controlador-descarga/controllers/InicioController.php

<?php

namespace app\controllers;

use yii\filters\AccessControl;

class InicioController extends \yii\web\Controller {

  public function behaviors() {
    return [
      'access' => [
        'class' => AccessControl::className(),
        'only' => ['index'],
        'rules' => [
          [
            'actions' => ['index'],
            'allow' => true,
            'roles' => ['@'],
          ],
        ],
      ],
    ];
  }

  public function actionIndex() {
    return $this->render('index');
  }

}