Re: [PATCH v4 5/7] Watchdog: introduce ARM SBSA watchdog driver

[Fu Wei <fu.wei@linaro.org>]

On 10 June 2015 at 22:36, Fu Wei <fu.wei@linaro.org> wrote:
> On 10 June 2015 at 22:22, Timur Tabi <timur@codeaurora.org> wrote:
>> Fu Wei wrote:
>>>
>>> Another weakness of only using WOR is the timeout limited by this
>>> 32bit register.
>>> 10s @400MHz generic Timer
>>>
>>> I don't think this limit is good for a server, once the server is in a
>>> heavy load
>>
>>
>> Perhaps, but if that's the limitation of the hardware, then so be it.
>
> it is not the real limitation, if we use WCV, SBSA spec has mentioned that.
>
> ------ 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
> ------ SBSA 2.3-------Page 23 ----------

------ SBSA 2.3-------Page 24 ----------
0x010 – 0x013 WCV[31:0]
0x014 – 0x017 WCV[63:32]
Watchdog compare value.
*Read/Write* registers
containing the current value in the watchdog compare
register.
------ SBSA 2.3-------Page 24 ----------

>
> if some hardware doesn't support writing WCV,
> that means this hardware is non-standard SBSA watchdog.
>
>>
>> --
>> 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



-- 
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