From: Alexandre Dilly <alexandre.dilly@openwide.fr>
To: u-boot@lists.denx.de
Subject: [U-Boot] [RFC] Bootcount improvements
Date: Tue, 2 Apr 2013 15:17:07 +0200 (CEST) [thread overview]
Message-ID: <603516380.1111802.1364908627236.JavaMail.root@openwide.fr> (raw)
In-Reply-To: <20130326171017.426462014CD@gemini.denx.de>
Hi,
> Dear Alexandre,
>
> >
> > In fact I would like to keep the bootcount value after a shutdown
> > to handle update failures. Some embedded systems have only network
> > access for administration and if you install an updated system with
> > a
> > misconfiguration of the network interface, you can't access anymore
> > to the machine and you can't reset it. So the only way to reset the
> > device is to unplug and replug but bootcount value is reset... So
> > you
> > can't switch back to a safe system...
>
> You can define your own mechanism to do something like that, but
> please do not misuse the bootcount for something it was never meant
> for. The bootcount is defined to count the number of boots after
> power on; i. e. when you power on a board, the boot counter must by
> definition start with the value zero.
>
> > > If you move the bootcount into a non-volatile memory, you add a
> > > history
> > > to the process and breaks this assumption.
> >
> > That's why I suggest to use an environment variable (and may be a
> > configuration option) to enable/disable this features.
>
> It should be easy and straightforward to implement such a feature by
> defining a new environment variable. All this can be done using
> standard scripting, i. e. you do not need any code changes and thus
> no
> new config options.
Thanks a lot for your answers! I will investigate in depth scripting capabilities of u-boot. I hope I will success to make a generic script with existing utilities for the purpose I've described before.
Best regards,
Alexandre Dilly
prev parent reply other threads:[~2013-04-02 13:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <2055038254.798610.1363956733033.JavaMail.root@openwide.fr>
2013-03-22 12:56 ` [U-Boot] [RFC] Bootcount improvements Alexandre Dilly
2013-03-22 16:25 ` Otavio Salvador
2013-03-23 9:49 ` Stefano Babic
2013-03-26 16:57 ` Alexandre Dilly
2013-03-26 17:10 ` Wolfgang Denk
2013-04-02 13:17 ` Alexandre Dilly [this message]
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