Uboot的使用-1

xiaoxiao2021-12-14 19

一、什么是uboot U-Boot -- the Universal Boot Loader u---通用的，所谓的通用： 1、支持多种架构的CPU：x86、powerPC、ARM、MIPS.... 2、支持多种CPU的电子板：mini2440、smdkv210、smdk2410....... 3、支持多种操作系统，如：linux、wince、vxworks...... boot是一个bootloader 1、boot 做CPU级初始化、板级初始化，完成一个硬件平台的启动 2、loader 加载操作系统内容，并启动内核.....，后面与uboot没有任何关系 uboot是一个源码开放的bootloader，源码可以随意修改，并免费使用。 uboot的官网： ftp://ftp.denx.de/pub/u-boot/ http://www.denx.de/wiki/U-Boot/WebHome 注意：我们uboot官网下载源码的时候，该uboot源码必须支持Samsung S5PV210，最好能支持基于S5PV210的某个电子板（SMDKV210）. ================================================================== ======================================= 二、uboot的使用 1、查看uboot支持的命令 GEC210 # ? GEC210 # help ? - alias for 'help' autoscr - run script from memory base - print or set address offset bdinfo - print Board Info structure boot - boot default, i.e., run 'bootcmd' bootd - boot default, i.e., run 'bootcmd' bootelf - Boot from an ELF image in memory bootm - boot application image from memory bootp - boot image via network using BootP/TFTP protocol bootvx - Boot vxWorks from an ELF image cmp - memory compare coninfo - print console devices and information cp - memory copy crc32 - checksum calculation dcache - enable or disable data cache dhcp - invoke DHCP client to obtain IP/boot params dnw - initialize USB device and ready to receive for Windows server (specific) echo - echo args to console erase - erase FLASH memory exit - exit script ext2format - disk format by ext2 ext2load- load binary file from a Ext2 filesystem ext2ls - list files in a directory (default /) ext3format - disk format by ext3 ext4format - disk format by ext4 fastboot- use USB Fastboot protocol fatformat - disk format by FAT32 fatinfo - print information about filesystem fatload - load binary file from a dos filesystem fatls - list files in a directory (default /) fdisk - fdisk for sd/mmc. flinfo - print FLASH memory information go - start application at address 'addr' help - print online help icache - enable or disable instruction cache iminfo - print header information for application image imls - list all images found in flash imxtract- extract a part of a multi-image itest - return true/false on integer compare loadb - load binary file over serial line (kermit mode) loads - load S-Record file over serial line loady - load binary file over serial line (ymodem mode) loop - infinite loop on address range md - memory display mm - memory modify (auto-incrementing) MMC sub systemprint MMC informationmovi - sd/mmc r/w sub system for SMDK board mtest - simple RAM test mw - memory write (fill) nand - NAND sub-system nfs - boot image 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 image via network using RARP/TFTP protocol reset - Perform RESET of the CPU reginfo - print register information reset - Perform RESET of the CPU run - run commands in an environment variable saveenv - save environment variables to persistent storage sdfuse - read images from FAT partition of SD card and write them to booting device. setenv - set environment variables sleep - delay execution for some time test - minimal test like /bin/sh tftpboot- boot image via network using TFTP protocol version - print monitor version 以上命令是uboot通用的命令，与具体的硬件平台和操作系统没有关系。我们可不可以向uboot中，增加一个命令？？？可以！！ 2、version GEC210 # version U-Boot 1.3.4 (Aug 9 2013 - 15:03:53) for GEC210 3、bdinfo（bd） GEC210 # bdinfo arch_number = 0x00000998 //uboot针对board的一个ID号，会与kernel对应ID做对比，如果相符，内核就会启动。 