1. Preface
U-boot is an open source bootloader, which is used to guide operations and provide developers with testing and debugging tools. It is a simplified Linux system, which is mainly responsible for the initialization and boot of hardware. It has some tools as the boot program, often as the boot of embedded devices. When the real system starts running, u-boot hands over the management authority.
Reasons for choosing U-Boot:
① Open source;
② Support a variety of embedded operating system cores, such as Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS, android;
③ Support multiple processor series, such as PowerPC, ARM, x86 and MIPS;
④ High reliability and stability;
⑤ Highly flexible function settings, suitable for U-Boot debugging, different boot requirements of operating system, product release, etc;
⑥ Rich device driver source code, such as serial port, Ethernet, SDRAM, FLASH, LCD, NVRAM, EEPROM, RTC, keyboard, etc;
⑦ Rich development and debugging documents and strong network technical support;
U-BOOT working mode
The working modes of U-Boot include startup loading mode and download mode. Boot loading mode is the normal working mode of bootloader. When the embedded product is released, bootloader must work in this mode. Bootloader loads the embedded operating system from FLASH to SDRAM for operation, and the whole process is automatic. The download mode is that the bootloader downloads the kernel image or root file system image from the PC to the FLASH of the target board through some communication means. Users can use some command interfaces provided by bootloader to complete their desired operations.
At present, the development board for testing uboot command is friendly arm tin441, which uses Samsung's EXYNOS4412. This article focuses on the command function and usage of uboot command line. The uboot version used is 2010.12, which is officially provided by friendly arm.
2. Introduction to uboot command
2.1 help command – help
See which commands are currently supported by UBOOT.
TINY4412 # help ? - alias for 'help' base - Print a set of address offsets bdinfo - Information structure of development board boot - boot default, i.e., run 'bootcmd' bootd - boot default, i.e., run 'bootcmd' bootelf - Boot from an ELF image in memory bootm - Launching an application from memory bootp - through the use of BOOTP / TFTP Network boot image of protocol bootvx - Boot vxWorks from an ELF image chpart - Change active partition cmp - memory compare coninfo - print console devices and information cp - Memory Copy crc32 - Calculation of inspection and dcache - Enable or disable data caching dnw - dnw - USB The device is initialized and ready to accept Windows server(Specific) echo - echo args to console editenv - Modify environment variables emmc - open/close eMMC Boot partition env - Environment processing command exit - Exit script ext2format- ext2 ext2format-Disk format ext2load- from Ext2 File system loading binaries ext2ls - List files in a directory(default/) ext3format- ext3 ext3format-Disk format false - Do nothing,But it didn't succeed fastboot- fastboot-use USB fastboot agreement fatformat- FAT32 fatformat-Disk format fatinfo - fatinfo-Print file system information fatload - fatload-from dos File system for loading binary files fatls - A directory list file(default/) fdisk - fdisk for sd/mmc. go - In“ addr"application was launched help - Print command description/Use help icache - enable or disable instruction cache iminfo - print header information for application image 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 address) mmc - MMC Subsystem mmcinfo - mmcinfo <dev num>-- display MMC info movi - movi - sd/mmc r/w sub system for SMDK board mtdparts- define flash/nand partitions mtest - simple RAM read/write test mw - memory write (fill) 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 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 image via network using TFTP protocol true - do nothing, successfully usb - USB sub-system version - print monitor version
2.2 view the usage of specific commands – help
Format:
Help < instructions you want to check >
Or< The command you want to check >,
Even h < the instruction abbreviation you want to check >.
TINY4412 # help sleep
sleep - Delay execution for a period of time
Usage:
sleep N
- Delayed execution N second(N yes_decimal_ ! ! !)
