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From: Wolfgang Wegner <wolfgang@leila.ping.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH RFC v3] add CONFIG_BOOTCOUNT_LIMIT for MCF5445x
Date: Sat, 24 Apr 2010 11:45:49 +0200	[thread overview]
Message-ID: <20100424094548.GW20047@leila.ping.de> (raw)
In-Reply-To: <20100423222742.B61FA1EC6E@gemini.denx.de>

Dear Wolfgang Denk,

On Sat, Apr 24, 2010 at 12:27:42AM +0200, Wolfgang Denk wrote:
> Dear Wolfgang Wegner,
> 
> In message <20100423205938.GU20047@leila.ping.de> you wrote:
> > This patch adds bootcount for Freescale MCF5445x. Two registers of
> > eDMA transfer control descriptors (TCD[1]) are used because these
> > are unused by linux kernel (freescale LTIB linux-2.6.25) and were
> > tested to keep their contents across resets.
> > TCD[1] is currently unused by the linux drivers, so using its registers
> > should be safe as long as no non-standard driver is loaded.
> > 
> > Signed-off-by: Wolfgang Wegner <w.wegner@astro-kom.de>
> > ---
> > I implemented and tested this bootcount on a custom MCF54455 board.
> > According to the data sheet, the internal SRAM is not supposed to be
> > useful for data storage across resets. There is no explicit statement
> > concerning the TCD registers, but in tests on our board the values
> > did always survive reset.
> > v2: updated comment
> > v3: moved updated comment to the right place :-)
> 
> Did you???

The part about how long the registers are untouched by other drivers -
yes. The other part not.
Originally the other part of the comment was more or less meant to be a
hint for others (probably having more experience with coldfire than me)
reviewing the patch, so that I could afterwards provide a completely
revised version.
Looking at it today, I should simply have moved everything up to the
commit message, but as it is now, I should probably simply wait to let
others comment before sending another patch?

Best regards,
Wolfgang

  reply	other threads:[~2010-04-24  9:45 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-23 12:38 [U-Boot] [PATCH RFC] add CONFIG_BOOTCOUNT_LIMIT for MCF5445x Wolfgang Wegner
2010-04-23 19:25 ` Wolfgang Denk
2010-04-23 19:43   ` Wolfgang Wegner
2010-04-23 20:03     ` Wolfgang Denk
2010-04-23 20:26       ` [U-Boot] [PATCH RFC v2] " Wolfgang Wegner
2010-04-23 20:47         ` Wolfgang Denk
2010-04-23 20:59           ` [U-Boot] [PATCH RFC v3] " Wolfgang Wegner
2010-04-23 22:27             ` Wolfgang Denk
2010-04-24  9:45               ` Wolfgang Wegner [this message]
2010-04-23 21:00           ` [U-Boot] [PATCH RFC v2] " Wolfgang Wegner

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