diff mbox

[v8,05/26] PM / Domains: Add helper functions to attach/detach CPUs to/from genpd

Message ID 20180620172226.15012-6-ulf.hansson@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Ulf Hansson June 20, 2018, 5:22 p.m. UTC
Introduce two new genpd helper functions, of_genpd_attach|detach_cpu(),
which takes the CPU-number as an in-parameter.

To attach a CPU to a genpd, of_genpd_attach_cpu() starts by fetching the
struct device belonging to the CPU. Then it calls genpd_dev_pm_attach(),
which via DT tries to hook up the CPU device to its corresponding PM
domain. If it succeeds, of_genpd_attach_cpu() continues to prepare/enable
runtime PM of the device.

To detach a CPU from its PM domain, of_genpd_attach_cpu() reverse the
operations made from of_genpd_attach_cpu(). However, first it checks that
the CPU device has a valid PM domain pointer assigned, as to make sure it
belongs to genpd.

Cc: Lina Iyer <ilina@codeaurora.org>
Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/base/power/domain.c | 69 +++++++++++++++++++++++++++++++++++++
 include/linux/pm_domain.h   |  9 +++++
 2 files changed, 78 insertions(+)

Comments

Rafael J. Wysocki July 19, 2018, 10:22 a.m. UTC | #1
On Wednesday, June 20, 2018 7:22:05 PM CEST Ulf Hansson wrote:
> Introduce two new genpd helper functions, of_genpd_attach|detach_cpu(),
> which takes the CPU-number as an in-parameter.
> 
> To attach a CPU to a genpd, of_genpd_attach_cpu() starts by fetching the
> struct device belonging to the CPU. Then it calls genpd_dev_pm_attach(),
> which via DT tries to hook up the CPU device to its corresponding PM
> domain. If it succeeds, of_genpd_attach_cpu() continues to prepare/enable
> runtime PM of the device.
> 
> To detach a CPU from its PM domain, of_genpd_attach_cpu() reverse the
> operations made from of_genpd_attach_cpu(). However, first it checks that
> the CPU device has a valid PM domain pointer assigned, as to make sure it
> belongs to genpd.
> 
> Cc: Lina Iyer <ilina@codeaurora.org>
> Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
>  drivers/base/power/domain.c | 69 +++++++++++++++++++++++++++++++++++++
>  include/linux/pm_domain.h   |  9 +++++
>  2 files changed, 78 insertions(+)
> 
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 6149ce0bfa7b..299fa2febbec 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -2445,6 +2445,75 @@ struct device *genpd_dev_pm_attach_by_id(struct device *dev,
>  }
>  EXPORT_SYMBOL_GPL(genpd_dev_pm_attach_by_id);
>  
> +/*
> + * of_genpd_attach_cpu() - Attach a CPU to its PM domain
> + * @cpu: The CPU to be attached.
> + *
> + * Parses the OF node of the CPU's device, to find a PM domain specifier. If
> + * such is found, attaches the CPU's device to the retrieved pm_domain ops and
> + * enables runtime PM for it. This to allow the CPU to be power managed through
> + * its PM domain.
> + *
> + * Returns zero when successfully attached the CPU's device to its PM domain,
> + * else a negative error code.
> + */
> +int of_genpd_attach_cpu(int cpu)
> +{
> +	struct device *dev = get_cpu_device(cpu);
> +	int ret;
> +
> +	if (!dev) {
> +		pr_warn("genpd: no dev for cpu%d\n", cpu);
> +		return -ENODEV;
> +	}

I'm not sure about the value of the above.  Is it possible even?

> +
> +	ret = genpd_dev_pm_attach(dev);
> +	if (ret != 1) {
> +		dev_warn(dev, "genpd: attach cpu failed %d\n", ret);

This looks like a debug message.  Do you really want to print it with high prio?

> +		return ret < 0 ? ret : -ENODEV;
> +	}
> +
> +	pm_runtime_irq_safe(dev);
> +	pm_runtime_get_noresume(dev);
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);
> +
> +	dev_info(dev, "genpd: attached cpu\n");

This definitely is a debug message.