2.3 print environment variable – printenv
TINY4412 # printenv baudrate=115200 bootargs=root=/dev/nfs nfsroot=192.168.18.3:/work/rootfs ip=192.168.18.123:192.168.18.3:192.168.18.1:255.255.255.0::eth0:off init=/linuxrc console=ttySAC0,115200 bootcmd=movi read kernel 0 40008000;movi read rootfs 0 41000000 400000;bootm 40008000 41000000 bootdelay=3 ethaddr=00:40:5c:26:0a:5b gatewayip=192.168.0.1 ipaddr=192.168.0.20 netmask=255.255.255.0 serverip=192.168.0.10 Environment size: 416/16380 bytes
baudrate: current baud rate. Generally not modified.
bootcmd: start command.
bootdelay: the time to delay the execution of the boot CMD command.
ethaddr: MAC address of network card.
Gateway IP: gateway IP address.
ipaddr: the IP address of the development board.
netmask: subnet mask.
serverip: server IP (generally the IP of the PC, the IP of the host that provides various network services to the development board)
Bootargs: the startup parameters passed by u-boot to the operating system kernel. (very important)
Use example
Prints the specified environment variables
Format: printenv name of environment variable for printing
TINY4412 # printenv bootargs bootargs=root=/dev/nfs nfsroot=192.168.18.3:/work/rootfs ip=192.168.18.123:192.168.18.3:192.168.18.1:255.255.255.0::eth0:off init=/linuxrc console=ttySAC0,115200
2.4 setting environment variables – setenv
View help:
TINY4412 # help setenv
setenv - set environment variables -->The function is to set environment variables
Usage: //Command usage
setenv name value ... //Use format
- set environment variable 'name' to 'value ...'
//Format environment variable name value
setenv name
- delete environment variable 'name'
//Delete environment variable
Use example
Set the power on delay time: TINY4412 # setenv bootdelay 10 / / set the power on delay time to 10 seconds TINY4412 # saveenv / / save settings Saving Environment to SMDK bootable device... done Example of setting baud rate: TINY4412 # setenv baudrate 115200 / / set the baud rate to 115200 ## Switch baudrate to 115200 bps and press ENTER ... // After setting, you need to restart the development board and it will take effect automatically Example of deleting an environment variable: setenv baudrate //Delete baudrate environment variable
Examples of reference environment variables:
TINY4412 # setenv timer 10 / / set any environment variable
TINY4412 # setenv bootdelay ${timer} / / reference environment variable
TINY4412 # Save / / save environment variables
Saving Environment to SMDK bootable device...
done
TINY4412 # print
baudrate=115200
bootargs=root=/dev/nfs nfsroot=192.168.18.3:/work/rootfs ip=192.168.18.123:192.168.18.3:192.168.18.1:255.255.255.0::eth0:off init=/linuxrc console=ttySAC0,115200
bootcmd=movi read kernel 0 40007fc0;bootm 40007fc0
bootdelay=10 //Set successfully
ethaddr=00:40:5c:26:0a:5b
gatewayip=192.168.18.1
ipaddr=192.168.18.123
netmask=255.255.255.0
serverip=192.168.18.124
timer=10 //Set new environment variables
Environment size: 389/16380 bytes
TINY4412 #
2.5 setting the bootargs parameter
Bootargs is the top priority of environment variables. It can even be said that the whole environment variables are set around bootargs.
coherent_pool parameters:
set up DMA Size of Example: coherent_pool=2M
Local mount example
set bootargs root=/dev/mmcblk0p2 rootfstype=ext3 init=/linuxrc console=ttySAC0,115200 set bootargs root=/dev/mmcblk0p2 rw rootfstype=ext3 init=/linuxrc console=ttySAC0,115200
NFS network mount example:
set bootargs root=/dev/nfs nfsroot=192.168.18.3:/work/nfs_root ip=192.168.18.123:192.168.18.3:192.168.18.1:255.255.255.0::eth0:off init=/linuxrc console=ttySAC0,115200
The root parameter is used to specify where the root file system is mounted.
The nfsroot parameter needs to be set only when the NFS network file system is mounted, followed by the NFS address and mounting directory of the server
The IP parameter is to set the IP address of the network card of the development board. It must be set when NFS network is mounted.
init is a script that is run after the file system is mounted. It is used for system initialization.
