the progression of the song is
I - V - VI - IV
1 - 5 - 6 - 4 (just incase i mixed up the roman numerals LOL)
The song is in the key of E major
So The progression is also
E - B - C#/Db - A
the little riff (and someone may have to correct me on this part i think I got it figured out)
2 - hammer on 4 - 2 - 1 - 6 - 5- 3-1 ( i need my bass i hope that is right)
F#/Gb - A - F#/Gb - E - C#/Db - B - G#/Ab - E