RE: how to change size of MTD partitions at runtime

From: "Stephan Linke" <Stephan.Linke@epygi.de>
To: "Kuefmann Andreas ICM CP RD SD 1" <andreas.kuefmann@siemens.com>,
	<linux-mtd@lists.infradead.org>
Subject: RE: how to change size of MTD partitions at runtime
Date: Thu, 2 Sep 2004 15:19:53 +0200	[thread overview]
Message-ID: <NGENJJFPMHGLPILEKKAMEEMGCEAA.Stephan.Linke@epygi.de> (raw)
In-Reply-To: <7F3FE9B2FBF6194691BC493C6699C0B1568B8D@mchh9esa.mchh.siemens.de>

Hi Andreas,

for the same purpose I am using an additional partition that covers the range of kernel and rootfs to update both of them at the
same time. Ofcourse in this case after writing the images the device has to be rebooted.
How do you handle remounting the rootfs and synchronization with current systems configuration so you don't have to reboot?

Regards, Stephan

> -----Original Message-----
> From: linux-mtd-bounces@lists.infradead.org
> [mailto:linux-mtd-bounces@lists.infradead.org]On Behalf Of Kuefmann
> Andreas ICM CP RD SD 1
> Sent: Mittwoch, 1. September 2004 13:42
> To: 'linux-mtd@lists.infradead.org'
> Subject: how to change size of MTD partitions at runtime
>
>
> Hi all,
>
> I'm searching for a solution to dynamically change the size of
> MTD partitions at runtime.
>
> This functionality is required for a flash update of kernel and/or
> rootfs in the special case that the new kernel/rootfs is larger
> than the old one. (in an embedded environment)
>
> 1.)
> there is no problem in erasing the flash, e.g eraseall /dev/mtd?,
> (acting from a chrooted environment)
>
> 2.)
> However, reprogramming the flash with a larger image (now
> exceeding the limits of the previous partition) isn't as
> easy as a cp newimage.img /dev/mtd?.
>
> The MTD layer will still rely on the (old) partition sizes
> that were valid during system startup. (taken over from a
> U-BOOT environment)
>
> My plans are as follows:
> - erase the flash partitions
> - adapt the u-boot environment to reflect the new mtd partition sizes
> - force the MTD subsystem to "re-read" the partition table in u-boot's
>   environment.
> - cp the new images to /dev/mtd? (which now reflect the changed
>   partition sizes)
>
> My question now is:
> - How can I manage to force a re-read of the partition table?
>
> Or can you think of another solution to change MTD partitions at
> runtime?
>
> Thank you,
> regards,
> - Andy
>
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