Rockusb (Rockchip USB protocol)
  =====================================================
  
  Overview
  --------
  
  Rockusb protocol is widely used by Rockchip SoC based devices. It can
  read/write info, image to/from devices. This document briefly describes how to
  use Rockusb for upgrading firmware (e.g. kernel, u-boot, rootfs, etc.).
  
  Tools
  --------
  There are many tools can support Rockusb protocol. rkdeveloptool
  (https://github.com/rockchip-linux/rkdeveloptool) is open source,
  It is maintained by Rockchip. People don't want to build from source
  can download from here
  (https://github.com/rockchip-linux/rkbin/blob/master/tools/rkdeveloptool)
  
  Usage
  --------
  The Usage of Rockusb command is:
  
  rockusb <USB_controller> <devtype> <dev[:part]>
  
  e.g. rockusb 0 mmc 0
  
  On your U-Boot console, type this command to enter rockusb mode.
  On your host PC. use lsusb command. you should see a usb device
  using 0x2207 as its USB verdor id.
  
  for more detail about the rkdeveloptool. please read the usage.
  
  rkdeveloptool -h
  
  use rkdeveloptool wl command to write lba. BeginSec is the lba on device
  you want to write.
  
  sudo rkdeveloptool wl  <BeginSec> <File>
  
  to flash U-Boot image use below command. U-Boot binary is made by mkimage.
  see doc/README.rockchip for more detail about how to get U-Boot binary.
  
  sudo rkdeveloptool wl  64 <U-Boot binary>
  
  There are plenty of Rockusb command. but wl(write lba) and
  rd(reboot) command. These two command can let people flash
  image to device.
  
  To do
  -----
  * Fully support Rockusb protocol