[U-Boot] fw_setenv device not accessible

[U-Boot] fw_setenv device not accessible

[pshambhu]

Hi,
 
    I am unable to change the u-boot environment variables from the Linux
environment using fw_setenv and fw_printenv. 
I am able to list out the variables from the particular partition, but i am
unable to change the variable value using fw_setenv.

[Linux promp]# fw_setenv Status 0
Can't open /dev/mtd4: Permission denied
Error: can't write fw_env to flash

i tried to change the permission of /dev/mtd4 as well, but i am getting the
same problem.

Regards
Pradeep S



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[U-Boot] fw_setenv device not accessible

[Wolfgang Denk]

Dear pshambhu,

In message <1383039837672-166275.post@n7.nabble.com> you wrote:
>  
>     I am unable to change the u-boot environment variables from the Linux
> environment using fw_setenv and fw_printenv. 
> I am able to list out the variables from the particular partition, but i am
> unable to change the variable value using fw_setenv.
> 
> [Linux promp]# fw_setenv Status 0
> Can't open /dev/mtd4: Permission denied
> Error: can't write fw_env to flash
> 
> i tried to change the permission of /dev/mtd4 as well, but i am getting the
> same problem.

Obviously partition mtd4 is mapped as read-only.  You need read-write
mode instead.  This has nothing to do with the permissions on the
/dev/mtd4 special file, but with the mapping of the MTD device in the
device tree or the mtdargs boot argument or however you pass that
information to Linux on your system.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
A Perl script is correct if it's halfway readable and  gets  the  job
done before your boss fires you.
                       - L. Wall & R. L. Schwartz, _Programming Perl_

[U-Boot] fw_setenv device not accessible

[pshambhu]

Hi,

      In u-boot i am passing mtdargs in RW mode only. but still i am unable
to change the values.Yeah its true that mtd4 device is in READ only mode,
but how can i change the access permission of the device, so that i can
set/change  the u-boot environment variable values from the Linux platform.

please provide me the solution for this ??

Thanks & Regards
Pradeep S



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[U-Boot] fw_setenv device not accessible

[Wolfgang Denk]

Dear pshambhu,

In message <1383894946586-167013.post@n7.nabble.com> you wrote:
> 
>       In u-boot i am passing mtdargs in RW mode only. but still i am unable
> to change the values.Yeah its true that mtd4 device is in READ only mode,
> but how can i change the access permission of the device, so that i can
> set/change  the u-boot environment variable values from the Linux platform.
> 
> please provide me the solution for this ??

first, this is effectively a Linux issue, so you are mostly off topic
here.

Second, it's very difficult to help at all if all you provide is some
vague statement without any details like an exact description of what
you attempted to do and what the result was - including for example a
complete boot log.

So I can only guess... It seems you are trying to pass MTD partition
information to Linux by using the mtdargs boot argument, and this
doesn't work.  Well, perhaps your Linux kernel is not configured to
use such information at all?  Eventually it takes the informantion
from somewhere else, like from the device tree?

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Inside every old person is a young person wondering what happened.
                              - Terry Pratchett, _Moving Pictures_