[U-Boot] Does uboot EBS(erase block summary) to reduce JFFS2 scaning time?

[Joakim Tjernlund]

HeLei <leon.he at msn.com> wrote on 03/11/2009 09:21:04:
>
> Thank you, Jocke
>
> > Subject: Re: [U-Boot] Does uboot EBS(erase block summary) to reduce JFFS2
> scaning time?
> > To: leon.he at msn.com
> > CC: u-boot at lists.denx.de
> > From: joakim.tjernlund at transmode.se
> > Date: Tue, 3 Nov 2009 08:41:08 +0100
> >
> >
> > >
> > > Hi, All
> > >
> > >
> > >
> > > Each time JFFS2 initialized, uboot need to scan the whole flash. This is
> > > fairly time consuming.
> > >
> > >
> > >
> > > So EBS(erase block summary) is used to JFFS2 to reduce mounting time. And I
> > > believe this can also be used to UBOOT to reduce booting time.
> > >
> > >
> > >
> > > Does UBOOT support this feature? or does any other solution in uboot to
> > > reduce JFFS2 scaning time?
> >
> > Don't think EBS is going to buy you much. The main problem is that the
>
>    You mean even EBS is used in UBOOT, it will not give me much help. But it
> seems there is great efficiency in jffs2 mounting, from some artical in
> internet, such as:http://www.embedded-linux.co.uk/tutorial/jffs2-summary
>
> > scanning of JFFS2 in u-boot is inefficient. u-boot could take a
> > hint from the kernel impl. of JFFS2 to reduce scanning. The biggest
> > ones are:
> > - do no scan the whole EB when it is empty.
>    If we don't scan the block, how can we tell the EB is empty?
>
> > - impl. a better crc32(use the one from linux)

Attaching a very crude port of linux crc32. This boots a linux img
for me and handles the environment crc as well. Feel free
to clean it up and submit to u-boot.

     Jocke

     (See attached file: crc32-new.c)(See attached file: crc32defs.h)(See attached file: crc32table.h)
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