The Mandarins at Atmel have made a serious error on Revision U of the ATmega128 datasheet. The diagram of Timer0 is different than the one from Revision S. of the same datasheet. TCCR0 now apparently allows clocking on rising and falling edges of pin T0. Problem is there is no pin T0 on an ATmega128.
Looks like some kind of cut and paste kerfuffle, and of course the real part does not match Revision U. of the datasheet.
I'm sticking with Revision S., Don't know about Rev T.