mlxsw: Add ability to control transceiver modules' power mode

Implement support for ethtool_ops::.get_module_power_mode and
ethtool_ops::set_module_power_mode.

The get operation is implemented using the Management Cable IO and
Notifications (MCION) register that reports the operational power mode
of the module and its presence. In case a module is not present, its
operational power mode is not reported to ethtool and user space. If not
set before, the power mode policy is reported as "high", which is the
default on Mellanox systems.

The set operation is implemented using the Port Module Memory Map
Properties (PMMP) register. The register instructs the device's firmware
to transition a plugged-in module to / out of low power mode by writing
to its memory map.

When the power mode policy is set to 'auto', a module will not
transition to low power mode as long as any ports using it are
administratively up. Example:

 # devlink port split swp11 count 4

 # ethtool --set-module swp11s0 power-mode-policy auto

 $ ethtool --show-module swp11s0
 Module parameters for swp11s0:
 power-mode-policy auto
 power-mode low

 # ip link set dev swp11s0 up

 # ip link set dev swp11s1 up

 $ ethtool --show-module swp11s0
 Module parameters for swp11s0:
 power-mode-policy auto
 power-mode high

 # ip link set dev swp11s1 down

 $ ethtool --show-module swp11s0
 Module parameters for swp11s0:
 power-mode-policy auto
 power-mode high

 # ip link set dev swp11s0 down

 $ ethtool --show-module swp11s0
 Module parameters for swp11s0:
 power-mode-policy auto
 power-mode low
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -17,6 +17,7 @@ struct mlxsw_env_module_info {
 	bool is_overheat;
 	int num_ports_mapped;
 	int num_ports_up;
+	enum ethtool_module_power_mode_policy power_mode_policy;
 };
 
 struct mlxsw_env {
@@ -445,6 +446,152 @@ int mlxsw_env_reset_module(struct net_device *netdev,
 }
 EXPORT_SYMBOL(mlxsw_env_reset_module);
 
