[U-Boot-Users] U-boot 1.2.0 JFFS2, and NAND flash

Wed Oct 17 13:55:47 CEST 2007

On two custom designs (ARM and PPC based) we switched from JFFS to YAFFS
after experiencing the same problem. Now we use YAFFS in U-Boot and Linux.

Since YAFFS is very fast we saw no reason to partition the device and
we have one
partition on 1 and 2 GB respectively. The scan/mount times are almost
negligible when
using checkpoints. Without checkpoints we are still experiencing
scan/mount times
below/around 1s.

Implementing YAFFS on U-boot and Linux we had problems configuring YAFFS/MTD
in such a way that we could use the same partition in both places.
That made us upgrade
MTD in U-boot to correspond with our version of Linux. I will suggest
an upgrade of U-boot
MTD in a separate thread. However, if you are only using a
boot-partition from U-boot you
should not experience such problems.

Best regards
William
-------------------------------------------------
William Juul, Senior Development Engineer
Data Respons Norge AS
Sandviksveien 26
P.O. Box 489
NO-1323 Høvik, Norway

Tel: +47 67 11 20 00    Fax: +47 67 11 20 50
Dir: +47 67 11 20 26    Mob: +47 95 79 32 53

www.datarespons.no
-------------------------------------------------

On 10/15/07, Dan Batryn <DBatryn at shoretel.com> wrote:
>
>         I am experiencing similar delays using an AMCC 440EP PowerPC and
> trying to boot Linux from the NAND flash via JFFS2.  I initially had 16
> MB partition devoted to booting the Linux kernel and found that he JFFS2
> scan time took several minutes.  Turning ON CFG_JFFS2_SORT_FRAGMENTS
> made matters even worse.  I finally reduced the partition size dedicated
> to the Linux kernel down to 5 MB and the JFFS2 scan time is now ONLY 30
> sec.  Does anyone have any experience using YAFFS in a UBOOT
> environment?  I have heard that the YAFFS file system does not suffer
> the long scan times of JFFS2.  Can anyone confirm this rumor?
>
>
> Daniel Batryn
> Shoretel Inc.
> 960 Stewart
> Sunnyvale, CA  94085
> (408) 331-3575 Phone
> (408) 331-3333 Fax
>
>
> |-----Original Message-----
> |From: u-boot-users-bounces at lists.sourceforge.net [mailto:u-boot-users-
> |bounces at lists.sourceforge.net] On Behalf Of Matt Gessner
> |Sent: Monday, October 15, 2007 8:50 AM
> |To: u-boot-users at lists.sourceforge.net
> |Subject: Re: [U-Boot-Users] U-boot 1.2.0 JFFS2, and NAND flash
> |
> |OK, more on this.
> |
> |I don't have CFG_JFFS2_SORT_FRAGMENTS set, so I don't think this is the
> |issue.
> |
> |Linux *can* mount this partition, but it only does so when the software
> |is being updated.  The rest of the time, the system ignores this
> |partition.
> |
> |So, I'm wondering if the sorting is even an issue.
> |
> |Any ideas?
> |
> |Thanks,
> |
> |Matt
> |
> |> -----Original Message-----
> |> From: u-boot-users-bounces at lists.sourceforge.net
> [mailto:u-boot-users-
> |> bounces at lists.sourceforge.net] On Behalf Of Joakim Tjernlund
> |> Sent: Monday, October 15, 2007 8:44 AM
> |> To: Detlev Zundel
> |> Cc: u-boot-users at lists.sourceforge.net; Matt Gessner
> |> Subject: Re: [U-Boot-Users] U-boot 1.2.0 JFFS2, and NAND flash
> |>
> |> On Mon, 2007-10-15 at 12:32 +0200, Detlev Zundel wrote:
> |> > Hi Matt,
> |> >
> |> > > I'm got an AT91RM9200 and an 16 MB ST Micro NAND flash,
> |partitioned
> |> into
> |> > > 3 blocks of 8, 4 and 4 MB.  U-boot boots linux from the first 8MB
> |> > > partition, and doesn't go searching in the others unless it's
> |> necessary.
> |> > >
> |> > > The JFFS2 scan for this takes 1:45.  I believe I followed all the
> |> > > instructions in the docs for setting up the NAND flash, and other
> |than
> |> > > seeming to be really slow, it seems to operate just fine.
> |> > >
> |> > > When I use nand write.jffs2 to write the image, it doesn't take
> |nearly
> |> > > this long.
> |> > >
> |> > > Has anyone else had a similar experience?  Is there some
> |configuration
> |> > > or other tip someone might be able to give me as to why this is
> so
> |> slow?
> |> >
> |> > As mentioned several times on this mailing list, this is a
> "feature"
> |> > of the data structures used by JFFS2.  So as not to repeat myself
> |too
> |> > much, JFFS2 has to find the "current" data blocks for the files
> |urging
> |> > it to scan the whole partition.
> |>
> |> This is not entierly true. The scaning can be made much faster.
> |> There was/is a patch on the ML that improves the scaning speed
> |> significantly. Search for subject "jffs2 fsload - SOLVED"
> |> Not sure if that patch impl. reduced scanning of empty EBs, scanning
> |> all empty space is very time consuming.
> |>
> |>  Jocke
> |>
> |> >
> |> > A simple workaround - also mentioned a few times already - is to
> use
> |a
> |> > small partition for what is needed during booting.
> |> >
> |> > Cheers
> |> >   Detlev
> |> >
> |>
> |>
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