1Contributor's Guide
2===================
3
4Getting Started
5---------------
6
7-  Make sure you have a Github account and you are logged on both
8   `developer.trustedfirmware.org`_ and `review.trustedfirmware.org`_.
9
10-  If you plan to contribute a major piece of work, it is usually a good idea to
11   start a discussion around it on the mailing list. This gives everyone
12   visibility of what is coming up, you might learn that somebody else is
13   already working on something similar or the community might be able to
14   provide some early input to help shaping the design of the feature.
15
16   If you intend to include Third Party IP in your contribution, please mention
17   it explicitly in the email thread and ensure that the changes that include
18   Third Party IP are made in a separate patch (or patch series).
19
20-  Clone `Trusted Firmware-A`_ on your own machine as described in
21   :ref:`prerequisites_get_source`.
22
23-  Create a local topic branch based on the `Trusted Firmware-A`_ ``master``
24   branch.
25
26Making Changes
27--------------
28
29-  Ensure commits adhere to the the project's :ref:`Commit Style`.
30
31-  Make commits of logical units. See these general `Git guidelines`_ for
32   contributing to a project.
33
34-  Keep the commits on topic. If you need to fix another bug or make another
35   enhancement, please address it on a separate topic branch.
36
37-  Split the patch in manageable units. Small patches are usually easier to
38   review so this will speed up the review process.
39
40-  Avoid long commit series. If you do have a long series, consider whether
41   some commits should be squashed together or addressed in a separate topic.
42
43-  Follow the :ref:`Coding Style` and :ref:`Coding Guidelines`.
44
45   -  Use the checkpatch.pl script provided with the Linux source tree. A
46      Makefile target is provided for convenience, see :ref:`this
47      section<automatic-compliance-checking>` for more details.
48
49-  Where appropriate, please update the documentation.
50
51   -  Consider whether the :ref:`Porting Guide`, :ref:`Firmware Design` document
52      or other in-source documentation needs updating.
53
54   -  If you are submitting new files that you intend to be the code owner for
55      (for example, a new platform port), then also update the
56      :ref:`code owners` file.
57
58   -  For topics with multiple commits, you should make all documentation changes
59      (and nothing else) in the last commit of the series. Otherwise, include
60      the documentation changes within the single commit.
61
62.. _copyright-license-guidance:
63
64-  Ensure that each changed file has the correct copyright and license
65   information. Files that entirely consist of contributions to this project
66   should have a copyright notice and BSD-3-Clause SPDX license identifier of
67   the form as shown in :ref:`license`. Files that contain changes to imported
68   Third Party IP files should retain their original copyright and license
69   notices.
70
71   For significant contributions you may add your own copyright notice in the
72   following format:
73
74   ::
75
76       Portions copyright (c) [XXXX-]YYYY, <OWNER>. All rights reserved.
77
78   where XXXX is the year of first contribution (if different to YYYY) and YYYY
79   is the year of most recent contribution. <OWNER> is your name or your company
80   name.
81
82-  Ensure that each patch in the patch series compiles in all supported
83   configurations. Patches which do not compile will not be merged.
84
85-  Please test your changes. As a minimum, ensure that Linux boots on the
86   Foundation FVP. See :ref:`Arm Fixed Virtual Platforms (FVP)` for more
87   information. For more extensive testing, consider running the `TF-A Tests`_
88   against your patches.
89
90-  Ensure that all CI automated tests pass. Failures should be fixed. They might
91   block a patch, depending on how critical they are.
92
93Submitting Changes
94------------------
95
96-  Submit your changes for review at https://review.trustedfirmware.org
97   targeting the ``integration`` branch.
98
99-  Add reviewers for your patch:
100
101   -  At least one code owner for each module modified by the patch. See the list
102      of modules and their :ref:`code owners`.
103
104   -  At least one maintainer. See the list of :ref:`maintainers`.
105
106   -  If some module has no code owner, try to identify a suitable (non-code
107      owner) reviewer. Running ``git blame`` on the module's source code can
108      help, as it shows who has been working the most recently on this area of
109      the code.
110
111      Alternatively, if it is impractical to identify such a reviewer, you might
112      send an email to the `TF-A mailing list`_ to broadcast your review request
113      to the community.
114
115   Note that self-reviewing a patch is prohibited, even if the patch author is
116   the only code owner of a module modified by the patch. Getting a second pair
117   of eyes on the code is essential to keep up with the quality standards the
118   project aspires to.
119
120-  The changes will then undergo further review by the designated people. Any
121   review comments will be made directly on your patch. This may require you to
122   do some rework. For controversial changes, the discussion might be moved to
123   the `TF-A mailing list`_ to involve more of the community.
124
125   Refer to the `Gerrit Uploading Changes documentation`_ for more details.
126
127-  The patch submission rules are the following. For a patch to be approved
128   and merged in the tree, it must get:
129
130   -  One ``Code-Owner-Review+1`` for each of the modules modified by the patch.
131   -  A ``Maintainer-Review+1``.
132
133   In the case where a code owner could not be found for a given module,
134   ``Code-Owner-Review+1`` is substituted by ``Code-Review+1``.
135
136   In addition to these various code review labels, the patch must also get a
137   ``Verified+1``. This is usually set by the Continuous Integration (CI) bot
138   when all automated tests passed on the patch. Sometimes, some of these
139   automated tests may fail for reasons unrelated to the patch. In this case,
140   the maintainers might (after analysis of the failures) override the CI bot
141   score to certify that the patch has been correctly tested.
