GTA04 PMU / Core arch block diagram v1

[Werner Almesberger]

Andy Green wrote:
> But it has effects on latency.  Today the resume latency on GTA02 is
> very noticeable.

Sure, but that's something that needs fixing anyway.

Also, when a "fast" response needs access to an interface the MPU
can't get to, e.g., USB or some high-bandwidth 3G modem port, then
the MPU-centric solution doesn't help, and you still have to solve
the general Linux resume problem, or live with the same inconsistent
behaviour we tried to get rid of in the first place.

Thus, the MPU only needs do things that can't be done sensibly by
the CPU if we assume that the CPU can respond (= wake up, find out
what happened, make a decision, act on it - in our scenario, the
peripherals it needs to talk to quickly are already awake) within,
say, 100ms.

- Werner