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Commit eb594b73 authored by Ulf Hansson's avatar Ulf Hansson Committed by Rafael J. Wysocki
Browse files

PM / Domains: Add support for CPU devices to genpd 



To enable a CPU device to be attached to a PM domain managed by genpd,
make a few changes to it for convenience.

To be able to quickly find out what CPUs are attached to a genpd,
which typically becomes useful from a genpd governor as subsequent
changes are about to show, add a cpumask to struct generic_pm_domain
to be updated when a CPU device gets attached to the genpd containing
that cpumask. Also, propagate the cpumask changes upwards in the
domain hierarchy to the master PM domains. This way, the cpumask for
a genpd hierarchically reflects all CPUs attached to the topology
below it.

Finally, make this an opt-in feature, to avoid having to manage CPUs
and the cpumask for a genpd that don't need it. To that end, add
a new genpd configuration bit, GENPD_FLAG_CPU_DOMAIN.

Co-developed-by: default avatarLina Iyer <lina.iyer@linaro.org>
Acked-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
[ rjw: Changelog ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 49a27e27

drivers/base/power/domain.c

+64 −1
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#include <linux/sched.h>

#include <linux/suspend.h>

#include <linux/export.h>

#include <linux/cpu.h>



#include "power.h"
@@ -128,6 +129,7 @@ static const struct genpd_lock_ops genpd_spin_ops = { 
#define genpd_is_irq_safe(genpd)	(genpd->flags & GENPD_FLAG_IRQ_SAFE)

#define genpd_is_always_on(genpd)	(genpd->flags & GENPD_FLAG_ALWAYS_ON)

#define genpd_is_active_wakeup(genpd)	(genpd->flags & GENPD_FLAG_ACTIVE_WAKEUP)

#define genpd_is_cpu_domain(genpd)	(genpd->flags & GENPD_FLAG_CPU_DOMAIN)



static inline bool irq_safe_dev_in_no_sleep_domain(struct device *dev,

		const struct generic_pm_domain *genpd)
@@ -1454,6 +1456,56 @@ static void genpd_free_dev_data(struct device *dev, 
	dev_pm_put_subsys_data(dev);

}



static void __genpd_update_cpumask(struct generic_pm_domain *genpd,

				   int cpu, bool set, unsigned int depth)

{

	struct gpd_link *link;



	if (!genpd_is_cpu_domain(genpd))

		return;



	list_for_each_entry(link, &genpd->slave_links, slave_node) {

		struct generic_pm_domain *master = link->master;



		genpd_lock_nested(master, depth + 1);

		__genpd_update_cpumask(master, cpu, set, depth + 1);

		genpd_unlock(master);

	}



	if (set)

		cpumask_set_cpu(cpu, genpd->cpus);

	else

		cpumask_clear_cpu(cpu, genpd->cpus);

}



static void genpd_update_cpumask(struct generic_pm_domain *genpd,

				 struct device *dev, bool set)

{

	int cpu;



	if (!genpd_is_cpu_domain(genpd))

		return;



	for_each_possible_cpu(cpu) {

		if (get_cpu_device(cpu) == dev) {

			__genpd_update_cpumask(genpd, cpu, set, 0);

			return;

		}

	}

}



static void genpd_set_cpumask(struct generic_pm_domain *genpd,

			      struct device *dev)

{

	genpd_update_cpumask(genpd, dev, true);

}



static void genpd_clear_cpumask(struct generic_pm_domain *genpd,

				struct device *dev)

{

	genpd_update_cpumask(genpd, dev, false);

}



static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,

			    struct gpd_timing_data *td)

{
@@ -1475,6 +1527,7 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, 


	genpd_lock(genpd);



	genpd_set_cpumask(genpd, dev);

	dev_pm_domain_set(dev, &genpd->domain);



	genpd->device_count++;
@@ -1532,6 +1585,7 @@ static int genpd_remove_device(struct generic_pm_domain *genpd, 
	genpd->device_count--;

	genpd->max_off_time_changed = true;



	genpd_clear_cpumask(genpd, dev);

	dev_pm_domain_set(dev, NULL);



	list_del_init(&pdd->list_node);
@@ -1768,11 +1822,18 @@ int pm_genpd_init(struct generic_pm_domain *genpd, 
	if (genpd_is_always_on(genpd) && !genpd_status_on(genpd))

		return -EINVAL;



	if (genpd_is_cpu_domain(genpd) &&

	    !zalloc_cpumask_var(&genpd->cpus, GFP_KERNEL))

		return -ENOMEM;



	/* Use only one "off" state if there were no states declared */

	if (genpd->state_count == 0) {

		ret = genpd_set_default_power_state(genpd);

		if (ret)

		if (ret) {

			if (genpd_is_cpu_domain(genpd))

				free_cpumask_var(genpd->cpus);

			return ret;

		}

	} else if (!gov && genpd->state_count > 1) {

		pr_warn("%s: no governor for states\n", genpd->name);

	}
@@ -1818,6 +1879,8 @@ static int genpd_remove(struct generic_pm_domain *genpd) 
	list_del(&genpd->gpd_list_node);

	genpd_unlock(genpd);

	cancel_work_sync(&genpd->power_off_work);

	if (genpd_is_cpu_domain(genpd))

		free_cpumask_var(genpd->cpus);

	if (genpd->free_states)

		genpd->free_states(genpd->states, genpd->state_count);

include/linux/pm_domain.h

+13 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/of.h>

#include <linux/notifier.h>

#include <linux/spinlock.h>

#include <linux/cpumask.h>



/*

 * Flags to control the behaviour of a genpd.
@@ -42,11 +43,22 @@ 
 * GENPD_FLAG_ACTIVE_WAKEUP:	Instructs genpd to keep the PM domain powered

 *				on, in case any of its attached devices is used

 *				in the wakeup path to serve system wakeups.

 *

 * GENPD_FLAG_CPU_DOMAIN:	Instructs genpd that it should expect to get

 *				devices attached, which may belong to CPUs or

 *				possibly have subdomains with CPUs attached.

 *				This flag enables the genpd backend driver to

 *				deploy idle power management support for CPUs

 *				and groups of CPUs. Note that, the backend

 *				driver must then comply with the so called,

 *				last-man-standing algorithm, for the CPUs in the

 *				PM domain.

 */

#define GENPD_FLAG_PM_CLK	 (1U << 0)

#define GENPD_FLAG_IRQ_SAFE	 (1U << 1)

#define GENPD_FLAG_ALWAYS_ON	 (1U << 2)

#define GENPD_FLAG_ACTIVE_WAKEUP (1U << 3)

#define GENPD_FLAG_CPU_DOMAIN	 (1U << 4)



enum gpd_status {

	GPD_STATE_ACTIVE = 0,	/* PM domain is active */
@@ -94,6 +106,7 @@ struct generic_pm_domain { 
	unsigned int suspended_count;	/* System suspend device counter */

	unsigned int prepared_count;	/* Suspend counter of prepared devices */

	unsigned int performance_state;	/* Aggregated max performance state */

	cpumask_var_t cpus;		/* A cpumask of the attached CPUs */

	int (*power_off)(struct generic_pm_domain *domain);

	int (*power_on)(struct generic_pm_domain *domain);

	struct opp_table *opp_table;	/* OPP table of the genpd */