142
143   In the event where the CI system lacks proper tests for a patch, the patch
144   author or a reviewer might agree to perform additional manual tests
145   in their review and the reviewer incorporates the review of the additional
146   testing in the ``Code-Review+1`` or ``Code-Owner-Review+1`` as applicable to
147   attest that the patch works as expected. Where possible additional tests should
148   be added to the CI system as a follow up task. For example, for a
149   platform-dependent patch where the said platform is not available in the CI
150   system's board farm.
151
152-  When the changes are accepted, the :ref:`maintainers` will integrate them.
153
154   -  Typically, the :ref:`maintainers` will merge the changes into the
155      ``integration`` branch.
156
157   -  If the changes are not based on a sufficiently-recent commit, or if they
158      cannot be automatically rebased, then the :ref:`maintainers` may rebase it
159      on the ``integration`` branch or ask you to do so.
160
161   -  After final integration testing, the changes will make their way into the
162      ``master`` branch. If a problem is found during integration, the
163      :ref:`maintainers` will request your help to solve the issue. They may
164      revert your patches and ask you to resubmit a reworked version of them or
165      they may ask you to provide a fix-up patch.
166
167Add Build Configurations
168------------------------
169
170-  TF-A uses Jenkins tool for Continuous Integration and testing activities.
171   Various CI Jobs are deployed which run tests on every patch before being
172   merged. So each of your patches go through a series of checks before they
173   get merged on to the master branch.
174
175-  ``Coverity Scan analysis`` is one of the tests we perform on our source code
176   at regular intervals. We maintain a build script ``tf-cov-make`` which contains the
177   build configurations of various platforms in order to cover the entire source
178   code being analysed by Coverity.
179
180-  When you submit your patches for review containing new source files, please
181   ensure to include them for the ``Coverity Scan analysis`` by adding the
182   respective build configurations in the ``tf-cov-make`` build script.
183
184-  In this section you find the details on how to append your new build
185   configurations for Coverity Scan analysis:
186
187#. We maintain a separate repository named `tf-a-ci-scripts repository`_
188   for placing all the test scripts which will be executed by the CI Jobs.
189
190#. In this repository, ``tf-cov-make`` script is located at
191   ``tf-a-ci-scripts/script/tf-coverity/tf-cov-make``
192
193#. Edit `tf-cov-make`_ script by appending all the possible build configurations with
194   the specific ``build-flags`` relevant to your platform, so that newly added
195   source files get built and analysed by Coverity.
196
197#. For better understanding follow the below specified examples listed in the
198   ``tf-cov-make`` script.
199
200.. code:: shell
201
202    Example 1:
203    #Intel
204    make PLAT=stratix10 $(common_flags) all
205    make PLAT=agilex $(common_flags) all
206
207-  In the above example there are two different SoCs ``stratix`` and ``agilex``
208   under the Intel platform and the build configurations has been added suitably
209   to include most of their source files.
210
211.. code:: shell
212
213    Example 2:
214    #Hikey
215    make PLAT=hikey $(common_flags) ${TBB_OPTIONS} ENABLE_PMF=1 all
216    make PLAT=hikey960 $(common_flags) ${TBB_OPTIONS} all
217    make PLAT=poplar $(common_flags) all
218
219-  In this case for ``Hikey`` boards additional ``build-flags`` has been included
220   along with the ``commom_flags`` to cover most of the files relevant to it.
221
222-  Similar to this you can still find many other different build configurations
223   of various other platforms listed in the ``tf-cov-make`` script. Kindly refer
224   them and append your build configurations respectively.
225
226Binary Components
227-----------------
228
229-  Platforms may depend on binary components submitted to the `Trusted Firmware
230   binary repository`_ if they require code that the contributor is unable or
231   unwilling to open-source. This should be used as a rare exception.
232-  All binary components must follow the contribution guidelines (in particular
233   licensing rules) outlined in the `readme.rst <tf-binaries-readme_>`_ file of
234   the binary repository.
235-  Binary components must be restricted to only the specific functionality that
236   cannot be open-sourced and must be linked into a larger open-source platform
237   port. The majority of the platform port must still be implemented in open
238   source. Platform ports that are merely a thin wrapper around a binary
239   component that contains all the actual code will not be accepted.
240-  Only platform port code (i.e. in the ``plat/<vendor>`` directory) may rely on
241   binary components. Generic code must always be fully open-source.
242
243--------------
244
245*Copyright (c) 2013-2021, Arm Limited and Contributors. All rights reserved.*
246
247.. _developer.trustedfirmware.org: https://developer.trustedfirmware.org
248.. _review.trustedfirmware.org: https://review.trustedfirmware.org
249.. _Trusted Firmware-A: https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git
250.. _Git guidelines: http://git-scm.com/book/ch5-2.html
251.. _Gerrit Uploading Changes documentation: https://review.trustedfirmware.org/Documentation/user-upload.html
252.. _TF-A Tests: https://trustedfirmware-a-tests.readthedocs.io
253.. _Trusted Firmware binary repository: https://review.trustedfirmware.org/admin/repos/tf-binaries
254.. _tf-binaries-readme: https://git.trustedfirmware.org/tf-binaries.git/tree/readme.rst
255.. _TF-A mailing list: https://lists.trustedfirmware.org/mailman/listinfo/tf-a
256.. _tf-a-ci-scripts repository: https://git.trustedfirmware.org/ci/tf-a-ci-scripts.git/
257.. _tf-cov-make: https://git.trustedfirmware.org/ci/tf-a-ci-scripts.git/tree/script/tf-coverity/tf-cov-make
258