doc: sending_patches.rst: Incorporate the old "Patches" wiki content

Import as-is much of the old "Patches" wiki page to the current
sending_patches.rst file. This means we need to move patman to being
included in the higher level ToC and add a reference for "Custodians" in
the process document. A very minimal amount of content changing and
rewording is done here as part of the import, in order to make the
conversion easier.

Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

3 files changed, 503 insertions, 3 deletions

diff --git a/doc/develop/index.rst b/doc/develop/index.rst
index f7ee09d..72332f7 100644
--- a/doc/develop/index.rst
+++ b/doc/develop/index.rst
@@ -11,6 +11,7 @@ General
 
    codingstyle
    designprinciples
+   patman
    process
    release_cycle
    system_configuration
diff --git a/doc/develop/process.rst b/doc/develop/process.rst
index 388945c..6a18a81 100644
--- a/doc/develop/process.rst
+++ b/doc/develop/process.rst
@@ -108,6 +108,8 @@ Differences to the Linux Development Process
   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:
+
 Custodians
 ----------
 
diff --git a/doc/develop/sending_patches.rst b/doc/develop/sending_patches.rst
index 0542ade..5065012 100644
--- a/doc/develop/sending_patches.rst
+++ b/doc/develop/sending_patches.rst
@@ -3,14 +3,511 @@
 Sending patches
 ===============
 
-.. toctree::
-   :maxdepth: 2
+*Before you begin* to implement any new ideas or concepts it is always a good
+idea to present your plans on the `U-Boot mailing list
+<https://lists.denx.de/listinfo/u-boot>`_. U-Boot supports a huge amount of
+very different systems, and it is often impossible for the individual developer
+to oversee the consequences of a specific change to all architectures.
+Discussing concepts early can help you to avoid spending effort on code which,
+when submitted as a patch, might be rejected and/or will need lots of rework
+because it does not fit for some reason. Early peer review is an important
+resource - use it.
 
-   patman
+A good introduction how to prepare for submitting patches can be found in the
+LWN article `How to Get Your Change Into the Linux Kernel
+<http://lwn.net/Articles/139918/>`_ as the same rules apply to U-Boot, too.
 
+Using patman
+------------
 
 You can use a tool called patman to prepare, check and sent patches. It creates
 change logs, cover letters and patch notes. It also simplified the process of
 sending multiple versions of a series.
 
