While marijuana has been legalized or decriminalized in other states, it is still illegal in Tennessee to have marijuana or the things used to consume it (pipes, bongs, grinders, etc.) in your possession.
While Tennessee does have a Simple Possession law, depending on the amount of marijuana and the circumstances, you can be charged with felony Possession with Intent to Sell charges. Generally, if you have less than half an ounce of marijuana (14.175 grams) you will be charged with Simple Possession.
Simple Possession is an A misdemeanor and can be punished with up to 11 months and 29 days in jail, probation and/or fines. Additionally, the court can require you to attend drug education classes. A third or subsequent Simple Possession will be a felony offense punishable by up to 6 years in prison or probation.