uboot移植之迷雾解码

按照蜗窝科技的步骤执行

一、有关硬件描述的填空题

1）CPU上电后，从哪种设备（       BOOTROM         ）的哪个地址（        0x0000_0000       ）开始执行。

2）用（                ）方式，可以让CPU进入USB download（或者UART download）模式。 no

3）进入USB download之后，设备使用哪个USB接口（        ）和主机通信。no

4）进入download模式后，哪一段地址范围（通常为SRAM）可以用来执行程序：（                ）~（                ），size有多大（                ）。

5）用什么协议（                ）可以通过USB将bin文件上传到指定的地址。no

6）用什么协议（                ）可以让CPU跳转到到指定地址继续执行。no

二、基本符号的定义

Board                ->  ql10_demo
Vendor              ->  fmxx
Machine(SoC)    ->  fmql10
Arch                  ->  arm
CPU                  ->  armv7

三、目录结构及K从Kconfig的确定

1）在board/目录中创建“fmxx/ql10_demo” 目录，并提供Kconfig和Makefile文件

mkdir -p board/fmxx/ql10_demo
touch board/fmxx/ql10_demo/Kconfig
touch board/fmxx/ql10_demo/Makefile

2）在arch/arm/Kconfig中，添加配置菜单
config TARGET_QL10_DEMO
       bool "Support fmxx ql10 demo board"
       select CPU_V7A
       select SUPPORT_SPL
       select SPL
       help
         Support for ql10 demo board platform based on fmxx  ql10 Psoc,
         with 4xA7 CPU, 1GB DDR.

endchoice

source "board/fmxx/ql10_demo/Kconfig"

3）根据符号定义，在board/fmxx/ql10_demo/Kconfig中，添加如下配置项：
if TARGET_QL10_DEMO

config SYS_BOARD
    default "ql10_demo"

config SYS_VENDOR
    default "fmxx"

config SYS_SOC
    default "fmql10"

config SYS_CONFIG_NAME
    default "ql10_demo"
endif

vi doc/README.kconfig
以上README中有大致的流程

Conversion from boards.cfg to Kconfig
-------------------------------------

Prior to Kconfig, boards.cfg was a primary database that contained Arch, CPU,
SoC, etc. of all the supported boards.  It was deleted when switching to
Kconfig.  Each field of boards.cfg was converted as follows:

Status      ->  "S:" entry of MAINTAINERS
 Arch        ->  CONFIG_SYS_ARCH defined by Kconfig　　
 CPU         ->  CONFIG_SYS_CPU defined by Kconfig
 SoC         ->  CONFIG_SYS_SOC defined by Kconfig
 Vendor      ->  CONFIG_SYS_VENDOR defined by Kconfig
 Board       ->  CONFIG_SYS_BOARD defined by Kconfig
 Target      ->  File name of defconfig (configs/<target>_defconfig)
 Options     ->  CONFIG_SYS_EXTRA_OPTIONS defined by Kconfig
 Maintainers ->  "M:" entry of MAINTAINERS

################# tips ####################

1.Arch       arm

arch/arm/Kconfig中

config SYS_ARCH
    default "arm"

2.CPU        armv7

arch/arm/Kconfig

config SYS_CPU
    default "armv7" if CPU_V7A

3.SoC        fmql10

Define CONFIG_SYS_SOC="soc" to compile arch/<arch>/cpu/<cpu>/<soc> 其实并没有这个目录

4.Vendor     fmxx

Define CONFIG_SYS_VENDOR="vendor" to compile board/<vendor>/common/*
         and board/<vendor>/<board>/*

5.Board      ql10_demo

Define CONFIG_SYS_BOARD="board" to compile board/<board>/*
         (or board/<vendor>/<board>/* if CONFIG_SYS_VENDOR is defined)

6.Target     ql10_demo

Define CONFIG_SYS_CONFIG_NAME="target" to include
         include/configs/<target>.h

Add configs/<target>_defconfig

Tips to add/remove boards
-------------------------

When adding a new board, the following steps are generally needed:

[1] Add a header file include/configs/<target>.h
 [2] Make sure to define necessary CONFIG_SYS_* in Kconfig:
       Define CONFIG_SYS_CPU="cpu" to compile arch/<arch>/cpu/<cpu>
       Define CONFIG_SYS_SOC="soc" to compile arch/<arch>/cpu/<cpu>/<soc>
       Define CONFIG_SYS_VENDOR="vendor" to compile board/<vendor>/common/*
         and board/<vendor>/<board>/*
       Define CONFIG_SYS_BOARD="board" to compile board/<board>/*
         (or board/<vendor>/<board>/* if CONFIG_SYS_VENDOR is defined)
       Define CONFIG_SYS_CONFIG_NAME="target" to include
         include/configs/<target>.h
 [3] Add a new entry to the board select menu in Kconfig.
     The board select menu is located in arch/<arch>/Kconfig or
     arch/<arch>/*/Kconfig.
 [4] Add a MAINTAINERS file
     It is generally placed at board/<board>/MAINTAINERS or
     board/<vendor>/<board>/MAINTAINERS
 [5] Add configs/<target>_defconfig

When removing an obsolete board, the following steps are generally needed:

[1] Remove configs/<target>_defconfig
 [2] Remove include/configs/<target>.h if it is not used by any other boards
 [3] Remove board/<vendor>/<board>/* or board/<board>/* if it is not used
     by any other boards
 [4] Update MAINTAINERS if necessary
 [5] Remove the unused entry from the board select menu in Kconfig
 [6] Add an entry to doc/README.scrapyard

根据README的描述，定义上述配置项之后，u-boot会编译如下的目录：

Define CONFIG_SYS_CPU="cpu" to compile arch//cpu/
        arch/arm/cpu/armv8
        Q：并没有看到CONFIG_SYS_CPU的定义？
        A：在“arm/Kconfig”中定义，“default "armv8" if ARM64”，这就是为什么在上面Target定义中“select ARM64”的原因。

Define CONFIG_SYS_SOC="soc" to compile arch//cpu//
        arch/arm/cpu/armv8/s900
        Q：如果该目录不存在，是否还会编译？
        A：应该不会。

Define CONFIG_SYS_VENDOR="vendor" to compile board//common/* and board///*
        board/actions/common/*
        board/actions/bubblegum/*

Define CONFIG_SYS_CONFIG_NAME="target" to include include/configs/.h
        include/configs/bubblegum.h

4）创建该板子有关的配置头文件

include/configs/ql10_demo.h

#ifndef __QL10_DEMO_H
#define __QL10_DEMO_H

#endif

5）使用menuconfig，生成.config，并保存为ql10_demo_defconfig

cd ~/work/x_project/u-boot

make menuconfig

配置Architecture和Target：

Architecture select (ARM architecture)  --->

ARM architecture  --->
    Target select (Support Bubblegum 96Board)  --->

关闭Command line interface配置项下面所有的内容：

Command line interface  --->

其它暂时用默认值，保存退出，得到.config文件，然后另存为ql10_demo_defconfig

cp .config configs/ql10_demo_defconfig

四、尝试编译一次