[Yaffs] Yaffs with 2k Pages OR Yaffs2

[Rajiv Dhingra]

Charles and Thomas:

Thank you very much for your responses.  It will be a while before we make =
a decision (enjoying the holidays), but for the very reasons that you =
mentioned Charles, it might well be that I end up back-porting mtd to =
2.4.20.    Any pointers in accomplishing this (in addition to the ones =
that you have already mentioned) would be truly appreciated.  Would most =
of the modifications be in the nand drivers or the mtd drivers?

Merry Christmas,

Rajiv


>>> "Charles Manning" <Charles.Manning@trimble.co.nz> 12/19/04 11:59AM >>>
Rajiv

I've thought about this a bit...
While Thomas it technically correct that YAFFS2 needs more recent mtd
(which no longer supports older kernels), I think it rather simple to
hack the mtd you have to support YAFFS2.

Basically, all you'd need to do is:
1) Modify the nand write/read functions to work with 2k pages (change
the size of the for loop), and a few other minor changes to handle ECC
etc.
2) Add a couple more required fields to the mtd_info structure.
3) Add two new functions block_markbad() and block_isbad() for bad block
handling.

Whether it is the right time for you to switch to a newer kernel or not
is your choice and should not be forced by mtd changes.

-- Charles
=20

> -----Original Message-----
> From: yaffs-admin@stoneboat.aleph1.co.uk=20
> [mailto:yaffs-admin@stoneboat.aleph1.co.uk] On Behalf Of=20
> Thomas Gleixner
> Sent: Thursday, 16 December 2004 9:41 p.m.
> To: Rajiv Dhingra
> Cc: YAFFS
> Subject: Re: [Yaffs] Yaffs with 2k Pages OR Yaffs2
>=20
>=20
> On Wed, 2004-12-15 at 15:50 -0800, Rajiv Dhingra wrote:
> > We were running Linux 2.4.20, Yaffs, and using a NAND
> > device with 512 byte pages.  Everything was working fine.
> > Then the hardware guys replaced the 512 byte page NAND
> > device with a 2k page NAND device.
> > So, I now have to hack yaffs to support a 2k page size,
> > or start using Yaffs2.  What would the recommendation
> > of this newsgroup be?  Would it be easy enough for me
> > to hack yaffs to start supporting the bigger page size?
> > Is yaffs2 stable enough and does it run with the 2.4.20
> > kernel, making it a better option.
>=20
> Be prepared to upgrade your kernel. The MTD NAND layer which=20
> has the support for 2k chips is definitely not portable to 2.4.20.
>=20
> Read http://www.linux-mtd.infradead.org/#kernelversions=20
>=20
> tglx
>=20
>=20
>=20
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