Current status JFFS2 on DOC

Current status JFFS2 on DOC

[Pieter Grimmerink]

I was quite happy to read about the recent efforts to support
JFFS2 on NAND devices.

Currently I'm about to make a decision on which flash device
to use for a new embedded device. 
Looking at prices NAND flash looks like the best option, 
especially if we can use JFFS2 on it.

>From a design point of view, DiscOnChip looks nice with
it's feature to boot from it.
SmartMedia looks a bit cheaper, but that would require
a separate NOR device, large enough to hold a compressed
kernel, total price going up above the DOC prices again.

However, all that I have found so far in mailinglists and
howto's, indicates that JFFS2 on smartmedia has been further
investigated then JFFS2 on DOC.
But as far as I understand, there should be no physical limitation
on a DOC to eventually host a JFFS2 filesystem.

Is this all true, and has someone managed to get a working 
JFFS2 filesystem on a DOC? 
and finaly, what are the chances of acutally booting into a 
JFFS2 root filesystem directly from a DOC?
(I heard something about a modified GNU GRUB to replace the DOC
firmware)

This would eventually all have to run on a non-x86 processor.

Is this a workable solution already, or would I have to go for
more 'conventional' hardware to be safe?

Best regards,

Pieter Grimmerink

Re: Current status JFFS2 on DOC

[Frederick Lefebvre]

I am working, among many, many other things on getting JFFS2 on a DOC
2000.  I do not know when it will be ready since I've got so much work
right now.

-- 
Frederick Lefebvre
flefebvre@irg.ca
Software Developer,
(418)523-4474 #242
Infomedia Research Group (IRG)
Quebec, Canada

On Wed, 2002-05-08 at 12:37, Pieter Grimmerink wrote:
> I was quite happy to read about the recent efforts to support
> JFFS2 on NAND devices.
> 
> Currently I'm about to make a decision on which flash device
> to use for a new embedded device. 
> Looking at prices NAND flash looks like the best option, 
> especially if we can use JFFS2 on it.
> 
> >From a design point of view, DiscOnChip looks nice with
> it's feature to boot from it.
> SmartMedia looks a bit cheaper, but that would require
> a separate NOR device, large enough to hold a compressed
> kernel, total price going up above the DOC prices again.
> 
> However, all that I have found so far in mailinglists and
> howto's, indicates that JFFS2 on smartmedia has been further
> investigated then JFFS2 on DOC.
> But as far as I understand, there should be no physical limitation
> on a DOC to eventually host a JFFS2 filesystem.
> 
> Is this all true, and has someone managed to get a working 
> JFFS2 filesystem on a DOC? 
> and finaly, what are the chances of acutally booting into a 
> JFFS2 root filesystem directly from a DOC?
> (I heard something about a modified GNU GRUB to replace the DOC
> firmware)
> 
> This would eventually all have to run on a non-x86 processor.
> 
> Is this a workable solution already, or would I have to go for
> more 'conventional' hardware to be safe?
> 
> Best regards,
> 
> Pieter Grimmerink
> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
> 

Re: Current status JFFS2 on DOC

[Thomas Gleixner]

On Wednesday, 8. May 2002 18:37, Pieter Grimmerink wrote:
> From a design point of view, DiscOnChip looks nice with
> it's feature to boot from it.
> SmartMedia looks a bit cheaper, but that would require
> a separate NOR device, large enough to hold a compressed
> kernel, total price going up above the DOC prices again.
The minimum requirement is 1MB for a compressed kernel image
and a bootloader. That's affordable and working :)

> However, all that I have found so far in mailinglists and
> howto's, indicates that JFFS2 on smartmedia has been further
> investigated then JFFS2 on DOC.
JFFS2 on SmartMedia and NAND can be considered as stable.
There are some small TODO's

> But as far as I understand, there should be no physical limitation
> on a DOC to eventually host a JFFS2 filesystem.
No, DOC is NAND with some glue logic around

> Is this all true, and has someone managed to get a working
> JFFS2 filesystem on a DOC?
Thats true, but AFAIK there's no DOC / JFFS2 at the moment.

> and finaly, what are the chances of acutally booting into a
> JFFS2 root filesystem directly from a DOC?
> (I heard something about a modified GNU GRUB to replace the DOC
> firmware)
Yep, grub replaces the bootloader.

> This would eventually all have to run on a non-x86 processor.
Should work

> Is this a workable solution already, or would I have to go for
> more 'conventional' hardware to be safe?
The DOC solution is not workable, because it's not available, but you are 
heartly invited to join the club and hack the neccecary drivers. There are 
some more people around, who are interrested. 

The NAND / Smartmedia solution is working reliable.

See also http://www.linux-mtd.infradead.org/tech/nand.html
-- 
Thomas
___________________________________
autronix automation GmbH
http://www.autronix.de gleixner@autronix.de

Re: Current status JFFS2 on DOC

[Thomas Gleixner]

On Wednesday, 8. May 2002 20:08, Frederick Lefebvre wrote:
> I am working, among many, many other things on getting JFFS2 on a DOC
> 2000.  I do not know when it will be ready since I've got so much work
> right now.
Just for my curiosity. Are you going to implement it on top of the generic 
NAND driver, with a DOC specific hardware driver ?

-- 
Thomas
___________________________________
autronix automation GmbH
http://www.autronix.de gleixner@autronix.de

RE: Current status JFFS2 on DOC

[Pieter Grimmerink]

> -----Original Message-----
> From: linux-mtd-admin@lists.infradead.org
> [mailto:linux-mtd-admin@lists.infradead.org]On Behalf Of Thomas Gleixner
> Sent: woensdag 8 mei 2002 20:23
> To: Pieter Grimmerink; linux-mtd@lists.infradead.org
> Subject: Re: Current status JFFS2 on DOC
>
>
> On Wednesday, 8. May 2002 18:37, Pieter Grimmerink wrote:
> > From a design point of view, DiscOnChip looks nice with
> > it's feature to boot from it.
> > SmartMedia looks a bit cheaper, but that would require
> > a separate NOR device, large enough to hold a compressed
> > kernel, total price going up above the DOC prices again.
> The minimum requirement is 1MB for a compressed kernel image
> and a bootloader. That's affordable and working :)

Well, it's still something like up to 10 $ extra. Might not sound
much for a few devices, but when numbers get higher...

> The DOC solution is not workable, because it's not available, but you are
> heartly invited to join the club and hack the neccecary drivers.
> There are
> some more people around, who are interrested.

I'd be happy to contribute, though this won't be the first thing I'll
be working on, there are a few devicedrivers to implement first.
I'll probably start off with a different fs, or even with a different
flash device, to get the main functionality right.
But judging by the information I've got so far, I think JFFS2 on DOC
is what I'll eventually go for.

Best regards,

Pieter

Re: Current status JFFS2 on DOC

[David Woodhouse]

mailinglists@grimmerink.nl said:
> > The minimum requirement is 1MB for a compressed kernel image
> > and a bootloader. That's affordable and working :)
> Well, it's still something like up to 10 $ extra. Might not sound much
> for a few devices, but when numbers get higher...

The minimum requirement is a lot less than that. All you need is enough 
code to set up DRAM and start pulling more off the NAND flash. The 
LinuxBIOS guys do this in 512 bytes -- which is all that the DiskOnChip 
Millennium has available.

--
dwmw2