mtd_debug usage

[Duke]

On 11/22/06, Duke <ezbonites at gmail.com> wrote:
> On 11/22/06, Ricard Wanderlof <ricard.wanderlof at axis.com> wrote:
> > mtdblock devices are normally only used with the mount/umount commands.
> > For erase /dev/mtdX is required - the mtdblock devices don't support the
> > required ioctls. Actually, since a while back, it's not necessary to use
> > /dev/mtdblockX devices for mount/umount either since they understand
> > 'mtdX' directly as in  mount -t cramfs mtd1 /mnt/mountpoint .
> >
> > mtdblock devices do support an automatic erase-before-write functionality
> > when writing. This used to be buggy, don't know the status of this. As far
> > as I'm concerned, it's of little use anyway, because if the image you are
> > writing is smaller than the partition, using this feature will leave the
> > end of the partition unerased which is probably not what you want. Doing
> > separate erase and write operations is thus preferable IMHO.
> >
> > > Creating 3 MTD partitions on "physmap-flash.0":
> > > 0x00000000-0x00040000 : "boot"
> > > 0x00040000-0x00200000 : "kernel"
> > > 0x00200000-0x00800000 : "cramfs"
> > >
> > > When I ran mtd_debug I get the following from the above mapping:
> > >
> > > # mtd_debug info /dev/mtd2
> > > mtd.size = 1835008 (1M)
> > >
> > > # mtd_debug info /dev/mtd1
> > > mtd.size = 262144 (256K)
> > >
> > > # mtd_debug info /dev/mtd0
> > > mtd.size = 262144 (256K)
> > >
> > > # mtd_debug info /dev/mtd3
> > > mtd.size = 1835008 (1M)
> >
> > Looks like your minor numbers are screwed up for the /dev/mtd devices. 0
> > and 1 seem to have the same size, as to 2 and 3. Normally mtd0 is the
> > whole flash, with the first partition being in mtd1 (someone please
> > correct me if I'm wrong here). mtd0/1 seems to refer to the first 256k
> > boot partition, with mtd2/3 referring to the kernel partition with the
> > size of 0x1c0000 = 1835008.
> >
> > What does  ls -l /dev/mtd*  (and ls -l /dev/mtdblock*) say?
>
> It looks like this:
>
> crw-r--r--    1 root     root      90,   0 Mar 22  2005 /dev/mtd0
> crw-r--r--    1 root     root      90,   1 Mar 22  2005 /dev/mtd1
> crw-r--r--    1 root     root      90,   2 Mar 22  2005 /dev/mtd2
> crw-r--r--    1 root     root      90,   3 Mar 22  2005 /dev/mtd3
> crw-r--r--    1 root     root      90,   4 Nov 22  2006 /dev/mtd4
> brw-r--r--    1 root     root      31,   0 Mar 22  2005 /dev/mtdblock0
> brw-r--r--    1 root     root      31,   1 Mar 22  2005 /dev/mtdblock1
> brw-r--r--    1 root     root      31,   2 Mar 22  2005 /dev/mtdblock2
> brw-r--r--    1 root     root      31,   3 Mar 22  2005 /dev/mtdblock3
> brw-r--r--    1 root     root      31,   4 Nov 22  2006 /dev/mtdblock4
>
> I've added the fourth block but that looks the same as the 0 and 1 blocks.

This is what it looks like for the following partitions (this looks
wierd to me):

cfi_cmdset_0001: Erase suspend on write enabled
4 cmdlinepart partitions found on MTD device physmap-flash.0
Creating 4 MTD partitions on "physmap-flash.0":
0x00000000-0x00040000 : "boot"
0x00040000-0x00200000 : "kernel"
0x00200000-0x00800000 : "cramfs"
0x00800000-0x01000000 : "jffs2"

#mtd_debug info /dev/mtd0
mtd.type = MTD_NORFLASH
mtd.flags =
mtd.size = 262144 (256K)
mtd.erasesize = 262144 (256K)
mtd.oobblock = 1
mtd.oobsize = 0
mtd.ecctype = MTD_ECC_NONE
regions = 0

# mtd_debug info /dev/mtd1
mtd.type = MTD_NORFLASH
mtd.flags =
mtd.size = 262144 (256K)
mtd.erasesize = 262144 (256K)
mtd.oobblock = 1
mtd.oobsize = 0
mtd.ecctype = MTD_ECC_NONE
regions = 0

#  mtd_debug info /dev/mtd2
mtd.type = MTD_NORFLASH
mtd.flags =
mtd.size = 1835008 (1M)
mtd.erasesize = 262144 (256K)
mtd.oobblock = 1
mtd.oobsize = 0
mtd.ecctype = MTD_ECC_NONE
regions = 0

#  mtd_debug info /dev/mtd3
mtd.type = MTD_NORFLASH
mtd.flags =
mtd.size = 1835008 (1M)
mtd.erasesize = 262144 (256K)
mtd.oobblock = 1
mtd.oobsize = 0
mtd.ecctype = MTD_ECC_NONE
regions = 0

#  mtd_debug info /dev/mtd4
mtd.type = MTD_NORFLASH
mtd.flags =
mtd.size = 6291456 (6M)
mtd.erasesize = 262144 (256K)
mtd.oobblock = 1
mtd.oobsize = 0
mtd.ecctype = MTD_ECC_NONE
regions = 0

#  mtd_debug info /dev/mtd5
mtd.type = MTD_NORFLASH
mtd.flags =
mtd.size = 6291456 (6M)
mtd.erasesize = 262144 (256K)
mtd.oobblock = 1
mtd.oobsize = 0
mtd.ecctype = MTD_ECC_NONE
regions = 0

#  mtd_debug info /dev/mtd6
mtd.type = MTD_NORFLASH
mtd.flags =
mtd.size = 8388608 (8M)
mtd.erasesize = 262144 (256K)
mtd.oobblock = 1
mtd.oobsize = 0
mtd.ecctype = MTD_ECC_NONE
regions = 0