常用u-boot命令详解（全）
（1）获取帮助
命令：help 或 ?
功能：查看当前U-boot版本中支持的所有命令。
| [u-boot@MINI2440]# help ? - alias for 'help' askenv - get environment variables from stdin base - print or set address offset bdinfo - print Board Info structure bmp - manipulate BMP p_w_picpath data boot - boot default, i.e., run 'bootcmd' bootd - boot default, i.e., run 'bootcmd' bootelf - Boot from an ELF p_w_picpath in memory bootm - boot application p_w_picpath from memory bootp - boot p_w_picpath via network using BOOTP/TFTP protocol bootvx - Boot vxWorks from an ELF p_w_picpath cmp - memory compare coninfo - print console devices and information cp - memory copy crc32 - checksum calculation date - get/set/reset date & time dcache - enable or disable data cache dhcp - boot p_w_picpath via network using DHCP/TFTP protocol echo - echo args to console editenv - edit environment variable eeprom - EEPROM sub-system erase - erase FLASH memory exit - exit script fatinfo - print information about filesystem fatload - load binary file from a dos filesystem fatls - list files in a directory (default /) flinfo - print FLASH memory information fsinfo - print information about filesystems fsload - load binary file from a filesystem p_w_picpath go - start application at address 'addr' help - print online help i2c - I2C sub-system icache - enable or disable instruction cache iminfo - print header information for application p_w_picpath imls - list all p_w_picpaths found in flash imxtract- extract a part of a multi-p_w_picpath itest - return true/false on integer compare loadb - load binary file over serial line (kermit mode) loads - load S-Record file over serial line loadx - load binary file over serial line (xmodem mode) loady - load binary file over serial line (ymodem mode) loop - infinite loop on address range ls - list files in a directory (default /) md - memory display mm - memory modify (auto-incrementing address) mmc - MMC sub-system mtest - simple RAM read/write test mw - memory write (fill) nand - NAND sub-system nboot - boot from NAND device nfs - boot p_w_picpath via network using NFS protocol nm - memory modify (constant address) ping - send ICMP ECHO_REQUEST to network host printenv- print environment variables protect - enable or disable FLASH write protection rarpboot- boot p_w_picpath via network using RARP/TFTP protocol reginfo - print register information reset - Perform RESET of the CPU run - run commands in an environment variable saveenv - save environment variables to persistent storage setenv - set environment variables showvar - print local hushshell variables sleep - delay execution for some time source - run script from memory test - minimal test like /bin/sh tftpboot- boot p_w_picpath via network using TFTP protocol unzip - unzip a memory region usb - USB sub-system usbboot - boot from USB device version - print monitor version |
如果你想获取某条命令的更详细的帮助，可以使用：
| help <你想要查的指令> 或者 ? <你想要查的指令> ， 甚至 h <你想要查的指令缩写>。 |
以bmp指令为例：
| [u-boot@MINI2440]# help bmp bmp - manipulate BMP p_w_picpath data Usage: bmp info <p_w_picpathAddr> - display p_w_picpath info bmp display <p_w_picpathAddr> [x y] - display p_w_picpath at x,y [u-boot@MINI2440]# ? bmp bmp - manipulate BMP p_w_picpath data Usage: bmp info <p_w_picpathAddr> - display p_w_picpath info bmp display <p_w_picpathAddr> [x y] - display p_w_picpath at x,y [u-boot@MINI2440]# h bm bmp - manipulate BMP p_w_picpath data Usage: bmp info <p_w_picpathAddr> - display p_w_picpath info bmp display <p_w_picpathAddr> [x y] - display p_w_picpath at x,y |
（2）环境变量（environment variables，简称ENV）与相关指令
和shell类似，U-Boot也有环境变量。一些U-boot默认的环境变量如下：
|
环 境 变 量
|
解 释 说 明
|
| bootdelay | 执行自动启动（bootcmd中的命令）的等候秒数 |
| baudrate | 串口控制台的波特率 |
| netmask | 以太网的网络掩码 |
| ethaddr | 以太网的MAC地址 |
| bootfile | 默认的下载文件名 |
| bootargs | 传递给Linux内核的启动参数 |
| bootcmd | 自动启动时执行命令 |
| serverip | TFTP服务器端的IP地址 |
| ipaddr | 本地的IP地址 |
| stdin | 标准输入设备，一般是串口 |
| stdout | 标准输出，一般是串口，也可是LCD（VGA） |
| stderr | 标准出错，一般是串口，也可是LCD（VGA） |
ENV可以放在许多固体存储器中，对于mini2440来说Nor Flash、Nand Flash或EEPROM都可以，就看你如何配置了（include/configs下的配置文件）。例如：
Nor Flash
：
| #define CONFIG_ENV_IS_IN_FLASH 1 #define CONFIG_ENV_OFFSET 0X40000 #define CONFIG_ENV_SIZE 0x20000 /* Total Size of Environment Sector */ |
Nand Flash：
| #define CONFIG_ENV_IS_IN_NAND 1 #define CONFIG_ENV_OFFSET 0X40000 #define CONFIG_ENV_SIZE 0x20000 /* Total Size of Environment Sector */ |
EEPROM：
| #define CONFIG_ENV_IS_IN_EEPROM 1 /* use EEPROM for environment vars */ #define CONFIG_ENV_OFFSET 0x000 /* environment starts at offset 0 */ #define CONFIG_ENV_SIZE 0x400 /* 1KB */ |
CONFIG_ENV_OFFSET是在整个存储器中的偏移地址；
CONFIG_ENV_SIZE是指其使用的大小。
注意 CONFIG_ENV_OFFSET和 CONFIG_ENV_SIZE 的设置，不要覆盖了其他分区。
四、U-boot的使用（二）
命令：
loadb - load binary file over serial line (kermit mode)
loadx - load binary file over serial line (xmodem mode)
loady - load binary file over serial line (ymodem mode)
功能：以不同的协议从串口获取文件.。
格式基本都为：
load？ [ off ] [ baud ]
第1个参数是下载到SDRAM的地址，如果不填，就是用默认配置：CONFIG_SYS_LOAD_ADDR
第2个参数是波特率，一般不填，用默认的115200.
在windows下的超级终端可以用这些协议发送文件，但是在ubuntu下基本只能用kermit协议。一下使用C-kermit来发送一个文件到mini2440。
| [u-boot@MINI2440]# loadb ## Ready for binary (kermit) download to 0x30008000 at 115200 bps... |
上面已经启动了U-boot的kermit传输协议，这时按下 Ctrl + \ , 再按 c, 切换到C-kermit的命令行模式，输入命令：send <文件路径>，回车。
| [u-boot@MINI2440]# loadb ## Ready for binary (kermit) download to 0x30008000 at 115200 bps... (Back at MAGI-Linux) ---------------------------------------------------- C-Kermit 8.0.211, 10 Apr 2004, for Linux Copyright (C) 1985, 2004, Trustees of Columbia University in the City of New York. Type ? or HELP for help. (/home/tekkaman/桌面/) C-Kermit>send/home/tekkaman/development/share/zImage.img |
C-kermit就开始传送，并且显示一个传送界面，并动态显示传送进度。
| C-Kermit 8.0.211, 10 Apr 2004, MAGI-Linux Current Directory: /home/tekkaman/��~L�~]� Communication Device: /dev/ttyUSB0 Communication Speed: 115200 Parity: none RTT/Timeout: 01 / 02 SENDING: /home/tekkaman/development/share/zImage.img => zImage.img File Type: BINARY File Size: 2277540 Percent Done: 19 /////////- ...10...20...30...40...50...60...70...80...90..100 Estimated Time Left: 00:03:35 Transfer Rate, CPS: 8536 Window Slots: 1 of 1 Packet Type: D Packet Count: 557 Packet Length: 1000 Error Count: 0 Last Error: Last Message: X to cancel file, Z to cancel group, <CR> to resend last packet, E to send Error packet, ^C to quit immediately, ^L to refresh screen. |
传送完毕后，输入c ，回到U-boot的串口界面。
| [u-boot@MINI2440]# loadb ## Ready for binary (kermit) download to 0x30008000 at 115200 bps... (Back at MAGI-Linux) ---------------------------------------------------- C-Kermit 8.0.211, 10 Apr 2004, for Linux Copyright (C) 1985, 2004, Trustees of Columbia University in the City of New York. Type ? or HELP for help. (/home/tekkaman/桌面/) C-Kermit>send/home/tekkaman/development/share/zImage.img (/home/tekkaman/桌面/) C-Kermit>c Connecting to /dev/ttyUSB0, speed 115200 Escape character: Ctrl-\ (ASCII 28, FS): enabled Type the escape character followed by C to get back, or followed by ? to see other options. ---------------------------------------------------- ## Total Size = 0x0022c0a4 = 2277540 Bytes ## Start Addr = 0x30008000 |
