There are some misconceptions with A320 (and possibly other Airbus FBW aircraft) about turbulence in cruise...
1. There is no special Airbus procedure, unless you are in severe turbulence. Below is an excerpt from FCTM regarding moderate turbulence:
If moderate turbulence is encountered, the flight crew should set the AP and A/THR to ON with managed speed.
2. If you have really severe turbulence, it's probably best to set fixed thrust and go along with the speed fluctuation rather than have A/THR go from idle to CL and vice versa to chase the desired speed.
If severe turbulence is encountered, the flight crew should keep the AP engaged. Thrust levers should be set to turbulence N1 (Refer to QRH), and the A/THR should then be disconnected. Use of the A/THR is, however, recommended during approach, in order to benefit from the GS mini.
3. A lot of stuff are valid only when you don't have protections (e.g. alternate and direct law). This includes, but is not limited to descending 4000ft below REC MAX FL (and not optimum), respecting VA, ... If you are so unlucky to get into alternate or even direct law in cruise, the ATC would probably want you to get out of RVSM at the first practical opportunity anyway.