Implement late binding for runtime hooks ...

At present SPD power management hooks and BL3-2 entry are implemented
using weak references. This would have the handlers bound and registered
with the core framework at build time, but leaves them dangling if a
service fails to initialize at runtime.

This patch replaces implementation by requiring runtime handlers to
register power management and deferred initialization hooks with the
core framework at runtime. The runtime services are to register the
hooks only as the last step, after having all states successfully
initialized.

Change-Id: Ibe788a2a381ef39aec1d4af5ba02376e67269782

Add power management support in the SPD ...

This patch implements a set of handlers in the SPD which are called by
the PSCI runtime service upon receiving a power management
operation. These handlers in turn pass control to the Secure Payload
image if required before returning control to PSCI. This ensures that
the Secure Payload has complete visibility of all power transitions in
the system and can prepare accordingly.

Change-Id: I2d1dba5629b7cf2d53999d39fe807dfcf3f62fe2

Add runtime services framework ...

This patch introduces the framework to enable registration and
initialisation of runtime services. PSCI is registered and initialised
as a runtime service. Handling of runtime service requests will be
implemented in subsequent patches.

Change-Id: Id21e7ddc5a33d42b7d6e455b41155fc5441a9547

psci: fix affinity level upgrade issue ...

The psci implementation does not track target affinity level requests
specified during cpu_suspend calls correctly as per the following
example.

1. cpu0.cluster0 calls cpu_suspend with the target affinity level as 0
2. Only the cpu0.cluster0 is powered down while cluster0 remains
   powered up
3. cpu1.cluster0 calls cpu_off to power itself down to highest
   possible affinity level
4. cluster0 will be powered off even though cpu0.cluster0 does not
   allow cluster shutdown

This patch introduces reference counts at affinity levels > 0 to track
the number of cpus which want an affinity instance at level X to
remain powered up. This instance can be turned off only if its
reference count is 0. Cpus still undergo the normal state transitions
(ON, OFF, ON_PENDING, SUSPEND) but the higher levels can only be
either ON or OFF depending upon their reference count.

The above issue is thus fixed as follows:

1. cluster0's reference count is incremented by two when cpu0 and cpu1
   are initially powered on.

2. cpu0.cluster0 calls cpu_suspend with the target affinity level as
   0. This does not affect the cluster0 reference count.

3. Only the cpu0.cluster0 is powered down while cluster0 remains
   powered up as it has a non-zero reference count.

4. cpu1.cluster0 call cpu_off to power itself down to highest possible
   affinity level. This decrements the cluster0 reference count.

5. cluster0 is still not powered off since its reference count will at
   least be 1 due to the restriction placed by cpu0.

Change-Id: I433dfe82b946f5f6985b1602c2de87800504f7a9

Update year in copyright text to 2014 ...

Change-Id: Ic7fb61aabae1d515b9e6baf3dd003807ff42da60

move timer #defines & remove duplicate declaration ...

This patch removes the duplicate declaration of psci_cpu_on in psci.h
and moves the constants for the system level implementation of the
generic timer from arch_helpers.h to arch.h. All other architectural
constants are defined in arch.h so there is no need to add them to
arch_helpers.h

Change-Id: Ia8ad3f91854f7e57fce31873773eede55c384ff1

psci: fix values of incorrectly defined constants ...

This patch fixes the following constant values in the psci.h:

1. The affinity level shift value in the power_state parameter of the
   cpu_suspend psci call. The previous value was preventing shutdown
   of the affinity level 1.

2. The values used for affinity state constants (ON, OFF,
   ON_PENDING). They did not match the values expected to be returned
   by the affinity_info psci api as mentioned in the spec.

3. The state id shift value in the power_state parameter of the
   cpu_suspend psci call.

Change-Id: I62ed5eb0e9640b4aa97b93923d6630e6b877a097

Enable third party contributions ...

- Add instructions for contributing to ARM Trusted Firmware.

- Update copyright text in all files to acknowledge contributors.

Change-Id: I9311aac81b00c6c167d2f8c889aea403b84450e5

ARMv8 Trusted Firmware release v0.2