Build: Convert docs directory to modern cmake

Add cmake files to docs directory. Remove unneeded cmake files.

By default, the targets are generated but not run by `make all` or
`make`. The documentation can be generated by running `make docs`

Please refer to the tfm_build_instructions document for
reference examples.

WARNING: This change will not build in isolation, it requires _all_
other cmake changes to successfully build. It is split out only for ease
of understanding.

Change-Id: I1b004a8f8ccfba2df901d91b093576fdc6bfa40d
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
Signed-off-by: Raef Coles <raef.coles@arm.com>
diff --git a/docs/CMakeLists.txt b/docs/CMakeLists.txt
new file mode 100644
index 0000000..f227c6e
--- /dev/null
+++ b/docs/CMakeLists.txt
@@ -0,0 +1,118 @@
+#-------------------------------------------------------------------------------
+# Copyright (c) 2020, Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+#-------------------------------------------------------------------------------
+
+cmake_minimum_required(VERSION 3.13)
+
+add_custom_target(docs)
+
+find_package(Python3)
+find_package(Sphinx)
+find_package(PythonModules COMPONENTS m2r sphinx-rtd-theme sphinxcontrib.plantuml)
+find_package(PlantUML)
+find_package(Doxygen 1.8.0)
+find_package(LATEX COMPONENTS PDFLATEX)
+
+################################## ENV #########################################
+
+set(SPHINXCFG_OUTPUT_PATH ${CMAKE_CURRENT_BINARY_DIR}/user_guide)
+set(SPHINX_TMP_DOC_DIR ${CMAKE_CURRENT_BINARY_DIR}/temp)
+set(SPHINXCFG_TEMPLATE_FILE "${CMAKE_CURRENT_SOURCE_DIR}/conf.py.in")
+set(DOXYCFG_OUTPUT_PATH ${CMAKE_CURRENT_BINARY_DIR}/reference_manual)
+set(DOXYCFG_DOXYGEN_CFG_DIR ${CMAKE_SOURCE_DIR}/doxygen)
+
+# Enable to request the interface to build the doxygen documentation as well
+set(DOXYCFG_DOXYGEN_BUILD False)
+
+################################## SPHINX ######################################
+set(SPHINXCFG_COPY_FILES True)
+set(SPHINXCFG_RENDER_CONF True)
+
+add_custom_target(tfm_docs_sphinx_cfg
+    DEPENDS ${SPHINX_TMP_DOC_DIR}/conf.py
+)
+add_custom_command(OUTPUT ${SPHINX_TMP_DOC_DIR}/conf.py
+    COMMAND ${CMAKE_COMMAND} -E make_directory ${SPHINX_TMP_DOC_DIR}
+    COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_SOURCE_DIR}/build_docs/conf.py ${SPHINX_TMP_DOC_DIR}/conf.py
+    MAIN_DEPENDENCY ${CMAKE_SOURCE_DIR}/build_docs/conf.py
+    BYPRODUCTS ${SPHINX_TMP_DOC_DIR}
+)
+
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/tfm_env.py.in ${SPHINX_TMP_DOC_DIR}/tfm_env.py @ONLY)
+
+if (SPHINX_FOUND AND PLANTUML_FOUND AND PY_M2R_FOUND AND PY_SPHINX-RTD-THEME_FOUND AND PY_SPHINXCONTRIB.PLANTUML)
+
+    file(GLOB_RECURSE SPHINXCFG_DOC_FILES ${CMAKE_CURRENT_SOURCE_DIR}/*.rst)
+
+    add_custom_command(OUTPUT "${SPHINXCFG_OUTPUT_PATH}/html/index.html"
+        OUTPUT "${SPHINXCFG_OUTPUT_PATH}/html/"
+        COMMAND "${SPHINX_EXECUTABLE}" -b html "${SPHINX_TMP_DOC_DIR}" "${SPHINXCFG_OUTPUT_PATH}/html"
