drivers: generic_delay_timer: Assert presence of Generic Timer ...

The Generic Timer is an optional extension to an ARMv7-A implementation.
The generic delay timer can be used from any architecture supported by
the Trusted Firmware. In ARMv7 it is needed to check that this feature
is present. In ARMv8 it is always present.

Change-Id: Ib7e8ec13ffbb2f64445d4ee48ed00f26e34b79b7
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

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>

Fix misra warnings in delay timer and console drivers ...

Change-Id: I43d2b3a0f672b4902edec3d3a39ffedbb0a701a3
Signed-off-by: Sathees Balya <sathees.balya@arm.com>

Fix MISRA rule 8.3 in common code ...

Rule 8.3: All declarations of an object or function shall
          use the same names and type qualifiers.

Change-Id: Iff384187c74a598a4e73f350a1893b60e9d16cec
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>

delay_timer: Guarantee that delay time can never be undershot ...

Delay functions like udelay() are often used to ensure that the
necessary time passed to allow some asynchronous event to finish, such
as the stabilization delay for a power rail. For these use cases it is
not very problematic if the delay is slightly longer than requested,
but it is critical that the delay must never be shorter.

The current udelay() implementation contains two hazards that may cause
the delay to be slightly shorter than intended: Firstly, the amount of
ticks to wait is calculated with an integer division, which may cut off
the last fraction of ticks needed. Secondly, the delay may be short by a
fraction of a tick because we do not know whether the initial ("start")
sample of the timer was near the start or near the end of the current
tick. Thus, if the code intends to wait for one tick, it might read the
timer value close to the end of the current tick and then read it again
right after the start of the next tick, concluding that the duration of
a full tick has passed when it in fact was just a fraction of it.

This patch rounds up the division and always adds one extra tick to
counteract both problems and ensure that delays will always be larger
but never smaller than requested.

Change-Id: Ic5fe5f858b5cdf3c0dbf3e488d4d5702d9569433
Signed-off-by: Julius Werner <jwerner@chromium.org>

delay_timer: correct sparse issues and warnings ...

Use NULL instead of 0 where required.
Include headers to have the prototype of the functions.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@st.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>

Implement generic delay timer ...

Add delay timer implementation based on the system generic counter.
This either uses the platform's implementation of
`plat_get_syscnt_freq()` or explicit clock multiplier/divider values
provided by the platform.

The current implementation of udelay has been modified to avoid
unnecessary calculations while waiting on the loop and to make it
easier to check for overflows.

Change-Id: I9062e1d506dc2f68367fd9289250b93444721732

Add a simple delay timer driver API ...

The API is simple. The BSP or specific timer driver creates an
instance of timer_ops_t, fills in the timer specific data, then calls
timer_init(). The timer specific data includes a function pointer
to return the timer value and a clock multiplier/divider. The ratio
of the multiplier and the divider is the clock frequency in MHz.

After that, mdelay() or udelay() can be called to delay execution for
the specified time (milliseconds or microseconds, respectively).

Change-Id: Icf8a295e1d25874f789bf28b7412156329dc975c
Co-authored-by: Dan Handley <dan.handley@arm.com>