What is Locke's Theory of Representation?

On a currently popular reading of Locke, an idea represents its cause, or what God intended to be its cause. Against Martha Bolton and my former self (among others), I argue that Locke cannot hold such a view, since it sins against his epistemology and theory of abstraction. I argue that Locke is committed to a resemblance theory of representation, with the result that ideas of secondary qualities are not representation