+int
+mlxsw_env_get_module_power_mode(struct mlxsw_core *mlxsw_core, u8 module,
+				struct ethtool_module_power_mode_params *params,
+				struct netlink_ext_ack *extack)
+{
+	struct mlxsw_env *mlxsw_env = mlxsw_core_env(mlxsw_core);
+	char mcion_pl[MLXSW_REG_MCION_LEN];
+	u32 status_bits;
+	int err;
+
+	if (WARN_ON_ONCE(module >= mlxsw_env->module_count))
+		return -EINVAL;
+
+	mutex_lock(&mlxsw_env->module_info_lock);
+
+	params->policy = mlxsw_env->module_info[module].power_mode_policy;
+
+	mlxsw_reg_mcion_pack(mcion_pl, module);
+	err = mlxsw_reg_query(mlxsw_core, MLXSW_REG(mcion), mcion_pl);
+	if (err) {
+		NL_SET_ERR_MSG_MOD(extack, "Failed to retrieve module's power mode");
+		goto out;
+	}
+
+	status_bits = mlxsw_reg_mcion_module_status_bits_get(mcion_pl);
+	if (!(status_bits & MLXSW_REG_MCION_MODULE_STATUS_BITS_PRESENT_MASK))
+		goto out;
+
+	if (status_bits & MLXSW_REG_MCION_MODULE_STATUS_BITS_LOW_POWER_MASK)
+		params->mode = ETHTOOL_MODULE_POWER_MODE_LOW;
+	else
+		params->mode = ETHTOOL_MODULE_POWER_MODE_HIGH;
+
+out:
+	mutex_unlock(&mlxsw_env->module_info_lock);
+	return err;
+}
+EXPORT_SYMBOL(mlxsw_env_get_module_power_mode);
+
+static int mlxsw_env_module_enable_set(struct mlxsw_core *mlxsw_core,
+				       u8 module, bool enable)
+{
+	enum mlxsw_reg_pmaos_admin_status admin_status;
+	char pmaos_pl[MLXSW_REG_PMAOS_LEN];
+
+	mlxsw_reg_pmaos_pack(pmaos_pl, module);
+	admin_status = enable ? MLXSW_REG_PMAOS_ADMIN_STATUS_ENABLED :
+				MLXSW_REG_PMAOS_ADMIN_STATUS_DISABLED;
+	mlxsw_reg_pmaos_admin_status_set(pmaos_pl, admin_status);
+	mlxsw_reg_pmaos_ase_set(pmaos_pl, true);
+
+	return mlxsw_reg_write(mlxsw_core, MLXSW_REG(pmaos), pmaos_pl);
+}
+
+static int mlxsw_env_module_low_power_set(struct mlxsw_core *mlxsw_core,
+					  u8 module, bool low_power)
+{
+	u16 eeprom_override_mask, eeprom_override;
+	char pmmp_pl[MLXSW_REG_PMMP_LEN];
+
+	mlxsw_reg_pmmp_pack(pmmp_pl, module);
+	mlxsw_reg_pmmp_sticky_set(pmmp_pl, true);
+	/* Mask all the bits except low power mode. */
+	eeprom_override_mask = ~MLXSW_REG_PMMP_EEPROM_OVERRIDE_LOW_POWER_MASK;
+	mlxsw_reg_pmmp_eeprom_override_mask_set(pmmp_pl, eeprom_override_mask);
+	eeprom_override = low_power ? MLXSW_REG_PMMP_EEPROM_OVERRIDE_LOW_POWER_MASK :
+				      0;
+	mlxsw_reg_pmmp_eeprom_override_set(pmmp_pl, eeprom_override);
+
+	return mlxsw_reg_write(mlxsw_core, MLXSW_REG(pmmp), pmmp_pl);
+}
+
+static int __mlxsw_env_set_module_power_mode(struct mlxsw_core *mlxsw_core,
+					     u8 module, bool low_power,
+					     struct netlink_ext_ack *extack)
+{
+	int err;
+
+	err = mlxsw_env_module_enable_set(mlxsw_core, module, false);
+	if (err) {
+		NL_SET_ERR_MSG_MOD(extack, "Failed to disable module");
+		return err;
+	}
+
+	err = mlxsw_env_module_low_power_set(mlxsw_core, module, low_power);
+	if (err) {
+		NL_SET_ERR_MSG_MOD(extack, "Failed to set module's power mode");
+		goto err_module_low_power_set;
+	}
+
+	err = mlxsw_env_module_enable_set(mlxsw_core, module, true);
+	if (err) {
+		NL_SET_ERR_MSG_MOD(extack, "Failed to enable module");
+		goto err_module_enable_set;
+	}
+
+	return 0;
+
+err_module_enable_set:
+	mlxsw_env_module_low_power_set(mlxsw_core, module, !low_power);
+err_module_low_power_set:
+	mlxsw_env_module_enable_set(mlxsw_core, module, true);
+	return err;
+}
+
+int
+mlxsw_env_set_module_power_mode(struct mlxsw_core *mlxsw_core, u8 module,
+				enum ethtool_module_power_mode_policy policy,
+				struct netlink_ext_ack *extack)
+{
+	struct mlxsw_env *mlxsw_env = mlxsw_core_env(mlxsw_core);
+	bool low_power;
+	int err = 0;
+
+	if (WARN_ON_ONCE(module >= mlxsw_env->module_count))
+		return -EINVAL;
+
+	if (policy != ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH &&
+	    policy != ETHTOOL_MODULE_POWER_MODE_POLICY_AUTO) {
+		NL_SET_ERR_MSG_MOD(extack, "Unsupported power mode policy");
+		return -EOPNOTSUPP;
+	}
+
+	mutex_lock(&mlxsw_env->module_info_lock);
+
+	if (mlxsw_env->module_info[module].power_mode_policy == policy)
+		goto out;
+
+	/* If any ports are up, we are already in high power mode. */
+	if (mlxsw_env->module_info[module].num_ports_up)
+		goto out_set_policy;
+
+	low_power = policy == ETHTOOL_MODULE_POWER_MODE_POLICY_AUTO;
+	err = __mlxsw_env_set_module_power_mode(mlxsw_core, module, low_power,
+						extack);
+	if (err)
+		goto out;
+
+out_set_policy:
+	mlxsw_env->module_info[module].power_mode_policy = policy;
+out:
+	mutex_unlock(&mlxsw_env->module_info_lock);
+	return err;
+}
+EXPORT_SYMBOL(mlxsw_env_set_module_power_mode);
+
 static int mlxsw_env_module_has_temp_sensor(struct mlxsw_core *mlxsw_core,
 					    u8 module,
 					    bool *p_has_temp_sensor)
@@ -794,15 +941,33 @@ EXPORT_SYMBOL(mlxsw_env_module_port_unmap);
 int mlxsw_env_module_port_up(struct mlxsw_core *mlxsw_core, u8 module)
 {
 	struct mlxsw_env *mlxsw_env = mlxsw_core_env(mlxsw_core);
+	int err = 0;
 
