[Linux bottom layer] U-boot debugging command usage tips

If you debug the driver at the uboot stage, you can make full use of the existing resources of uboot. This is more convenient and can speed up the development process. Only by standing on the shoulders of giants can you achieve twice the result with half the effort.

1. uboot provides operation commands to cover

2. Nand Flash operation, reading, writing, erasing, and status printing;

3. DDR operation, memory byte printing;

4. Network operation, ping command, ftp download function, command code details see [Linux bottom layer] U-boot burning script introduction SecureCRT

=> ping 192.168.2.108

5. Operation of MAC controller, MII can read the data of MAC controller and change the data controlled by MAC;

//Dual network cards, activate the current network card setting ethprime=ethernet@f0028000, the current network card

=> setenv ethprime ethernet@f0028000 //eth0 gmac

=> setenv ethprime ethernet@f802c000 //eth1 emac

=> mii device ethernet@f802c000 //MII interface switch PHY

=> mii device ethernet@f0028000        

=> mii device //Query which PHY is enabled on the current MII interface

MII devices: 'ethernet@f0028000' 'ethernet@f802c000' 

Current device: 'ethernet@f802c000'

=>mii read 0 3 //Use the MII interface to read the information of register address 3 of eht0

=>mii read 1 3 //Use the MII interface to read the information of register address 3 of eht1

uboot command can correctly read PHY information

Use the MII interface to read PHY information

=> mii info

MII_PHYSID2 @ 0x0 = 0xb8a0

PHY_PHYIDR[1,2] @ 0x0 = 0x0181b8a0

PHY 0x00: OUI = 0x606E, Model = 0x0A, Rev = 0x00, 10baseT, HDX

6. Change startup parameters

bootargs=console=ttyS0,115200 earlyprintk mtdparts=atmel_nand:256k(bootstrap)ro,768k(uboot)ro,256K(env_redundant),256k(env),512k(dtb),6M(kernel)ro,-(rootfs) rootfstype=ubifs ubi.mtd=6 root=ubi0:rootfs

bootcmd=nand read 0x21000000 0x180000 0x80000;nand read 0x22000000 0x200000 0x600000;bootz 0x22000000 - 0x21000000

7. Setting and viewing environment variables

//Environment variables

=>pri

arch=arm

baudrate=115200

board=sama5d3_xplained

board_name=sama5d3_xplained

bootargs=console=ttyS0,115200 earlyprintk mtdparts=atmel_nand:256k(bootstrap)ro,768k(uboot)ro,256K(env_redundant),256k(env),512k(dtb),6M(kernel)ro,-(rootfs) rootfstype=ubifs ubi.mtd=6 root=ubi0:rootfs

bootcmd=nand read 0x21000000 0x180000 0x80000;nand read 0x22000000 0x200000 0x600000;bootz 0x22000000 - 0x21000000

bootdelay=3

cpu=armv7

eth1addr=EE:AB:C1:D2:E6:C6

ethact=ethernet@f802c000

ethaddr=EE:AB:C1:D2:E6:C6

fdtcontroladdr=2fb16b48

ipaddr=192.168.1.100

ipaddr1=192.168.2.100

serverip=192.168.1.108

soc=at91

stderr=serial@ffffee00

stdin=serial@ffffee00

stdout=serial@ffffee00

vendor=atmel

8. The debugging command of EMMC can check whether the drive is successful and print out the size;

9. Use the help command to check which commands uboot supports, and the list will be printed out;

10. Command usage can also be obtained through help, for example: command line $mii help