Back in 2011 AMD announced they would support Coreboot on all future CPUs. AMD had been doing pretty good about supporting Coreboot on their processors and chipsets over the years, as frequently mentioned in my many Coreboot news posts.
While many recent generations of past AMD CPU/APUs have worked with Coreboot, it's not clear going forward. One of AMD's key partners in supporting Coreboot, Sage Electronic Engineering, went out of business last year. It was a few months ago that Sage went bust, but it was quiet and I didn't even realize it until a Phoronix reader recently mentioned that fact.
Sage Electronic is now no more and was frequently cited by AMD as their contractor for Coreboot work. Sage's web-site is no longer active, but their final blog post about shutting down can be found here. Since Sage Electronic Engineering closed up shop, at least we've seen some commits by a few AMD engineers.
In the absence of Sage, there's been a few commits by just two AMD.com email addresses. However, it's not nearly the amount of work done by Sage nor comparable to the amount of work invested in Coreboot for Google Chromebooks, etc.
More worrying about the prospects for Coreboot on future hardware is that since the end of 2014, AMD stopped providing open-source AGESA code. AGESA releases by AMD are now binary-only, with this being the bootstrap protocol needed to initialize AMD processor cores, memory, and HyperTransport. Binary AGESA is similar to Intel not opening up their firmware support packages.
I haven't been able to get any official comment yet on whether AMD remains committed to supporting Coreboot on future products, so for now we can only hope for the best.