Making your own Self rising cornmeal mix

Karen's really good Sweet potato cornbread calls for self-rising cornmeal.  We sent Nathan to the store and he couldn't find self rising white cornmeal so bought white cornmeal and I found a recipe on line to make it self rising.  Here is the recipe:  For each cup of self rising cornmeal:  3/4 C cornmeal, 3 T flour, 1 T baking powder, 1/2 tsp salt.  It was really good and a hit with everyone, even the kids!