mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-14 17:07:38 +00:00
105bccb3b9
For quite a long time we've been using a 3 week, rather than 2 week, merge window as it was only 2 weeks during the timeframe where we did 2 month rather than 3 month releases. This corrects the places that still had 2 weeks and tries to make things a bit clearer overall. Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Signed-off-by: Tom Rini <trini@konsulko.com>
198 lines
8 KiB
ReStructuredText
198 lines
8 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+:
|
|
|
|
U-Boot Development Process
|
|
==========================
|
|
|
|
Management Summary
|
|
------------------
|
|
|
|
* Development happens in Release Cycles of 3 months.
|
|
|
|
* The first 3 weeks of the cycle are referred to as the Merge Window, which is
|
|
followed by a Stabilization Period.
|
|
|
|
* Patches with new code get only accepted while the Merge Window is open.
|
|
|
|
* A patch that is generally in good shape and that was submitted while the
|
|
Merge Window was open is eligible to go into the upcoming release, even if
|
|
changes and resubmits are needed.
|
|
|
|
* During the Stabilization Period, only patches that contain bug fixes get
|
|
applied.
|
|
|
|
Phases of the Development Process
|
|
---------------------------------
|
|
|
|
U-Boot development takes place in `Release Cycles
|
|
<https://www.denx.de/wiki/U-Boot/ReleaseCycle>`_. A Release Cycle lasts
|
|
normally for three months.
|
|
|
|
The first three weeks of each Release Cycle are called *Merge Window*.
|
|
|
|
It is followed by a *Stabilization Period*.
|
|
|
|
The end of a Release Cycle is marked by the release of a new U-Boot version.
|
|
|
|
Merge Window
|
|
------------
|
|
|
|
The Merge Window is the period when new patches get submitted (and hopefully
|
|
accepted) for inclusion into U-Boot mainline. This period lasts for 21 days (3
|
|
weeks) and ends with the release of ``"-rc1"``.
|
|
|
|
This is the only time when new code (like support for new processors or new
|
|
boards, or other new features or reorganization of code) is accepted.
|
|
|
|
Twilight Time
|
|
-------------
|
|
|
|
Usually patches do not get accepted as they are - the peer review that takes
|
|
place will usually require changes and resubmissions of the patches before they
|
|
are considered to be ripe for inclusion into mainline.
|
|
|
|
Also the review often happens not immediately after a patch was submitted,
|
|
but only when somebody (usually the responsible custodian) finds time to do
|
|
this.
|
|
|
|
The result is that the final version of such patches gets submitted after the
|
|
merge window has been closed.
|
|
|
|
It is current practice in U-Boot that such patches are eligible to go into the
|
|
upcoming release.
|
|
|
|
The result is that the release of the ``"-rc1"`` version and formal closing of
|
|
the Merge Window does not preclude patches that were already posted from being
|
|
merged for the upcoming release.
|
|
|
|
Stabilization Period
|
|
--------------------
|
|
|
|
During the Stabilization Period only patches containing bug fixes get
|
|
applied.
|
|
|
|
Corner Cases
|
|
------------
|
|
|
|
Sometimes it is not clear if a patch contains a bug fix or not.
|
|
For example, changes that remove dead code, unused macros etc. or
|
|
that contain Coding Style fixes are not strict bug fixes.
|
|
|
|
In such situations it is up to the responsible custodian to decide if they
|
|
apply such patches even when the Merge Window is closed.
|
|
|
|
Exception: at the end of the Stabilization Period only strict bug
|
|
fixes my be applied.
|
|
|
|
Sometimes patches miss the Merge Window slightly - say by a few
|
|
hours or even a day. Patch acceptance is not as critical as a
|
|
financial transaction, or such. So if there is such a slight delay,
|
|
the custodian is free to turn a blind eye and accept it anyway. The
|
|
idea of the development process is to make it foreseeable,
|
|
but not to slow down development.
|
|
|
|
It makes more sense if an engineer spends another day on testing and
|
|
cleanup and submits the patch a couple of hours late, instead of
|
|
submitting a green patch which will waste efforts from several people
|
|
during several rounds of review and reposts.
|
|
|
|
Differences to the Linux Development Process
|
|
--------------------------------------------
|
|
|
|
* In Linux, top-level maintainers will collect patches in their trees and send
|
|
pull requests to Linus as soon as the merge window opens.
|
|
So far, most U-Boot custodians do not work like that; they send pull requests
|
|
only at (or even after) the end of the merge window.
