net/mlx5: Support enable_eth devlink dev param

Enable user to disable Ethernet auxiliary device so that when it is not
required, user can disable it.

For example,

$ devlink dev param set pci/0000:06:00.0 \
              name enable_eth value false cmode driverinit
$ devlink dev reload pci/0000:06:00.0

At this point devlink instance do not create mlx5_core.eth.2 auxiliary
device for the Ethernet functionality.
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -53,7 +53,7 @@ static bool is_eth_rep_supported(struct mlx5_core_dev *dev)
 	return true;
 }
 
-static bool is_eth_supported(struct mlx5_core_dev *dev)
+bool mlx5_eth_supported(struct mlx5_core_dev *dev)
 {
 	if (!IS_ENABLED(CONFIG_MLX5_CORE_EN))
 		return false;
@@ -105,6 +105,17 @@ static bool is_eth_supported(struct mlx5_core_dev *dev)
 	return true;
 }
 
+static bool is_eth_enabled(struct mlx5_core_dev *dev)
+{
+	union devlink_param_value val;
+	int err;
+
+	err = devlink_param_driverinit_value_get(priv_to_devlink(dev),
+						 DEVLINK_PARAM_GENERIC_ID_ENABLE_ETH,
+						 &val);
+	return err ? false : val.vbool;
+}
+
 static bool is_vnet_supported(struct mlx5_core_dev *dev)
 {
 	if (!IS_ENABLED(CONFIG_MLX5_VDPA_NET))
@@ -201,13 +212,15 @@ enum {
 static const struct mlx5_adev_device {
 	const char *suffix;
 	bool (*is_supported)(struct mlx5_core_dev *dev);
+	bool (*is_enabled)(struct mlx5_core_dev *dev);
 } mlx5_adev_devices[] = {
 	[MLX5_INTERFACE_PROTOCOL_VNET] = { .suffix = "vnet",
 					   .is_supported = &is_vnet_supported },
 	[MLX5_INTERFACE_PROTOCOL_IB] = { .suffix = "rdma",
 					 .is_supported = &is_ib_supported },
 	[MLX5_INTERFACE_PROTOCOL_ETH] = { .suffix = "eth",
-					  .is_supported = &is_eth_supported },
+					  .is_supported = &mlx5_eth_supported,
+					  .is_enabled = &is_eth_enabled },
 	[MLX5_INTERFACE_PROTOCOL_ETH_REP] = { .suffix = "eth-rep",
 					   .is_supported = &is_eth_rep_supported },
 	[MLX5_INTERFACE_PROTOCOL_IB_REP] = { .suffix = "rdma-rep",
@@ -308,6 +321,14 @@ int mlx5_attach_device(struct mlx5_core_dev *dev)
 		if (!priv->adev[i]) {
 			bool is_supported = false;
 
+			if (mlx5_adev_devices[i].is_enabled) {
+				bool enabled;
+
+				enabled = mlx5_adev_devices[i].is_enabled(dev);
+				if (!enabled)
+					continue;
+			}
+
 			if (mlx5_adev_devices[i].is_supported)
 				is_supported = mlx5_adev_devices[i].is_supported(dev);
 
@@ -360,6 +381,14 @@ void mlx5_detach_device(struct mlx5_core_dev *dev)
 		if (!priv->adev[i])
 			continue;
 
+		if (mlx5_adev_devices[i].is_enabled) {
+			bool enabled;
+
+			enabled = mlx5_adev_devices[i].is_enabled(dev);
+			if (!enabled)
+				goto skip_suspend;
+		}
+
 		adev = &priv->adev[i]->adev;
 		/* Auxiliary driver was unbind manually through sysfs */
 		if (!adev->dev.driver)
@@ -447,12 +476,21 @@ static void delete_drivers(struct mlx5_core_dev *dev)
 		if (!priv->adev[i])
 			continue;
 
+		if (mlx5_adev_devices[i].is_enabled) {
+			bool enabled;
+
+			enabled = mlx5_adev_devices[i].is_enabled(dev);
+			if (!enabled)
+				goto del_adev;
+		}
+
 		if (mlx5_adev_devices[i].is_supported && !delete_all)
 			is_supported = mlx5_adev_devices[i].is_supported(dev);
 
 		if (is_supported)
 			continue;
 
