Re: [meta-fsl-arm PATCH 4/4] mxs-base.inc: Add default settings for UBI filesystem generation

["Eric Bénard" <eric@eukrea.com>]

Hi Daiane,

Le Wed, 18 Sep 2013 09:58:47 -0300,
Daiane Angolini <daiane.list@gmail.com> a écrit :
> On Wed, Sep 18, 2013 at 9:32 AM, Eric Bénard <eric@eukrea.com> wrote:
> > Le Wed, 18 Sep 2013 09:23:22 -0300,
> > Otavio Salvador <otavio@ossystems.com.br> a écrit :
> >> I had this for loooooong time in my queue and I recall to try it, but
> >> not lately. I will also extend the commit log and move it to mx28evk
> >> board.
> >>
> > no these values are wrong as they come from an i.MX35 tutorial so that
> > won't work on an i.MX28EVK (moreover this board hasn't any NAND
> > populated by default so the values will depend on the NAND flash the
> > user puts in the socket - here I tested with 2k and 4k flashes).
> >
> > So if you can't test it please don't add default values.
> 
> If not use default values, what do you suggest?
> 
you need a default value for a pair of CPU/NAND flash.

In the present case the values in the log come from
https://community.freescale.com/docs/DOC-1579 which is an i.MX35 and
not a MXS (and is not embedding the same nand flash controller and as
stated on the page : "Values only for iMX35 PDK NAND - K9LBG08U0D-PCB0")
so I'm quite sure the i.MX35 values won't work.

Moreover "-s 512" is wrong vs the webpage content, other values are
not in sync with the patch's log and surprisingly for our i.MX35 boards
I have :
MKUBIFS_ARGS = "-m 2048 -e 129024 -c 2030"
UBINIZE_ARGS = "-m 2048 -p 128KiB -s 512"
which are exactly the values Otavio wants to put in mxs-base.inc (so I
assume he took them from our cpuimx35 board's conf file but copied the
community's log values and both don't match as I assume iMX35 PDK's log
comes from the LTIB generated kernel when we are using mainline and so
a different NAND driver).

Last but not least I have tested some 2k and 4k NAND flashs on i.MX28
with UBI files generated using OE-Core and for example for 2k I have :
MKUBIFS_ARGS = "-m 2048 -e 126976 -c 1900"
UBINIZE_ARGS = "-m 2048 -p 128KiB -s 2048"
which corresponds to the values reported by the (3.10.x) kernel running
on the boards (and other i.MX28 boards embedding NAND are using the same
values for the key parameters of these variables - Denx's m28 for
example as you can see in their manual :
http://www.denx.de/wiki/publish/DULG/DULG-m28evk.pdf )

> Even if we can test it (I think I have access to one NAND to attach on imx28)
> it will be only *one* NAND
> 
True. As i.MX28 EVK comes without a NAND I think it's better to not
allow generating UBI rootfs for this board with random values and let
user who need UBI add the right values vs the flash they are really
using (same for all the other EVK as now Freescale ship empty sockets
by default).

Best regards
Eric