Re: [PATCH V6 14/21] clk: tegra210: Add suspend and resume support

Sowjanya Komatineni
2019-08-02T20:40:07Z

On 8/2/19 10:51 AM, Stephen Boyd wrote:
> Quoting Dmitry Osipenko (2019-07-22 00:12:17)
>> 22.07.2019 10:09, Dmitry Osipenko пишет:
>>> 22.07.2019 9:52, Sowjanya Komatineni пишет:
>>>> On 7/21/19 11:10 PM, Dmitry Osipenko wrote:
>>>>> 22.07.2019 1:45, Sowjanya Komatineni пишет:
>>>>>> On 7/21/19 2:38 PM, Dmitry Osipenko wrote:
>>>>>>> 21.07.2019 22:40, Sowjanya Komatineni пишет:
>>>>>>>> @@ -2853,9 +2859,8 @@ static int tegra210_enable_pllu(void)
>>>>>>>>        reg |= PLL_ENABLE;
>>>>>>>>        writel(reg, clk_base + PLLU_BASE);
>>>>>>>>    -    readl_relaxed_poll_timeout_atomic(clk_base + PLLU_BASE, reg,
>>>>>>>> -                      reg & PLL_BASE_LOCK, 2, 1000);
>>>>>>>> -    if (!(reg & PLL_BASE_LOCK)) {
>>>>>>>> +    ret = tegra210_wait_for_mask(&pllu, PLLU_BASE, PLL_BASE_LOCK);
>>>>>>>> +    if (ret) {
>>>>>>> Why this is needed? Was there a bug?
>>>>>>>
>>>>>> during resume pllu init is needed and to use same terga210_init_pllu,
>>>>>> poll_timeout_atomic can't be used as its ony for atomic context.
>>>>>>
>>>>>> So changed to use wait_for_mask which should work in both cases.
>>>>> Atomic variant could be used from any context, not sure what do you
>>>>> mean. The 'atomic' part only means that function won't cause scheduling
>>>>> and that's it.
>>>> Sorry, replied incorrect. readx_poll_timeout_atomic uses ktime_get() and
>>>> during resume timekeeping suspend/resume happens later than clock
>>>> suspend/resume. So using tegra210_wait_for_mask.
>>>>
>>>> both timekeeping and clk-tegra210 drivers are registered as syscore but
>>>> not ordered.
>>> Okay, thank you for the clarification.
>>>
>>> [snip]
>>>
>> You should remove the 'iopoll.h' then, since it's not used anymore.
> And also add a comment to this location in the code because it's
> non-obvious that we can't use iopoll here.
>
Actually added comment during function usage instead of during include
as iopoll.h is removed.

Will add additional comment in include section as well highlighting
reason for removal of iopoll.h