2.6 view the configuration information of the development board – bdinfo
TINY4412 # bdinfo arch_number = 0x00001200 ->The machine code of the development board is used to boot the kernel of the operating system boot_params = 0x40000100 ->Memory location of startup parameter storage DRAM bank = 0x00000000 -> DRAM Number, which means the 0 th DDR -> start = 0x40000000 -->DRAM Start address of -> size = 0x10000000 -->DRAM Size of ( 0x10000000 /1024 /1024 = 256M) DRAM bank = 0x00000001 -> DRAM Number, which means the first one here DDR -> start = 0x50000000 -->DRAM Start address of -> size = 0x10000000 -->DRAM Size of( 0x10000000 /1024 /1024 = 256M) DRAM bank = 0x00000002-> DRAM Number, which means the second one DDR -> start = 0x60000000 -->DRAM Start address of -> size = 0x10000000 ->DRAM Size of( 0x10000000 /1024 /1024 = 256M) DRAM bank = 0x00000003-> DRAM Number, which means the third DDR -> start = 0x70000000 ->DRAM Start address of -> size = 0x0FF00000 ->DRAM Size of( 0x10000000 /1024 /1024 = 256M) ethaddr = 00:40:5c:26:0a:5b ->network card MAC address(DM9600) ip_addr = 192.168.0.20 ->Development board IP baudrate = 0 bps ->Baud rate. Here is the code. There is a problem. It should be 115200 TLB addr = 0x3FFF0000 ->MMU(CPU) Mapping table storage location relocaddr = 0xC3E00000 ->Address of code relocation reloc off = 0x00000000 ->Relocation address irq_sp = 0xC3CFBF58 ->irq Stack pointer sp start = 0xC3CFBF50 ->Start address stack pointer FB base = 0x00000000 ->framebuffer Base address
2.7 memory data display - > MD
View help:
TINY4412 # ? md md - memory display Memory data display---Only data in memory can be displayed, that is, only in DDR Operation in address Usage: md [.b, .w, .l] address [# of objects]
Md.b: display data in bytes
Word in MW. D
Md.l: double word (4 bytes)
The above representation is displayed in bytes, words (2 bytes) and double words (4 bytes)
**Format: * * md.b < address to be displayed > [number of data displayed]
TINY4412 # Md.b 10 / / display 10 data at the starting address 1000000 to the terminal 01000000: 06 00 00 ea fe ff ff ea fe ff ff ea fe ff ff ea ................
Example:
TINY4412 # md.b 1000000 10 one byte display: 01000000: 06 00 00 ea fe ff ff ea fe ff ff ea fe ff ff ea ................ TINY4412 # md.w 1000000 10 two byte display 01000000: 0006 ea00 fffe eaff fffe eaff fffe eaff ................ 01000010: fffe eaff fffe eaff 301a ea00 301b ea00 .........0...0.. TINY4412 # md.l 1000000 10 four byte display 01000000: ea000006 eafffffe eafffffe eafffffe ................ 01000010: eafffffe eafffffe ea00301a ea00301b .........0...0.. 01000020: e59f01a4 e3a01000 e5801000 e59f019c ................ 01000030: e5900000 e200003e e330003e 1a00000d ....>...>.0.....
2.8 copy memory command cp
View help:
TINY4412 # help cp cp - memory copy Memory Copy --It can only be copied in memory, that is, it can only be copied in memory DDR Operation in address Usage: cp [.b, .w, .l] source target count Number of source and destination addresses
Example 1:
TINY4412 # cp 100000 4000000 10 Copy 10 data from the starting address of 100000 to the address of 4000000
Example 2:
TINY4412 # md.b 46000000 46000000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ TINY4412 # md.b 10000000 10000000: 11 20 41 e4 08 00 05 08 05 00 00 00 10 00 00 00 . A............. TINY4412 # cp 10000000 46000000 10 copies 10 data from the starting address 10000000 to the address of 46000000 TINY4412 # md.b 46000000 46000000: 11 20 41 e4 08 00 05 08 05 00 00 00 10 00 00 00 . A.............
