[U-Boot] mx23-olinuxino: occasional memory errors

[Kiril Zyapkov]

Hi all,

I was told I should report this.

The tests are performed on two imx233-olinuxino boards: maxi and mini.
I've removed R17 (120 ohms between CLK and CLKN) from the mini board
as advised in #olimex and the Olimex forum board, but kept it on the
maxi board.

I am testing U-Boot 2013-04 with a patchset for mx23, build recipe is
at [1] with a 3.7.2 kernel [2]. I ran `memtester 24M 100` 3 times on
each board, the memtester program is built using [3] on a computer
running ArchlinuxARM with armv5 architecture.

The maxi board shows no signs of errors -- somewhat strange, given the
popular opinion that R17 introduces instability and should be removed.

The mini board, despite having R17 removed, shows occasional memory
errors, here are some:

------------------------------------------------------------------------
Loop 3/100:
  Stuck Address       : testing   6FAILURE: possible bad address line
at offset 0x000392a0.
Skipping to next test...
...
Loop 15/100:
  Stuck Address       : testing   8FAILURE: possible bad address line
at offset 0x010321b0.
Skipping to next test...
...
FAILURE: 0x7e0ba0a0 != 0x7e4ba0a0 at offset 0x0082f8e0.
  Compare OR          : FAILURE: 0x4e032000 != 0x4e432000 at offset 0x0088bf50.
...
  8-bit Writes        : /FAILURE: 0xfe0f01b0 != 0xfe4f01b0 at offset 0x007de9a4.
------------------------------------------------------------------------

As advised by Marek, I've repeated the test with disabled pullup on
MX23_PAD_EMI_CLKN__EMI_CLKN, changing the line in
board/olimex/mx23_olinuxino/spl_boot.c to:
       MX23_PAD_EMI_CLKN__EMI_CLKN | (MXS_PAD_3V3 | MXS_PAD_12MA |
MXS_PAD_NOPULL),
, but this doesn't fix the errors on the mini board.

I've prepared a rootfs tarball which can be used to replicate the
tests. Please see [4].

Thanks,

-- Kiril

[1] https://github.com/kzyapkov/PKGBUILDs/blob/master/alarm/uboot-olinuxino/PKGBUILD
[2] https://github.com/kzyapkov/PKGBUILDs/blob/master/core/linux-olinuxino/PKGBUILD
[3] https://aur.archlinux.org/packages/memtester/
[4] http://promptly.undo.it/alarm-memtester/