Date:	Thu, 13 Nov 2014 15:10:07 +0100
From:	Pavel Machek <pavel@....cz>
To:	Geert Uytterhoeven <geert+renesas@...der.be>
Cc:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PM / Domains: Extract code to power off/on a PM domain

On Mon 2014-11-10 19:39:19, Geert Uytterhoeven wrote:
> PM domains are powered on/off from various places. Some callers do
> latency measurements, others don't. Consolidate using two helper
> functions, which always measure the latencies, and update the stored
> latencies when needed.
> 
> Other minor changes:
>   - Use pr_warn() instead of pr_warning(),
>   - There's no need to check genpd->name, %s handles NULL pointers fine,
>   - Make the warning format strings identical, to save memory.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
> Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>
> Reviewed-by: Kevin Hilman <khilman@...aro.org>

Acked-by: Pavel Machek <pavel@....cz>

> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index a841bab441147b3d..2fccf2c2575e4fa3 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -151,6 +151,59 @@ static void genpd_recalc_cpu_exit_latency(struct generic_pm_domain *genpd)
>  	genpd->cpuidle_data->idle_state->exit_latency = usecs64;
>  }
>  
> +static int genpd_power_on(struct generic_pm_domain *genpd)
> +{
> +	ktime_t time_start;
> +	s64 elapsed_ns;
> +	int ret;
> +
> +	if (!genpd->power_on)
> +		return 0;
> +
> +	time_start = ktime_get();
> +	ret = genpd->power_on(genpd);
> +	if (ret)
> +		return ret;
> +
> +	elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
> +	if (elapsed_ns <= genpd->power_on_latency_ns)
> +		return ret;
> +
> +	genpd->power_on_latency_ns = elapsed_ns;
> +	genpd->max_off_time_changed = true;
> +	genpd_recalc_cpu_exit_latency(genpd);
> +	pr_warn("%s: Power-%s latency exceeded, new value %lld ns\n",
> +		genpd->name, "on", elapsed_ns);
> +
> +	return ret;
> +}
> +
> +static int genpd_power_off(struct generic_pm_domain *genpd)
> +{
> +	ktime_t time_start;
> +	s64 elapsed_ns;
> +	int ret;
> +
> +	if (!genpd->power_off)
> +		return 0;
> +
> +	time_start = ktime_get();
> +	ret = genpd->power_off(genpd);
> +	if (ret == -EBUSY)
> +		return ret;
> +
> +	elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
> +	if (elapsed_ns <= genpd->power_off_latency_ns)
> +		return ret;
> +
> +	genpd->power_off_latency_ns = elapsed_ns;
> +	genpd->max_off_time_changed = true;
> +	pr_warn("%s: Power-%s latency exceeded, new value %lld ns\n",
> +		genpd->name, "off", elapsed_ns);
> +
> +	return ret;
> +}
> +
>  /**
>   * __pm_genpd_poweron - Restore power to a given PM domain and its masters.
>   * @genpd: PM domain to power up.
> @@ -222,25 +275,9 @@ static int __pm_genpd_poweron(struct generic_pm_domain *genpd)
>  		}
>  	}
>  
> -	if (genpd->power_on) {
> -		ktime_t time_start = ktime_get();
> -		s64 elapsed_ns;
> -
> -		ret = genpd->power_on(genpd);
> -		if (ret)
> -			goto err;
> -
> -		elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
> -		if (elapsed_ns > genpd->power_on_latency_ns) {
> -			genpd->power_on_latency_ns = elapsed_ns;
> -			genpd->max_off_time_changed = true;
> -			genpd_recalc_cpu_exit_latency(genpd);
> -			if (genpd->name)
> -				pr_warning("%s: Power-on latency exceeded, "
> -					"new value %lld ns\n", genpd->name,
> -					elapsed_ns);
> -		}
> -	}
> +	ret = genpd_power_on(genpd);
> +	if (ret)
> +		goto err;
>  
>   out:
>  	genpd_set_active(genpd);
> @@ -529,16 +566,11 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
>  	}
>  
>  	if (genpd->power_off) {
> -		ktime_t time_start;
> -		s64 elapsed_ns;
> -
>  		if (atomic_read(&genpd->sd_count) > 0) {
>  			ret = -EBUSY;
>  			goto out;
>  		}
>  
> -		time_start = ktime_get();
> -
>  		/*
>  		 * If sd_count > 0 at this point, one of the subdomains hasn't
>  		 * managed to call pm_genpd_poweron() for the master yet after
> @@ -547,21 +579,11 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
>  		 * the pm_genpd_poweron() restore power for us (this shouldn't
>  		 * happen very often).
>  		 */
> -		ret = genpd->power_off(genpd);
> +		ret = genpd_power_off(genpd);
>  		if (ret == -EBUSY) {
>  			genpd_set_active(genpd);
>  			goto out;
>  		}
> -
> -		elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
> -		if (elapsed_ns > genpd->power_off_latency_ns) {
> -			genpd->power_off_latency_ns = elapsed_ns;
> -			genpd->max_off_time_changed = true;
> -			if (genpd->name)
> -				pr_warning("%s: Power-off latency exceeded, "
> -					"new value %lld ns\n", genpd->name,
> -					elapsed_ns);
> -		}
>  	}
>  
>  	genpd->status = GPD_STATE_POWER_OFF;
> @@ -796,8 +818,7 @@ static void pm_genpd_sync_poweroff(struct generic_pm_domain *genpd)
>  	    || atomic_read(&genpd->sd_count) > 0)
>  		return;
>  
> -	if (genpd->power_off)
> -		genpd->power_off(genpd);
> +	genpd_power_off(genpd);
>  
>  	genpd->status = GPD_STATE_POWER_OFF;
>  
> @@ -828,8 +849,7 @@ static void pm_genpd_sync_poweron(struct generic_pm_domain *genpd)
>  		genpd_sd_counter_inc(link->master);
>  	}
>  
> -	if (genpd->power_on)
> -		genpd->power_on(genpd);
> +	genpd_power_on(genpd);
>  
>  	genpd->status = GPD_STATE_ACTIVE;
>  }
> @@ -1251,8 +1271,7 @@ static int pm_genpd_restore_noirq(struct device *dev)
>  			 * If the domain was off before the hibernation, make
>  			 * sure it will be off going forward.
>  			 */
> -			if (genpd->power_off)
> -				genpd->power_off(genpd);
> +			genpd_power_off(genpd);
>  
>  			return 0;
>  		}

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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