Preheat the oven 350°F; butter a 9-inch Pyrex pie plate.
Gently combine the berries with the sugar, flour, and the cinnamon; place in the prepared pie plate.
Prepare the topping; Combine the oats, flour, both sugars, and salt in a bowl. Use a pastry blender or 2 knives to work until topping resembles coarse meal. Sprinkle evenly over the berries.
Place the pie plate on a baking sheet. Bake in the center of the oven until the fruit is bubbling and the topping is golden brown, about 1 hour. Remove the crisp to a rack to cool slightly. Serve in desert bowls with whipped cream or ice cream.