Docs: Deprecate previous design proposal process

Replace previous design proposal process with the new design proposal
guideline. Remove the document.
Update contributing process document.

Change-Id: Ia31dbe2dad6c91bb6821c456e3929b9dd1b18d04
Signed-off-by: David Hu <david.hu@arm.com>
diff --git a/docs/contributing/contributing_process.rst b/docs/contributing/contributing_process.rst
index 8bd7e52..60faaec 100644
--- a/docs/contributing/contributing_process.rst
+++ b/docs/contributing/contributing_process.rst
@@ -19,7 +19,7 @@
   <https://developer.trustedfirmware.org/maniphest>`_, put as many details as
   possible in the description. Add 'Trusted Firmware M' in the 'Tags' field.
 - For non-trivial changes, need to follow the design proposal process
-  :doc:`Design Proposal Process </docs/contributing/tfm_design_proposal_process>`
+  :doc:`Design Proposal Guideline </docs/contributing/tfm_design_proposal_guideline>`
   for the TF-M project.
 - After the design has been accepted by the maintainer(s), a corresponding
   patch should be posted; follow guidelines below:
@@ -77,4 +77,4 @@
 
 --------------
 
-*Copyright (c) 2017-2021, Arm Limited. All rights reserved.*
+*Copyright (c) 2017-2022, Arm Limited. All rights reserved.*
diff --git a/docs/contributing/tfm_design_proposal_guideline.rst b/docs/contributing/tfm_design_proposal_guideline.rst
index 0bd50e9..14f3804 100755
--- a/docs/contributing/tfm_design_proposal_guideline.rst
+++ b/docs/contributing/tfm_design_proposal_guideline.rst
@@ -2,54 +2,12 @@
 Design proposal guideline
 #########################
 
-**********
-Background
-**********
-
-The existing TF-M design proposal process [1]_ requires developers to upstream a
-formal design document in reStructuredText format to describe their design.
-That process further defines a 2-stage review process to review and approve the
-design document. That process ensures that critical designs are thoroughly
-reviewed by key reviewers, especially when TF-M was built up from scratch.
-
-Currently, since more and more developers are contributing to TF-M community
-with new requirements and features, the existing process sometimes becomes
-heavyweight for contributors and reviewers.
-
-  - It is an additional effort for contributors to get familiar with
-    reStructuredText syntax and complete the document with reStructuredText
-    coding.
-  - The whole review process may take a long time. It is required that design
-    document shall be approved before code review starts. However, reviews of
-    design document details and implementation details sometimes can be combined
-    from the point of view of reviewers.
-  - The approved design document might be frequently updated during later code
-    review. The changes to design documents require review and approval again.
-
-Furthermore, it also brings some maintenance difficulties.
-
-  - When implementation in code is changed, in theory, it is unnecessary to
-    update the corresponding design document since it is a pure design proposal
-    instead of a user guide.
-    However, it is confusing if design document doesn't align with the
-    implementation.
-  - If the implementation is deprecated or the design document is out of date,
-    there is no guideline yet to discuss whether or how the design document
-    shall be deprecated as well or archived.
-
-TF-M design proposal process shall be simplified to speed up contribution,
-review and maintenance stages.
-
-*************
-New guideline
-*************
-
-The steps in the new design proposal guideline are lightweight and flexible to
-make sure that contributors can focus more on actual code implementation and
-iteration.
+The design proposal guideline specifies the steps to propose and upload design
+proposals to TF-M. Those steps are lightweight and flexible to make sure that
+contributors can focus more on actual code implementation and iteration.
 
 The guideline encourages developers to share design proposal via
-TF-M mailing list [2]_ and TF-M technical forum (tech forum) [3]_.
+TF-M mailing list [1]_ and TF-M technical forum (tech forum) [2]_.
 The design details can be discussed via code reviews of actual implementations.
 
 Typical steps are shown as the diagram below.
@@ -112,7 +70,7 @@
 deliberate over design and implementation details via code review.
 
