synquacer: Add platform makefile and documentation

Add Makefile and plaform definations file.
My thanks to Daniel Thompson and Ard Biesheuvel for the bits and pieces
I've taken from their earlier work regarding build and deploy steps for
Developerbox based on Synquacer SoCs. They deserve much of the credit
for this work although, since I assembled and tested things, any blame
is probably mine.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
diff --git a/docs/plat/synquacer.rst b/docs/plat/synquacer.rst
new file mode 100644
index 0000000..ca53deb
--- /dev/null
+++ b/docs/plat/synquacer.rst
@@ -0,0 +1,117 @@
+Trusted Firmware-A for Socionext Synquacer SoCs
+===============================================
+
+Socionext's Synquacer SC2A11 is a multi-core processor with 24 cores of Arm
+Cortex-A53. The Developerbox, of 96boards, is a platform that contains this
+processor. This port of the Trusted Firmware only supports this platform at
+the moment.
+
+More information are listed in `link`_.
+
+How to build
+============
+
+Code Locations
+--------------
+
+-  Trusted Firmware-A:
+   `link <https://github.com/ARM-software/arm-trusted-firmware>`__
+
+-  edk2:
+   `link <https://github.com/tianocore/edk2>`__
+
+-  edk2-platforms:
+   `link <https://github.com/tianocore/edk2-platforms>`__
+
+-  edk2-non-osi:
+   `link <https://github.com/tianocore/edk2-non-osi>`__
+
+Boot Flow
+---------
+
+SCP firmware --> TF-A BL31 --> UEFI(edk2)
+
+Build Procedure
+---------------
+
+-  Firstly, in addition to the “normal” build tools you will also need a
+   few specialist tools. On a Debian or Ubuntu operating system try:
+
+   .. code:: shell
+
+       sudo apt install acpica-tools device-tree-compiler uuid-dev
+
+-  Secondly, create a new working directory and store the absolute path to this
+   directory in an environment variable, WORKSPACE. It does not matter where
+   this directory is created but as an example:
+
+   .. code:: shell
+
+       export WORKSPACE=$HOME/build/developerbox-firmware
+       mkdir -p $WORKSPACE
+
+-  Run the following commands to clone the source code:
+
+   .. code:: shell
+
+       cd $WORKSPACE
+       git clone https://github.com/ARM-software/arm-trusted-firmware -b master
+       git clone https://github.com/tianocore/edk2.git -b master
+       git clone https://github.com/tianocore/edk2-platforms.git -b master
+       git clone https://github.com/tianocore/edk2-non-osi.git -b master
+
+-  Build ATF:
+
+   .. code:: shell
+
+       cd $WORKSPACE/arm-trusted-firmware
+       make -j`nproc` PLAT=synquacer PRELOADED_BL33_BASE=0x8200000 bl31 fiptool
+       tools/fiptool/fiptool create \
+             --tb-fw ./build/synquacer/release/bl31.bin \
+             --soc-fw ./build/synquacer/release/bl31.bin \
+             --scp-fw ./build/synquacer/release/bl31.bin \
+             ../edk2-non-osi/Platform/Socionext/DeveloperBox/fip_all_arm_tf.bin
+
+-  Build EDK2:
+
+   .. code:: shell
+
+       cd $WORKSPACE
+       export PACKAGES_PATH=$WORKSPACE/edk2:$WORKSPACE/edk2-platforms:$WORKSPACE/edk2-non-osi
+       export ACTIVE_PLATFORM="Platform/Socionext/DeveloperBox/DeveloperBox.dsc"
+       export GCC5_AARCH64_PREFIX=aarch64-linux-gnu-
+       unset ARCH
+
+       . edk2/edksetup.sh
+       make -C edk2/BaseTools
+
+       build -p $ACTIVE_PLATFORM -b RELEASE -a AARCH64 -t GCC5 -n `nproc` -D DO_X86EMU=TRUE
+
+-  The firmware image, which comprises the option ROM, ARM trusted firmware and
+   EDK2 itself, can be found $WORKSPACE/../Build/DeveloperBox/RELEASE_GCC5/FV/.
+   Use SYNQUACERFIRMWAREUPDATECAPSULEFMPPKCS7.Cap for UEFI capsule update and
+   SPI_NOR_IMAGE.fd for the serial flasher.
+
+   Note #1: -t GCC5 can be loosely translated as “enable link-time-optimization”;
+   any version of gcc >= 5 will support this feature and may be used to build EDK2.
+
+   Note #2: Replace -b RELEASE with -b DEBUG to build a debug.
+
+Install the System Firmware
+---------------------------
+
+-  Providing your Developerbox is fully working and has on operating system
+   installed then you can adopt your the newly compiled system firmware using
+   the capsule update method:.
+
+   .. code:: shell
+
+       sudo apt install fwupdate
+       sudo fwupdate --apply {50b94ce5-8b63-4849-8af4-ea479356f0e3} \
+                     SYNQUACERFIRMWAREUPDATECAPSULEFMPPKCS7.Cap
+       sudo reboot
+
+-  Alternatively you can install SPI_NOR_IMAGE.fd using the `board recovery method`_.
+
+.. _link: https://www.96boards.org/product/developerbox/
+.. _board recovery method: https://www.96boards.org/documentation/enterprise/developerbox/installation/board-recovery.md.html