["According to His purpose" is foreordination.]

Let me give both verses

"And we know that all things work together for good to them that love God, to them who are the called according to [his] purpose." v. 28

"For whom he did foreknow, he also did predestinate [to be] conformed to the image of his Son, that he might be the firstborn among many brethren." v. 29

The "For" in v. 29 seems to me like it's setting up an explanation for the phrase "according to his purpose", and not the other way around. And in explaining what v. 28 means, I get the impression that it works like this: foreknowledge comes first, followed by predestination.

So this is primary to any discussion that follows, whether it be about foreknowledge as fore-love, or how free will affects foreknowlege.