 	if (WARN_ON_ONCE(module >= mlxsw_env->module_count))
 		return -EINVAL;
 
 	mutex_lock(&mlxsw_env->module_info_lock);
+
+	if (mlxsw_env->module_info[module].power_mode_policy !=
+	    ETHTOOL_MODULE_POWER_MODE_POLICY_AUTO)
+		goto out_inc;
+
+	if (mlxsw_env->module_info[module].num_ports_up != 0)
+		goto out_inc;
+
+	/* Transition to high power mode following first port using the module
+	 * being put administratively up.
+	 */
+	err = __mlxsw_env_set_module_power_mode(mlxsw_core, module, false,
+						NULL);
+	if (err)
+		goto out_unlock;
+
+out_inc:
 	mlxsw_env->module_info[module].num_ports_up++;
+out_unlock:
 	mutex_unlock(&mlxsw_env->module_info_lock);
-
-	return 0;
+	return err;
 }
 EXPORT_SYMBOL(mlxsw_env_module_port_up);
 
@@ -814,7 +979,22 @@ void mlxsw_env_module_port_down(struct mlxsw_core *mlxsw_core, u8 module)
 		return;
 
 	mutex_lock(&mlxsw_env->module_info_lock);
+
 	mlxsw_env->module_info[module].num_ports_up--;
+
+	if (mlxsw_env->module_info[module].power_mode_policy !=
+	    ETHTOOL_MODULE_POWER_MODE_POLICY_AUTO)
+		goto out_unlock;
+
+	if (mlxsw_env->module_info[module].num_ports_up != 0)
+		goto out_unlock;
+
+	/* Transition to low power mode following last port using the module
+	 * being put administratively down.
+	 */
+	__mlxsw_env_set_module_power_mode(mlxsw_core, module, true, NULL);
+
+out_unlock:
 	mutex_unlock(&mlxsw_env->module_info_lock);
 }
 EXPORT_SYMBOL(mlxsw_env_module_port_down);
@@ -824,7 +1004,7 @@ int mlxsw_env_init(struct mlxsw_core *mlxsw_core, struct mlxsw_env **p_env)
 	char mgpir_pl[MLXSW_REG_MGPIR_LEN];
 	struct mlxsw_env *env;
 	u8 module_count;
-	int err;
+	int i, err;
 
 	mlxsw_reg_mgpir_pack(mgpir_pl);
 	err = mlxsw_reg_query(mlxsw_core, MLXSW_REG(mgpir), mgpir_pl);
@@ -837,6 +1017,13 @@ int mlxsw_env_init(struct mlxsw_core *mlxsw_core, struct mlxsw_env **p_env)
 	if (!env)
 		return -ENOMEM;
 
+	/* Firmware defaults to high power mode policy where modules are
+	 * transitioned to high power mode following plug-in.
+	 */
+	for (i = 0; i < module_count; i++)
+		env->module_info[i].power_mode_policy =
+			ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH;
+
 	mutex_init(&env->module_info_lock);
 	env->core = mlxsw_core;
 	env->module_count = module_count;

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

@@ -28,6 +28,16 @@ int mlxsw_env_reset_module(struct net_device *netdev,
 			   struct mlxsw_core *mlxsw_core, u8 module,
 			   u32 *flags);
 