 See more details at :doc:`patman`.
+
+General Patch Submission Rules
+------------------------------
+
+* All patches must be sent to the `u-boot@lists.denx.de
+  <https://lists.denx.de/listinfo/u-boot>`_ mailing list.
+
+* If your patch affects the code maintained by one of the :ref:`custodians`, CC
+  them when emailing your patch. The easiest way to make sure you don't forget
+  this even when you resubmit the patch later is to add a ``Cc: name
+  <address>`` line after your ``Signed-off-by:`` line (see the example below).
+
+* Take a look at the commit logs of the files you are modifying. Authors of
+  past commits might have input to your change, so also CC them if you think
+  they may have feedback.
+
+* Patches should always contain exactly one complete logical change, i. e.
+
+   * Changes that contain different, unrelated modifications shall be submitted
+     as *separate* patches, one patch per changeset.
+
+   * If one logical set of modifications affects or creates several files, all
+     these changes shall be submitted in a *single* patch.
+
+* Non-functional changes, i.e. whitespace and reformatting changes, should be
+  done in separate patches marked as ``cosmetic``. This separation of functional
+  and cosmetic changes greatly facilitates the review process.
+
+* Some comments on running ``checkpatch.pl``:
+
+   * Checkpatch is a tool that can help you find some style problems, but is
+     imperfect, and the things it complains about are of varying importance.
+     So use common sense in interpreting the results.
+
+   * Warnings that clearly only make sense in the Linux kernel can be ignored.
+     This includes ``Use #include <linux/$file> instead of <asm/$file>`` for
+     example.
+
+   * If you encounter warnings for existing code, not modified by your patch,
+     consider submitting a separate, cosmetic-only patch -- clearly described
+     as such -- that *precedes* your substantive patch.
+
+   * For minor modifications (e.g. changed arguments of a function call),
+     adhere to the present codingstyle of the module. Relating checkpatch
+     warnings can be ignored in this case. A respective note in the commit or
+     cover letter why they are ignored is desired.
+
+* Send your patches as plain text messages: no HTML, no MIME, no links, no
+  compression, no attachments. Just plain text. The best way the generate
+  patches is by using the ``git format-patch`` command. Please use the
+  ``master`` branch of the mainline U-Boot git repository
+  (``https://source.denx.de/u-boot/u-boot.git``) as reference, unless (usually
+  late in a release cycle) there has been an announcement to use the ``next``
+  branch of this repository instead.
+
+* Make sure that your mailer does not mangle the patch by automatic changes
+  like wrapping of longer lines etc.
+  The best way to send patches is by not using your regular mail tool, but by
+  using either ``git send-email`` or the ``git imap-send`` command instead.
+  If you believe you need to use a mailing list for testing (instead of any
+  regular mail address you own), we have a special test list for such purposes.
+  It would be best to subscribe to the list for the duration of your tests to
+  avoid repeated moderation - see https://lists.denx.de/listinfo/test
+
+* Choose a meaningful Subject: - keep in mind that the Subject will also be
+  visible as headline of your commit message. Make sure the subject does not
+  exceed 60 characters or so.
+
+* The start of the subject should be a meaningfull tag (arm:, ppc:, tegra:,
+  net:, ext2:, etc)
+
+* Include the string "PATCH" in the Subject: line of your message, e. g.
+  "[PATCH] Add support for feature X". ``git format-patch`` should automatically
+  do this.
+
+* If you are sending a patch series composed of multiple patches, make sure
+  their titles clearly state the patch order and total number of patches (``git
+  format-patch -n``). Also, often times an introductory email describing what
+  the patchset does is useful (``git format-patch -n --cover-letter``). As an
+  example::
+
+   [PATCH 0/3] Add support for new SuperCPU2000
+      (This email does not contain a patch, just a description)
+   [PATCH 1/3] Add core support for SuperCPU2000
+   [PATCH 2/3] Add support for SuperCPU2000's on-chip I2C controller
+   [PATCH 3/3] Add support for SuperCPU2000's on-chip UART
+
+* In the message body, include a description of your changes.
+
+   * For bug fixes: a description of the bug and how your patch fixes this bug.
+     Please try to include a way of demonstrating that the patch actually fixes
+     something.
+
+   * For new features: a description of the feature and your implementation.
+
+* Additional comments which you don't want included in U-Boot's history can be
+  included below the first "---" in the message body.
+
+* If your description gets too long, that's a strong indication that you should
+  split up your patch.
+
+* Remember that there is a size limit of 100 kB on the mailing list. In most
+  cases, you did something wrong if your patch exceeds this limit. Think again
+  if you should not split it into separate logical parts.
+
+Attributing Code, Copyrights, Signing
+-------------------------------------
+
+* Sign your changes, i. e. add a *Signed-off-by:* line to the message body.
+  This can be automated by using ``git commit -s``.
