[php] Converting <br /> into a new line for use in a text area

If I have a variable:

$var1 = "Line 1 info blah blah <br /> Line 2 info blah blah";

And a text area:

<textarea>echo $var1</textarea>

How can I get the text area to display a new line instead of displaying the text on a single like with a <br /> in it?

Edit: I have tried the following:

<textarea class="hobbieTalk" id="hobbieTalk" name="hobbieTalk" cols="35" rows="5" onchange="contentHandler('userInterests',this.id,this.value,0)"><?php

$convert=$_SESSION["hobbieTalk"];
$convert = str_replace("<br />", "\n", $convert);
echo $convert;

?></textarea>

However the text area still contains the br tags in the lines.

i am use following construction to convert back nl2br

function br2nl( $input ) {
    return preg_replace('/<br\s?\/?>/ius', "\n", str_replace("\n","",str_replace("\r","", htmlspecialchars_decode($input))));
}

here i replaced \n and \r symbols from $input because nl2br dosen't remove them and this causes wrong output with \n\n or \r<br>.

<?php

$var1 = "Line 1 info blah blah <br /> Line 2 info blah blah";
$var1 = str_replace("<br />", "\n", $var1);

?>

<textarea><?php echo $var1; ?></textarea>

The answer by @Mobilpadde is nice. But this is my solution with regex using preg_replace which might be faster according to my tests.

echo preg_replace('/<br\s?\/?>/i', "\r\n", "testing<br/><br /><BR><br>");

function function_one() {
    preg_replace('/<br\s?\/?>/i', "\r\n", "testing<br/><br /><BR><br>");
}

function function_two() {
    str_ireplace(['<br />','<br>','<br/>'], "\r\n", "testing<br/><br /><BR><br>");
}

function benchmark() {
    $count = 10000000;
    $before = microtime(true);

    for ($i=0 ; $i<$count; $i++) {
        function_one();
    }

    $after = microtime(true);
    echo ($after-$before)/$i . " sec/function one\n";



    $before = microtime(true);

    for ($i=0 ; $i<$count; $i++) {
        function_two();
    }

    $after = microtime(true);
    echo ($after-$before)/$i . " sec/function two\n";
}
benchmark();

Results:

1.1471637010574E-6 sec/function one (preg_replace)
1.6027762889862E-6 sec/function two (str_ireplace)

Here is another approach.

class orbisius_custom_string {
    /**
     * The reverse of nl2br. Handles <br/> <br/> <br />
     * usage: orbisius_custom_string::br2nl('Your buffer goes here ...');
     * @param str $buff
     * @return str
     * @author Slavi Marinov | http://orbisius.com
     */
    public static function br2nl($buff = '') {
        $buff = preg_replace('#<br[/\s]*>#si', "\n", $buff);
        $buff = trim($buff);

        return $buff;
    }
}

EDIT: previous answer was backwards of what you wanted. Use str_replace. replace <br> with \n

echo str_replace('<br>', "\n", $var1);