linux-kernel - Re: [PATCH 12/14] OMAP: CLK: CLKSRC: Add suspend resume hooks

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Date:   Tue, 22 May 2018 13:27:10 +0530
From:   Keerthy <j-keerthy@...com>
To:     Tony Lindgren <tony@...mide.com>
CC:     <linus.walleij@...aro.org>, <grygorii.strashko@...com>,
        <t-kristo@...com>, <Russ.Dill@...com>,
        <linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <ssantosh@...nel.org>, <haojian.zhuang@...aro.org>,
        <linux-arm-kernel@...ts.infradead.org>, <d-gerlach@...com>
Subject: Re: [PATCH 12/14] OMAP: CLK: CLKSRC: Add suspend resume hooks



On Thursday 12 April 2018 07:57 PM, Tony Lindgren wrote:
> * Keerthy <j-keerthy@...com> [180412 03:56]:
>> Add the save and restore for clksrc as part of suspend and resume
>> so that it saves the counter value and restores. This is needed in
>> modes like rtc+ddr in self-refresh not doing this stalls the time.
> 
> I suspect this too should really happen with cpu_pm.

I believe going by the previous set of patches this fits better with
suspend/resume?

> 
>> --- a/arch/arm/mach-omap2/timer.c
>> +++ b/arch/arm/mach-omap2/timer.c
>> @@ -442,6 +442,38 @@ static int __init __maybe_unused omap2_sync32k_clocksource_init(void)
>>  	return ret;
>>  }
>>  
>> +static unsigned int omap2_gptimer_clksrc_load;
>> +
>> +static void omap2_gptimer_clksrc_suspend(struct clocksource *unused)
>> +{
>> +	struct omap_hwmod *oh;
>> +
>> +	omap2_gptimer_clksrc_load =
>> +		__omap_dm_timer_read_counter(&clksrc, OMAP_TIMER_NONPOSTED);
>> +
>> +	oh = omap_hwmod_lookup(clocksource_gpt.name);
>> +	if (!oh)
>> +		return;
>> +
>> +	omap_hwmod_idle(oh);
>> +}
> 
> Probably no need to look up the hwmod every time? Especially if am437x
> will start supporting deeper idle modes during runtime.

Like clockevent i will store the hwmod pointer for clocksource as well.

> 
> And probably the cpu_pm notifies should be directly in the hwmod
> code so we don't need to add more any more dependencies to hwmod
> functions to timer code. We should have this code move to drivers
> anyways at some point.
> 
> Regards,
> 
> Tony
>