I just looked it up on the website. You can tailgate from 5AM until 1 hour after kickoff. No tailgating in ramps, etc. Charcoal is allowed but must be disposed of in "hot coal" disposal areas. No grilling under tents or by trees. Otherwise very similar to U of MN.
Google USC and in their site search for "tailgating".
Planning on being there also but haven't purchased tix yet...