[PATCH V2] PM / Domains: Add pm_genpd_lookup() API to lookup domain by firmware node

[PATCH V2] PM / Domains: Add pm_genpd_lookup() API to lookup domain by firmware node

[Ulf Hansson]

In a step to move away from using genpd's name based APIs, such as the
pm_genpd_add_subdomain_names(), provide an API to lookup an already
initialized generic PM domain by its firmware node.

This API would typically be a called from SOC specific code, to fetch a
handle to the domain. Especially convenient to configure subdomains and
when the hierarchy of the domains are described in DT.

Do note, before pm_genpd_init() is invoked to initialize a generic PM
domain, it's the callers responsibility to assign the new ->fwnode
pointer in the struct generic_pm_domain, to enable pm_genpd_lookup() to
find the domain.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---

Changes in v2:
	Change from using struct device_node to struct fwnode_handle.
	Updated commit header accordingly.

---
 drivers/base/power/domain.c | 27 +++++++++++++++++++++++++++
 include/linux/pm_domain.h   |  4 ++++
 2 files changed, 31 insertions(+)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 735c473..2d881d5 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -75,6 +75,33 @@ struct generic_pm_domain *dev_to_genpd(struct device *dev)
 	return pd_to_genpd(dev->pm_domain);
 }
 
+/**
+ * pm_genpd_lookup - Fetch a generic PM domain object by firmware node.
+ * @node: Firmware node to a corresponding genpd.
+ *
+ * Returns a valid pointer to struct generic_pm_domain on success or ERR_PTR()
+ * on failure.
+ */
+struct generic_pm_domain *pm_genpd_lookup(struct fwnode_handle *node)
+{
+	struct generic_pm_domain *genpd = ERR_PTR(-ENOENT), *gpd;
+
+	if (IS_ERR_OR_NULL(node))
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&gpd_list_lock);
+	list_for_each_entry(gpd, &gpd_list, gpd_list_node) {
+		if (gpd->fwnode == node) {
+			genpd = gpd;
+			break;
+		}
+	}
+	mutex_unlock(&gpd_list_lock);
+
+	return genpd;
+}
+EXPORT_SYMBOL_GPL(pm_genpd_lookup);
+
 static int genpd_stop_dev(struct generic_pm_domain *genpd, struct device *dev)
 {
 	return GENPD_DEV_TIMED_CALLBACK(genpd, int, stop, dev,
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 8cbd32e..aa01050 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -43,6 +43,8 @@ struct gpd_cpuidle_data {
 	struct cpuidle_state *idle_state;
 };
 
+struct fwnode_handle;
+
 struct generic_pm_domain {
 	struct dev_pm_domain domain;	/* PM domain operations */
 	struct list_head gpd_list_node;	/* Node in the global PM domains list */
@@ -53,6 +55,7 @@ struct generic_pm_domain {
 	struct dev_power_governor *gov;
 	struct work_struct power_off_work;
 	const char *name;
+	struct fwnode_handle *fwnode;	/* Firware node for the PM domain */
 	unsigned int in_progress;	/* Number of devices being suspended now */
 	atomic_t sd_count;	/* Number of subdomains with power "on" */
 	enum gpd_status status;	/* Current state of the domain */
@@ -126,6 +129,7 @@ static inline struct generic_pm_domain_data *dev_gpd_data(struct device *dev)
 }
 
 extern struct generic_pm_domain *dev_to_genpd(struct device *dev);
+extern struct generic_pm_domain *pm_genpd_lookup(struct fwnode_handle *node);
 extern int __pm_genpd_add_device(struct generic_pm_domain *genpd,
 				 struct device *dev,
 				 struct gpd_timing_data *td);
-- 
1.9.1

Re: [PATCH V2] PM / Domains: Add pm_genpd_lookup() API to lookup domain by firmware node

[Rafael J. Wysocki]

On Friday, November 28, 2014 11:38:35 AM Ulf Hansson wrote:
> In a step to move away from using genpd's name based APIs, such as the
> pm_genpd_add_subdomain_names(), provide an API to lookup an already
> initialized generic PM domain by its firmware node.
> 
> This API would typically be a called from SOC specific code, to fetch a
> handle to the domain. Especially convenient to configure subdomains and
> when the hierarchy of the domains are described in DT.
> 
> Do note, before pm_genpd_init() is invoked to initialize a generic PM
> domain, it's the callers responsibility to assign the new ->fwnode
> pointer in the struct generic_pm_domain, to enable pm_genpd_lookup() to
> find the domain.
> 
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

I have no problems with that, but do you have a user for it?

