mlxsw: spectrum: Initialize netdev's module overheat counter

The overheat counter is a per-module counter, but it is exposed as part
of the corresponding netdev's statistics. It should therefore be
presented to user space relative to the netdev's lifetime.

Query the counter just before registering the netdev, so that the value
exposed to user space will be relative to this initial value.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -1365,6 +1365,22 @@ static int mlxsw_sp_port_tc_mc_mode_set(struct mlxsw_sp_port *mlxsw_sp_port,
 	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(qtctm), qtctm_pl);
 }
 
+static int mlxsw_sp_port_overheat_init_val_set(struct mlxsw_sp_port *mlxsw_sp_port)
+{
+	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
+	u8 module = mlxsw_sp_port->mapping.module;
+	u64 overheat_counter;
+	int err;
+
+	err = mlxsw_env_module_overheat_counter_get(mlxsw_sp->core, module,
+						    &overheat_counter);
+	if (err)
+		return err;
+
+	mlxsw_sp_port->module_overheat_initial_val = overheat_counter;
+	return 0;
+}
+
 static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port,
 				u8 split_base_local_port,
 				struct mlxsw_sp_port_mapping *port_mapping)
@@ -1575,6 +1591,14 @@ static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port,
 			  mlxsw_sp->ptp_ops->shaper_work);
 
 	mlxsw_sp->ports[local_port] = mlxsw_sp_port;
+
+	err = mlxsw_sp_port_overheat_init_val_set(mlxsw_sp_port);
+	if (err) {
+		dev_err(mlxsw_sp->bus_info->dev, "Port %d: Failed to set overheat initial value\n",
+			mlxsw_sp_port->local_port);
+		goto err_port_overheat_init_val_set;
+	}
+
 	err = register_netdev(dev);
 	if (err) {
 		dev_err(mlxsw_sp->bus_info->dev, "Port %d: Failed to register netdev\n",
@@ -1588,6 +1612,7 @@ static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port,
 	return 0;
 
 err_register_netdev:
+err_port_overheat_init_val_set:
 	mlxsw_sp->ports[local_port] = NULL;
 	mlxsw_sp_port_vlan_destroy(mlxsw_sp_port_vlan);
 err_port_vlan_create:

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

@@ -319,6 +319,7 @@ struct mlxsw_sp_port {
 	int max_mtu;
 	u32 max_speed;
 	struct mlxsw_sp_hdroom *hdroom;
+	u64 module_overheat_initial_val;
 };
 
 struct mlxsw_sp_port_type_speed_ops {