jffs, jffs2

jffs, jffs2

[Simon Posnjak]

Hi all,

I have some newbie quastions about jffs and jffs2. Our SA1110 based
board has 16MB of NOR based FLASH (Intel StrataFlesh).

-Which one (jffs or jffs2) would be a better choice(I need stability and
good back up on power fail)? Which version should I use (CVS or the one
that comes with vanila Linux kernel). 

-Have can I create a empty image? (I have a partition of 8 MB and I want
to put jffs or jffs2 on it)

-Have can I write the image from my bootloader - I mean how should I
modify my bootloader to support writing of a jffs/jffs2 image to flash
so that I can boot my system from it(only root will be on jffs - the
kernel will be preloaded and booted by bootloader). (My bootloader is
blob) 

	lp simon

RE: jffs, jffs2

[Christopher Hoover]

Use jffs2 over jffs.

Caveat with 2.5: if your flash has variable-sized blocks (e.g. Intel C3
flash), you'll need to either use the mtd CVS or patch the 2.5 sources
accordingly. 

Use mkfs.jffs2 to build the image.

With blob, just pretend "ramdisk" is "root".  You'll need to have
configured the proper partitioning into both blob and the sa1100 mtd
partition code. 

Write the image by doing "erase ramdisk; xdownload ramdisk; {send the
file}; flash ramdisk".  The erase is important.    

One final thing: be sure to configure your blob parameters to tell it
not to load the ramdisk automatically.  

-ch

RE: jffs, jffs2

[Simon Posnjak]

On Tue, 2002-09-24 at 21:54, Christopher Hoover wrote:
> 
> Use jffs2 over jffs.
> 
> Caveat with 2.5: if your flash has variable-sized blocks (e.g. Intel C3
> flash), you'll need to either use the mtd CVS or patch the 2.5 sources
> accordingly. 
I wasn't to clear: I will be using 2.4.18. The date in TODO file which
is located in fs/jffs2 directory is 2001/03/01 which seams to be a bit
old. What I would like to now is there a newer (stable) version. (What
to pull out of the CVS - HEAD or some other taged version)

> Use mkfs.jffs2 to build the image.
> 
> With blob, just pretend "ramdisk" is "root".  You'll need to have
> configured the proper partitioning into both blob and the sa1100 mtd
> partition code. 
> 
> Write the image by doing "erase ramdisk; xdownload ramdisk; {send the
> file}; flash ramdisk".  The erase is important.    
> 
> One final thing: be sure to configure your blob parameters to tell it
> not to load the ramdisk automatically.  

OK I got this, thank you for your help. Just one more thing:

So to mount an empty mtd partition as jffs/jffs2 all I have to do is to
erase it (using erase utilty from mtd)and then just do mount -t jffs2
/dev/mtdblock5 /somedir. Is this correct?

	Regards Simon

RE: jffs, jffs2

[Christopher Hoover]

> I wasn't to clear: I will be using 2.4.18.

I don't know.  I haven't run 2.4.18 on ARM in a long time.  (Why are you
deliberately using an old kernel?)

> So to mount an empty mtd partition as jffs/jffs2 all I have to do is
to
> erase it (using erase utilty from mtd)and then just do mount -t jffs2
> /dev/mtdblock5 /somedir. Is this correct?

You need to use mkfs.jffs2, just as you would use mkfs.ext2 to create an
ext2 filesystem.  See my original prescription.

-ch