> +	return 0;
> +}
> +EXPORT_SYMBOL(of_genpd_attach_cpu);
> +
> +/**
> + * of_genpd_detach_cpu() - Detach a CPU from its PM domain
> + * @cpu: The CPU to be detached.
> + *
> + * Detach the CPU's device from its corresponding PM domain. If detaching is
> + * completed successfully, disable runtime PM and restore the runtime PM usage
> + * count for the CPU's device.
> + */
> +void of_genpd_detach_cpu(int cpu)
> +{
> +	struct device *dev = get_cpu_device(cpu);
> +
> +	if (!dev) {
> +		pr_warn("genpd: no dev for cpu%d\n", cpu);
> +		return;
> +	}
> +
> +	/* Check that the device is attached to a genpd. */
> +	if (!(dev->pm_domain && dev->pm_domain->detach == genpd_dev_pm_detach))
> +		return;
> +
> +	genpd_dev_pm_detach(dev, true);
> +
> +	pm_runtime_disable(dev);
> +	pm_runtime_put_noidle(dev);
> +	pm_runtime_reinit(dev);
> +
> +	dev_info(dev, "genpd: detached cpu\n");
> +}
> +EXPORT_SYMBOL(of_genpd_detach_cpu);
> +
>  static const struct of_device_id idle_state_match[] = {
>  	{ .compatible = "domain-idle-state", },
>  	{ }
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 3f67ff0c1c69..2c09cf80b285 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -243,6 +243,8 @@ unsigned int of_genpd_opp_to_performance_state(struct device *dev,
>  int genpd_dev_pm_attach(struct device *dev);
>  struct device *genpd_dev_pm_attach_by_id(struct device *dev,
>  					 unsigned int index);
> +int of_genpd_attach_cpu(int cpu);
> +void of_genpd_detach_cpu(int cpu);
>  #else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
>  static inline int of_genpd_add_provider_simple(struct device_node *np,
>  					struct generic_pm_domain *genpd)
> @@ -294,6 +296,13 @@ static inline struct device *genpd_dev_pm_attach_by_id(struct device *dev,
>  	return NULL;
>  }
>  
> +static inline int of_genpd_attach_cpu(int cpu)
> +{
> +	return -ENODEV;
> +}
> +
> +static inline void of_genpd_detach_cpu(int cpu) {}
> +
>  static inline
>  struct generic_pm_domain *of_genpd_remove_last(struct device_node *np)
>  {
> 

I'd combine this with patch [04/26].  The split here is somewhat artificial IMO.
Ulf Hansson Aug. 3, 2018, 11:44 a.m. UTC | #2
On 19 July 2018 at 12:22, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> On Wednesday, June 20, 2018 7:22:05 PM CEST Ulf Hansson wrote:
>> Introduce two new genpd helper functions, of_genpd_attach|detach_cpu(),
>> which takes the CPU-number as an in-parameter.
>>
>> To attach a CPU to a genpd, of_genpd_attach_cpu() starts by fetching the
>> struct device belonging to the CPU. Then it calls genpd_dev_pm_attach(),
>> which via DT tries to hook up the CPU device to its corresponding PM
>> domain. If it succeeds, of_genpd_attach_cpu() continues to prepare/enable
>> runtime PM of the device.
>>
>> To detach a CPU from its PM domain, of_genpd_attach_cpu() reverse the
>> operations made from of_genpd_attach_cpu(). However, first it checks that
>> the CPU device has a valid PM domain pointer assigned, as to make sure it
>> belongs to genpd.
>>
>> Cc: Lina Iyer <ilina@codeaurora.org>
>> Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
>> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
>> ---
>>  drivers/base/power/domain.c | 69 +++++++++++++++++++++++++++++++++++++
>>  include/linux/pm_domain.h   |  9 +++++
>>  2 files changed, 78 insertions(+)

[...]

> I'd combine this with patch [04/26].  The split here is somewhat artificial IMO.