+        WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"
+        DEPENDS tfm_docs_sphinx_cfg
+        DEPENDS ${SPHINXCFG_DOC_FILES}
+    )
+    add_custom_target(tfm_docs_userguide_html
+        DEPENDS "${SPHINXCFG_OUTPUT_PATH}/html/index.html"
+        DEPENDS "${SPHINXCFG_OUTPUT_PATH}/html/"
+    )
+    add_dependencies(docs tfm_docs_userguide_html)
+
+    if (LATEX_PDFLATEX_FOUND)
+        add_custom_command(OUTPUT "${SPHINXCFG_OUTPUT_PATH}/latex/TF-M.tex"
+            OUTPUT "${SPHINXCFG_OUTPUT_PATH}/latex/"
+            COMMAND "${SPHINX_EXECUTABLE}" -b latex "${SPHINX_TMP_DOC_DIR}" "${SPHINXCFG_OUTPUT_PATH}/latex"
+            WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"
+            DEPENDS tfm_docs_sphinx_cfg
+            DEPENDS ${SPHINXCFG_DOC_FILES}
+        )
+        add_custom_command(OUTPUT "${SPHINXCFG_OUTPUT_PATH}/latex/TF-M.pdf"
+            COMMAND ${PDFLATEX_COMPILER} TF-M.tex
+            COMMAND ${CMAKE_COMMAND} -E copy TF-M.tex ${SPHINXCFG_OUTPUT_PATH}/tf-m_user_guide.pdf
+            WORKING_DIRECTORY ${SPHINXCFG_OUTPUT_PATH}/latex/
+            DEPENDS "${SPHINXCFG_OUTPUT_PATH}/latex/TF-M.tex"
+        )
+        add_custom_target(tfm_docs_userguide_pdf
+            DEPENDS "${SPHINXCFG_OUTPUT_PATH}/latex/TF-M.pdf"
+        )
+        add_dependencies(docs tfm_docs_userguide_pdf)
+    endif()
+endif()
+
+################################## DOXYGEN #####################################
+
+configure_file(${CMAKE_SOURCE_DIR}/doxygen/Doxyfile.in ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile @ONLY)
+
+if (DOXYGEN_FOUND AND DOXYGEN_DOT_FOUND AND PLANTUML_FOUND)
+
+    file(GLOB_RECURSE DOXYCFG_DOC_FILES ${CMAKE_SOURCE_DIR}/*.c ${CMAKE_SOURCE_DIR}/*.h)
+
+    add_custom_command(OUTPUT ${DOXYCFG_OUTPUT_PATH}/html
+        OUTPUT ${DOXYCFG_OUTPUT_PATH}/latex
+        OUTPUT ${DOXYCFG_OUTPUT_PATH}/latex/refman.pdf
+        COMMAND ${DOXYGEN_EXECUTABLE} ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile
+        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+        DEPENDS ${DOXYCFG_DOC_FILES}
+    )
+    add_custom_target(tfm_docs_refman_html
+        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+        DEPENDS ${DOXYCFG_OUTPUT_PATH}/html
+    )
+    add_dependencies(docs tfm_docs_refman_html)
+
+    if (LATEX_PDFLATEX_FOUND)
+        add_custom_command(OUTPUT "${DOXYCFG_OUTPUT_PATH}/latex/refman.pdf"
+            COMMAND "${PDFLATEX_COMPILER} refman.tex"
+            COMMAND ${CMAKE_COMMAND} -E copy refman.tex ${DOXYCFG_OUTPUT_PATH}/tf-m_reference_manual.pdf
+            WORKING_DIRECTORY ${DOXYCFG_OUTPUT_PATH}/latex/
+            DEPENDS "${DOXYCFG_OUTPUT_PATH}/latex/refman.tex"
+        )
+        add_custom_target(tfm_docs_refman_pdf
+            DEPENDS ${DOXYCFG_OUTPUT_PATH}/latex/refman.pdf
+            DEPENDS tfm_docs_refman_html
+        )
+        add_dependencies(docs tfm_docs_refman_pdf)
+    endif()
+endif()