"Timing issue when we use SPANSION 8MB Flash"

"Timing issue when we use SPANSION 8MB Flash"

[nreddy]

Hi ,

We are developing an embedded system with u-boot and Montavista Emebededd
linux ( Kernel Version 2.4.20).
Here we have put AMD 4MB flash  and the system is working is working fine.
Recently we have increased Flash size to 8MB(SPANSION ( S29GL064M90FAIR10)
make).

Now the system works fine but with one problem.

When i try to copy files to /mnt/jffs2 directory it is taking very long
time(around 8 Minutes for 2.2 MB files).
But when i try to copy files on 4MB Flash (AMD(AM29LV320DT) Make) it is
taking only 1.7 Min to copy same size of files.

Can any one throw a light on this...

Thanks in advance,
--Nagi Reddy

Re: "Timing issue when we use SPANSION 8MB Flash"

[Vitaly Wool]

Hi,

am I right that it's a NOR flash? What's the reason for using JFFS2 on 
it then?
Also questionable is whether you're sure that you have right timings 
configuration for the flash. I'm afraid that 8MB Spansion flash might 
have timing values different from 4 MB's.

Best regards,
   Vitaly

nreddy@netenrich.com wrote:

>Hi ,
>
>We are developing an embedded system with u-boot and Montavista Emebededd
>linux ( Kernel Version 2.4.20).
>Here we have put AMD 4MB flash  and the system is working is working fine.
>Recently we have increased Flash size to 8MB(SPANSION ( S29GL064M90FAIR10)
>make).
>
>Now the system works fine but with one problem.
>
>When i try to copy files to /mnt/jffs2 directory it is taking very long
>time(around 8 Minutes for 2.2 MB files).
>But when i try to copy files on 4MB Flash (AMD(AM29LV320DT) Make) it is
>taking only 1.7 Min to copy same size of files.
>
>Can any one throw a light on this...
>
>Thanks in advance,
>--Nagi Reddy
>
>
>______________________________________________________
>Linux MTD discussion mailing list
>http://lists.infradead.org/mailman/listinfo/linux-mtd/
>
>
>  
>

Re: "Timing issue when we use SPANSION 8MB Flash"

[Thomas Gleixner]

On Sat, 2005-10-08 at 13:55 +0400, Vitaly Wool wrote:
> Hi,
> 
> am I right that it's a NOR flash? What's the reason for using JFFS2 on 
> it then?

Err, why shouldnt he use JFFS2 on NOR ? Is there a better suited file
system which can handle NOR FLASH?

tglx

Re: "Timing issue when we use SPANSION 8MB Flash"

[Vitaly Wool]

Thomas Gleixner wrote:

>On Sat, 2005-10-08 at 13:55 +0400, Vitaly Wool wrote:
>  
>
>>Hi,
>>
>>am I right that it's a NOR flash? What's the reason for using JFFS2 on 
>>it then?
>>    
>>
>
>Err, why shouldnt he use JFFS2 on NOR ? Is there a better suited file
>system which can handle NOR FLASH?
>
>tglx
>
>  
>
cramfs ;)

Re: "Timing issue when we use SPANSION 8MB Flash"

[David Vrabel]

Vitaly Wool wrote:
> Thomas Gleixner wrote:
>> Vitaly Wool wrote:
>>>
>>> am I right that it's a NOR flash? What's the reason for using JFFS2
>>> on it then?
>>
>> Err, why shouldnt he use JFFS2 on NOR ? Is there a better suited file
>> system which can handle NOR FLASH?
>
> cramfs ;)

When you can write to cramfs let me know!

In case you didn't know, JFFS2 (and its predecessor, JFFS) was actually
originally designed for NOR flash -- NAND support was added later.

David Vrabel
-- 
David Vrabel, Design Engineer

Arcom, Clifton Road           Tel: +44 (0)1223 411200 ext. 3233
Cambridge CB1 7EA, UK         Web: http://www.arcom.com/

Re: "Timing issue when we use SPANSION 8MB Flash"

[Josh Boyer]

On Mon, 2005-10-10 at 09:20 +0100, David Vrabel wrote:
> Vitaly Wool wrote:
> > Thomas Gleixner wrote:
> >> Vitaly Wool wrote:
> >>>
> >>> am I right that it's a NOR flash? What's the reason for using JFFS2
> >>> on it then?
> >>
> >> Err, why shouldnt he use JFFS2 on NOR ? Is there a better suited file
> >> system which can handle NOR FLASH?
> >
> > cramfs ;)
> 
> When you can write to cramfs let me know!
> 
> In case you didn't know, JFFS2 (and its predecessor, JFFS) was actually
> originally designed for NOR flash -- NAND support was added later.

And if what you are after is a read-only compressed filesystem, I would
recommend squashfs over cramfs.

josh

Re: "Timing issue when we use SPANSION 8MB Flash"

[Jörn Engel]

On Mon, 10 October 2005 10:38:13 -0500, Josh Boyer wrote:
> 
> And if what you are after is a read-only compressed filesystem, I would
> recommend squashfs over cramfs.

Not unconditionally.  There is a reason why cramfs is not merged into
the kernel yet.  While its pure performance numbers (compression rate,
etc) are better, the code has its issues.  Biggest offender is the use
of bitfields, which are duplicated depending on the endianness of the
filesystem and the host machine.

YMMV, so I won't give any recommendation either way.

Jörn

-- 
A surrounded army must be given a way out.
-- Sun Tzu