> ---
> 
> Changes in v2:
> 	Change from using struct device_node to struct fwnode_handle.
> 	Updated commit header accordingly.
> 
> ---
>  drivers/base/power/domain.c | 27 +++++++++++++++++++++++++++
>  include/linux/pm_domain.h   |  4 ++++
>  2 files changed, 31 insertions(+)
> 
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 735c473..2d881d5 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -75,6 +75,33 @@ struct generic_pm_domain *dev_to_genpd(struct device *dev)
>  	return pd_to_genpd(dev->pm_domain);
>  }
>  
> +/**
> + * pm_genpd_lookup - Fetch a generic PM domain object by firmware node.
> + * @node: Firmware node to a corresponding genpd.
> + *
> + * Returns a valid pointer to struct generic_pm_domain on success or ERR_PTR()
> + * on failure.
> + */
> +struct generic_pm_domain *pm_genpd_lookup(struct fwnode_handle *node)
> +{
> +	struct generic_pm_domain *genpd = ERR_PTR(-ENOENT), *gpd;
> +
> +	if (IS_ERR_OR_NULL(node))
> +		return ERR_PTR(-EINVAL);
> +
> +	mutex_lock(&gpd_list_lock);
> +	list_for_each_entry(gpd, &gpd_list, gpd_list_node) {
> +		if (gpd->fwnode == node) {
> +			genpd = gpd;
> +			break;
> +		}
> +	}
> +	mutex_unlock(&gpd_list_lock);
> +
> +	return genpd;
> +}
> +EXPORT_SYMBOL_GPL(pm_genpd_lookup);
> +
>  static int genpd_stop_dev(struct generic_pm_domain *genpd, struct device *dev)
>  {
>  	return GENPD_DEV_TIMED_CALLBACK(genpd, int, stop, dev,
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 8cbd32e..aa01050 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -43,6 +43,8 @@ struct gpd_cpuidle_data {
>  	struct cpuidle_state *idle_state;
>  };
>  
> +struct fwnode_handle;
> +
>  struct generic_pm_domain {
>  	struct dev_pm_domain domain;	/* PM domain operations */
>  	struct list_head gpd_list_node;	/* Node in the global PM domains list */
> @@ -53,6 +55,7 @@ struct generic_pm_domain {
>  	struct dev_power_governor *gov;
>  	struct work_struct power_off_work;
>  	const char *name;
> +	struct fwnode_handle *fwnode;	/* Firware node for the PM domain */
>  	unsigned int in_progress;	/* Number of devices being suspended now */
>  	atomic_t sd_count;	/* Number of subdomains with power "on" */
>  	enum gpd_status status;	/* Current state of the domain */
> @@ -126,6 +129,7 @@ static inline struct generic_pm_domain_data *dev_gpd_data(struct device *dev)
>  }
>  
>  extern struct generic_pm_domain *dev_to_genpd(struct device *dev);
> +extern struct generic_pm_domain *pm_genpd_lookup(struct fwnode_handle *node);
>  extern int __pm_genpd_add_device(struct generic_pm_domain *genpd,
>  				 struct device *dev,
>  				 struct gpd_timing_data *td);
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.

Re: [PATCH V2] PM / Domains: Add pm_genpd_lookup() API to lookup domain by firmware node

[Ulf Hansson]

On 29 November 2014 at 01:30, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> On Friday, November 28, 2014 11:38:35 AM Ulf Hansson wrote:
>> In a step to move away from using genpd's name based APIs, such as the
>> pm_genpd_add_subdomain_names(), provide an API to lookup an already
>> initialized generic PM domain by its firmware node.
>>
>> This API would typically be a called from SOC specific code, to fetch a
>> handle to the domain. Especially convenient to configure subdomains and
>> when the hierarchy of the domains are described in DT.
>>
>> Do note, before pm_genpd_init() is invoked to initialize a generic PM
>> domain, it's the callers responsibility to assign the new ->fwnode
>> pointer in the struct generic_pm_domain, to enable pm_genpd_lookup() to
>> find the domain.
>>
>> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
>
> I have no problems with that, but do you have a user for it?

