Wake-up bugle call (8)
I believe the answer is:
reveille
'wake-up bugle call' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for reveille that I've seen before include "Military wake-up call" , "Rousing bugle-call" , "Military signal to wake up" , "Early morning sound in the barracks" , "Morning call" .)