+int
+mlxsw_env_get_module_power_mode(struct mlxsw_core *mlxsw_core, u8 module,
+				struct ethtool_module_power_mode_params *params,
+				struct netlink_ext_ack *extack);
+
+int
+mlxsw_env_set_module_power_mode(struct mlxsw_core *mlxsw_core, u8 module,
+				enum ethtool_module_power_mode_policy policy,
+				struct netlink_ext_ack *extack);
+
 int
 mlxsw_env_module_overheat_counter_get(struct mlxsw_core *mlxsw_core, u8 module,
 				      u64 *p_counter);

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

@@ -145,12 +145,38 @@ static int mlxsw_m_reset(struct net_device *netdev, u32 *flags)
 				      flags);
 }
 
+static int
+mlxsw_m_get_module_power_mode(struct net_device *netdev,
+			      struct ethtool_module_power_mode_params *params,
+			      struct netlink_ext_ack *extack)
+{
+	struct mlxsw_m_port *mlxsw_m_port = netdev_priv(netdev);
+	struct mlxsw_core *core = mlxsw_m_port->mlxsw_m->core;
+
+	return mlxsw_env_get_module_power_mode(core, mlxsw_m_port->module,
+					       params, extack);
+}
+
+static int
+mlxsw_m_set_module_power_mode(struct net_device *netdev,
+			      const struct ethtool_module_power_mode_params *params,
+			      struct netlink_ext_ack *extack)
+{
+	struct mlxsw_m_port *mlxsw_m_port = netdev_priv(netdev);
+	struct mlxsw_core *core = mlxsw_m_port->mlxsw_m->core;
+
+	return mlxsw_env_set_module_power_mode(core, mlxsw_m_port->module,
+					       params->policy, extack);
+}
+
 static const struct ethtool_ops mlxsw_m_port_ethtool_ops = {
 	.get_drvinfo		= mlxsw_m_module_get_drvinfo,
 	.get_module_info	= mlxsw_m_get_module_info,
 	.get_module_eeprom	= mlxsw_m_get_module_eeprom,
 	.get_module_eeprom_by_page = mlxsw_m_get_module_eeprom_by_page,
 	.reset			= mlxsw_m_reset,
+	.get_module_power_mode	= mlxsw_m_get_module_power_mode,
+	.set_module_power_mode	= mlxsw_m_set_module_power_mode,
 };
 
 static int

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

@@ -1206,6 +1206,32 @@ static int mlxsw_sp_reset(struct net_device *dev, u32 *flags)
 	return mlxsw_env_reset_module(dev, mlxsw_sp->core, module, flags);
 }
 
+static int
+mlxsw_sp_get_module_power_mode(struct net_device *dev,
+			       struct ethtool_module_power_mode_params *params,
+			       struct netlink_ext_ack *extack)
+{
+	struct mlxsw_sp_port *mlxsw_sp_port = netdev_priv(dev);
+	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
+	u8 module = mlxsw_sp_port->mapping.module;
+
+	return mlxsw_env_get_module_power_mode(mlxsw_sp->core, module, params,
+					       extack);
+}
+
+static int
+mlxsw_sp_set_module_power_mode(struct net_device *dev,
+			       const struct ethtool_module_power_mode_params *params,
+			       struct netlink_ext_ack *extack)
+{
+	struct mlxsw_sp_port *mlxsw_sp_port = netdev_priv(dev);
+	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
+	u8 module = mlxsw_sp_port->mapping.module;
+
+	return mlxsw_env_set_module_power_mode(mlxsw_sp->core, module,
+					       params->policy, extack);
+}
+
 const struct ethtool_ops mlxsw_sp_port_ethtool_ops = {
 	.cap_link_lanes_supported	= true,
 	.get_drvinfo			= mlxsw_sp_port_get_drvinfo,
@@ -1228,6 +1254,8 @@ const struct ethtool_ops mlxsw_sp_port_ethtool_ops = {
 	.get_eth_ctrl_stats		= mlxsw_sp_get_eth_ctrl_stats,
 	.get_rmon_stats			= mlxsw_sp_get_rmon_stats,
 	.reset				= mlxsw_sp_reset,
+	.get_module_power_mode		= mlxsw_sp_get_module_power_mode,
+	.set_module_power_mode		= mlxsw_sp_set_module_power_mode,
 };
 
 struct mlxsw_sp1_port_link_mode {