How to modify U-boot configuration in Linux user space

[jiye]

I want to change the u-boot variable in the linux userspace instead of the u-boot prompt window before starting kernel.

I am using lsdk1906 and my kernel is 4.19. I am booting from SD card.

I heard there is a way to do that by downloading the u-boot-tools

However,

After I run "apt-get install u-boot-tools"  

then I perform fw_printenv in the linux it tells me that 

Cannot parse config file '/etc/fw_env.config': No such file or directory

I checked this link:

Accessing U-Boot environment variables from Linux - ArmadeusWiki 

I need to know 

# MTD device name       Device offset   Env. size       Flash sector size       Number of sectors

I do not know what is the value of the location of my uboot.

Can anyone help?

[pvsnsubhash]

I know I am little late to the discussion but this is how i was able to fetch and set the u-boot environment variables from Userspace. Firstly install u-boot-fw-utils package from which you can get the fw_printenv and fw_setenv binaries in /sbin.

Also it will create the fw_env.config file in the path /etc. And the format of the file is as follows

# Device name                Offset                               Size
/dev/mmcblk0p1              0xE0000                          0x20000

There are some other parameters too like number of sectors and etc but all those are optional. Only the Offset and Size are mandatory params. These values you can get from the u-boot config file which is located in the path include/config inside your u-boot-source. If you can't find the u-boot source you need to patch it using the command bitbake -c patch virtual/bootloader . Search for the values CONFIG_ENV_OFFSET and CONFIG_ENV_SIZE in your board specific header file (as long as you use the default bootloader config). Mention these 2 values in the fw_env.config.

If the values are correct then you can get all the u-boot env params from linux userspace without any Bad CRC errors.

[Pavel]

Set the CONFIG_MTD = y.

See README and example from LSDK 1906 in the attachment.

Have a great day,
Pavel Chubakov

[Pavel]

fw_printenv is built into LSDK1906 Ubuntu rootfs by default. Just need to create /etc/fw_env.config and edit it to:

/dev/mtd0 0x60000000 0x2000 0x100000

See some message example below:

root@localhost:~# fw_printenv
Warning: Bad CRC, using default environment
bootcmd=run distro_bootcmd
bootdelay=2
baudrate=115200
stdin=serial,cros-ec-keyb,usbkbd
stdout=serial,vidconsole
stderr=serial,vidconsole
ethaddr=00:00:11:22:33:44
eth1addr=00:00:11:22:33:45
eth3addr=00:00:11:22:33:46
eth5addr=00:00:11:22:33:47
ipaddr=1.2.3.4
host_boot=if host dev ${devnum}; then setenv devtype host; run scan_dev_for_boot_part; fi
sata_boot=if sata dev ${devnum}; then setenv devtype sata; run scan_dev_for_boot_part; fi
scsi_init=if ${scsi_need_init}; then setenv scsi_need_init false; scsi scan; fi
scsi_boot=run scsi_init; if scsi dev ${devnum}; then setenv devtype scsi; run scan_dev_for_boot_part; fi
boot_prefixes=/ /boot/
boot_scripts=boot.scr.uimg boot.scr
boot_script_dhcp=boot.scr.uimg
boot_targets=host1 host0
boot_extlinux=sysboot ${devtype} ${devnum}:${distro_bootpart} any ${scriptaddr} ${prefix}extlinux/extlinux.conf
scan_dev_for_extlinux=if test -e ${devtype} ${devnum}:${distro_bootpart} ${prefix}extlinux/extlinux.conf; then echo Found ${prefix}extlinux/extlinux.conf; run boot_extlinux; echo SCRIPT FAILED: continuing...; fi
boot_a_script=load ${devtype} ${devnum}:${distro_bootpart} ${scriptaddr} ${prefix}${script}; source ${scriptaddr}
scan_dev_for_scripts=for script in ${boot_scripts}; do if test -e ${devtype} ${devnum}:${distro_bootpart} ${prefix}${script}; then echo Found U-Boot script ${prefix}${script}; run boot_a_script; echo SCRIPT FAILED: continuing...; fi; done
scan_dev_for_boot=echo Scanning ${devtype} ${devnum}:${distro_bootpart}...; for prefix in ${boot_prefixes}; do run scan_dev_for_extlinux; run scan_dev_for_scripts; done;
scan_dev_for_boot_part=part list ${devtype} ${devnum} -bootable devplist; env exists devplist || setenv devplist 1; for distro_bootpart in ${devplist}; do if fstype ${devtype} ${devnum}:${distro_bootpart} bootfstype; then run scan_dev_for_boot; fi; done
bootcmd_host1=setenv devnum 1; run host_boot
bootcmd_host0=setenv devnum 0; run host_boot
distro_bootcmd=setenv scsi_need_init; for target in ${boot_targets}; do run bootcmd_${target}; done
bootm_size=0x10000000
kernel_addr_r=0x1000000
fdt_addr_r=0xc00000
ramdisk_addr_r=0x2000000
scriptaddr=0x1000
pxefile_addr_r=0x2000
root@localhost:~#

Have a great day,
Pavel Chubakov

[jiye]

yeah but yours showing CRC error which means it’s not access the right location of the u-boot. Which means it’s not taking effective otherwise your eth address should be some real mac addresses. Also my device is booting from SD card and once I am in the userspace I could not find /proc/mtd 

Besides, in the fw_env.config file should it be /dev/mmcblk0 and it’s sector size and offset ?

Also do i need to set CONFIG_MTD = y during the kernel compilation.

[Pavel]

See attached file.

This file is available using the following path in LSDK 1906:

/LSDK_1906/flexbuild_lsdk1906/packages/firmware/u-boot/tools/env

Have a great day,
Pavel Chubakov

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[jiye]

Hi Pavel,

(1) I did not see the u-boot folder under /LSDK_1906/flexbuild_lsdk1906/packages/firmware

I could only see 

Makefile pfe_bin uefi_bin

(2) regarding the REDEME file you sent it says 

In order to cross-compile fw_printenv, run
make CROSS_COMPILE=<your cross-compiler prefix> envtools
in the root directory of the U-Boot distribution. For example,
make CROSS_COMPILE=arm-linux- envtools

where should I run this command is that under the flexbuild_lsdk1906/build/linux/linux/arm32/LS/output/LSDK-19.06-V4.19 ?

[jiye]

when I was using  make CROSS_COMPILE=arm-linux-gnueabihf- envtools

under flexbuild_lsdk1906/build/linux/linux/arm32/LS/output/LSDK-19.06-V4.19 

I encountered an error says:

make[2]: *** No rule to make target 'envtools'. Stop.
Makefile:146: recipe for target 'sub-make' failed
make[1]: *** [sub-make] Error 2
Makefile:24: recipe for target '__sub-make' failed
make: *** [__sub-make] Error 2

[shirishaReddy]

Hi, I am using flex-build (ls1046ardb ) in that fw_env.config file was there in u-boot/tool/env but not located in /etc folder all are files are is there related fw_printenv and fw_setenv but when I am giving command fw_printenv and fw_setenv commands I am getting error like fw_printenv command not found .I tried to install sudo apt-get install u-boot-tools its showing already installed u-boot-tools 

can  anybody help me how to enable fw_printenv and fw_setenv commands and it works in target baord