net/mlx5: Add devlink param enable_remote_dev_reset support

The enable_remote_dev_reset devlink param flags that the host admin
allows resets by other hosts. In case it is cleared mlx5 host PF driver
will send NACK on pci sync for firmware update reset request and the
command will fail.
By default enable_remote_dev_reset parameter is true, so pci sync for
firmware update reset is enabled.
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -278,6 +278,24 @@ static int mlx5_devlink_large_group_num_validate(struct devlink *devlink, u32 id
 }
 #endif
 
+static int mlx5_devlink_enable_remote_dev_reset_set(struct devlink *devlink, u32 id,
+						    struct devlink_param_gset_ctx *ctx)
+{
+	struct mlx5_core_dev *dev = devlink_priv(devlink);
+
+	mlx5_fw_reset_enable_remote_dev_reset_set(dev, ctx->val.vbool);
+	return 0;
+}
+
+static int mlx5_devlink_enable_remote_dev_reset_get(struct devlink *devlink, u32 id,
+						    struct devlink_param_gset_ctx *ctx)
+{
+	struct mlx5_core_dev *dev = devlink_priv(devlink);
+
+	ctx->val.vbool = mlx5_fw_reset_enable_remote_dev_reset_get(dev);
+	return 0;
+}
+
 static const struct devlink_param mlx5_devlink_params[] = {
 	DEVLINK_PARAM_DRIVER(MLX5_DEVLINK_PARAM_ID_FLOW_STEERING_MODE,
 			     "flow_steering_mode", DEVLINK_PARAM_TYPE_STRING,
@@ -293,6 +311,9 @@ static const struct devlink_param mlx5_devlink_params[] = {
 			     NULL, NULL,
 			     mlx5_devlink_large_group_num_validate),
 #endif
+	DEVLINK_PARAM_GENERIC(ENABLE_REMOTE_DEV_RESET, BIT(DEVLINK_PARAM_CMODE_RUNTIME),
+			      mlx5_devlink_enable_remote_dev_reset_get,
+			      mlx5_devlink_enable_remote_dev_reset_set, NULL),
 };
 
 static void mlx5_devlink_set_params_init_values(struct devlink *devlink)

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

@@ -5,6 +5,7 @@
 
 enum {
 	MLX5_FW_RESET_FLAGS_RESET_REQUESTED,
+	MLX5_FW_RESET_FLAGS_NACK_RESET_REQUEST,
 	MLX5_FW_RESET_FLAGS_PENDING_COMP
 };
 
@@ -22,6 +23,23 @@ struct mlx5_fw_reset {
 	int ret;
 };
 
+void mlx5_fw_reset_enable_remote_dev_reset_set(struct mlx5_core_dev *dev, bool enable)
+{
+	struct mlx5_fw_reset *fw_reset = dev->priv.fw_reset;
+
+	if (enable)
+		clear_bit(MLX5_FW_RESET_FLAGS_NACK_RESET_REQUEST, &fw_reset->reset_flags);
+	else
+		set_bit(MLX5_FW_RESET_FLAGS_NACK_RESET_REQUEST, &fw_reset->reset_flags);
+}
+
+bool mlx5_fw_reset_enable_remote_dev_reset_get(struct mlx5_core_dev *dev)
+{
+	struct mlx5_fw_reset *fw_reset = dev->priv.fw_reset;
+
+	return !test_bit(MLX5_FW_RESET_FLAGS_NACK_RESET_REQUEST, &fw_reset->reset_flags);
+}
+
 static int mlx5_reg_mfrl_set(struct mlx5_core_dev *dev, u8 reset_level,
 			     u8 reset_type_sel, u8 sync_resp, bool sync_start)
 {
@@ -160,6 +178,11 @@ static int mlx5_fw_reset_set_reset_sync_ack(struct mlx5_core_dev *dev)
 	return mlx5_reg_mfrl_set(dev, MLX5_MFRL_REG_RESET_LEVEL3, 0, 1, false);
 }
 
+static int mlx5_fw_reset_set_reset_sync_nack(struct mlx5_core_dev *dev)
+{
+	return mlx5_reg_mfrl_set(dev, MLX5_MFRL_REG_RESET_LEVEL3, 0, 2, false);
+}
+
 static void mlx5_sync_reset_set_reset_requested(struct mlx5_core_dev *dev)
 {
 	struct mlx5_fw_reset *fw_reset = dev->priv.fw_reset;
@@ -176,6 +199,12 @@ static void mlx5_sync_reset_request_event(struct work_struct *work)
 	struct mlx5_core_dev *dev = fw_reset->dev;
 	int err;
 
+	if (test_bit(MLX5_FW_RESET_FLAGS_NACK_RESET_REQUEST, &fw_reset->reset_flags)) {
+		err = mlx5_fw_reset_set_reset_sync_nack(dev);
+		mlx5_core_warn(dev, "PCI Sync FW Update Reset Nack %s",
+			       err ? "Failed" : "Sent");
+		return;
+	}
 	mlx5_sync_reset_set_reset_requested(dev);
 	err = mlx5_fw_reset_set_reset_sync_ack(dev);
 	if (err)

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

@@ -6,6 +6,8 @@
 
 #include "mlx5_core.h"
 
+void mlx5_fw_reset_enable_remote_dev_reset_set(struct mlx5_core_dev *dev, bool enable);
+bool mlx5_fw_reset_enable_remote_dev_reset_get(struct mlx5_core_dev *dev);
 int mlx5_fw_reset_query(struct mlx5_core_dev *dev, u8 *reset_level, u8 *reset_type);
 int mlx5_fw_reset_set_reset_sync(struct mlx5_core_dev *dev, u8 reset_type_sel);
 int mlx5_fw_reset_set_live_patch(struct mlx5_core_dev *dev);