Possible race condition when accessing SPI NOR Flash ?

Wolfgang Denk wd at denx.de
Thu May 1 15:31:26 PDT 2014

Dear Valentin,

In message <53623597.8040909 at keymile.com> you wrote:
> Now when fw_setenv ([1], [2]) updates the environment variables, it sometimes
> (approximately 1 out of 100 runs) triggers such kernel errors:
> I see the same behavior with both the 2013.10 and the 2014.04 releases of
> u-boot/fw_env. The kernel we are using is 3.10.36.
> I suspect that the problem is related to SPI NOR/m25p80 driver: on the system we
> have a NAND Flash device with UBI volumes. If I create 2 ubi volumes on the NAND
> Flash and configure fw_setenv (/etc/fw_env.config) to use them instead of the
> the mtd devices targetting the s25fl256s1, I am not able to reproduce the
> problem, even over more than 10'000 runs.

Um... this is _Linux_ crashing - at this point the U-Boot driver has
nothing to do with it..  If there is a problem, then with the Linux
kernel / driver code.  I guess you should rather post this on the MTD
mailing ist.

> One other possible culprit that I see is the fsl_espi.c driver for the
> underlying hardware connection from the CPU to the NOR Flash, but I wanted to
> ask here if someone had an idea about what's going wrong.

It's Linux code....

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
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