|
|
|
|
* In Linux, the closing of the merge window is marked by the release of the
|
|
next ``"-rc1"``
|
|
In U-Boot, ``"-rc1"`` will only be released after all (or at least most of
|
|
the) patches that were submitted during the merge window have been applied.
|
|
|
|
Custodians
|
|
----------
|
|
|
|
The Custodians take responsibility for some area of the U-Boot code. The
|
|
in-tree ``MAINTAINERS`` files list who is responsible for which areas.
|
|
|
|
It is their responsibility to pick up patches from the mailing list
|
|
that fall into their responsibility, and to process these.
|
|
|
|
A very important responsibility of each custodian is to provide
|
|
feedback to the submitter of a patch about what is going on: if the
|
|
patch was accepted, or if it was rejected (which exact list of
|
|
reasons), if it needs to be reworked (with respective review
|
|
comments). Even a "I have no time now, will look into it later"
|
|
message is better than nothing. Also, if there are remarks to a
|
|
patch, these should leave no doubt if they were just comments and the
|
|
patch will be accepted anyway, or if the patch should be
|
|
reworked/resubmitted, or if it was rejected.
|
|
|
|
Work flow of a Custodian
|
|
------------------------
|
|
|
|
The normal flow of work in the U-Boot development process will look
|
|
like this:
|
|
|
|
#. A developer submits a patch via e-mail to the u-boot mailing list. In
|
|
U-Boot, we make use of the `Developer Certificate of Origin
|
|
<https://developercertificate.org/>`_ that is common in other projects such
|
|
as the Linux kernel. Following this and adding a ``Signed-off-by:`` line
|
|
that contains the developer's name and email address is required.
|
|
|
|
#. Everybody who can is invited to review and test the changes. Typically, we
|
|
follow the same guidelines as the Linux kernel for `Acked-by
|
|
<https://www.kernel.org/doc/html/latest/process/submitting-patches.html#when-to-use-acked-by-cc-and-co-developed-by>`_
|
|
as well as `Reviewed-by
|
|
<https://www.kernel.org/doc/html/latest/process/submitting-patches.html#using-reported-by-tested-by-reviewed-by-suggested-by-and-fixes>`_
|
|
and similar additional tags.
|
|
|
|
#. The responsible custodian inspects this patch, especially for:
|
|
|
|
#. :doc:`codingstyle`
|
|
|
|
#. Basic logic:
|
|
|
|
* The patch fixes a real problem.
|
|
|
|
* The patch does not introduce new problems, especially it does not break
|
|
other boards or architectures
|
|
|
|
#. U-Boot Philosophy, as documented in :doc:`designprinciples`.
|
|
|
|
#. Applies cleanly to the source tree. The custodian is expected to put in
|
|
a "best effort" if a patch does not apply cleanly, but can be made to apply
|
|
still. It is up to the custodian to decide how recent of a commit the
|
|
patch must be against. It is acceptable to request patches against the
|
|
last officially released version of U-Boot or newer. Of course a
|
|
custodian can also accept patches against older code. It can be
|
|
difficult to find the correct balance between putting too much work on
|
|
the custodian or too much work on an individual submitting a patch when
|
|
something does not apply cleanly.
|
|
|
|
#. Passes :doc:`ci_testing` as this checks for new warnings and other issues.
|
|
|
|
#. Note that in some cases more than one custodian may feel responsible for a
|
|
particular change. To avoid duplicated efforts, the custodian who starts
|
|
processing the patch should follow up to the email saying they intend to
|
|
pick it up.
|
|
|
|
#. Commits must show original author in the ``author`` field and include all of
|
|
the ``Signed-off-by``, ``Reviewed-by``, etc, tags that have been submitted.
|
|
|
|
#. The final decision to accept or reject a patch comes down to the custodian
|
|
in question.
|
|
|
|
#. If accepted, the custodian adds the patch to their public git repository.
|
|
Ideally, they will also follow up on the mailing list with some notification
|
|
that it has been applied. This is not always easy given different custodian
|
|
workflows and environments however.
|
|
|
|
#. Although a custodian is supposed to perform their own tests it is a
|
|
well-known and accepted fact that they needs help from other developers who
|
|
- for example - have access to the required hardware or other relevant
|
|
environments. Custodians are expected to ask for assistance with testing
|
|
when required.
|
|
|
|
#. Custodians are expected to submit a timely pull request of their git
|
|
repository to the main repository. It is strongly encouraged that a CI run
|
|
has been completed prior to submission, but not required.
|