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Date: Mon, 25 May 2015 10:00:24 +0800
Message-ID: <CADyBb7vma9Ur72xyC5mVKfM=Kx3TgeM4LodgLnzjecRu4JPemQ@mail.gmail.com>
Subject: Re: [PATCH v2 6/7] Watchdog: introduce ARM SBSA watchdog driver
From: Fu Wei <fu.wei@linaro.org>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Timur Tabi <timur@codeaurora.org>,
        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>,
        Ashwin Chaugule <ashwin.chaugule@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>, vgandhi@codeaurora.org, wim@iguana.be,
        Jon Masters <jcm@redhat.com>, Leo Duran <leo.duran@amd.com>,
        Jon Corbet <corbet@lwn.net>, Mark Rutland <mark.rutland@arm.com>
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Hi, Guenter,



On 25 May 2015 at 01:32, Guenter Roeck <linux@roeck-us.net> wrote:
> On 05/24/2015 10:19 AM, Timur Tabi wrote:
>>
>> Fu Wei wrote:
>>>
>>> I don't know why you want to do this tricky way.  you can always
>>> register the interrupt handler,
>>> if pre-timeout is 0, system will just trigger WS1 right after WS0
>>
>>
>> But that only works if the pre-timeout and timeout can be programmed to
>> separate values.  And as Guenter says, the SBSA may not guarantee that.
>>
>
> The pseudo-code in the specification suggests that if WCV is configured,
>         WS0 = WCV
>         WS1 = WCV + WOR
>
> Assuming that the implementation follows the pseudo-code in the
> specification,
> we would have separately programmable values. Since the pretimeout (per ABI)
> is the difference in seconds to the timeout, and not an absolute value,
> we would have to program the registers as follows.
>
>         WCV = timeout - pretimeout;
>         WOR = pretimeout;

yes, this patchset is doing this way.

>
> Does this make sense ?
>
> Thanks,
> Guenter
>



-- 
Best regards,

Fu Wei
Software Engineer
Red Hat Software (Beijing) Co.,Ltd.Shanghai Branch
Ph: +86 21 61221326(direct)
Ph: +86 186 2020 4684 (mobile)
Room 1512, Regus One Corporate Avenue,Level 15,
One Corporate Avenue,222 Hubin Road,Huangpu District,
Shanghai,China 200021