I wanted to keep one change per patch, hence the split.

$subject patch introduces helpers to add CPU devices to genpd and
isn't really part of making genpd to cope with CPU devices. So
$subject patch is about avoiding open coding.

Are you still sure you want me to squash the changes?

Kind regards
Uffe
diff mbox

Patch

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 6149ce0bfa7b..299fa2febbec 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -2445,6 +2445,75 @@  struct device *genpd_dev_pm_attach_by_id(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(genpd_dev_pm_attach_by_id);
 
+/*
+ * of_genpd_attach_cpu() - Attach a CPU to its PM domain
+ * @cpu: The CPU to be attached.
+ *
+ * Parses the OF node of the CPU's device, to find a PM domain specifier. If
+ * such is found, attaches the CPU's device to the retrieved pm_domain ops and
+ * enables runtime PM for it. This to allow the CPU to be power managed through
+ * its PM domain.
+ *
+ * Returns zero when successfully attached the CPU's device to its PM domain,
+ * else a negative error code.
+ */
+int of_genpd_attach_cpu(int cpu)
+{
+	struct device *dev = get_cpu_device(cpu);
+	int ret;
+
+	if (!dev) {
+		pr_warn("genpd: no dev for cpu%d\n", cpu);
+		return -ENODEV;
+	}
+
+	ret = genpd_dev_pm_attach(dev);
+	if (ret != 1) {
+		dev_warn(dev, "genpd: attach cpu failed %d\n", ret);
+		return ret < 0 ? ret : -ENODEV;
+	}
+
+	pm_runtime_irq_safe(dev);
+	pm_runtime_get_noresume(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	dev_info(dev, "genpd: attached cpu\n");
+	return 0;
+}
+EXPORT_SYMBOL(of_genpd_attach_cpu);
+
+/**
+ * of_genpd_detach_cpu() - Detach a CPU from its PM domain
+ * @cpu: The CPU to be detached.
+ *
+ * Detach the CPU's device from its corresponding PM domain. If detaching is
+ * completed successfully, disable runtime PM and restore the runtime PM usage
+ * count for the CPU's device.
+ */
+void of_genpd_detach_cpu(int cpu)
+{
+	struct device *dev = get_cpu_device(cpu);
+
+	if (!dev) {
+		pr_warn("genpd: no dev for cpu%d\n", cpu);
+		return;
+	}
+
+	/* Check that the device is attached to a genpd. */
+	if (!(dev->pm_domain && dev->pm_domain->detach == genpd_dev_pm_detach))
+		return;
+
+	genpd_dev_pm_detach(dev, true);
+
+	pm_runtime_disable(dev);
+	pm_runtime_put_noidle(dev);
+	pm_runtime_reinit(dev);
+
+	dev_info(dev, "genpd: detached cpu\n");
+}
+EXPORT_SYMBOL(of_genpd_detach_cpu);
+
 static const struct of_device_id idle_state_match[] = {
 	{ .compatible = "domain-idle-state", },
 	{ }
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 3f67ff0c1c69..2c09cf80b285 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -243,6 +243,8 @@  unsigned int of_genpd_opp_to_performance_state(struct device *dev,
 int genpd_dev_pm_attach(struct device *dev);
 struct device *genpd_dev_pm_attach_by_id(struct device *dev,
 					 unsigned int index);
+int of_genpd_attach_cpu(int cpu);
+void of_genpd_detach_cpu(int cpu);
 #else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
 static inline int of_genpd_add_provider_simple(struct device_node *np,
 					struct generic_pm_domain *genpd)
@@ -294,6 +296,13 @@  static inline struct device *genpd_dev_pm_attach_by_id(struct device *dev,
 	return NULL;
 }
 
+static inline int of_genpd_attach_cpu(int cpu)
+{
+	return -ENODEV;
+}
+
+static inline void of_genpd_detach_cpu(int cpu) {}
+
 static inline
 struct generic_pm_domain *of_genpd_remove_last(struct device_node *np)
 {