 Contributors can implement their design proposal and upstream the patch set to
-TF-M gerrit [4]_ for code review.
+TF-M gerrit [3]_ for code review.
 For non-trivial changes or new major features, it is **strongly suggested** to
 propose the design to TF-M mailing list and tech forum in advance.
 
@@ -120,7 +78,7 @@
 even if the changes are non-trivial.
 No formal design document in advance is required anymore.
 
-The review process is the same as the general one [5]_, with some specific
+The review process is the same as the general one [4]_, with some specific
 requirements:
 
   - Contributors can send an email to TF-M mailing list to ask for review.
@@ -147,15 +105,13 @@
 Reference
 *********
 
-.. [1] :doc:`Design proposal process </docs/contributing/tfm_design_proposal_process>`
+.. [1] `TF-M mailing list <https://lists.trustedfirmware.org/mailman3/lists/tf-m.lists.trustedfirmware.org/>`_
 
-.. [2] `TF-M mailing list <https://lists.trustedfirmware.org/mailman3/lists/tf-m.lists.trustedfirmware.org/>`_
+.. [2] `TF-M technical forum <https://www.trustedfirmware.org/meetings/tf-m-technical-forum/>`_
 
-.. [3] `TF-M technical forum <https://www.trustedfirmware.org/meetings/tf-m-technical-forum/>`_
+.. [3] `TF-M gerrit <https://review.trustedfirmware.org/q/project:TF-M/trusted-firmware-m>`_
 
-.. [4] `TF-M gerrit <https://review.trustedfirmware.org/q/project:TF-M/trusted-firmware-m>`_
-
-.. [5] :doc:`Contributing process </docs/contributing/contributing_process>`
+.. [4] :doc:`Contributing process </docs/contributing/contributing_process>`
 
 -------------------
 
diff --git a/docs/contributing/tfm_design_proposal_process.rst b/docs/contributing/tfm_design_proposal_process.rst
deleted file mode 100644
index 1f56140..0000000
--- a/docs/contributing/tfm_design_proposal_process.rst
+++ /dev/null
@@ -1,155 +0,0 @@
-Design proposal process
-=======================
-
-:Author: Gyorgy Szing
-:Organisation: Arm Limited
-:Contact: Gyorgy Szing <gyorgy.szing@arm.com>
-
-Purpose and Content
--------------------
-This document describes the steps of adding/changing Trusted Firmware design. It
-specifies:
-
-  - The documentation format to be used.
-  - The information which shall be captured.
-  - The steps of the process.
-  - The location where the information shall be captured during the process.
-
-General
--------
-The Trusted Firmware project uses the
-`reStructuredText <http://docutils.sourceforge.net/rst.html>`_ format with
-`Sphinx <http://www.sphinx-doc.org/en/master/usage/restructuredtext/index.html>`_
-extensions for documentation. Design documents shall be captured in this format.
-
-Design documents are kept under version control at the project's
-`Gerrit server <https://review.trustedfirmware.org>`_. All decisions made and
-important information gathered during the design discussion, which is  not part
-of the design document shall be captured as Gerrit comments or notes for
-archiving purposes. To meet this requirement this process encourages the use of
-the Gerrit web UI for communication.
-
-
-Status of a document
----------------------
-The status of the document is captured in a *reST filed* called *Status*.
-Bibliographic fields like the *Status* shall be kept near to the top of the
-document after the document title.
-
-Example document fragment::
-
-    TF-M Crypto Service design
-    --------------------------
-
-    :Author: Antonio de Angelis
-    :Organization: Arm Limited
-    :Contact: Antonio de Angelis <antonio.deangelis@arm.com>
-
-Design documents are kept in three different sections of the documentation
-reflecting the status of the document. The status of the document determines
-the section it is in. Open (*Draft* and *Detailed* status) and accepted design
-documents shall be put to the ``docs/technical_references`` directory.
-
-.. important::
-  - 'Author' and 'Organization' can be *OPTIONAL* but at least one of them is
-    *MANDATORY*.
-  - 'Contact' is *MANDATORY* and must be valid for contacting with 'Author'
-    or 'Organization'.
-  - 'Status' is *OPTIONAL* if the design document is managed under a version
-    control tool. In this 'Status' field not available case, a guideline can be:
-
-    - No review comments given design is a *Draft* design.
-    - Positive review comments given design is a *Detailed* design.
-    - Merged design is an *Accepted* design.
-
-Preparation
--------------
-In order to work on TF-M documentation the TF-M git repository has to be
-available locally. Setting up the documentation tools will allow pre-viewing the
-documentation file in preparation.
-For information on what tools are needed please refer to
-:doc:`TF-M getting started </docs/getting_started/tfm_getting_started>`. To see
-how to get a local copy of the TF-M repository please see
-:doc:`build instructions </docs/technical_references/instructions/tfm_build_instruction>`
-
-Process steps
--------------
-
-- Write the design proposal in the format that is described in this document
-  with the *Status* set to *Draft* if *Status* field is provided. Put it to the
-  ``docs/technical_references`` directory and create a pull request.
-- Start an e-mail thread on the
-  `TF-M mailing list <mailto:tf-m@lists.trustedfirmware.org>`_ for discussing
-  the proposal.
-- Build initial consensus within the community about the proposed design
-  change, rework it according to the feedbacks and identify members who would
-  like to participate in the detailed review.
-- When the "short list" of members who are willing to participate in the
-  detailed review is established, set the *Status* field to *Detailed* if
-  *Status* field is provided and push the change to Gerrit.
-- Add the members of the "short list" to the Gerrit review as reviewers.
-- The detailed discussion then takes place in the Gerrit review and gets
-  recorded there.
-  Additional changes are submitted as new commits to the review.
-- When the proposal is accepted and *Status* field is provided, the *Status*
-  field is set to *Accepted* and update the change then get merged.
-
-.. uml::
-
-  @startuml
-  !define DRAFT_DIR **docs/technical_references/**
-  !define REJECTED_DIR **docs/technical_references/rejected/**
-  !define GERRIT_URL https://review.trustedfirmware.org
-  !define GERRIT_LINK [[GERRIT_URL trustedfirmware.org]]
-  !define MAINTAINER_RST_URL https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/tree/docs/maintainers.rst
-  !define TFM_MAILING_LIST mailto:tf-m@lists.trustedfirmware.org
-  !define NO_DECISION **no**
-  !define YES_DECISION **yes**
-  !define STATUS_DRAFT **Draft**
-  !define STATUS_DETAILED **Detailed**
-  !define STATUS_REJECTED **Rejected**
-  !define STATUS_ACCEPTED **Accepted**
-
-  title Design Proposal Process
-
-  start
-  :Create first draft.in [[http://docutils.sourceforge.net/rst.html ReST format]];
-  :Set it's available 'Status' field to STATUS_DRAFT.;
-
-  :Add your document under DRAFT_DIR.;
-  :Create pull-request at GERRIT_LINK.;
-  partition "Initial review." {
-      :Start an e-mail thread at [[TFM_MAILING_LIST tf-m mailing list]].;
-      repeat
-          :Build initial consensus within the
-           community about the proposed design change.;
-          :Gather developers interested in detailed review.;
-       repeat while (Ready for detailed review?)
-  }
-
-  partition "Detailed review." {
-      :Set available 'Status' field to STATUS_DETAILED.;
-      :Add reviewers to pull request.;
-
-      repeat
-         :Discuss design in Gerrit comments/notes.;
-         :Log the result of discussions over
-          other communication channels
-          as Gerrit comments/notes.;
-         :Push new document version if needed.;
-      repeat while (Consensus reached?)
-  }
-
-  if (Design is accepted?) then (STATUS_ACCEPTED)
-      :Sets available 'Status' field to STATUS_ACCEPTED.;
-      ://Submit// the pull-request.;
-  else (STATUS_REJECTED)
-  endif
-
-  stop
-
-  @enduml
-
---------------
-
-*Copyright (c) 2019-2021, Arm Limited. All rights reserved.*