How to create import functionality on grid page in magneto

Open Grid.php
protected function _prepareMassaction()
    {
..................
..................
//Upload your csv file into var/import directory
$dir = new DirectoryIterator(Mage::getBaseDir() . DS . 'var' . DS . 'import' . DS);
$extensions = "csv";
$csv = array();
foreach ($dir as $fileinfo) {
    if ($fileinfo->isFile() && stristr($extensions, $fileinfo->getExtension())) {
        $csv[$fileinfo->getFilename()] = $fileinfo->getFilename();
    }            
}
$csv = array_merge(array(''=>'Please select'),$csv);
$this->getMassactionBlock()->addItem('import', array(
    'label'        => Mage::helper('metizsoft_taxgenerate')->__('Import'),
    'url'          => $this->getUrl('*/*/massCsv', array('_current'=>true)),
    'confirm'  => Mage::helper('metizsoft_taxgenerate')->__('Are you sure?'),
    'additional'   => array(
        'subgroup'    => array(
            'name'     => 'csv',
            'type'     => 'select',
            'class'    => 'required-entry',
            'label'    => Mage::helper('customer')->__('Select Csv'),
            'values'   => $csv
        )
    )
));
return $this;
}

Open your controller file. and put this code.public function massCsvAction()
{
$csvfile = $this->getRequest()->getParam('csv');
if (!$csvfile) {
  Mage::getSingleton('adminhtml/session')->addError(
      Mage::helper('metizsoft_taxgenerate')->__('Please select statetaxs.')
  );
} else {
  try {
     $csv = new Varien_File_Csv;
     $csvpath = Mage::getBaseDir() . DS . 'var' . DS . 'import' . DS . $csvfile;
             
     $datas = $csv->getData($csvpath);
     print_r($datas);
   } catch (Mage_Core_Exception $e) {
     Mage::getSingleton('adminhtml/session')->addError($e->getMessage());
   } catch (Exception $e) {
     Mage::getSingleton('adminhtml/session')->addError(
        Mage::helper('metizsoft_taxgenerate')->__('There was an error updating statetaxs.')
     );
     Mage::logException($e);
   }
}
$this->_redirect('*/*/index');
}