rk3399_ARM-atf/docs/architecture_features.rst

5 almost every year listed in `Feature_description`_. While most of these features require no control
10 in TF-A.
16 versions (8.X, 9.X) to which they apply can be found in `Feature_description`_
25    * ``WIP``: Implementation in progress;
456 FEAT_xxx in the architecure manual. Some of those features require setup code in
459 Most of the feature flags defined in the TF-A build system are allowed to take
466     ENABLE_FEAT_* = 2: Feature support is compiled in, but only enabled if the
477 If the feature flag is set to 2, support for the feature will be compiled in,
480 multiple different CPUs, or where the CPU is configured at runtime, like in
495 in this case a fictional ``FEAT_ABC``. This is not an exhaustive list on how to
501   - The flag's name should be in the form ``ENABLE_FEAT_ABC``.
503   - Add it to the ``assert_numerics`` and ``add_defines`` lists in the
506   - Add a default of ``0`` for it in ``make_helpers/arch_features.mk``. If the
510   - Add any constraints in ``make_helpers/constraints.mk``. This will usually be
512     be found in the main description of the feature in the Arm ARM.
514 - Add the feature accessor functions in ``include/arch/aarch64/arch_features.h``.
516   A pair of functions must be defined in the form of ``is_feat_abc_present()``
524   - In rare occasions, the feature must be checked in assembly. A
528 - Register the feature in ``common/feat_detect.c``.
532   lines in ``lib/el3_runtime/aarch64/context_mgmt.c``. Some common things to do
536     file in ``lib/extensions/abc/``. Functions in this file must be named
542    worlds by setting/clearing the bit in the context copy of this register.
544  - If the feature introduces any control bits in ``SCR_EL3``, ``MDCR_EL3``,
546    in ``include/services/arm_arch_svc.h`` to register with
547    ``ARCH_FEATURE_AVAILABILITY``. This must also be done in the
548    ``test_smccc_arch_feature_availability`` test in TFTF, otherwise CI will
557 - Add documentation in ``docs/getting_started/build-options.rst``. This should
561   in exceptional cases.
563 - Enable the feature for the FVP platform in ``plat/arm/board/fvp/platform.mk``,
566 - If the feature is optional, enable it in CI in the "allconfig" fragments.
572 - Optionally, although recommended, is to add a test in TFTF. This should only