Clarification on multiple mtdram devices - HowTo

MikeW mw_phil at yahoo.co.uk
Wed Mar 21 08:39:54 EDT 2007


MikeW <mw_phil <at> yahoo.co.uk> writes:

> 
>From a (much) earlier post, I note that the mtdram driver can emulate
>several /dev/mtd's by "loading the driver more than once".
> 
>Does this mean modprobing *once* but then setting up multiple
>device nodes with the same major number and different minor numbers ?
> 
>I presume this also implies that each device must have the same
size & erasesize.
> 
> Regards,
> MikeW

Found out about doing this here:
http://electrons.psychogenic.com/modules/wordpress/rants/
2005/08/28/13/linux-on-the-go-exploring-ipaq-options.html

(I would like a section doing this properly on the MTD website FAQ
written by an authoritative person - please !)
>>>>>
To start we load a few modules, creating a fake 32M flash device
 in RAM and ensure we have appropriate /dev/ entries:

# modprobe mtdcore
# modprobe mtdram total_size=32768 erase_size=256
# mkdir /dev/mtdblock ; for i in 0 1 2 3 ;
 do mknod /dev/mtdblock/$i b 31 $i; done

Then we write the contents of one of the JFFS2 images
to the MTD RAM device, and take a look:

# dd if=gpe-image-h3600-20050407124742.rootfs.jffs2 of=/dev/mtdblock/0
# mkdir -p /mnt/ipaq/
# mount -t jffs2 /dev/mtdblock/0 /mnt/ipaq
# cd /mnt/ipaq; ls;

The output will be something like:

	bin  boot  dev  etc  home  lib  media  mnt  proc  sbin
  sys  tmp  usr  var
<<<<





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