[Codeigniter] Data Cart tidak masuk

Mohon pencerahanya saya bingung ini knp data cart gak masuk e cart->contents(); sayanya pusing udah 5 hari ngakalin :v

Controller

 <?php

class Cart extends CI_Controller{

  function __construct(){
    parent::__construct();
    $this->load->library("cart");
    $this->load->model("m_cart");
  }

  function index(){
   $data["produk"] = $this->m_cart->get_all();
   $this->load->view("template-h/cart/index", $data);
 }

 function add(){
  $data = array(

    'code_products' => $this->input->post('cd'),
    'title_products' => $this->input->post('titel'),
    'qty' => $this->input->post('qty'),
    'ukuran' => $this->input->post('ukuran'),
    'gambar' => $this->input->post('img'),
    'price_products' => $this->input->post('prc'),
  );

  // print_r($data);

  $this->cart->insert($data);

  redirect('/cart', 'refresh');
}

View cart

    <?php
            //for($i=1;$i<=2;$i++){
            error_reporting(0);
            if ($cart = $this->cart->contents()):
                $grand_total = 0;
                foreach ($cart as $item):
                    ?>
                    <div class="cart-header">
                        <div class="close1">
                            <a href="<?php echo base_url(); ?>cart/remove/<?php echo $item['rowid']; ?>">
                                <img src="<?php echo base_url(); ?>assets/home/images/close.png"/>
                            </a>
                        </div>
                        <div class="cart-sec">
                            <div class="cart-item cyc">
                                <img src="<?php echo base_url(); ?>assets/home/<?php echo $item['picture']; ?>"/>
                            </div>
                            <div class="cart-item-info">
                                <h3><?php echo $item['name']; ?><span></span></h3>
                                <h4><span>Rp.</span> <?php echo number_format($item['price'], 0, ',', '.'); ?>,00</h4>
                                <p class="qty">Qty ::</p>
                                <input min="1" type="number" id="quantity" name="quantity" value="1"
                                       class="form-control input-small">
                                <?php
                                $grand_total = $grand_total + $item['price'];
                                //echo "Total :".$grand_total;
                                ?>
                            </div>
                            <div class="clearfix"></div>
                            <div class="delivery">
                                <p></p>
                                <span></span>
                                <div class="clearfix"></div>
                            </div>
                        </div>
                    </div>
                    <?php

                endforeach;
            endif;
            ?>

Form Produk

 	<?= form_open('cart/add') ?>
								<div class="row">
									<div class="col-md-6">
										<div class="form-group" style="margin-top:10px; text-align: center!important;">
											<label class="form-control-label">Ukuran</label>
											<?php
											$options = array('xl'=> 'XL','m' => 'M','s' => 'S');
											$att     = array('class' => 'form-control');
											echo form_dropdown('ukuran', $options, 'XL', $att);
											?>
										</div>
									</div>
									<div class="col-md-6">
										<div class="form-group" style="margin-top:10px; text-align: center!important;">
											<label class="form-control-label">Jumlah</label>
											<input id="qty" type="number" name="qty" class="form-control" value="1">
										</div>
									</div>
								</div>

								<div class="form-group">
									<?php

									$cd = $produk->code_products;
									$name = $produk->title_products;
									$picture = $produk->gambar;
									$price = $produk->price_products;

									echo form_hidden('cd', $cd);
									echo form_hidden('titel', $name);
									echo form_hidden('img', $picture);
									echo form_hidden('prc', $price);
									?>
								</div>
								<button type="submit" name="add" class="btn btn-light" style="margin-top: -15px;    margin-bottom: -20px;color: #5b6366"> Add To Cart</button>
								<?= form_close(); ?>

mohon pencerahanya ya suhu beneran saya pusing 5 hari berturut2 ngakalin ini doang >_<