I think there's a lot of confusion about foam rolling and soft tissue work in general.
Foam rolling is a good tool to achieve a short window of better movement, but by itself isn't very effective.
Use the foam roller before you train on muscles that cause restrictions to your movements.
Spend about 30 seconds per area, its not going to be as effective for mobility as doing a movement with perfect form, so no need to spend half a workout on a foam roller.
Your focus is always best spent nailing down perfect movement patterns, this is were you will unlock better mobility. Foam rolling is just one tool to help us get there.