What is the meaning of the "one mind" in the awakening of faith? You can read that shastra here. I'm quite fond of it, though I don't have my own meditation practice.

If I had to narrow the question down, I'd ask if it contains different practices, of different sentient beings. Not absolutely sure that makes sense, though. I like the idea of it substituting for 'heaven' on those grounds, of others.
'One mind' means reality, the reality which is in front of you now and which you are part of. It manifests in two ways - as the absolute, when you don't concieve in terms of self and others; and the phenomenal, when you do.