Timeout in denali.c on Micron nandflash (Altera SoC)

[Thorsten Christiansson <thorsten.christiansson@idquantique.com>]

Hi all,

I'm using Linux on an Altera SoC (Arria V), on which I'm using UBIFS on a
nandflash from Micron (MT29F8G08ADADAH4).  I have a 400Mb r/w partition on
which I have a sqlite3-based database. We're running an application that
reads/writes fairly small blocks. After running for about a week at moderate
load, I get an error message, and the filesystem becomes read-only.

The message I get is a timeout, originating in the denali.c driver.
[11744.733748] timeout occurred, status = 0x0, mask = 0x4
[11745.733685] timeout occurred, status = 0x0, mask = 0x120

I can also reproduce the error much faster (in ~1h) using the GNU 'stress'
command, writing/reading small files continuously.

I'm using Linux 4.4, with some patches from Altera. I have compared the
denali.c that I'm using with the current HEAD on github, and the differences
appear to be only cosmetic.

I have asked Altera for help, but their only response so far has been that
they can reproduce the issue on their latest SoCs (it apparently appears on
both Arria10 and CycloneV) with the same flash. (We have also tested with a
Macronix MX66U51235FMI-10G, with the same results.)

At first we used the FASTMAP feature of the UBIFS, but then we ran into this
issue after only a couple of hours running at moderate load. When we
disabled
that, we thought the problem was gone, but it appears that it was only
hiding,
and now comes out to bite us after about a week.


My questions are the following:
- Are there any known issues with the denali driver that could cause this?
- Could it be an issue in the MTD/UBI/UBIFS layers?
- Are there any other parameters that can be tuned in order to alleviate the
  problem?

and of course
- Have I missed something obvious? I'm pulling my hair here...


best regards,
-- 
Thorsten Christiansson