2.9 view EMMC information - > mmcinfo
View help:
TINY4412 # help mmcinfo mmcinfo - mmcinfo <dev num>-- display MMC info >Output assigned number mmc Information, <dev num>Is the number to assign Usage: mmcinfo
Number Description:
The number of MMC will change. There are EMMC and SD card on Tiny4412 board. Both are classified as MMC. The number is 0, 1. But who is 0 and who is 1 is uncertain, which is related to the startup mode. In which memory is started, the number is 0.
View SD card information:
TINY4412 # mmcinfo 0 Device: S3C_HSMMC2 Equipment name Manufacturer ID: 2 Manufacturer identification ID OEM: 544d Equipment manufacturer Name: SE08G name Tran Speed: 0 Rd Block Len: 512 The size of each block, in bytes SD version 2.0 SD Card version High Capacity: Yes Is it a mass capacity card Size: 7460MB (block: 15278080) Capacity size,(How many blocks are there altogether) Bus Width: 4-bit Bus width, SD The card interface is 4 lines Boot Partition Size: 0 KB Boot partition size
View EMMC information:
TINY4412 # mmcinfo 1 Device: S5P_MSHC4 equipment Manufacturer ID: 15 manufacturer ID OEM: 100 Original equipment manufacturer Name: 4YMD3 name Tran Speed: 0 Tran speed Rd Block Len: 512 The size of each block, in bytes MMC version 4.0 MMC edition High Capacity: Yes Is it a mass capacity card Size: 3728MB (block: 7634944) Card capacity and total block size Bus Width: 8-bit Bus width Boot Partition Size: 4096 KB Boot partition size
2.10 mmc command subsystem
mmc is not a single command. It is a subsystem that supports multiple commands.
View help information for mmc subsystem
TINY4412 # help mmc mmc - MMC sub system MMC Subsystem Usage: mmc read <device num> addr blk# cnt -- read data from the sector specified by mmc into ddr mmc write <device num> addr blk# cnt -- write the data in ddr to the specified mmc sector mmc rescan <device num> --Rescanning the specified device is equivalent to reinitializing mmc erase <boot | user> <device num> <start block> <block count> --Erase the specified sector mmc list - lists available devices --List valid mmc equipment
Parameter Description:
<device num>: mmc The numbering principle is the same as that mentioned above, that is, which equipment to operate. addr: DDR3 Memory address; blk#: start address of mmc sector to be read / written; cnt: To read/Written mmc Number of sectors; boot: Reference partition is generally an operation bl1,bl2,u-boot of mmc Sector range. user: User partitions are generally used to operate the kernel and file system mmc Sector range. <start block>: To erase mmc Sector start address; <block count>: To erase mmc Number of sectors;
The parameters in the mmc command are expressed in hexadecimal, not in hexadecimal
(1) Read data from MMC sector to DDR memory - > MMC read
Format: mmc read <device num> addr blk# cnt blk#: the starting address (in hexadecimal) of the mmc sector to be read / written Cnt : To read/Written mmc Number of sectors(Hexadecimal representation) addr: DDR3 Memory address; TINY4412 # mmc read 0 45000000 1 1 MMC read: dev # 0, block # 1, count 1 ... 1 blocks read: OK This is from SD Starting from the first sector of the card, read the data of one sector to DDR 45 million address! Example: TINY4412 # md.b 48000000 10 48000000: ff ff ff ff ff ff ff ff ff ff ff ff bf ff ff ff ................ //Starting from the first sector of the SD card, read the data of one sector to the address of 48 million DDR TINY4412 # mmc read 0 48000000 1 1 MMC read: dev # 0, block # 1, count 1 ... 1 blocks read: OK TINY4412 # md.b 48000000 10 48000000: a3 69 d3 18 e9 7d b9 66 d1 6b d5 6e d4 79 a6 79 .i...}.f.k.n.y.y
(2) mmc write -- write the data in ddr to the specified mmc sector
