Ember.js: How to re-render component on change in controller?

template.hbs

route.js

setupController: function(controller, model) {  
    controller.set('actions', {
      bar(param){
        controller.set('value',param);
      }
    });
  }

the action bar is called by different other components which changes the value in controller. This value is passed to the foo component. The problem is the foo component didn't get updated after change in value.How to re-render the component on change in controller ?