net/mlx5: E-switch, Introduce rate limiting groups API

Extend eswitch API with rate limiting groups:

- Define new struct mlx5_esw_rate_group that is used to hold all
  internal group data.

- Implement functions that allow creation, destruction and cleanup of
  groups.

- Assign all vports to internal unlimited zero group by default.

This commit lays the groundwork for group rate limiting by implementing
devlink_ops->rate_node_{new|del}() callbacks to support creating and
deleting groups through devlink rate node objects. APIs that allows
setting rates and adding/removing members are implemented in following
patches.

Co-developed-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: Dmytro Linkin <dlinkin@nvidia.com>
Reviewed-by: Huy Nguyen <huyn@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/devlink.c

@@ -295,6 +295,8 @@ static const struct devlink_ops mlx5_devlink_ops = {
 	.port_function_hw_addr_set = mlx5_devlink_port_function_hw_addr_set,
 	.rate_leaf_tx_share_set = mlx5_esw_devlink_rate_leaf_tx_share_set,
 	.rate_leaf_tx_max_set = mlx5_esw_devlink_rate_leaf_tx_max_set,
+	.rate_node_new = mlx5_esw_devlink_rate_node_new,
+	.rate_node_del = mlx5_esw_devlink_rate_node_del,
 #endif
 #ifdef CONFIG_MLX5_SF_MANAGER
 	.port_new = mlx5_devlink_sf_port_new,

drivers/net/ethernet/mellanox/mlx5/core/esw/qos.c

@@ -11,6 +11,13 @@
 #define MLX5_RATE_TO_BW_SHARE(rate, divider, limit) \
 	min_t(u32, max_t(u32, DIV_ROUND_UP(rate, divider), MLX5_MIN_BW_SHARE), limit)
 
+struct mlx5_esw_rate_group {
+	u32 tsar_ix;
+	u32 max_rate;
+	u32 min_rate;
+	u32 bw_share;
+};
+
 static int esw_qos_vport_config(struct mlx5_eswitch *esw,
 				struct mlx5_vport *vport,
 				u32 max_rate, u32 bw_share,
@@ -159,6 +166,54 @@ int mlx5_esw_qos_set_vport_max_rate(struct mlx5_eswitch *esw,
 	return err;
 }
 
+static struct mlx5_esw_rate_group *
+esw_qos_create_rate_group(struct mlx5_eswitch *esw, struct netlink_ext_ack *extack)
+{
+	u32 tsar_ctx[MLX5_ST_SZ_DW(scheduling_context)] = {};
+	struct mlx5_esw_rate_group *group;
+	int err;
+
+	if (!MLX5_CAP_QOS(esw->dev, log_esw_max_sched_depth))
+		return ERR_PTR(-EOPNOTSUPP);
+
+	group = kzalloc(sizeof(*group), GFP_KERNEL);
+	if (!group)
+		return ERR_PTR(-ENOMEM);
+
+	MLX5_SET(scheduling_context, tsar_ctx, parent_element_id,
+		 esw->qos.root_tsar_ix);
+	err = mlx5_create_scheduling_element_cmd(esw->dev,
+						 SCHEDULING_HIERARCHY_E_SWITCH,
+						 tsar_ctx,
+						 &group->tsar_ix);
+	if (err) {
+		NL_SET_ERR_MSG_MOD(extack, "E-Switch create TSAR for group failed");
+		goto err_sched_elem;
+	}
+
+	return group;
+
+err_sched_elem:
+	kfree(group);
+	return ERR_PTR(err);
+}
+
+static int esw_qos_destroy_rate_group(struct mlx5_eswitch *esw,
+				      struct mlx5_esw_rate_group *group,
+				      struct netlink_ext_ack *extack)
+{
+	int err;
+
+	err = mlx5_destroy_scheduling_element_cmd(esw->dev,
+						  SCHEDULING_HIERARCHY_E_SWITCH,
+						  group->tsar_ix);
+	if (err)
+		NL_SET_ERR_MSG_MOD(extack, "E-Switch destroy TSAR_ID failed");
+
+	kfree(group);
+	return err;
+}
+
 static bool esw_qos_element_type_supported(struct mlx5_core_dev *dev, int type)
 {
 	switch (type) {
@@ -191,8 +246,9 @@ void mlx5_esw_qos_create(struct mlx5_eswitch *esw)
 	if (!esw_qos_element_type_supported(dev, SCHEDULING_CONTEXT_ELEMENT_TYPE_TSAR))
 		return;
 
+	mutex_lock(&esw->state_lock);
 	if (esw->qos.enabled)
-		return;
+		goto unlock;
 
 	MLX5_SET(scheduling_context, tsar_ctx, element_type,
 		 SCHEDULING_CONTEXT_ELEMENT_TYPE_TSAR);
@@ -205,27 +261,54 @@ void mlx5_esw_qos_create(struct mlx5_eswitch *esw)
 						 tsar_ctx,
 						 &esw->qos.root_tsar_ix);
 	if (err) {
-		esw_warn(dev, "E-Switch create TSAR failed (%d)\n", err);
-		return;
+		esw_warn(dev, "E-Switch create root TSAR failed (%d)\n", err);
+		goto unlock;
 	}
 
