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Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA watchdog driver

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Hi Timur,

On 5 November 2015 at 22:08, Timur Tabi <timur@codeaurora.org> wrote:
> Fu Wei wrote:
>>
>> SBSA 2.3 Page 23 :
>> Note: the watchdog offset register is 32 bits wide. This gives a
>> maximum watch period of around 10s at a system
>> counter frequency of 400MHz. If a larger watch period is required then
>> the compare value can be programmed
>> directly into the compare value register.
>>
>> 214s means your system counter is approximately at 20MHz which is in
>> the range of (10MHz ~ 400MHz)
>>
>> SBSA 2.3 Page 13 :
>> The System Counter (of the Generic Timer) shall run at a minimum
>> frequency of 10MHz and maximum of
>> 400MHz.
>
>
> Thanks, that explains a lot.
>
> If we expected customers to have a lower system counter frequency, then we
> wouldn't have to worry about the timeouts being too short.  It seems to me
> that the SBSA spec says that if you want a longer timeout, you have to lower
> the frequency.

Did you really read the "Note" above???????? OK, let me paste it again
and again:

SBSA 2.3 Page 23 :
If a larger watch period is required then the compare value can be
programmed directly into the compare value register.

> We shouldn't be complicating the driver because some
> customers might not follow the spec.

OK it this customer might not follow the spec, that watchdog is not a
SBSA watchdog,
So please don't use SBSA watchdog driver on that non-SBSA watchdog
device, Thanks a lot

>
>
> --
> Sent by an employee of the Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the
> Code Aurora Forum, hosted by The Linux Foundation.



-- 
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
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Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Timur Tabi <timur@codeaurora.org> - 2015-11-05 03:00 +0100
  Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Guenter Roeck <linux@roeck-us.net> - 2015-11-05 06:20 +0100
    Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Fu Wei <fu.wei@linaro.org> - 2015-11-05 13:00 +0100
      Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Timur Tabi <timur@codeaurora.org> - 2015-11-05 14:50 +0100
    Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Timur Tabi <timur@codeaurora.org> - 2015-11-05 14:50 +0100
      Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Timur Tabi <timur@codeaurora.org> - 2015-11-05 15:10 +0100
        Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Fu Wei <fu.wei@linaro.org> - 2015-11-05 15:40 +0100
          Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Timur Tabi <timur@codeaurora.org> - 2015-11-05 15:50 +0100
            Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Fu Wei <fu.wei@linaro.org> - 2015-11-05 16:10 +0100
              Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Guenter Roeck <linux@roeck-us.net> - 2015-11-05 17:50 +0100
                Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Fu Wei <fu.wei@linaro.org> - 2015-11-05 19:00 +0100
                Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Timur Tabi <timur@codeaurora.org> - 2015-11-05 19:00 +0100
                Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Fu Wei <fu.wei@linaro.org> - 2015-11-05 19:10 +0100
                Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Al Stone <al.stone@linaro.org> - 2015-11-13 01:10 +0100
                Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Guenter Roeck <linux@roeck-us.net> - 2015-11-13 01:30 +0100
                Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Timur Tabi <timur@codeaurora.org> - 2015-11-13 01:30 +0100
      Re: [Linaro-acpi] [PATCH v8 5/5] Watchdog: introduce ARM SBSA  watchdog driver Fu Wei <fu.wei@linaro.org> - 2015-11-05 15:10 +0100

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