linux-kernel - Re: [PATCH 4/4] PM / Domains: Allow to attach a CPU via genpd_dev_pm_attach_by

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Message-ID: <20190425094741.olaw3zgfox3yc7bc@vireshk-i7>
Date:   Thu, 25 Apr 2019 15:17:41 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Ulf Hansson <ulf.hansson@...aro.org>
Cc:     "Rafael J . Wysocki" <rjw@...ysocki.net>, linux-pm@...r.kernel.org,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        "Raju P . L . S . S . S . N" <rplsssn@...eaurora.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Tony Lindgren <tony@...mide.com>,
        Kevin Hilman <khilman@...nel.org>,
        Lina Iyer <ilina@...eaurora.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Niklas Cassel <niklas.cassel@...aro.org>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 4/4] PM / Domains: Allow to attach a CPU via
 genpd_dev_pm_attach_by_id|name()

On 25-04-19, 11:04, Ulf Hansson wrote:
> Attaching a device via genpd_dev_pm_attach_by_id|name() makes genpd to
> allocate a virtual device that it attaches instead. This leads to a problem
> in case the base device belongs to a CPU. More precisely, it means
> genpd_get_cpu() compares against the virtual device, thus it fails to find
> a matching CPU device.
> 
> Address this limitation, by passing the base device to genpd_get_cpu()
> rather than the virtual device. Moreover, to deal with detach correctly
> from genpd_remove_device(), let's store the CPU number in the struct
> generic_pm_domain_data, as to be able to clear the corresponding bit in the
> cpumask for the genpd.
> 
> Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
> ---
>  drivers/base/power/domain.c | 20 ++++++++++----------
>  include/linux/pm_domain.h   |  1 +
>  2 files changed, 11 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index da1c99178943..3d899e8abd58 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1499,10 +1499,11 @@ static int genpd_get_cpu(struct generic_pm_domain *genpd, struct device *dev)
>  	return -1;
>  }
>  
> -static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
> +static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
> +			    struct device *base_dev)
>  {
>  	struct generic_pm_domain_data *gpd_data;
> -	int ret, cpu;
> +	int ret;
>  
>  	dev_dbg(dev, "%s()\n", __func__);
>  
> @@ -1513,7 +1514,7 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
>  	if (IS_ERR(gpd_data))
>  		return PTR_ERR(gpd_data);
>  
> -	cpu = genpd_get_cpu(genpd, dev);
> +	gpd_data->cpu = genpd_get_cpu(genpd, base_dev);
>  
>  	ret = genpd->attach_dev ? genpd->attach_dev(genpd, dev) : 0;
>  	if (ret)
> @@ -1521,7 +1522,7 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
>  
>  	genpd_lock(genpd);
>  
> -	genpd_set_cpumask(genpd, cpu);
> +	genpd_set_cpumask(genpd, gpd_data->cpu);
>  	dev_pm_domain_set(dev, &genpd->domain);
>  
>  	genpd->device_count++;
> @@ -1549,7 +1550,7 @@ int pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
>  	int ret;
>  
>  	mutex_lock(&gpd_list_lock);
> -	ret = genpd_add_device(genpd, dev);
> +	ret = genpd_add_device(genpd, dev, dev);
>  	mutex_unlock(&gpd_list_lock);
>  
>  	return ret;
> @@ -1561,14 +1562,13 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
>  {
>  	struct generic_pm_domain_data *gpd_data;
>  	struct pm_domain_data *pdd;
> -	int cpu, ret = 0;
> +	int ret = 0;
>  
>  	dev_dbg(dev, "%s()\n", __func__);
>  
>  	pdd = dev->power.subsys_data->domain_data;
>  	gpd_data = to_gpd_data(pdd);
>  	dev_pm_qos_remove_notifier(dev, &gpd_data->nb);
> -	cpu = genpd_get_cpu(genpd, dev);
>  
>  	genpd_lock(genpd);
>  
> @@ -1580,7 +1580,7 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
>  	genpd->device_count--;
>  	genpd->max_off_time_changed = true;
>  
> -	genpd_clear_cpumask(genpd, cpu);
> +	genpd_clear_cpumask(genpd, gpd_data->cpu);
>  	dev_pm_domain_set(dev, NULL);
>  
>  	list_del_init(&pdd->list_node);
> @@ -2256,7 +2256,7 @@ int of_genpd_add_device(struct of_phandle_args *genpdspec, struct device *dev)
>  		goto out;
>  	}
>  
> -	ret = genpd_add_device(genpd, dev);
> +	ret = genpd_add_device(genpd, dev, dev);
>  
>  out:
>  	mutex_unlock(&gpd_list_lock);
> @@ -2426,7 +2426,7 @@ static int __genpd_dev_pm_attach(struct device *dev, struct device *base_dev,
>  
>  	dev_dbg(dev, "adding to PM domain %s\n", pd->name);
>  
> -	ret = genpd_add_device(pd, dev);
> +	ret = genpd_add_device(pd, dev, base_dev);
>  	mutex_unlock(&gpd_list_lock);
>  
>  	if (ret < 0) {
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index bc82e74560ee..0e8e356bed6a 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -175,6 +175,7 @@ struct generic_pm_domain_data {
>  	struct pm_domain_data base;
>  	struct gpd_timing_data td;
>  	struct notifier_block nb;
> +	int cpu;
>  	unsigned int performance_state;
>  	void *data;
>  };

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh