doc: Move documents into subdirectories

This change creates the following directories under docs/
in order to provide a grouping for the content:

- components
- design
- getting_started
- perf
- process

In each of these directories an index.rst file is created
and this serves as an index / landing page for each of the
groups when the pages are compiled. Proper layout of the
top-level table of contents relies on this directory/index
structure.

Without this patch it is possible to build the documents
correctly with Sphinx but the output looks messy because
there is no overall hierarchy.

Change-Id: I3c9f4443ec98571a56a6edf775f2c8d74d7f429f
Signed-off-by: Paul Beesley <paul.beesley@arm.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/docs/process/platform-compatibility-policy.rst b/docs/process/platform-compatibility-policy.rst
new file mode 100644
index 00000000..e977e63a
--- /dev/null
+++ b/docs/process/platform-compatibility-policy.rst
@@ -0,0 +1,44 @@
+TF-A Platform Compatibility Policy
+==================================
+
+
+
+
+.. contents::
+
+--------------
+
+Introduction
+------------
+
+This document clarifies the project's policy around compatibility for upstream
+platforms.
+
+Platform compatibility policy
+-----------------------------
+
+Platform compatibility is mainly affected by changes to Platform APIs (as
+documented in the `Porting Guide`_), driver APIs (like the GICv3 drivers) or
+library interfaces (like xlat_table library). The project will try to maintain
+compatibility for upstream platforms. Due to evolving requirements and
+enhancements, there might be changes affecting platform compatibility which
+means the previous interface needs to be deprecated and a new interface
+introduced to replace it. In case the migration to the new interface is trivial,
+the contributor of the change is expected to make good effort to migrate the
+upstream platforms to the new interface.
+
+The `Release information`_ documents the deprecated interfaces and the intended
+release after which it will be removed. When an interface is deprecated, the
+page must be updated to indicate the release after which the interface will be
+removed. This must be at least 1 full release cycle in future. For non-trivial
+interface changes, a `tf-issue`_ should be posted to notify platforms that they
+should migrate away from the deprecated interfaces. Platforms are expected to
+migrate before the removal of the deprecated interface.
+
+--------------
+
+*Copyright (c) 2018, Arm Limited and Contributors. All rights reserved.*
+
+.. _Porting Guide: ../getting_started/porting-guide.rst
+.. _Release information: https://github.com/ARM-software/arm-trusted-firmware/wiki/TF-A-Release-information#removal-of-deprecated-interfaces
+.. _tf-issue: https://github.com/ARM-software/tf-issues/issues