feat(cpufeat): enable USE_SPINLOCK_CAS to FEAT_STATE_CHECKED

The FEAT_LSE enablement predates the FEAT_STATE framework and has never
been converted. Since the introduction of USE_SPINLOCK_CAS we've

feat(cpufeat): enable USE_SPINLOCK_CAS to FEAT_STATE_CHECKED

The FEAT_LSE enablement predates the FEAT_STATE framework and has never
been converted. Since the introduction of USE_SPINLOCK_CAS we've gained
lots of quality of life features that allow for better feature
enablement. This patch converts USE_SPINLOCK_CAS to tri-state and adds
it to FEATURE_DETECTION to align with all other features.

Instead of introducing the assembly checking for tri-state, this patch
translates all locking routines to C inline assembly and uses the
standard C helpers. The main benefit is that this gives greater
visibility to the compiler about what the functions are doing and lets
it optimise better. Namely, it is able to allocate registers itself and
inline the functions when LTO is enabled.

An unsuccessful attempt was made to use the instructions directly and
have even flow control in C. This, however, made code very complicated
and less efficient in the tight loops of the spinlock.

The last use of ARM_ARCH_AT_LEAST goes away with this change and so this
macro is removed. It has now been fully superseded by the FEAT_STATE
framework.

This change exposes a limitation - RME_GPT_BITLOCK_BLOCK requires
USE_SPINLOCK_CAS. This patch does not address this in any way but makes
the relationship explicit.

Change-Id: I580081549aceded2dca3e0f4564ee7510a7e56ae
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>

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fix(locks): mark spin_trylock as a public function

This patch updates spinlock.S to make the spin_trylock helper
function as public. This will allow other parts of the TF-A
to use this function.

Ch

fix(locks): mark spin_trylock as a public function

This patch updates spinlock.S to make the spin_trylock helper
function as public. This will allow other parts of the TF-A
to use this function.

Change-Id: Id264a36490707a9377a221ed2b5bd27ca90bf459
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>

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feat(locks): add non-blocking spinlock_try() API

Add a non-blocking `spin_trylock()` function to the existing spinlock
implementation. This API attempts to acquire the lock and returns `1`
on succes

feat(locks): add non-blocking spinlock_try() API

Add a non-blocking `spin_trylock()` function to the existing spinlock
implementation. This API attempts to acquire the lock and returns `1`
on success or `0` if the lock is already held. It enables conditional
locking scenarios where blocking is undesirable.

Change-Id: I9483206952d1a34dc245ebf69e80c3645b658946
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>

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feat(locks): add bitlock

This patch adds 'bitlock_t' type and bit_lock() and
bit_unlock() to support locking/release functionality
based on individual bit position. These functions use
atomic bit se

feat(locks): add bitlock

This patch adds 'bitlock_t' type and bit_lock() and
bit_unlock() to support locking/release functionality
based on individual bit position. These functions use
atomic bit set and clear instructions which require
FEAT_LSE mandatory from Armv8.1.

Change-Id: I3eb0f29bbccefe6c0f69061aa701187a6364df0c
Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>

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