The following is a quote from this post but I’d suggest to read the entire thing:
In order to achieve this garage wall fire rating, the house – garage common wall needs to be sheathed with at least 1/2? thick drywall, and the ceiling surface requires minimum 5/8? thick, type X gypsum board.
All drywall seams must be taped / finished with joint compound and some jurisdictions might require fire rated joint tape for this purpose.
From your description I understand that at this moment the garage is simply occupying a designated for that purpose section of your basement, and has unfinished walls and ceiling (exposed framing). Please let me know if you still have any questions after reading my garage firewall post. Just click “comment” below.