12v dc motor rotate once and then stop
The most common method of doing what you want is to use a cam that actuates a microswitch at the desired stop point.

To do the sequence that you want, you need to add a tiny bit of smarts.  This can be a couple of relays or a microcontroller.

As mentioned in the comments, most automobiles have windshield wiper motors that have such a switch mechanism built in.  However, because you want the motor to operate only one full cycle upon power-up, you do need to add the smarts that I mentioned.