbind(struct mlxsw_sp *mlxsw_sp,
+				enum mlxsw_sp_span_trigger trigger,
+				struct mlxsw_sp_port *mlxsw_sp_port,
+				const struct mlxsw_sp_span_trigger_parms *parms)
+{
+	struct mlxsw_sp_span_trigger_entry *trigger_entry;
+
+	ASSERT_RTNL();
+
+	if (WARN_ON_ONCE(!mlxsw_sp_span_entry_find_by_id(mlxsw_sp,
+							 parms->span_id)))
+		return;
+
+	trigger_entry = mlxsw_sp_span_trigger_entry_find(mlxsw_sp->span,
+							 trigger,
+							 mlxsw_sp_port);
+	if (WARN_ON_ONCE(!trigger_entry))
+		return;
+
+	if (!refcount_dec_and_test(&trigger_entry->ref_count))
+		return;
+
+	mlxsw_sp_span_trigger_entry_destroy(mlxsw_sp->span, trigger_entry);
+}

drivers/net/ethernet/mellanox/mlxsw/spectrum_span.h

@@ -37,6 +37,15 @@ struct mlxsw_sp_span_parms {
 	u16 vid;
 };
 
+enum mlxsw_sp_span_trigger {
+	MLXSW_SP_SPAN_TRIGGER_INGRESS,
+	MLXSW_SP_SPAN_TRIGGER_EGRESS,
+};
+
+struct mlxsw_sp_span_trigger_parms {
+	int span_id;
+};
+
 struct mlxsw_sp_span_entry_ops;
 
 struct mlxsw_sp_span_entry {
@@ -84,5 +93,14 @@ int mlxsw_sp_span_analyzed_port_get(struct mlxsw_sp_port *mlxsw_sp_port,
 				    bool ingress);
 void mlxsw_sp_span_analyzed_port_put(struct mlxsw_sp_port *mlxsw_sp_port,
 				     bool ingress);
+int mlxsw_sp_span_agent_bind(struct mlxsw_sp *mlxsw_sp,
+			     enum mlxsw_sp_span_trigger trigger,
+			     struct mlxsw_sp_port *mlxsw_sp_port,
+			     const struct mlxsw_sp_span_trigger_parms *parms);
+void
+mlxsw_sp_span_agent_unbind(struct mlxsw_sp *mlxsw_sp,
+			   enum mlxsw_sp_span_trigger trigger,
+			   struct mlxsw_sp_port *mlxsw_sp_port,
+			   const struct mlxsw_sp_span_trigger_parms *parms);
 
 #endif