sr = smart reflex
vdd = voltage (for the domain of...)
1 = mpu (cpu/arm + dsp), 2 = core (the interconnects between subsystems and peripherals)

so if you set sr vdd1 = 1 it means "enable dynamic voltage for mpu"
and it tries to perform continuous dynamic voltage scaling around the nominal operating point voltage according to silicon characteristics and operating conditions but its not going to work if you also overclock it too high.

looks like we might be able to view and modify the voltage tables it's using if we enable "testing mode", take a look here

also found a GOOD document, meaning it actually explains things in ENGLISH here