net/mlx5: Add support for devlink reload limit no reset

Add support for devlink reload action fw_activate with reload limit
no_reset which does firmware live patching, updating the firmware image
without reset, no downtime and no configuration lose. The driver checks
if the firmware is capable of handling the pending firmware changes as a
live patch. If it is then it triggers firmware live patching flow.

Signed-off-by: Moshe Shemesh <[e-mail]>
Reviewed-by: Saeed Mahameed <[e-mail]>
Signed-off-by: Jakub Kicinski <[e-mail]>

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

···
 	return err;
 }
 
+static int mlx5_devlink_trigger_fw_live_patch(struct devlink *devlink,
+					      struct netlink_ext_ack *extack)
+{
+	struct mlx5_core_dev *dev = devlink_priv(devlink);
+	u8 reset_level;
+	int err;
+
+	err = mlx5_fw_reset_query(dev, &reset_level, NULL);
+	if (err)
+		return err;
+	if (!(reset_level & MLX5_MFRL_REG_RESET_LEVEL0)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "FW upgrade to the stored FW can't be done by FW live patching");
+		return -EINVAL;
+	}
+
+	return mlx5_fw_reset_set_live_patch(dev);
+}
+
 static int mlx5_devlink_reload_down(struct devlink *devlink, bool netns_change,
 				    enum devlink_reload_action action,
 				    enum devlink_reload_limit limit,
···
 		mlx5_unload_one(dev, false);
 		return 0;
 	case DEVLINK_RELOAD_ACTION_FW_ACTIVATE:
+		if (limit == DEVLINK_RELOAD_LIMIT_NO_RESET)
+			return mlx5_devlink_trigger_fw_live_patch(devlink, extack);
 		return mlx5_devlink_reload_fw_activate(devlink, extack);
 	default:
 		/* Unsupported action should not get to this function */
···
 	*actions_performed = BIT(action);
 	switch (action) {
 	case DEVLINK_RELOAD_ACTION_DRIVER_REINIT:
+		return mlx5_load_one(dev, false);
 	case DEVLINK_RELOAD_ACTION_FW_ACTIVATE:
+		if (limit == DEVLINK_RELOAD_LIMIT_NO_RESET)
+			break;
 		/* On fw_activate action, also driver is reloaded and reinit performed */
 		*actions_performed |= BIT(DEVLINK_RELOAD_ACTION_DRIVER_REINIT);
 		return mlx5_load_one(dev, false);
···
 	.info_get = mlx5_devlink_info_get,
 	.reload_actions = BIT(DEVLINK_RELOAD_ACTION_DRIVER_REINIT) |
 			  BIT(DEVLINK_RELOAD_ACTION_FW_ACTIVATE),
+	.reload_limits = BIT(DEVLINK_RELOAD_LIMIT_NO_RESET),
 	.reload_down = mlx5_devlink_reload_down,
 	.reload_up = mlx5_devlink_reload_up,
 };