public inbox for u-boot@lists.denx.de
 help / color / mirror / Atom feed
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

      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]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=603516380.1111802.1364908627236.JavaMail.root@openwide.fr \
    --to=alexandre.dilly@openwide.fr \
    --cc=u-boot@lists.denx.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox