u-boot-2016.01移植

Posted 2021-01-22 zhu-g5may

1、了解uboot：
 阅读uboot源码顶层目录下的README.TXT可以提取如下信息：
     made to support booting of Linux images.   //引导内核程序
     make <board_name>_defconfig ：see boards.cfg for supported names
     check the file doc/README.scrapyard for a list of no longer supported boards
    
     lowlevel_init(): essential init to permit execution to reach board_init_f()
                    //底层硬件相关的初始化，没有global_data 和 BSS
     board_init_f()：set up the machine ready for running board_init_r():
                   //有global_data，栈位于SRAM，清除bss段
     board_init_r(): main execution, common code   
                   //有global_data 和 BSS，主要的执行程序，初始化SDRAM和UART
  
配置选项：
       配置文件在"include/configs/<board_name>.h"

      一般不要使能icache和dcache(configuration option CONFIG_CMD_CACHE)
单板初始化设置：
  - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
  - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
  - CONFIG_BOARD_LATE_INIT:    Call board_late_init()
  - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()  

修改源代码之后要相应地更新<board>/u-boot.lds*
底层硬件相关的配置：
在Makefile中需要配置CROSS_COMPILE

 

如果uboot没有支持我们所用的单板：
1.1、在boards.cfg中为你的单板添加新的配置选项，可以使用已经存在的单板作为参考;
1.2、新建一个目录以支持你的单板，单板目录下至少包含Makefilea, <board>.c, flash.c and u-boot.lds; 
1.3、为你的单板创建一个新的配置文件include/configs/<board>.h;
1.4、如果你是移植U-Boot到你的CPU, 也创建一个新的目录支持你CPU的特定程序
1.5、运行make <board>_defconfig
1.6、make
1.7、调试并且解决问题

Monitor Commands：
常用的：
    md - memory display
  mm - memory modify (auto-incrementing)
  nm - memory modify (constant address)
  mw - memory write (fill)
  nand - NAND memory operations (see doc/README.nand)
  erase - erase FLASH memory
  flinfo - print FLASH memory information
  bdinfo - print Board Info structure
  iminfo - print header information for application image
  coninfo - print console devices and informations
  bootm - boot application image from memory
  tftpboot- boot image via network using TFTP protocol
          and env variables "ipaddr" and "serverip"
          (and eventually "gatewayip")
不常用：
  cp - memory copy
    go - start application at address ‘addr‘
  run - run commands in an environment variable
  bootp - boot image via network using BootP/TFTP protocol
  bootz   - boot zImage from memory
  tftpput - upload a file via network using TFTP protocol
  rarpboot- boot image via network using RARP/TFTP protocol
  diskboot- boot from IDE devicebootd   - boot default, i.e., run ‘bootcmd‘
  loads - load S-Record file over serial line
  loadb - load binary file over serial line (kermit mode)
  cmp - memory compare
  crc32 - checksum calculation
  i2c - I2C sub-system
  sspi - SPI utility commands
  base - print or set address offset
  printenv- print environment variables
  setenv - set environment variables
  saveenv - save environment variables to persistent storage
  protect - enable or disable FLASH write protection
  ide - IDE sub-system
  loop - infinite loop on address range
  loopw - infinite write loop on address range
  mtest - simple RAM test
  icache - enable or disable instruction cache
  dcache - enable or disable data cache
  reset - Perform RESET of the CPU
  echo - echo args to console
  version - print monitor version
  help - print online help
 
环境变量的设置：
setenv: 设置环境变量
printenv: 打印环境变量
saveenv: 保存环境变量
设置列表：baudrate、bootdelay、bootcmd、bootargs、bootfile、ipaddr、serverip
uImage format：New uImage format (FIT) 、Old uImage format 
引导内核会打印内核相关信息：
     Checking Image at 40100000 ...
    Image Name:  2.2.13 for initrd on TQM850L
    Image Type:  PowerPC Linux Kernel Image (gzip compressed)
    Data Size:  335725 Bytes = 327 kB = 0 MB
    Load Address: 00000000
    Entry Point:  0000000c
    Verifying Checksum ... OK