doc: boards: Add rockchip documentation

Rockchip has documentation file, doc/README.rockchip but
which is not so readable to add or understand the existing
contents. Even the format that support is legacy readme
in U-Boot.

Add rockchip specific documentation file using new rst
format, which describes the information about Rockchip
supported boards and it's usage steps.

Added minimal information about rk3288, rk3328, rk3368
and rk3399 boards and usage. This would indeed updated
further based on the requirements and updates.

Cc: Kever Yang <kever.yang@rock-chips.com>
Cc: Matwey V. Kornilov <matwey.kornilov@gmail.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>

doc/board/rockchip/index.rst

@@ -0,0 +1,10 @@
+.. SPDX-License-Identifier: GPL-2.0+
+.. Copyright (C) 2019 Jagan Teki <jagan@amarulasolutions.com>
+
+Rockchip
+========
+
+.. toctree::
+   :maxdepth: 2
+
+   rockchip

doc/board/rockchip/rockchip.rst

@@ -0,0 +1,130 @@
+.. SPDX-License-Identifier: GPL-2.0+
+.. Copyright (C) 2019 Jagan Teki <jagan@amarulasolutions.com>
+
+ROCKCHIP
+========
+
+About this
+----------
+
+This document describes the information about Rockchip supported boards
+and it's usage steps.
+
+Rockchip boards
+---------------
+
+Rockchip is SoC solutions provider for tablets & PCs, streaming media
+TV boxes, AI audio & vision, IoT hardware.
+
+A wide range of Rockchip SoCs with associated boardsare supported in
+mainline U-Boot.
+
+List of mainline supported rockchip boards:
+
+* rk3288
+     - Evb-RK3288
+     - Firefly-RK3288
+     - mqmaker MiQi
+     - Phytec RK3288 PCM-947
+     - PopMetal-RK3288
+     - Radxa Rock 2 Square
+     - Tinker-RK3288
+     - Google Jerry
+     - Google Mickey
+     - Google Minnie
+     - Google Speedy
+     - Amarula Vyasa-RK3288
+* rk3328
+     - Rockchip RK3328 EVB
+     - Pine64 Rock64
+* rk3368
+     - GeekBox
+     - PX5 EVB
+     - Rockchip sheep board
+     - Theobroma Systems RK3368-uQ7 SoM
+* rk3399
+     - 96boards RK3399 Ficus
+     - 96boards Rock960
+     - Firefly-RK3399 Board
+     - Firefly ROC-RK3399-PC Board
+     - FriendlyElec NanoPC-T4
+     - FriendlyElec NanoPi M4
+     - FriendlyARM NanoPi NEO4
+     - Google Bob
+     - Khadas Edge
+     - Khadas Edge-Captain
+     - Khadas Edge-V
+     - Orange Pi RK3399 Board
+     - Pine64 RockPro64
+     - Radxa ROCK Pi 4
+     - Rockchip RK3399 Evaluation Board
+     - Theobroma Systems RK3399-Q7 SoM
+
+Building
+--------
+
+TF-A
+^^^^
+
+TF-A would require to build for ARM64 Rockchip SoCs platforms.
+
+To build TF-A::
+
+        git clone https://github.com/ARM-software/arm-trusted-firmware.git
+        cd arm-trusted-firmware
+        make realclean
+        make CROSS_COMPILE=aarch64-linux-gnu- PLAT=rk3399
+
+Specify the PLAT= with desired rockchip platform to build TF-A for.
+
+U-Boot
+^^^^^^
+
+To build rk3328 boards::
+
+        export BL31=/path/to/arm-trusted-firmware/to/bl31.elf
+        make evb-rk3328_defconfig
+        make
+
+To build rk3288 boards::
+
+        make evb-rk3288_defconfig
+        make
+
+To build rk3368 boards::
+
+        export BL31=/path/to/arm-trusted-firmware/to/bl31.elf
+        make evb-px5_defconfig
+        make
+
+To build rk3399 boards::
+
+        export BL31=/path/to/arm-trusted-firmware/to/bl31.elf
+        make evb-rk3399_defconfig
+        make
+
+Flashing
+--------
+
+SD Card
+^^^^^^^
+
+All rockchip platforms, except rk3128 (which doesn't use SPL) are now
+supporting single boot image using binman and pad_cat.
+
+To write an image that boots from an SD card (assumed to be /dev/sda)::
+
+        sudo dd if=u-boot-rockchip.bin of=/dev/sda seek=64
+        sync
+
+TODO
+----
+
+- Add rockchip idbloader image building
+- Add rockchip TPL image building
+- Document SPI flash boot
+- Describe steps for eMMC flashing
+- Add missing SoC's with it boards list
+
+.. Jagan Teki <jagan@amarulasolutions.com>
+.. Fri Jan 10 00:08:40 IST 2020