+
+* If you change or add *significant* parts to a file, then please make sure to
+  add your copyright to that file, for example like this::
+
+   (C) Copyright 2010  Joe Hacker <jh@hackers.paradise.com>
+
+	  Please do *not* include a detailed description of your
+	  changes. We use the *git* commit messages for this purpose.
+
+* If you add new files, please always make sure that these contain your
+  copyright note and a GPLv2+ SPDX-License-Identifier, for example like this::
+
+   (C) Copyright 2010  Joe Hacker <jh@hackers.paradise.com>
+
+   SPDX-License-Identifier:<TAB>GPL-2.0+
+
+* If you are copying or adapting code from other projects, like the Linux
+  kernel, or BusyBox, or similar, please make sure to state clearly where you
+  copied the code from, and provide terse but precise information which exact
+  version or even commit ID was used. Follow the ideas of this note from the
+  Linux "SubmittingPatches" document::
+
+   Special note to back-porters: It seems to be a common and useful practice
+   to insert an indication of the origin of a patch at the top of the commit
+   message (just after the subject line) to facilitate tracking. For instance,
+   here's what we see in 2.6-stable :
+
+	 Date:	Tue May 13 19:10:30 2008 +0000
+
+		  SCSI: libiscsi regression in 2.6.25: fix nop timer handling
+
+		  commit 4cf1043593db6a337f10e006c23c69e5fc93e722 upstream
+
+   And here's what appears in 2.4 :
+
+	 Date:	Tue May 13 22:12:27 2008 +0200
+
+		  wireless, airo: waitbusy() won't delay
+
+		  [backport of 2.6 commit b7acbdfbd1f277c1eb23f344f899cfa4cd0bf36a]
+
+Whatever the format, this information provides a valuable help to people
+tracking your trees, and to people trying to trouble-shoot bugs in your
+tree.
+
+Commit message conventions
+--------------------------
+
+Please adhere to the following conventions when writing your commit
+log messages.
+
+* The first line of the log message is the summary line. Keep this less than 70
+  characters long.
+
+* Don't use periods to end the summary line (e.g., don't do "Add support for
+  X.")
+
+* Use the present tense in your summary line (e.g., "Add support for X" rather
+  than "Added support for X"). Furthermore, use the present tense in your log
+  message to describe what the patch is doing. This isn't a strict rule -- it's
+  OK to use the past tense for describing things that were happening in the old
+  code for example.
+
+* Use the imperative tense in your summary line (e.g., "Add support for X"
+  rather than "Adds support for X"). In general, you can think of the summary
+  line as "this commit is meant to 'Add support for X'"
+
+* If applicable, prefix the summary line with a word describing what area of
+  code is being affected followed by a colon. This is a standard adopted by
+  both U-Boot and Linux. For example, if your change affects all mpc85xx
+  boards, prefix your summary line with "mpc85xx:". If your change affects the
+  PCI common code, prefix your summary line with "pci:". The best thing to do
+  is look at the "git log <file>" output to see what others have done so you
+  don't break conventions.
+
+* Insert a blank line after the summary line
+
+* For bug fixes, it's good practice to briefly describe how things behaved
+  before this commit
+
+* Put a detailed description after the summary and blank line. If the summary
+  line is sufficient to describe the change (e.g. it is a trivial spelling
+  correction or whitespace update), you can omit the blank line and detailed
+  description.
+
+* End your log message with S.O.B. (Signed-off-by) line. This is done
+  automatically when you use ``git commit -s``.
+
+* Keep EVERY line under 72 characters. That is, your message should be
+  line-wrapped with line-feeds. However, don't get carried away and wrap it too
+  short either since this also looks funny.
+
+* Detail level: The audience of the commit log message that you should cater to
+  is those familiar with the underlying source code you are modifying, but who
+  are _not_ familiar with the patch you are submitting. They should be able to
+  determine what is being changed and why. Avoid excessive low-level detail.
+  Before submitting, re-read your commit log message with this audience in mind
+  and adjust as needed.
+
+Sending updated patch versions
+------------------------------
+
+It is pretty normal that the first version of a patch you are submitting does
+not get accepted as is, and that you are asked to submit another, improved
+version.
+
+When re-posting such a new version of your patch(es), please always make sure
+to observe the following rules.
+
+* Make an appropriate note that this is a re-submission in the subject line,
+  eg. "[PATCH v2] Add support for feature X". ``git format-patch
+  --subject-prefix="PATCH v2"`` can be used in this case (see the example
+  below).
+
+* Please make sure to keep a "change log", i. e. a description of what you have
+  changed compared to previous versions of this patch. This change log should
+  be added below the "---" line in the patch, which starts the "comment
+  section", i. e. which contains text that does not get included into the
+  actual commit message.
+  Note: it is *not* sufficient to provide a change log in some cover letter
+  that gets sent as a separate message with the patch series. The reason is