+del_adev:
 		del_adev(&priv->adev[i]->adev);
 		priv->adev[i] = NULL;
 	}

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

@@ -596,6 +596,52 @@ static void mlx5_devlink_set_params_init_values(struct devlink *devlink)
 #endif
 }
 
+static const struct devlink_param enable_eth_param =
+	DEVLINK_PARAM_GENERIC(ENABLE_ETH, BIT(DEVLINK_PARAM_CMODE_DRIVERINIT),
+			      NULL, NULL, NULL);
+
+static int mlx5_devlink_eth_param_register(struct devlink *devlink)
+{
+	struct mlx5_core_dev *dev = devlink_priv(devlink);
+	union devlink_param_value value;
+	int err;
+
+	if (!mlx5_eth_supported(dev))
+		return 0;
+
+	err = devlink_param_register(devlink, &enable_eth_param);
+	if (err)
+		return err;
+
+	value.vbool = true;
+	devlink_param_driverinit_value_set(devlink,
+					   DEVLINK_PARAM_GENERIC_ID_ENABLE_ETH,
+					   value);
+	devlink_param_publish(devlink, &enable_eth_param);
+	return 0;
+}
+
+static void mlx5_devlink_eth_param_unregister(struct devlink *devlink)
+{
+	struct mlx5_core_dev *dev = devlink_priv(devlink);
+
+	if (!mlx5_eth_supported(dev))
+		return;
+
+	devlink_param_unpublish(devlink, &enable_eth_param);
+	devlink_param_unregister(devlink, &enable_eth_param);
+}
+
+static int mlx5_devlink_auxdev_params_register(struct devlink *devlink)
+{
+	return mlx5_devlink_eth_param_register(devlink);
+}
+
+static void mlx5_devlink_auxdev_params_unregister(struct devlink *devlink)
+{
+	mlx5_devlink_eth_param_unregister(devlink);
+}
+
 #define MLX5_TRAP_DROP(_id, _group_id)					\
 	DEVLINK_TRAP_GENERIC(DROP, DROP, _id,				\
 			     DEVLINK_TRAP_GROUP_GENERIC_ID_##_group_id, \
@@ -654,6 +700,10 @@ int mlx5_devlink_register(struct devlink *devlink)
 	mlx5_devlink_set_params_init_values(devlink);
 	devlink_params_publish(devlink);
 
+	err = mlx5_devlink_auxdev_params_register(devlink);
+	if (err)
+		goto auxdev_reg_err;
+
 	err = mlx5_devlink_traps_register(devlink);
 	if (err)
 		goto traps_reg_err;
@@ -661,6 +711,8 @@ int mlx5_devlink_register(struct devlink *devlink)
 	return 0;
 
 traps_reg_err:
+	mlx5_devlink_auxdev_params_unregister(devlink);
+auxdev_reg_err:
 	devlink_params_unregister(devlink, mlx5_devlink_params,
 				  ARRAY_SIZE(mlx5_devlink_params));
 params_reg_err:
@@ -671,6 +723,7 @@ int mlx5_devlink_register(struct devlink *devlink)
 void mlx5_devlink_unregister(struct devlink *devlink)
 {
 	mlx5_devlink_traps_unregister(devlink);
+	mlx5_devlink_auxdev_params_unregister(devlink);
 	devlink_params_unpublish(devlink);
 	devlink_params_unregister(devlink, mlx5_devlink_params,
 				  ARRAY_SIZE(mlx5_devlink_params));

drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.h

@@ -272,4 +272,7 @@ static inline u32 mlx5_sriov_get_vf_total_msix(struct pci_dev *pdev)
 
 	return MLX5_CAP_GEN_MAX(dev, num_total_dynamic_vf_msix);
 }
+
+bool mlx5_eth_supported(struct mlx5_core_dev *dev);
+
 #endif /* __MLX5_CORE_H__ */