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

Message ID 20180620172226.15012-6-ulf.hansson@linaro.org
State New
Headers show
Series
  • PM / Domains: Support hierarchical CPU arrangement (PSCI/ARM)
Related show

Commit Message

Ulf Hansson June 20, 2018, 5:22 p.m.
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(+)

-- 
2.17.1

Comments

Rafael J. Wysocki July 19, 2018, 10:22 a.m. | #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.

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)
 {