Corn gluten meal will control some weeds by limiting their root growth. It mostly works on crabgrass, purslane, lambsquarters, bentgrass and a few others.
Its not the same as corn meal though, CGM is a by product of the corm kernel milling process for corn starch and corn syrup. Its also used in animal feeds. It makes a good fertilizer too, because it's about 10%nitrogen.
Corn meal is just the whole ground up corn kernel. It probably could smother some weeds if applied heavily enough but it will also start to smell as it ferments in your garden. And technically its not organic because most corn is GMO