Amit Daniel Kachhap, posted a patchset which is adding subdomains
configured from DT for Exynos. It's from there the idea to this patch
comes from. Amit is about to post a new version, based on this patch.

https://lkml.org/lkml/2014/11/24/290

Kind regards
Uffe

Re: [PATCH V2] PM / Domains: Add pm_genpd_lookup() API to lookup domain by firmware node

[amit daniel kachhap]

On Mon, Dec 1, 2014 at 3:56 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> On 29 November 2014 at 01:30, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>> On Friday, November 28, 2014 11:38:35 AM Ulf Hansson wrote:
>>> In a step to move away from using genpd's name based APIs, such as the
>>> pm_genpd_add_subdomain_names(), provide an API to lookup an already
>>> initialized generic PM domain by its firmware node.
>>>
>>> This API would typically be a called from SOC specific code, to fetch a
>>> handle to the domain. Especially convenient to configure subdomains and
>>> when the hierarchy of the domains are described in DT.
>>>
>>> Do note, before pm_genpd_init() is invoked to initialize a generic PM
>>> domain, it's the callers responsibility to assign the new ->fwnode
>>> pointer in the struct generic_pm_domain, to enable pm_genpd_lookup() to
>>> find the domain.
>>>
>>> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
>>
>> I have no problems with that, but do you have a user for it?
>
> Amit Daniel Kachhap, posted a patchset which is adding subdomains
> configured from DT for Exynos. It's from there the idea to this patch
> comes from. Amit is about to post a new version, based on this patch.

Hi Ulf,

I was trying to use this API but i felt there is a better way of just exporting
of_genpd_get_from_provider as a similar API is used to register the
power domain.

Check if this make sense www.spinics.net/lists/arm-kernel/msg382665.html.

Regards,
Amit


>
> https://lkml.org/lkml/2014/11/24/290
>
> Kind regards
> Uffe
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Re: [PATCH V2] PM / Domains: Add pm_genpd_lookup() API to lookup domain by firmware node

[Ulf Hansson]

On 1 December 2014 at 12:57, amit daniel kachhap
<amit.daniel@samsung.com> wrote:
> On Mon, Dec 1, 2014 at 3:56 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote:
>> On 29 November 2014 at 01:30, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>>> On Friday, November 28, 2014 11:38:35 AM Ulf Hansson wrote:
>>>> In a step to move away from using genpd's name based APIs, such as the
>>>> pm_genpd_add_subdomain_names(), provide an API to lookup an already
>>>> initialized generic PM domain by its firmware node.
>>>>
>>>> This API would typically be a called from SOC specific code, to fetch a
>>>> handle to the domain. Especially convenient to configure subdomains and
>>>> when the hierarchy of the domains are described in DT.
>>>>
>>>> Do note, before pm_genpd_init() is invoked to initialize a generic PM
>>>> domain, it's the callers responsibility to assign the new ->fwnode
>>>> pointer in the struct generic_pm_domain, to enable pm_genpd_lookup() to
>>>> find the domain.
>>>>
>>>> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
>>>
>>> I have no problems with that, but do you have a user for it?
>>
>> Amit Daniel Kachhap, posted a patchset which is adding subdomains
>> configured from DT for Exynos. It's from there the idea to this patch
>> comes from. Amit is about to post a new version, based on this patch.
>
> Hi Ulf,
>
> I was trying to use this API but i felt there is a better way of just exporting
> of_genpd_get_from_provider as a similar API is used to register the
> power domain.
>
> Check if this make sense www.spinics.net/lists/arm-kernel/msg382665.html.
>

That makes sense!

So, let's drop $subject patch.

Kind regards
Uffe