+	if (MLX5_CAP_QOS(dev, log_esw_max_sched_depth)) {
+		esw->qos.group0 = esw_qos_create_rate_group(esw, NULL);
+		if (IS_ERR(esw->qos.group0)) {
+			esw_warn(dev, "E-Switch create rate group 0 failed (%ld)\n",
+				 PTR_ERR(esw->qos.group0));
+			goto err_group0;
+		}
+	}
 	esw->qos.enabled = true;
+unlock:
+	mutex_unlock(&esw->state_lock);
+	return;
+
+err_group0:
+	err = mlx5_destroy_scheduling_element_cmd(esw->dev,
+						  SCHEDULING_HIERARCHY_E_SWITCH,
+						  esw->qos.root_tsar_ix);
+	if (err)
+		esw_warn(esw->dev, "E-Switch destroy root TSAR failed (%d)\n", err);
+	mutex_unlock(&esw->state_lock);
 }
 
 void mlx5_esw_qos_destroy(struct mlx5_eswitch *esw)
 {
+	struct devlink *devlink = priv_to_devlink(esw->dev);
 	int err;
 
+	devlink_rate_nodes_destroy(devlink);
+	mutex_lock(&esw->state_lock);
 	if (!esw->qos.enabled)
-		return;
+		goto unlock;
+
+	if (esw->qos.group0)
+		esw_qos_destroy_rate_group(esw, esw->qos.group0, NULL);
 
 	err = mlx5_destroy_scheduling_element_cmd(esw->dev,
 						  SCHEDULING_HIERARCHY_E_SWITCH,
 						  esw->qos.root_tsar_ix);
 	if (err)
-		esw_warn(esw->dev, "E-Switch destroy TSAR failed (%d)\n", err);
+		esw_warn(esw->dev, "E-Switch destroy root TSAR failed (%d)\n", err);
 
 	esw->qos.enabled = false;
+unlock:
+	mutex_unlock(&esw->state_lock);
 }
 
 int mlx5_esw_qos_vport_enable(struct mlx5_eswitch *esw, struct mlx5_vport *vport,
@@ -386,3 +469,51 @@ int mlx5_esw_devlink_rate_leaf_tx_max_set(struct devlink_rate *rate_leaf, void *
 	mutex_unlock(&esw->state_lock);
 	return err;
 }
+
+int mlx5_esw_devlink_rate_node_new(struct devlink_rate *rate_node, void **priv,
+				   struct netlink_ext_ack *extack)
+{
+	struct mlx5_esw_rate_group *group;
+	struct mlx5_eswitch *esw;
+	int err = 0;
+
+	esw = mlx5_devlink_eswitch_get(rate_node->devlink);
+	if (IS_ERR(esw))
+		return PTR_ERR(esw);
+
+	mutex_lock(&esw->state_lock);
+	if (esw->mode != MLX5_ESWITCH_OFFLOADS) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Rate node creation supported only in switchdev mode");
+		err = -EOPNOTSUPP;
+		goto unlock;
+	}
+
+	group = esw_qos_create_rate_group(esw, extack);
+	if (IS_ERR(group)) {
+		err = PTR_ERR(group);
+		goto unlock;
+	}
+
+	*priv = group;
+unlock:
+	mutex_unlock(&esw->state_lock);
+	return err;
+}
+
+int mlx5_esw_devlink_rate_node_del(struct devlink_rate *rate_node, void *priv,
+				   struct netlink_ext_ack *extack)
+{
+	struct mlx5_esw_rate_group *group = priv;
+	struct mlx5_eswitch *esw;
+	int err;
+
+	esw = mlx5_devlink_eswitch_get(rate_node->devlink);
+	if (IS_ERR(esw))
+		return PTR_ERR(esw);
+
+	mutex_lock(&esw->state_lock);
+	err = esw_qos_destroy_rate_group(esw, group, extack);
+	mutex_unlock(&esw->state_lock);
+	return err;
+}

drivers/net/ethernet/mellanox/mlx5/core/esw/qos.h

@@ -24,6 +24,10 @@ int mlx5_esw_devlink_rate_leaf_tx_share_set(struct devlink_rate *rate_leaf, void
 					    u64 tx_share, struct netlink_ext_ack *extack);
 int mlx5_esw_devlink_rate_leaf_tx_max_set(struct devlink_rate *rate_leaf, void *priv,
 					  u64 tx_max, struct netlink_ext_ack *extack);
+int mlx5_esw_devlink_rate_node_new(struct devlink_rate *rate_node, void **priv,
+				   struct netlink_ext_ack *extack);
+int mlx5_esw_devlink_rate_node_del(struct devlink_rate *rate_node, void *priv,
+				   struct netlink_ext_ack *extack);
 #endif
 
 #endif

drivers/net/ethernet/mellanox/mlx5/core/eswitch.h

@@ -306,6 +306,7 @@ struct mlx5_eswitch {
 	struct {
 		bool            enabled;
 		u32             root_tsar_ix;
+		struct mlx5_esw_rate_group *group0;
 	} qos;
 
 	struct mlx5_esw_bridge_offloads *br_offloads;

include/linux/mlx5/mlx5_ifc.h

@@ -865,7 +865,8 @@ struct mlx5_ifc_qos_cap_bits {
 	u8         nic_bw_share[0x1];
 	u8         nic_rate_limit[0x1];
 	u8         packet_pacing_uid[0x1];
-	u8         reserved_at_c[0x14];
+	u8         log_esw_max_sched_depth[0x4];
+	u8         reserved_at_10[0x10];
 
 	u8         reserved_at_20[0xb];
 	u8         log_max_qos_nic_queue_group[0x5];