+  that such cover letters are not as easily reviewed in our `patchwork queue
+  <http://patchwork.ozlabs.org/project/uboot/list/>`_ so they are not helpful
+  to any reviewers using this tool. Example::
+
+   From: Joe Hacker <jh@hackers.paradise.com>
+   Date: Thu, 1 Jan 2222 12:21:22 +0200
+   Subject: [PATCH 1/2 v3] FOO: add timewarp-support
+
+   This patch adds timewarp-support for the FOO family of processors.
+
+   adapted for the current kernel structures.
+
+   Signed-off-by: Joe Hacker <jh@hackers.paradise.com>
+   Cc: Tom Maintainer <tm@u-boot.custodians.org>
+   ---
+   Changes for v2:
+   - Coding Style cleanup
+   - fixed miscalculation of time-space discontinuities
+   Changes for v3:
+   - fixed compiler warnings observed with GCC-17.3.5
+   - worked around integer overflow in warp driver
+
+    arch/foo/cpu/spacetime.c |	 8 +
+    drivers/warp/Kconfig     |	 7 +
+    drivers/warp/Makefile    |	42 +++
+    drivers/warp/warp-core.c | 255 +++++++++++++++++++++++++
+
+* Make sure that your mailer adds or keeps correct ``In-reply-to:`` and
+  ``References:`` headers, so threading of messages is working and everybody
+  can see that the new message refers to some older posting of the same topic.
+
+Uncommented and un-threaded repostings are extremely annoying and
+time-consuming, as we have to try to remember if anything similar has been
+posted before, look up the old threads, and then manually compare if anything
+has been changed, or what.
+
+If you have problems with your e-mail client, for example because it mangles
+white space or wraps long lines, then please read this article about `Email
+Clients and Patches <http://kerneltrap.org/Linux/Email_Clients_and_Patches>`_.
+
+Notes
+-----
+
+1. U-Boot is Free Software that can redistributed and/or modified under the
+   terms of the `GNU General Public License
+   <http://www.fsf.org/licensing/licenses/gpl.html>`_ (GPL). Currently (July
+   2009) version 2 of the GPL applies. Please see :download:`Licensing
+   <../../Licenses/README>` for details. To allow that later versions of U-Boot
+   may be released under a later version of the GPL, all new code that gets
+   added to U-Boot shall use a "GPL-2.0+" SPDX-License-Identifier.
+
+2. All code must follow the :doc:`codingstyle` requirements.
+
+3. Before sending the patch, you *must* run the ``MAKEALL`` script on your
+   patched source tree and make sure that no errors or warnings are reported
+   for any of the boards. Well, at least not any more warnings than without
+   your patch. It is *strongly* recommended to verify that out-of-tree
+   building (with ``-O`` _make_ option resp. ``BUILD_DIR`` environment
+   variable) is still working. For example, run ``BUILD_DIR=/tmp/u-boot-build ./MAKEALL``.
+   Please also run ``MAKEALL`` for *at least one other architecture* than the one
+   you made your modifications in.
+
+4. If you modify existing code, make sure that your new code does not add to
+   the memory footprint of the code. Remember: Small is beautiful! When adding
+   new features, these should compile conditionally only (using the
+   configuration system resp. #ifdef), and the resulting code with the new
+   feature disabled must not need more memory than the old code without your
+   modification.
+
+Patch Tracking
+--------------
+
+Like some other project U-Boot uses `Patchwork <http://patchwork.ozlabs.org/>`_
+to track the state of patches. This is one of the reasons why it is mandatory
+to submit all patches to the U-Boot mailing list - only then they will be
+picked up by patchwork.
+
+At http://patchwork.ozlabs.org/project/uboot/list/ you can find the list of
+open U-Boot patches. By using the "Filters" link (Note: requires JavaScript)
+you can also select other views, for example, to include old patches that have,
+for example, already been applied or rejected.
+
+A Custodian has additional privileges and can:
+
+* **Delegate** a patch
+
+* **Change the state** of a patch. The following states exist:
+
+   * New
+
+   * Under Review
+
+   * Accepted
+
+   * Rejected
+
+   * RFC
+
+   * Not Applicable
+
+   * Changes Requested
+
+   * Awaiting Upstream
+
+   * Superseeded
+
+   * Deferred
+
+   * Archived
+
+Patchwork work-flow
+^^^^^^^^^^^^^^^^^^^
+
+At the moment we are in the process of defining our work-flow with
+Patchwork, so I try to summarize what the states and state changes
+mean; most of this information is based on this `mail thread
+<http://old.nabble.com/patchwork-states-and-workflow-td19579954.html>`_.
+
+* New: Patch has been submitted to the list, and none of the maintainers has
+  changed it's state since.
+
+* Under Review:
+
+* Accepted: When a patch has been applied to a custodian repository that gets
+  used for pulling from into upstream, they are put into "accepted" state.
+
+* Rejected: Rejected means we just don't want to do what the patch does.
+
+* RFC: The patch is not intended to be applied to any of the mainline
+  repositories, but merely for discussing or testing some idea or new feature.
+
+* Not Applicable: The patch does not apply cleanly against the current U-Boot
+  repository, most probably because it was made against a much older version of
+  U-Boot, or because the submitter's mailer mangled it (for example by
+  converting TABs into SPACEs, or by breaking long lines).
+
