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Date: Fri, 29 May 2015 07:54:18 -0700
From: Guenter Roeck <linux@roeck-us.net>
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To: Fu Wei <fu.wei@linaro.org>
CC: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>,
        Linaro ACPI Mailman List <linaro-acpi@lists.linaro.org>,
        linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
        Wei Fu <tekkamanninja@gmail.com>,
        G Gregory <graeme.gregory@linaro.org>, Al Stone <al.stone@linaro.org>,
        Hanjun Guo <hanjun.guo@linaro.org>, Timur Tabi <timur@codeaurora.org>,
        Ashwin Chaugule <ashwin.chaugule@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>, vgandhi@codeaurora.org, wim@iguana.be,
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        Jon Corbet <corbet@lwn.net>, Mark Rutland <mark.rutland@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH v3 5/6] Watchdog: introduce ARM SBSA watchdog driver
References: <=fu.wei@linaro.org>	<1432548193-19569-1-git-send-email-fu.wei@linaro.org>	<1432548193-19569-6-git-send-email-fu.wei@linaro.org>	<55637A6D.3080403@roeck-us.net> <CADyBb7t_OC0FwoCeOr-umZhjTMxXZ65g7U8Ca+SUgmiWwjvm2w@mail.gmail.com>
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On 05/29/2015 02:11 AM, Fu Wei wrote:
[ ... ]

>>> +
>>> +       status = sbsa_gwdt_cf_read(SBSA_GWDT_WCS, wdd);
>>> +       if (status & SBSA_GWDT_WCS_WS1) {
>>> +               dev_warn(dev, "System reset by WDT(WCS: %x, WCV: %llx)\n",
>>> +                        status, sbsa_gwdt_get_wcv(wdd));
>>
>>
>> Does this message (specifically the WCS / WCV values) have any
>> useful meaning for the user ?
>
> I think so, according to SBSA spec:
> If WS0 is asserted and a timeout refresh occurs then the following must occur:
>      If the system is compliant to SBSA level 2 or higher the compare
> value must retain its current value. This means that the compare value
> records the time that WS1 is asserted.
>
> So, I think WCV can log the time when system reset by WDT, that may
> help user figure out the problem. but WCS can be delete I think.
>

How would that help ? It is just a number with no reference to anything.

Thanks,
Guenter