topic Re: i.MX6 Linux: fw_printenv/fw_setenv problems in i.MX Processors

i.MX6 Linux: fw_printenv/fw_setenv problems

ganesank — Thu, 08 Dec 2016 12:13:04 GMT

Problem Statement: Problem in updating u-boot environment variables from Linux using fw_setenv/fw_printenv tools. I observed the following,

What is working:

Able to print environment variables without any problem
Able to modify a default environment variable

What is not working:

Not able to create a new environment variables using fw_setenv. It is leading to Bad CRC issue when new variables are added
Not allowing more than one default environment variable to be modified in one power cycle. Modifying more than one variable is also leading to Bad CRC. If I modify one variable, reboot the system and then modify the second one then there is no issue

Our Environment:

We are using Yocto 2.1 - Linux 4.1 Freescale community BSP for our custom board based on Advantech Q7 - i.MX6 CPU module. The u-boot version is 2016.07. The u-boot binary and environment variables are stored in SPI NOR Flash (n25q032)

Any one has faced similar issues?. Any pointers to debug this would be welcome.

Re: i.MX6 Linux: fw_printenv/fw_setenv problems

jimmychan — Fri, 09 Dec 2016 08:27:14 GMT

Could you show me the fw_env.config?

Re: i.MX6 Linux: fw_printenv/fw_setenv problems

ganesank — Fri, 09 Dec 2016 10:56:32 GMT

fw_env.config:

/dev/mtd1 0x0000 0x2000 0x10000

CONFIG_ENV_SIZE is set to (8 * 1024)

and sector size is 64 KBytes

Re: i.MX6 Linux: fw_printenv/fw_setenv problems

jimmychan — Mon, 12 Dec 2016 08:19:22 GMT

you may try to set the ENV_SIZE to 0x10000.

If still not work, I think you can try to add some printk in the fw_env.c to see why CRC error happen when modify one more variable.

Re: i.MX6 Linux: fw_printenv/fw_setenv problems

ganesank — Tue, 13 Dec 2016 09:53:14 GMT

I found the root cause of this problem. The flash sectors are protected so it has to be unlocked before erase & write operations which I expected to be handled in fw_setenv tool. In fact I checked about it in the code and there are unlock and lock ioctl calls being made but it doesn't seem to work properly. I have to debug this further. Any suggestion is most welcome.

Workaround: If I run "flash_unlock /dev/mtd1" command before every "fw_setenv <var> <value>" command then all use-cases like multiple modifications and creation of new variables are working fine.

Re: i.MX6 Linux: fw_printenv/fw_setenv problems

pietercardoen — Mon, 19 Jun 2017 19:26:35 GMT

I am facing the same problem, however slightly different. If I use fw_setenv in user space, I get in u-boot: spi flash protected.

Has someone already solved this issue or should I use the workaround?

Best regards

Pieter

Re: i.MX6 Linux: fw_printenv/fw_setenv problems

benjaminp — Wed, 06 Sep 2017 06:12:19 GMT

Same as me. I can unlock the spi flash with the command

'sf protect unlock 0x0 <FLASH_SIZE>',

and after doing so I can change the value of an environment variable as often as I want in the bootloader cli, and exactly once in linux by running the 'fw_setenv' command. After this command, the SPI-flash is protected again.

Does anyone know why the SPI flash gets locked? Is this somehow adjustable by a define during U-Boot configuration?

I use the u-boot-imx 2016.03

Best Regards

Benjamin

Re: i.MX6 Linux: fw_printenv/fw_setenv problems

pietercardoen — Wed, 06 Sep 2017 07:05:50 GMT

I used a workaround. I searched for the code which is executed if saveenv is applied. At a certain point it tries to write to the SPI flash. Just before, I added a command to unprotect the SPI flash. So now every time I do saveenv, I first get the message: "Unprotecting SPI Flash".

Maybe not the best way but it works.

Best regards

Pieter Cardoen

Re: i.MX6 Linux: fw_printenv/fw_setenv problems

woutervh — Mon, 14 Jan 2019 12:48:27 GMT

Anyone has a valable solution for this one yet?

Re: i.MX6 Linux: fw_printenv/fw_setenv problems

Niebel-TQ — Mon, 14 Jan 2019 13:15:10 GMT

fw_setenv code from U-Boot assumes wrong protection scheme. SPI NOR usaually protects not sector by sector but a region beginning from bottom or top. So after first usage a complete region is protected. Maybe disabling the whole protection stuff in fw_setenv optionally if env is on SPI_NOR is a way to go. Maybe should be patched in U-Boot mainline?

Re: i.MX6 Linux: fw_printenv/fw_setenv problems

woutervh — Tue, 15 Jan 2019 08:53:56 GMT

Yes, maybe. But I'm a bit surprised we are having this issue. This question dates back to 2016... Nobody else is using spi nor for uboot environment storage? And why not?