+* Changes Requested: The patch looks mostly OK, but requires some rework before
+  it will be accepted for mainline.
+
+* Awaiting Upstream:
+
+* Superseeded: Patches are marked as 'superseeded' when the poster submits a
+  new version of these patches.
+
+* Deferred: Deferred usually means the patch depends on something else that
+  isn't upstream, such as patches that only apply against some specific other
+  repository.
+
+* Archived: Archiving puts the patch away somewhere where it doesn't appear in
+  the normal pages and needs extra effort to get to.
+
+We also can put patches in a "bundle". I don't know yet if that has any deeper
+sense but to mark them to be handled together, like a patch series that
+logically belongs together.
+
+Apply patches
+^^^^^^^^^^^^^
+
+To apply a patch from the `patchwork queue
+<http://patchwork.ozlabs.org/project/uboot/list/>`_ using ``git``, download the
+mbox file and apply it using::
+
+   git am file
+
+The `openembedded wiki <http://wiki.openembedded.net/>`_ also provides a script
+named `pw-am.sh
+<http://cgit.openembedded.org/cgit.cgi/openembedded/tree/contrib/patchwork/pw-am.sh>`_
+which can be used to fetch an 'mbox' patch from patchwork and git am it::
+
+   usage: pw-am.sh <number>
+   example: 'pw-am.sh 71002' will get and apply the patch from http://patchwork.ozlabs.org/patch/71002/
+
+Update the state of patches
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+You have to register to be able to update the state of patches. You can use the
+Web interface, `pwclient`, or `pwparser`.
+
+pwclient
+^^^^^^^^
+
+The `pwclient` command line tool can be used for example to retrieve patches,
+search the queue or update the state.
+
+All necessary information for `pwclient` is linked from the bottom of
+http://patchwork.ozlabs.org/project/uboot/
+
+Use::
+
+   pwclient help
+
+for an overview on how to use it.
+
+pwparser
+^^^^^^^^
+
+See http://www.mail-archive.com/patchwork@lists.ozlabs.org/msg00057.html
+
+Review Process, Git Tags
+------------------------
+
+There are a number of *git tags* that are used to document the origin
+and the processing of patches on their way into the mainline U-Boot
+code. The following is an attempt to document how these are usually
+handled in the U-Boot project. In general, we try to follow the
+established procedures from other projects, especially the Linux
+kernel, but there may be smaller differences. For reference, see
+the Linux kernel's `Submitting patches <https://www.kernel.org/doc/html/latest/process/submitting-patches.html>`_ document.
+
+* Signed-off-by: the *Signed-off-by:* is a line at the end of the commit
+  message by which the signer certifies that he was involved in the development
+  of the patch and that he accepts the `Developer Certificate of Origin
+  <https://developercertificate.org/>`_. In U-Boot, we typically do not add a
+  *Signed-off-by:* if we just pass on a patch without any changes.
+
+* Reviewed-by: The patch has been reviewed and found acceptible according to
+  the `Reveiwer's statement of oversight
+  <https://www.kernel.org/doc/html/latest/process/submitting-patches.html#reviewer-s-statement-of-oversight>`_.
+  A *Reviewed-by:* tag is a statement of opinion that the patch is an
+  appropriate modification of the code without any remaining serious technical
+  issues. Any interested reviewer (who has done the work) can offer a
+  *Reviewed-by:* tag for a patch.
+
+* Acked-by: If a person was not directly involved in the preparation or
+  handling of a patch but wishes to signify and record their approval of it
+  then they can arrange to have an *Acked-by:* line added to the patch's
+  changelog.
+
+* Tested-by: A *Tested-by:* tag indicates that the patch has been successfully
+  tested (in some environment) by the person named. Andrew Morton: "I think
+  it's very useful information to have. For a start, it tells you who has the
+  hardware and knows how to build a kernel. So if you're making a change to a
+  driver and want it tested, you can troll the file's changelog looking for
+  people who might be able to help."
+
+* Reported-by: If this patch fixes a problem reported by somebody else,
+  consider adding a *Reported-by:* tag to credit the reporter for their
+  contribution. Please note that this tag should not be added without the
+  reporter's permission, especially if the problem was not reported in a public
+  forum.
+
+* Cc: If a person should have the opportunity to comment on a patch, you may
+  optionally add a *Cc:* tag to the patch. Git tools (git send-email) will then
+  automatically arrange that he receives a copy of the patch when you submit it
+  to the mainling list. This is the only tag which might be added without an
+  explicit action by the person it names. This tag documents that potentially
+  interested parties have been included in the discussion.
+  For example, when your change affects a specific board or driver, then makes
+  a lot of sense to put the respective maintainer of this code on Cc:
+
+Note that Patchwork automatically tracks and collects such git tags
+from follow-up mails, so it is usually better to apply a patch through
+the Patchwork commandline interface than just manually applying it
+from a posting on the mailing list (in which case you have to do all
+the tracking and adding of git tags yourself).