rtems-docs/eng/req/howto.rst

.. SPDX-License-Identifier: CC-BY-SA-4.0

.. Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)

How-To
======

Getting Started
---------------

The RTEMS specification items and qualification tools are work in progress and
not fully integrated in the RTEMS Project.  The first step to work with the
RTEMS specification and the corresponding tools is a clone of the following
repository:

.. code-block:: none

    git clone git://git.rtems.org/sebh/rtems-qual.git
    git submodule init
    git submodule update

The tools need a virtual Python 3 environment. To set it up use:

.. code-block:: none

    cd rtems-qual
    make env

Each time you want to use one of the tools, you have to activate the
environment in your shell:

.. code-block:: none

    cd rtems-qual
    . env/bin/activate

Glossary Specification
----------------------

The glossary of terms for the RTEMS Project is defined by
:ref:`SpecTypeGlossaryTermItemType` items in the :file:`spec/glossary`
directory.  For a new glossary term add a glossary item to this directory.  As
the file name use the term in lower case with all white space and special
characters removed or replaced by alphanumeric characters, for example
:file:`spec/glossary/magicpower.yml` for the term `magic power`.

Use ``${uid:/attribute}`` substitutions to reference other parts of the
specification.

.. code-block:: yaml

    SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
    copyrights:
    - Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
    enabled-by: true
    glossary-type: term
    links:
    - role: glossary-member
      uid: ../glossary-general
    term: magic power
    text: |
      Magic power enables a caller to create magic objects using a
      ${magicwand:/term}.
    type: glossary

Define acronyms with the phrase `This term is an acronym for *.` in the
``text`` attribute:

.. code-block:: yaml

    ...
    term: MP
    ...
    text: |
      This term is an acronym for Magic Power.
    ...

Once you are done with the glossary items, run the script :file:`spec2doc.py`
to generate the derived documentation content.  Send patches for the generated
documentation and the specification to the :r:list:`devel` and follow the
normal patch review process.

Interface Specification
-----------------------

.. _ReqEngAddAPIHeaderFile:

Specify an API Header File
^^^^^^^^^^^^^^^^^^^^^^^^^^

The RTEMS :term:`API` header files are specified under ``spec:/if/rtems/*``.
Create a subdirectory with a corresponding name for the API, for example in
:file:`spec/if/rtems/foo` for the `foo` API.  In this new subdirectory place an
:ref:`SpecTypeInterfaceHeaderFileItemType` item named :file:`header.yml`
(:file:`spec/if/rtems/foo/header.yml`) and populate it with the required
attributes.

.. code-block:: yaml

    SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
    copyrights:
    - Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
    enabled-by: true
    interface-type: header-file
    links:
    - role: interface-placement
      uid: /if/domains/api
    path: rtems/rtems/foo.h
    prefix: cpukit/include
    type: interface

Specify an API Element
^^^^^^^^^^^^^^^^^^^^^^

Figure out the corresponding header file item.  If it does not exist, see
:ref:`ReqEngAddAPIHeaderFile`.  Place a specialization of an
:ref:`SpecTypeInterfaceItemType` item into the directory of the header file
item, for example :file:`spec/if/rtems/foo/bar.yml` for the :c:func:`bar`
function.  Add the required attributes for the new interface item.  Do not hard
code interface names which are used to define the new interface.  Use
``${uid-of-interface-item:/name}`` instead.  If the referenced interface is
specified in the same directory, then use a relative UID.  Using interface
references creates implicit dependencies and helps the header file generator to
resolve the interface dependencies and header file includes for you.  Use
:ref:`SpecTypeInterfaceUnspecifiedItemType` items for interface dependencies to
other domains such as the C language, the compiler, the implementation, or
user-provided defines.  To avoid cyclic dependencies between types you may use
an :ref:`SpecTypeInterfaceForwardDeclarationItemType` item.

.. code-block:: yaml

    SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
    brief: Tries to create a magic object and returns it.
    copyrights:
    - Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
    definition:
      default:
        body: null
        params:
        - ${magic-wand:/name} ${.:/params[0]/name}
        return: ${magic-type:/name} *
      variants: []
    description: |
      The magic object is created out of nothing with the help of a magic wand.
    enabled-by: true
    interface-type: function
    links:
    - role: interface-placement
      uid: header
    - role: interface-ingroup
      uid: /groups/api/classic/foo
    name: bar
    notes: null
    params:
    - description: is the magic wand.
      dir: null
      name: magic_wand
    return:
      return: Otherwise, the magic object is returned.
      return-values:
      - description: The caller did not have enough magic power.
        value: ${/if/c/null}
    type: interface