Virtual MTD-Device

Virtual MTD-Device

[Frank Neuber]

Hi,
I work on a MIPS based platform with different types of flash chips.
So it is possible that one board has a 4MB flash and a 8MB flash bank
with different size of sectors. Also the flash is not linear mapped. I
will say there are holes between the 4MB and the 8MB chips.
What I wish to do is to use this flash as one virtual MTD so that I can
place a filesystem on both chips.
I'm looking for things like LVM or Softraid what only support striping 
in the MTD-Driver. Also it should be simple enough that the bootloader
can handle this.
Has anyone thought about this problem, maybe there is a ready to run solution :-))

Regards,
 Frank 
-- 
Dipl.-Ing. Elektrotechnik           convergence / HW
Frank Neuber                        Rosenthalerstr.51 / 10178 Berlin
Email:  neuber@convergence.de           Phone:  +49(0)30-72 62 06 76
WWW:    www.convergence.de              Fax:    +49(0)30-72 62 06 55

Re: Virtual MTD-Device

[Frank Neuber]

On Mon, Oct 14, 2002 at 11:27:38AM +0200, Frank Neuber wrote:
Hi again,
> I'm looking for things like LVM or Softraid what only support striping 
> in the MTD-Driver. Also it should be simple enough that the bootloader
> can handle this.
> Has anyone thought about this problem, maybe there is a ready to run solution :-))
I feel that mtdconcat is that what I need :-)

Regards,
 Frank 
-- 
Dipl.-Ing. Elektrotechnik           convergence / HW
Frank Neuber                        Rosenthalerstr.51 / 10178 Berlin
Email:  neuber@convergence.de           Phone:  +49(0)30-72 62 06 76
WWW:    www.convergence.de              Fax:    +49(0)30-72 62 06 55

Re: Virtual MTD-Device

[Robert Kaiser]

Tach auch,

Am Montag, 14. Oktober 2002 11:27 schrieben Sie:
> So it is possible that one board has a 4MB flash and a 8MB flash bank
> with different size of sectors. Also the flash is not linear mapped. I
> will say there are holes between the 4MB and the 8MB chips.
> What I wish to do is to use this flash as one virtual MTD so that I can
> place a filesystem on both chips.
> I'm looking for things like LVM or Softraid what only support striping
> in the MTD-Driver. Also it should be simple enough that the bootloader
> can handle this.
> Has anyone thought about this problem, maybe there is a ready to run
> solution :-))

Yep. Have a look at the MTD concat layer (mtdconcat.c). See the map drivers 
for the DIL/NetPC (dilnetpc.c) and the SC520 CDP (sc520cdp.c) for examples on 
how to use this layer. On these two reference platforms, the chips that are 
being concatenated happen to have uniform sector sizes, but I did test this 
stuff in at least one configuration with varying sector sizes. So, this 
_should_ work out ot the box.

Rob


----------------------------------------------------------------
Robert Kaiser                         email: rkaiser@sysgo.de
SYSGO AG
Am Pfaffenstein 14                    phone: (49) 6136 9948-762
D-55270 Klein-Winternheim / Germany   fax:   (49) 6136 9948-10

Re: Virtual MTD-Device

[Frank Neuber]

On Mon, Oct 14, 2002 at 12:57:48PM +0200, Robert Kaiser wrote:
> Tach auch,
Ebenso ...

> > Has anyone thought about this problem, maybe there is a ready to run
> > solution :-))
> 
> Yep. Have a look at the MTD concat layer (mtdconcat.c). See the map drivers 
> for the DIL/NetPC (dilnetpc.c) and the SC520 CDP (sc520cdp.c) for examples on 
> how to use this layer. On these two reference platforms, the chips that are 
It seems that is exactly that what I want :-)

> being concatenated happen to have uniform sector sizes, but I did test this 
> stuff in at least one configuration with varying sector sizes. So, this 
> _should_ work out ot the box.
Ahh, interresting. I will check this out and let you know when it works.

Additionally I will add the exact flash configuration to the kernel
command line, so that I can use the same kernel for different flash
placements on the target platform.

