How to have two images installed and if one breaks bootloader will switch to another automatically ls1021a

[jiye]

Hi,

I am running on kernel 4.19.46 Ubuntu distro. 

I have a LS1021a - twr eva board and it's booted from SD card but in the future will be an external eMMC. I am thinking to have two copies of image in the system if one is broken the u-boot or bootloader can detect next time upon boot and it will switch to the working version automatically. Any one knows how to achieve this purpose?

[yipingwang]

Hello Elias Bitbaker,

You could define a u-boot environment variable boot_status, if boot_status is 1, boot system 1 and reset boot_status  as 0, after boot into system 1 Linux, then modify u-boot environment variable boot_status as 1. If the system enter into watchdog exception, the variable boot_status  is still 0, then boot system 2 after reset.

Thanks,

Yiping

[jiye]

Hi Yipin,

Changing the variable as you mentioned needs to be done in the linux userspace right?  I am able to switch partition to boot different distro now but I installed u-boot-tool in the linux and it shows error :

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

[yipingwang]

On the target, please create a configuration file /etc/fw_env.config, the content like this

 /dev/mtd5 0x60000 0x2000 0x100000

 MTD device name
 Device Offset
 Environment Size
 Flash sector size

 Then execute "fw_printenv" and "fw_setenv" to read and write u-boot environment

[jiye]

Also in my .conf file do I need to uncomment this line:

# CONFIG_MTD is not set

[yipingwang]

Please refer to the following definition in include/configs/ls1021atwr.h in u-boot source code.

#if defined(CONFIG_SD_BOOT)
#define CONFIG_ENV_OFFSET               0x300000
#define CONFIG_SYS_MMC_ENV_DEV          0
#define CONFIG_ENV_SIZE                 0x20000

Please refer to the content in /etc/fw_env.config

# Device name        Offset          Size

/dev/mmcblk0        0x300000     0x20000

[jiye]

Hi Yiping,

I do not think I used this u-boot source code while compiling my kernel. How am I able to add this into my device after?

I mean after I copy this new offset and size into the fw_env.config it still show me CRC warning. Do I need to install the u-boot source code into the target device and run first ?

[yipingwang]

Hello Elias Bitbaker,

After editing /etc/fw_env.config, you could write u-boot environment variable with fw_setenv command.

Thanks,

Yiping

[jiye]

Hi Yiping,

Everything is set up correctly now, but I want to purposely damage the first filesystem and trigger the watchdog timer to throw exception so that the system can automatically reboot after the watchdog timer expires.

I was doing something in the uboot:

=> mm.b 0x2ad0000
02ad0000: 00 ?
02ad0001: 30 ?

according to the date sheet 1021ARM let's assume I want to set the time to 8 seconds so 

02ad0000: 00 ? --------------------------------->  0000 1111 --------->0x0f     

since 0x00 is 0.5 seconds 

.

.

so 0x 0f is 8 seconds

then enable the watch dog timer by setting up bit 13 to 1 which is 

02ad0001: 30 ? -----------------------------------> 0000 0100 ------->0x04

not sure if the value I gave is correct. But after I set up the values and reboot the device the values go back to default:

02ad0000: 00 ? 
02ad0001: 30 ?

do you know how to save the changes ?

ufedor‌

yipingwang‌

[yipingwang]

Please create a new thread to track your latest problem.

[jiye]

Hi Yiping,

But I am booting from the SD card not from the NOR flash should this be /dev/mmcblk0 and the correct 

 Device Offset
 Environment Size
 Flash sector size

values ?

[jiye]

I put something like this:

/dev/mmcblk0 0x7000 0x1000 0x1000

then it works but I am not sure if it's correct when I use command fw_printenv

it shows:

===================

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

========================

Seems like the mac address of the eth0 eth1 eht2 is not correct compares to the one I saw in the u-boot prompt  "printenv"

Also when i perform

"setenv devpart_root 3" in the uboot prompt I am able to boot the roof file system that is saved from my partition 3

but  when I was trying to set a variable called:

fw_setenv devpart_root 3 

from the userspace it will crash the device 

[jiye]

Hi Yiping,

I get the point. I really want to know

(1) how to wording the bootargs so that the system will know it will boot into system 2 (what arguments or format I can use)

take this in the boot environment as an example:

==========================================================================================

bootcmd=run distro_bootcmd; run sd_bootcmd; env exists secureboot && esbc_halt;
bootcmd_mmc0=devnum=0; run mmc_boot
bootcmd_usb0=devnum=0; run usb_boot

==========================================================================================

How to write a system 2 in these arguments in my case must be in bootcmd_mmc0.

(2) Where or what partition should I save the second system. Is it under a different partition? if so do I need to mount that partition into the system first ? 

or I am using lsdk1906 There are 4 partitions in the sd card:

/dev/mmcblk0p1 880K 72K 240K 24% /media/misc
/dev/mmcblk0p2 37M 14M 19M 42% /media/boot
/dev/mmcblk0p3 104M 3.1M 89M 4% /media/backup
/dev/mmcblk0p4 6.0G 481M 5.3G 9% /media/system

How can I take use of the backup partition? In other words how to make this partition bootable?

(3) When "modify u-boot environment variable boot_status as 1" is this done via the userspace? if so do I need to write a script like bash to change the values automatically or it is done by u-boot-tools? This should not be done manually. 

Thanks !