From: Stefan Roese <sr@denx.de>
To: "Marek Behún" <marek.behun@nic.cz>
Cc: u-boot@lists.denx.de, pali@kernel.org
Subject: Re: [PATCH u-boot-mvebu 3/3] arm: mvebu: turris_omnia: disable MCU watchdog in SPL when booting over UART
Date: Mon, 16 Aug 2021 15:13:25 +0200 [thread overview]
Message-ID: <753289ee-911f-1476-591e-fe2249b2f505@denx.de> (raw)
In-Reply-To: <20210816151100.0d9e7cc0@dellmb>
On 16.08.21 15:11, Marek Behún wrote:
> On Mon, 16 Aug 2021 15:07:33 +0200
> Stefan Roese <sr@denx.de> wrote:
>
>> So the MCU watchdog is some kind of very early WD and only used until
>> the SoC WD is used / enabled?
>
> Yes, this is how it was first thought of for Omnia. Looking at the MCU
> code it seems that the watchdog can be started again after being
> disabled, so it could theoretically be used as a normal watchdog. The
> problem is that it cannot be pinged to reset the counter. It has to be
> stopped and started again, meaning there is a small window when it is
> disabled. If the system used this watchdog, this small window would
> make it vulnerable, so I don't think we should use it.
Agreed. With such a WD concept including this "window of vulnerability",
it really shouldn't be used.
Thanks,
Stefan
>>> Shall I resend this series with this new patch?
>
>> Yes, please do.
>
> Will do.
>
> Marek
>
Viele Grüße,
Stefan
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-51 Fax: (+49)-8142-66989-80 Email: sr@denx.de
prev parent reply other threads:[~2021-08-16 13:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-16 12:27 [PATCH u-boot-mvebu 0/3] turris_omnia: Disable MCU watchdog in SPL when booting over UART Marek Behún
2021-08-16 12:27 ` [PATCH u-boot-mvebu 1/3] arm: mvebu: Move get_boot_device() to cpu.c and make visible Marek Behún
2021-08-16 12:27 ` [PATCH u-boot-mvebu 2/3] arm: mvebu: turris_omnia: don't guard by CONFIG_SPL_BUILD macro Marek Behún
2021-08-16 12:27 ` [PATCH u-boot-mvebu 3/3] arm: mvebu: turris_omnia: disable MCU watchdog in SPL when booting over UART Marek Behún
2021-08-16 12:50 ` Stefan Roese
2021-08-16 13:01 ` Marek Behún
2021-08-16 13:07 ` Stefan Roese
2021-08-16 13:11 ` Marek Behún
2021-08-16 13:13 ` Stefan Roese [this message]
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