env_t = 0x00000000 boot_params = 0x30000100 //uboot在启动kernel的时候，会传递参数给 kernel，uboot将参数放在0x30000100地址上 DRAM bank = 0x00000000 //DDR2 ch0 -> start = 0x30000000 -> size = 0x10000000 DRAM bank = 0x00000001 //DDR2 ch1 -> start = 0x40000000 -> size = 0x10000000 ethaddr = 00:40:5C:26:0A:5B //MAC地址 ip_addr = 192.168.1.190 //ip地址 baudrate = 115200 bps //串口的波特率 4、printenv（pri） GEC210 # printenv baudrate=115200 ethaddr=00:40:5c:26:0a:5b netmask=255.255.255.0 bootargs=console=ttySAC0,115200 init=/linuxrc root=/dev/mtdblock4 rootfstype=yaffs rw machid=0x998 ipaddr=192.168.1.190 gatewayip=192.168.1.1 bootdelay=5 bootcmd=nand read 0x30008000 0x600000 0x500000;bootm 0x30008000 serverip=192.168.1.9 stdin=serial stdout=serial stderr=serial 1）bootargs ----启动参数 args ---arguments 告诉内核，如何找到rootfs，并且启动linux的第一个进程（init）（1）console=ttySAC0,115200 //内核使用的控制台是uart0，115200bps （2）init=/linuxrc 启动的linux第一个进程是/linuxrc ，即启动shell 命令环境 lrwxrwxrwx 1 root root 11 Sep 5 2012 linuxrc -> bin/busybox busybox---->生成shell工具（3）root=/dev/mtdblock4 //存放的是rootfs（nand的第四个分区），告诉内核去哪里挂在rootfs [root@YueQian /]# ls /dev/mtdblock4 -l brw-rw---- 1 root root 31, 4 Jan 1 13:08 /dev/mtdblock4 //nand flash的第四个分区（4）rootfstype=yaffs rw 挂在的rootfs的格式，并且是可读写的。 #setenv bootargs 'console=ttySAC0,115200 init=/linuxrc root=/dev/mtdblock4 rootfstype=yaffs rw' #saveenv 2）machid=0x998 uboot针对该平台的机器ID #setenv machid 0x999 3)ipaddr=192.168.1.190 //GEC210平台IP #setenv ipaddr 192.168.1.110 #saveenv 4）gatewayip=192.168.1.1 #setenv gatewayip 192.168.1.1 #saveenv 5）serverip=192.168.1.9 #setenv serverip 192.168.1.9 #saveenv 技巧： # setenv severip 192.168.1.9 #setenv severip #saveenv 6）bootdelay=5 //启动操作系统的等待时间 #setenv bootdelay 3 #saveenv 7）bootcmd 启动命令 cmd ---command 告诉uboot去哪里找内核映像（uImage/zImage）,并且启动内核映像（1）read 0x30008000 0x600000 0x500000; 从nand flash的0x600000地址拷贝0x500000大小的内容（linux的内核映像）到DDR2内存的0x30008000地址下（2）bootm 0x30008000 从0x30008000地址上开始启动内核映像从nand中启动内核 #setenv bootcmd 'nand read 0x30008000 0x600000 0x500000;bootm 0x30008000' #saveenv 自动下载裸机程序，并启动裸机程序 #setenv bootcmd 'tftp 0x30000000 led.bin; go 0x30000000' #saveenv 从网络启动内核映像 #setenv bootcmd 'tftp 0x30008000 uImage; bootm 0x30008000' #saveenv ================================================================== ======================================= 三、如何应用uboot去更新u-boot.bin、zImage、rootfs.img 思路：先使用tftp将要更新的文件下载到DDR2内存中，然后在进行nand的烧写 1、如何更新uboot #tftp 0x400000000 u-boot.bin #nand erase 0x0 0x100000 #nand write 0x40000000 0x0 0x100000 2、使用uboot更新自zImage #tftp 0x40000000 zImage #nand erase 0x600000 0x500000 #nand write 0x40000000 0x600000 0x500000 3、使用uboot更新rootfs #tftp 0x40000000 rootfs.img #nand erase 0xe00000 0xf200000 //242MB #nand write.yaffs 0x40000000 0xe00000 0xxxxx //0xxxx--->实际的下载大小，tftp的传输后的报告 ================================================================== ======================================= 四、uboot输出 stage1：相当于BL1，这段代码完成CPU级初始化，最关键初始化时钟和内存，该阶段代码是汇编写的。 stage2：相当于BL2，使用C做的，这部分代码都是通用的代码。主要是完成 uboot工具和操作系统的启动..... //1、在ARM汇编，BL1 OK //2、BL2 U-Boot 1.3.4 (Aug 9 2013 - 15:03:53) for GEC210 CPU: S5PV210@1000MHz(OK) APLL = 1000MHz, HclkMsys = 200MHz, PclkMsys = 100MHz MPLL = 667MHz, EPLL = 96MHz HclkDsys = 166MHz, PclkDsys = 83MHz HclkPsys = 133MHz, PclkPsys = 66MHz SCLKA2M = 200MHz Serial = CLKUART Board: GEC210 DRAM: 512 MB Flash: 8 MB //nor flash SD/MMC: 3724MB NAND: 256 MB In: serial Out: serial Err: serial backlight_brigness_init Enter into Normal mode Hit any key to stop autoboot: 0 //3、去启动设备（nand flash、SD卡），找内核映像（uImage、zImage）,拷贝到DDR2内存中 NAND read: device 0 offset 0x600000, size 0x500000 Main area read (40 blocks): 5242880 bytes read: OK get_format //4、uboot去分析内核映像文件的头（uImage） -------- 1 -------- ## Booting kernel from Legacy Image at 30008000 ... Image Name: linux-2.6.35.7 Created: 2013-07-02 7:40:27 UTC Image Type: ARM Linux Kernel Image (uncompressed) Data Size: 4065428 Bytes = 3.9 MB Load Address: 30008000 //加载地址 Entry Point: 30008040 //入口地址 Verifying Checksum ... OK get_format -------- 1 -------- XIP Kernel Image ... OK OK Using machid 0x998 from environment //5、启动内核 Starting kernel ... Uncompressing Linux... done, booting the kernel. //6、调用了kernel [ 0.000000] Initializing cgroup subsys cpu [ 0.000000] Linux version 2.6.35.7-GEC210 (root@localhost.localdomain) (gcc version 4.4.1 (Sourcery G++ Lite 2009q3-67) ) #183 PREEMPT Tue Jul 2 15:38:19 CST 2013 [ 0.000000] CPU: ARMv7 Processor [412fc082] revision 2 (ARMv7), cr=10c53c7f [ 0.000000] CPU: VIPT nonaliasing data cache, VIPT nonaliasing instruction cache

[ 0.000000] Machine: GEC210

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