Does the movie, "Inception," leave loose ends about Cobb's real life? Will he be in a coma?

i saw the end at least 12 times. many people say that the totem was about to fall, but it wasn't, it only jittered a little. it possible that cobb was dreaming the entire movie, or just the ending. nut by no means can one say that he wasn't dreaming just because the totem moved a bit