hikey960: add document

Add document on HiKey960 platform and how to build.
Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>

docs/plat/hikey960.md

+
+Description
+====================
+  HiKey960 is one of 96boards. Hisilicon Hi3660 processor is installed on HiKey960.
+
+  More information are listed in [link](http://www.96boards.org/documentation/ConsumerEdition/HiKey960/README.md).
+
+
+How to build
+====================
+
+1. Code Locations
+-----------------
+
+   * ARM Trusted Firmware:
+   [link](https://github.com/ARM-software/arm-trusted-firmware)
+
+   * edk2:
+   [link](https://github.com/96boards-hikey/edk2/tree/testing/hikey960_v2.5)
+
+   * OpenPlatformPkg:
+   [link](https://github.com/96boards-hikey/OpenPlatformPkg/tree/testing/hikey960_v1.3.4)
+
+   * l-loader:
+   [link](https://github.com/96boards-hikey/l-loader/tree/testing/hikey960_v1.2)
+
+   * uefi-tools:
+   [link](https://github.com/96boards-hikey/uefi-tools/tree/hikey960_v1)
+
+
+2. Build Procedure
+------------------
+
+   * Fetch all the above 5 repositories into local host.
+     Make all the repositories in the same ${BUILD_PATH}.
+
+   * Create the symbol link to OpenPlatformPkg in edk2.
+     <br>`$cd ${BUILD_PATH}/edk2`</br>
+     <br>`$ln -sf ../OpenPlatformPkg`</br>
+
+   * Prepare AARCH64 toolchain.
+
+   * If your hikey960 hardware is v1, update _uefi-tools/platform.config_ first. _(optional)_
+     <br>__Uncomment the below sentence. Otherwise, UEFI can't output messages on serial
+     console on hikey960 v1.__</br>
+     <br>`BUILDFLAGS=-DSERIAL_BASE=0xFDF05000`</br>
+     <br>If your hikey960 hardware is v2 or newer, nothing to do.</br>
+
+   * Build it as debug mode. Create script file for build.
+     <br>`BUILD_OPTION=DEBUG`</br>
+     <br>`export AARCH64_TOOLCHAIN=GCC48`</br>
+     <br>`export UEFI_TOOLS_DIR=${BUILD_PATH}/uefi-tools`<br>
+     <br>`export EDK2_DIR=${BUILD_PATH}/edk2`</br>
+     <br>`EDK2_OUTPUT_DIR=${EDK2_DIR}/Build/HiKey960/${BUILD_OPTION}_${AARCH64_TOOLCHAIN}`</br>
+     <br>`cd ${EDK2_DIR}`</br>
+     <br>`# Build UEFI & ARM Trust Firmware`</br>
+     <br>`${UEFI_TOOLS_DIR}/uefi-build.sh -b ${BUILD_OPTION} -a ../arm-trusted-firmware hikey960`</br>
+     <br>`# Generate l-loader.bin`</br>
+     <br>`cd ${BUILD_PATH}/l-loader`</br>
+     <br>`ln -sf ${EDK2_OUTPUT_DIR}/FV/bl1.bin`</br>
+     <br>`ln -sf ${EDK2_OUTPUT_DIR}/FV/fip.bin`</br>
+     <br>`ln -sf ${EDK2_OUTPUT_DIR}/FV/BL33_AP_UEFI.fd`</br>
+     <br>`python gen_loader.py -o l-loader.bin --img_bl1=bl1.bin --img_ns_bl1u=BL33_AP_UEFI.fd`</br>
+
+   * Generate partition table.
+     <br>_Make sure that you're using the sgdisk in the l-loader directory._</br>
+     <br>`$PTABLE=aosp-32g SECTOR_SIZE=4096 SGDISK=./sgdisk bash -x generate_ptable.sh`</br>
+
+
+3. Setup Console
+----------------
+
+   * Install ser2net. Use telnet as the console since UEFI will output window
+     that fails to display in minicom.
+     <br>`$sudo apt-get install ser2net`</br>
+
+   * Configure ser2net.
+     <br>`$sudo vi /etc/ser2net.conf`</br>
+     <br>Append one line for serial-over-USB in below.</br>
+     <br>_#ser2net.conf_</br>
+     <br>`2004:telnet:0:/dev/ttyUSB0:115200 8DATABITS NONE 1STOPBIT banner`</br>
+
+   * Open the console.
+     <br>`$telnet localhost 2004`</br>
+     <br>And you could open the console remotely, too.</br>
+
+
+4. Boot UEFI in recovery mode
+-----------------------------
+
+   * Fetch that are used in recovery mode. The code location is in below.
+     [link](https://github.com/96boards-hikey/tools-images-hikey960)
+
+   * Generate l-loader.bin.
+     <br>`$cd tools-images-hikey960`</br>
+     <br>`$ln -sf ${BUILD_PATH}/l-loader/l-loader.bin`</br>
+
+   * Prepare config file.
+     <br>_$vi config_</br>
+     <br>_# The content of config file_</br>
+     <br>`./sec_user_xloader.img 0x00020000`</br>
+     <br>`./sec_uce_boot.img 0x6A908000`</br>
+     <br>`./l-loader.bin 0x1AC00000`</br>
+
+   * Remove the modemmanager package. This package may causes hikey_idt tool failure.
+     <br>`$sudo apt-get purge modemmanager`</br>
+
+   * Run the command to download l-loader.bin into HiKey960.
+     <br>`$sudo ./hikey_idt -c config -p /dev/ttyUSB1`</br>
+
+   * UEFI running in recovery mode.
+     <br>When prompt '.' is displayed on console, press hotkey 'f' in keyboard. Then Android fastboot app is running.</br>
+     <br>The timeout of prompt '.' is 10 seconds.</br>
+
+   * Update images.
+     <br>`$sudo fastboot flash ptable prm_ptable.img`</br>
+     <br>`$sudo fastboot flash xloader sec_xloader.img`</br>
+     <br>`$sudo fastboot flash fastboot l-loader.bin`</br>
+     <br>`$sudo fastboot flash fip fip.bin`</br>
+     <br>`$sudo fastboot flash boot boot.img`</br>
+     <br>`$sudo fastboot flash cache cache.img`</br>
+     <br>`$sudo fastboot flash system system.img`</br>
+     <br>`$sudo fastboot flash userdata userdata.img`</br>
+
+   * Notice: UEFI could also boot kernel in recovery mode, but BL31 isn't loaded in
+     recovery mode.
+
+
+5. Boot UEFI in normal mode
+-----------------------------
+
+   * Make sure "Boot Mode" switch is OFF for normal boot mode. Then power on HiKey960.
+
+   * Reference [link](https://github.com/96boards-hikey/tools-images-hikey960/blob/master/build-from-source/README-ATF-UEFI-build-from-source.md)