From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>,
linux-watchdog@vger.kernel.org
Subject: Re: What to set in struct watchdog_device::bootstatus?
Date: Wed, 20 Feb 2019 21:14:08 +0100 [thread overview]
Message-ID: <20190220201408.gcgsg43uonwc4ucs@pengutronix.de> (raw)
In-Reply-To: <f9ec94d7-8365-e733-81ff-34c501cce89a@roeck-us.net>
Hello Guenter,
On Fri, Feb 08, 2019 at 06:05:43AM -0800, Guenter Roeck wrote:
> On 2/8/19 2:52 AM, Uwe Kleine-König wrote:
> > Hello,
> >
> > it's unclear to me, which bits I am supposed to set in the bootstatus
> > member of struct watchdog_device at probe time.
> >
> > The i.MX watchdog differentiates the following reset causes:
> >
> > - Power On
> None.
>
> > - external reset
>
> None.
>
> > - watchdog timeout
>
> WDIOF_CARDRESET
>
> > - software reset using a bit in the watchdog register set
> >
> > (Not all i.MX variants implement all bits according to the respective
> > reference manuals.)
> >
> > Should "Power On" result in setting WDIOF_POWERUNDER?
> >
> No.
>
> > Should "software reset [...]" result in WDIOF_CARDRESET?
> >
> That would be the best fit if you want a bit to be set, but it would be
> misleading since it would suggest that the watchdog fired.
>
> > Should "external reset" result in WDIOF_EXTERN1? (I guess that no)
>
> No.
In a custom kernel patch stack I found a patch that uses (apart from
WDIOF_CARDRESET also) WDIOF_POWERUNDER and WDIOF_EXTERN1 to
differentiate the different reset causes. Now that you told using this
is wrong, I wonder how these are supposed to be used instead; and there
are a few more that according to
Documentation/watchdog/watchdog-kernel-api.txt might be used to set
bootstatus. Are these a relic? What do these signal?
IMHO there is a patch opportunity waiting to improve the documenation
:-) Or maybe even change watchdog_get_status() to ensure that only
WDIOF_CARDRESET, WDIOF_MAGICCLOSE and WDIOF_KEEPALIVEPING can be set?
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
next prev parent reply other threads:[~2019-02-20 20:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-08 10:52 What to set in struct watchdog_device::bootstatus? Uwe Kleine-König
2019-02-08 14:05 ` Guenter Roeck
2019-02-20 20:14 ` Uwe Kleine-König [this message]
2019-05-09 19:25 ` Uwe Kleine-König
2019-05-10 3:53 ` Guenter Roeck
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