In a medium saucepan, bring 4 cups water and salt to a boil over medium-high heat. Whisk in oats and cinnamon; reduce heat to medium and simmer, uncovered, for about 40 minutes or until water is absorbed and oats are tender. Remove from heat; stir in half-and-half and brown sugar. Keep warm.
Meanwhile, combine strawberries, blackberries, blueberries, granulated sugar and remaining 1 Tablespoon water in a small saucepan; bring to a simmer over medium heat. Cook 8 to 9 minutes or until berries are tender but still hold their shape, stirring occasionally. Divide porridge among 4 bowls; top with berry compote.