Format: mmc write <device num> addr blk# cnt -- write the data in ddr to the specified mmc sector blk#: the starting address (in hexadecimal) of the mmc sector to be read / written Cnt : To read/Written mmc Number of sectors(Hexadecimal representation) addr: DDR3 Memory address; Example: TINY4412 # mmc write 0 48000000 1 1 1 write data of one sector to the first sector of SD from DDR 48000000 address MMC write: dev # 0, block # 1, count 1 ... 1 blocks written: OK
(3) Erase the specified sector
Format: mmc erase <boot | user> <device num> <start block> <block count> --Erase the specified sector Parameter Description: <start block>: To erase mmc Sector start address <block count>: To erase mmc Number of sectors boot: Reference partition User: User partition For the convenience of comparison, first SD Read the contents of the first sector of the card DDR Yes. Read out the data of the 10th sector TINY4412 # mmc read 0 48000000 1 1 MMC read: dev # 0, block # 1, count 1 ... 1 blocks read: OK Display the data of the first sector TINY4412 # md.b 48000000 30 48000000: a3 69 d3 18 e9 7d b9 66 d1 6b d5 6e d4 79 a6 79 .i...}.f.k.n.y.y 48000010: 07 00 00 ea fe ff ff ea fe ff ff ea fe ff ff ea ................ 48000020: fe ff ff ea fe ff ff ea fe ff ff ea fe ff ff ea ................ Erase SD First sector of the card TINY4412 # mmc erase user 0 1 1 START: 1 BLOCK: 1 Start sector 1, erase sector 1 high_capacity: 1 High capacity Capacity: 15278080 capacity Erase Erase 512 B erase Done 512 byte MMC erase Success.!! MMC Erase succeeded.! ! Reread and display TINY4412 # mmc read 0 40000000 1 1 MMC read: dev # 0, block # 1, count 1 ... 1 blocks read: OK TINY4412 # md.b 40000000 30 40000000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 40000010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 40000020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ Recover the data, read it again and then display it TINY4412 # mmc write 0 48000000 1 1 1 write data from DDR to SD card MMC write: dev # 0, block # 1, count 1 ... 1 blocks written: OK TINY4412 # mmc read 0 40000000 1 1 1 read data again MMC read: dev # 0, block # 1, count 1 ... 1 blocks read: OK TINY4412 # md.b 40000000 30 display --- data recovered 40000000: a3 69 d3 18 e9 7d b9 66 d1 6b d5 6e d4 79 a6 79 .i...}.f.k.n.y.y 40000010: 07 00 00 ea fe ff ff ea fe ff ff ea fe ff ff ea ................ 40000020: fe ff ff ea fe ff ff ea fe ff ff ea fe ff ff ea ................
(4) List MMC devices – mmc list
TINY4412 # mmc list S3C_HSMMC2: 0 --- 0 Numbered mmc Equipment, connect here SD card S5P_MSHC4: 1 --- 1 Numbered mmc Equipment, which is connected to the development board EMMC
2.11 viewing MMC partition information - fatinfo
TINY4412 # help fatinfo
fatinfo - fatinfo - print information about filesystem
Print file system information
Usage:
fatinfo <interface> <dev[:part]> Format description
- print information about filesystem from 'dev' on 'interface'
Parameter Description:
<interface>: mmc or usb；
dev: Equipment number;
part: Equipment partition number
View the information of the 0th device---Here is SD Card:
TINY4412 # fatinfo mmc 0
-----Partition 1-----
Partition1: Start Address(0x2e2e2e2e), Size(0x2e2e2e2e)
Zone 1 Starting address size
------------------------
-----Partition 2-----
Partition1: Start Address(0x2e2e2e2e), Size(0x2e2e2e2e)
------------------------
-----Partition 3-----
Partition1: Start Address(0x2e2e2e2e), Size(0x2e2e2e2e)
------------------------
-----Partition 4-----
Partition1: Start Address(0x2e2e2e2e), Size(0x2e2e2e2e)
------------------------
Interface: SD/MMC
Interface
Device 0: Vendor: Man 02544d Snr c9226e33 Rev: 2.1 Prod: SE08G
Type: Removable Hard Disk
Type: removable hard disk
Capacity: 14.5 MB = 0.0 GB (29840 x 512)
Partition 1: Filesystem: FAT32 "NO NAME "
The space is limited. The next article will continue to introduce.