Sanitise includes across codebase ...

Enforce full include path for includes. Deprecate old paths.

The following folders inside include/lib have been left unchanged:

- include/lib/cpus/${ARCH}
- include/lib/el3_runtime/${ARCH}

The reason for this change is that having a global namespace for
includes isn't a good idea. It defeats one of the advantages of having
folders and it introduces problems that are sometimes subtle (because
you may not know the header you are actually including if there are two
of them).

For example, this patch had to be created because two headers were
called the same way: e0ea0928d5b7 ("Fix gpio includes of mt8173 platform
to avoid collision."). More recently, this patch has had similar
problems: 46f9b2c3a282 ("drivers: add tzc380 support").

This problem was introduced in commit 4ecca33988b9 ("Move include and
source files to logical locations"). At that time, there weren't too
many headers so it wasn't a real issue. However, time has shown that
this creates problems.

Platforms that want to preserve the way they include headers may add the
removed paths to PLAT_INCLUDES, but this is discouraged.

Change-Id: I39dc53ed98f9e297a5966e723d1936d6ccf2fc8f
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

Standardise header guards across codebase ...

All identifiers, regardless of use, that start with two underscores are
reserved. This means they can't be used in header guards.

The style that this project is now to use the full name of the file in
capital letters followed by 'H'. For example, for a file called
"uart_example.h", the header guard is UART_EXAMPLE_H.

The exceptions are files that are imported from other projects:

- CryptoCell driver
- dt-bindings folders
- zlib headers

Change-Id: I50561bf6c88b491ec440d0c8385c74650f3c106e
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

Remove some MISRA defects in common code ...

No functional changes.

Change-Id: I9638e02acb9b22eb794ebf45aad84348a710287e
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

Use SPDX license identifiers ...

To make software license auditing simpler, use SPDX[0] license
identifiers instead of duplicating the license text in every file.

NOTE: Files that have been imported by FreeBSD have not been modified.

[0]: https://spdx.org/

Change-Id: I80a00e1f641b8cc075ca5a95b10607ed9ed8761a
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

Add two timestamps to measure PSCI cache flush overhead ...

Testing showed that the time spent in a cluster power down
operation is dominated by cache flushes.  Add two more timestamps
in runtime instrumentation to keep track of the time spent
flushing the L1/L2 caches.

Change-Id: I4c5a04e7663543225a85d3c6b271d7b706deffc4
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

Add PMF instrumentation points in TF ...

In order to quantify the overall time spent in the PSCI software
implementation, an initial collection of PMF instrumentation points
has been added.

Instrumentation has been added to the following code paths:

- Entry to PSCI SMC handler.  The timestamp is captured as early
  as possible during the runtime exception and stored in memory
  before entering the PSCI SMC handler.

- Exit from PSCI SMC handler.  The timestamp is captured after
  normal return from the PSCI SMC handler or if a low power state
  was requested it is captured in the bl31 warm boot path before
  return to normal world.

- Entry to low power state.  The timestamp is captured before entry
  to a low power state which implies either standby or power down.
  As these power states are mutually exclusive, only one timestamp
  is defined to describe both.  It is possible to differentiate between
  the two power states using the PSCI STAT interface.

- Exit from low power state.  The timestamp is captured after a standby
  or power up operation has completed.

To calculate the number of cycles spent running code in Trusted Firmware
one can perform the following calculation:

(exit_psci - enter_psci) - (exit_low_pwr - enter_low_pwr).

The resulting number of cycles can be converted to time given the
frequency of the counter.

Change-Id: Ie3b8f3d16409b6703747093b3a2d5c7429ad0166
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>