FOSS as in the BSP? Freescale’s chips tend to be decent (we’ll see how long that lasts now that Qualcomm owns them.) although I don’t think most of them have modems or GPUs.

I liked TI’s stuff but it’s definitely not meant for anything like a modern smart phone.

If you meant the SOC itself... I haven’t even heard of any outside of some fringe kickstarter things.