rk35xx-android12/u-boot/board/rockchip/nanopi_r2

Introduction
============

RK3328 key features we might use in U-Boot:
* CPU: ARMv8 64bit quad-core Cortex-A53
* IRAM: 36KB
* DRAM: 4GB-16MB dual-channel
* eMMC: support eMMC 5.0/5.1, suport HS400, HS200, DDR50
* SD/MMC: support SD 3.0, MMC 4.51
* USB: USB2.0 EHCI host port *2
* Display: RGB/HDMI/DP/MIPI/EDP

NanoPi R2 key features:
* regulator: pwm regulator for CPU B/L
* PMIC: rk808
* debug console: UART2

In order to support Arm Trust Firmware(ATF), we need to use the
miniloader from rockchip which:
* do DRAM init
* load and verify ATF image
* load and verify U-Boot image

Here is the step-by-step to boot to U-Boot on rk3328.

Get the Source and prebuild binary
==================================

  > mkdir ~/nanopi_r2
  > cd ~/nanopi_r2
  > git clone https://github.com/ARM-software/arm-trusted-firmware.git
  > git clone https://github.com/rockchip-linux/rkbin
  > git clone https://github.com/rockchip-linux/rkflashtool

Compile ATF
===============

  > cd arm-trusted-firmware
  > make realclean
  > make CROSS_COMPILE=aarch64-linux-gnu- PLAT=rk3328 bl31

Compile U-Boot
==================

  > cd ../u-boot
  > make CROSS_COMPILE=aarch64-linux-gnu- nanopi_r2_defconfig all

Compile rkflashtool
=======================

  > cd ../rkflashtool
  > make

Package image for miniloader
================================
  > cd ..
  > cp arm-trusted-firmware/build/rk3328/release/bl31.bin rkbin/rk33
  > ./rkbin/tools/trust_merger rkbin/tools/RK3328TRUST.ini
  > ./rkbin/tools/loaderimage --pack --uboot u-boot/u-boot-dtb.bin uboot.img
  > mkdir image
  > mv trust.img ./image/
  > mv uboot.img ./image/nanopi_r2-uboot.bin

Flash image
===============
Power on(or reset with RESET KEY) with MASKROM KEY preesed, and then:

  > ./rkflashtool/rkflashloader nanopi_r2

You should be able to get U-Boot log message in console/UART2 now.