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Date:   Fri, 24 May 2019 15:52:37 +0200
From:   Wolfram Sang <wsa@the-dreams.de>
To:     Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc:     linux-watchdog@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Guenter Roeck <linux@roeck-us.net>
Subject: Re: [RFC PATCH] watchdog: renesas_wdt: support handover from
 bootloader
Message-ID: <20190524135237.GC15892@kunai>
References: <20190415105201.2078-1-wsa+renesas@sang-engineering.com>
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On Mon, Apr 15, 2019 at 12:52:01PM +0200, Wolfram Sang wrote:
> Support an already running watchdog by checking its enable bit and set
> up the status accordingly before registering the device.
>=20
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

After second thought, I am getting confused a little. If the WDT is
already running then

a) before this patch: after successful probe, RPM will disable the
clock until userspace opens the watchdog device

b) after this patch: during probe, our default timeout will be
programmed and because of WDOG_HW_RUNNING, the core will generate pings
until userspace opens the watchdog device.

So, b) will protect from a crashing kernel (no pings anymore) but not
=66rom something like missing rootfs, or?

The usecase I had in mind ("give the kernel <x> seconds to boot into
working userspace") seems to be achieved by loading the WDT driver as a
module then, I guess?


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