Re: the procedure setting up jffs2

Re: the procedure setting up jffs2

[Karim Yaghmour]

Jack Lu wrote:
> I am using RPX850 Lite with 16MB flash(4 chips of Am29Lv320MB) with buswidth
> 32 and interleave 4.
> I have complied the MTD and JFFS2 module into the kernel.
> When I start up the Linux, Linux found the 16MB flash, the whole flash
> corresponds to /dev/mtd0.
> 
> 1. where can I get the mkfs.jffs2 excutable for MPC850?

Hmm... There are quite a few places that provide pre-packaged PPC tools,
Denx (denx.de) is one of those. If you have the cross-compiling tools
already, then building it on your own should be fairly easy also.

> 2. the bottom 256KB is the boot loader code of the 16MB flash. the rest si
> for storing data
>         if I do
>         #cat jffs2.image > /dev/mtd0
>         will the bootloader be erased?

The chip you mention is bottom-boot, so the above will very likely wipe-out
the bootloader. You probably want to partition your MTD device by modifying
the mapping driver and then write the JFFS2 image to another partition then
/dev/mtd0. Check drivers/mtd/tqm8xxl.c for an example.

Karim

===================================================
                 Karim Yaghmour
               karim@opersys.com
      Embedded and Real-Time Linux Expert
===================================================

Re: the procedure setting up jffs2

[Wolfgang Denk]

Hi Karim,

in message <3D811741.FB5178A@opersys.com> you wrote:
> 
> The chip you mention is bottom-boot, so the above will very likely wipe-out
> the bootloader. You probably want to partition your MTD device by modifying
> the mapping driver and then write the JFFS2 image to another partition then
> /dev/mtd0. Check drivers/mtd/tqm8xxl.c for an example.

We (more  or  less)  consider  this  method  of  static  partitioning
obsolete.   We  use  (and  recommend  to  our  customers)  a  dynamic
partitioning, where "partition table" information is  passed  to  the
Linux kernel by PPCBoot using the kernel command line.

For example, passing the kernel a boot argument of

	mtdparts=0:256k(PPCboot)ro,768k(Kernel),-(Rest);1:-(myJFFS2)

results in this partitioning:

	...
	TQM flash bank 0: Using command line partition definition
	Creating 3 MTD partitions on "TQM8xxL Bank 0":
	0x00000000-0x00040000 : "PPCboot"
	0x00040000-0x00100000 : "Kernel"
	0x00100000-0x00400000 : "Rest"
	TQM flash bank 1: Using command line partition definition
	Creating 1 MTD partitions on "TQM8xxL Bank 1":
	0x00000000-0x00400000 : "myJFFS2"
	...

See the config option "CONFIG_MTD_CMDLINE_PARTS" in our kernel
sources.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
The price one pays for pursuing any profession,  or  calling,  is  an
intimate knowledge of its ugly side.                  - James Baldwin

Re: the procedure setting up jffs2

[Karim Yaghmour]

Wolfgang Denk wrote:
> in message <3D811741.FB5178A@opersys.com> you wrote:
> >
> > The chip you mention is bottom-boot, so the above will very likely wipe-out
> > the bootloader. You probably want to partition your MTD device by modifying
> > the mapping driver and then write the JFFS2 image to another partition then
> > /dev/mtd0. Check drivers/mtd/tqm8xxl.c for an example.
> 
> We (more  or  less)  consider  this  method  of  static  partitioning
> obsolete.  

So do I. Unfortunately, drivers/mtd/cmdline.c is only available in the MTD
CVS for the time being (and Denx's kernel sources ;). Neither 2.5.34 nor
2.4.19 include this code. Instead, they currently include drivers/mtd/bootldr.c
which is only for ARM. Do you have any idea when cmdline.c will be part of the
mainline kernel?

Karim

===================================================
                 Karim Yaghmour
               karim@opersys.com
      Embedded and Real-Time Linux Expert
===================================================

Re: the procedure setting up jffs2

[Marius Groeger]

On Thu, 12 Sep 2002, Karim Yaghmour wrote:

> So do I. Unfortunately, drivers/mtd/cmdline.c is only available in the MTD
> CVS for the time being (and Denx's kernel sources ;). Neither 2.5.34 nor

For the records, I'd like to add that obviously (since we developed
it), the cmdline partitioning is also a standard feature of our Elinos
distribution.

Regarding the main-line kernel: don't forget that updating
kernel.org's MTD is one thing -- having more mapping drivers actually
_use_ cmdline.c is another. This is the job of the corresponding
maintainers.

Regards,
Marius

-----------------------------------------------------------------------------
Marius Groeger           SYSGO Real-Time Solutions GmbH     mgroeger@sysgo.de
Software Engineering     Embedded and Real-Time Software    www.sysgo.de
Voice: +49-6136-9948-0   Am Pfaffenstein 14                 www.osek.de
FAX:   +49-6136-9948-10  55270 Klein-Winternheim, Germany   www.elinos.com

the procedure setting up jffs2

[Jack Lu]

Hi

I am using RPX850 Lite with 16MB flash(4 chips of Am29Lv320MB) with buswidth
32 and interleave 4.
I have complied the MTD and JFFS2 module into the kernel.
When I start up the Linux, Linux found the 16MB flash, the whole flash
corresponds to /dev/mtd0.

1. where can I get the mkfs.jffs2 excutable for MPC850?

2. the bottom 256KB is the boot loader code of the 16MB flash. the rest si
for storing data
	if I do
	#cat jffs2.image > /dev/mtd0
	will the bootloader be erased?

I appreciate your help.
Thanks.

Re: the procedure setting up jffs2

[David Woodhouse]

mag@sysgo.de said:
>  Regarding the main-line kernel: don't forget that updating
> kernel.org's MTD is one thing -- having more mapping drivers actually
> _use_ cmdline.c is another. This is the job of the corresponding
> maintainers.

I need to push the current stuff to Linus fairly soon, after which we can 
go through Jörn's new partition stuff and argue about the details for a 
while before merging it :)

--
dwmw2