Problem with iPhone 6 16GB Restart and white screen with line

In the last few days my iphone had a problem when i lock the screen in 2,3 seconds reboots itself and after enter into a reboot loop continue and show a white background with a line on top or middle or bottom .. i can't describe that screen to well but i try my best. Please give me an advice or something. Can be the battery ? I mention the glass of display is broke on the top but the touchscreen and display works fine. It can be the display ? Maybe i should change all the display with glass ?