remoteproc: add framework for controlling remote processors

remoteproc: add framework for controlling remote processors

Modern SoCs typically employ a central symmetric multiprocessing (SMP)
application processor running Linux, with several other asymmetric
multiprocessing (AMP) heterogeneous processors running different instances
of operating system, whether Linux or any other flavor of real-time OS.

Booting a remote processor in an AMP configuration typically involves:
- Loading a firmware which contains the OS image
- Allocating and providing it required system resources (e.g. memory)
- Programming an IOMMU (when relevant)
- Powering on the device

This patch introduces a generic framework that allows drivers to do
that. In the future, this framework will also include runtime power
management and error recovery.

Based on (but now quite far from) work done by Fernando Guzman Lugo
<[email protected]>.

ELF loader was written by Mark Grosen <[email protected]>, based on
msm's Peripheral Image Loader (PIL) by Stephen Boyd <[email protected]>.

Designed with Brian Swetland <[email protected]>.

Signed-off-by: Ohad Ben-Cohen <[email protected]>
Acked-by: Grant Likely <[email protected]>
Cc: Brian Swetland <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Tony Lindgren <[email protected]>
Cc: Russell King <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Greg KH <[email protected]>
Cc: Stephen Boyd <[email protected]>