Bis dann,
 Frank
-- 
Dipl.-Ing. Elektrotechnik           convergence / HW
Frank Neuber                        Rosenthalerstr.51 / 10178 Berlin
Email:  neuber@convergence.de           Phone:  +49(0)30-72 62 06 76
WWW:    www.convergence.de              Fax:    +49(0)30-72 62 06 55

Re: Virtual MTD-Device

[Robert Kaiser]

On Mon, 14 Oct 2002, Frank Neuber wrote:
> Additionally I will add the exact flash configuration to the kernel
> command line, so that I can use the same kernel for different flash
> placements on the target platform.

You probably have noticed this already, but just to to be sure: there is
support in MTD for specifying partitions via the commandline (cmdline.c).

Rob

----------------------------------------------------------------
Robert Kaiser                         email: rkaiser@sysgo.de
SYSGO AG
Am Pfaffenstein 14                    phone: (49) 6136 9948-762
D-55270 Klein-Winternheim / Germany   fax:   (49) 6136 9948-10

Re: Virtual MTD-Device

[Frank Neuber]

On Mon, Oct 14, 2002 at 05:28:19PM +0200, Frank Neuber wrote:
> > > Has anyone thought about this problem, maybe there is a ready to run
> > > solution :-))
> > 
> > Yep. Have a look at the MTD concat layer (mtdconcat.c). See the map drivers 
> > for the DIL/NetPC (dilnetpc.c) and the SC520 CDP (sc520cdp.c) for examples on 
> > how to use this layer. On these two reference platforms, the chips that are 
> It seems that is exactly that what I want :-)
> 
> > being concatenated happen to have uniform sector sizes, but I did test this 
> > stuff in at least one configuration with varying sector sizes. So, this 
> > _should_ work out ot the box.
> Ahh, interresting. I will check this out and let you know when it works.
And it works well, thanks ... great work!
I did a mix between dilnetpc.c and sc520cdp.c because I have two chips
with partitioning information.
It was easy to collect the free space to one mtd into the kernel.

> Additionally I will add the exact flash configuration to the kernel
> command line, so that I can use the same kernel for different flash
> placements on the target platform.
This is the thing I will do next.

Regards,
  Frank
-- 
Dipl.-Ing. Elektrotechnik           convergence / HW
Frank Neuber                        Rosenthalerstr.51 / 10178 Berlin
Email:  neuber@convergence.de           Phone:  +49(0)30-72 62 06 76
WWW:    www.convergence.de              Fax:    +49(0)30-72 62 06 55

Re: Virtual MTD-Device

[Robert Kaiser]

On Thu, 17 Oct 2002, Frank Neuber wrote:

> On Mon, Oct 14, 2002 at 05:28:19PM +0200, Frank Neuber wrote:
> And it works well, thanks ... great work!
> I did a mix between dilnetpc.c and sc520cdp.c because I have two chips
> with partitioning information.
> It was easy to collect the free space to one mtd into the kernel.

Glad to hear it works for you :-)

<hint>
If your hardware is something off the shelf (i.e. if your mapping driver 
could be useful to other people), it would be nice if you could contribute
it to the MTD project when you're done.
</hint>

Rob

----------------------------------------------------------------
Robert Kaiser                         email: rkaiser@sysgo.de
SYSGO AG
Am Pfaffenstein 14                    phone: (49) 6136 9948-762
D-55270 Klein-Winternheim / Germany   fax:   (49) 6136 9948-10

Re: Virtual MTD-Device

[Frank Neuber]

On Fri, Oct 18, 2002 at 08:35:30AM +0200, Robert Kaiser wrote:

Hi Robert,
> Glad to hear it works for you :-)
:-)

> <hint>
> If your hardware is something off the shelf (i.e. if your mapping driver 
> could be useful to other people), it would be nice if you could contribute
> it to the MTD project when you're done.
> </hint>
Maybe this mapping driver could be useful to other people which have the
same requirements (only as an example).
This driver is an integral part of a new Galaxis MHP-SetTopBox. Because
this box is made for the customer market it could be a good idea to
publish this driver.

 Frank

-- 
Dipl.-Ing. Elektrotechnik           convergence / HW
Frank Neuber                        Rosenthalerstr.51 / 10178 Berlin
Email:  neuber@convergence.de           Phone:  +49(0)30-72 62 06 76
WWW:    www.convergence.de              Fax:    +49(0)30-72 62 06 55