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Subject[PATCH v8 04/26] PM / Domains: Add support for CPU devices to genpd
Date
To enable a device belonging to a CPU to be attached to a PM domain managed
by genpd, let's do a few changes to genpd as to make it convenient to
manage the specifics around CPUs.

First, as to be able to quickly find out what CPUs that are attached to a
genpd, which typically becomes useful from a genpd governor as following
changes is about to show, let's add a cpumask 'cpus' to the struct
generic_pm_domain.

At the point when a device that belongs to a CPU, is attached/detached to
its corresponding PM domain via genpd_add_device(), let's update the
cpumask in genpd->cpus. Moreover, propagate the update of the cpumask to
the master domains, which makes the genpd->cpus to contain a cpumask that
hierarchically reflect all CPUs for a genpd, including CPUs attached to
subdomains.

Second, to unconditionally manage CPUs and the cpumask in genpd->cpus, is
unnecessary for cases when only non-CPU devices are parts of a genpd.
Let's avoid this by adding a new configuration bit, GENPD_FLAG_CPU_DOMAIN.
Clients must set the bit before they call pm_genpd_init(), as to instruct
genpd that it shall deal with CPUs and thus manage the cpumask in
genpd->cpus.

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 | 3 ++
2 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 21d298e1820b..6149ce0bfa7b 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -20,6 +20,7 @@
#include <linux/sched.h>
#include <linux/suspend.h>
#include <linux/export.h>
+#include <linux/cpu.h>

#include "power.h"

@@ -126,6 +127,7 @@ 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)
@@ -1377,6 +1379,62 @@ 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)
+{
+ bool is_cpu = false;
+ int cpu;
+
+ if (!genpd_is_cpu_domain(genpd))
+ return;
+
+ for_each_possible_cpu(cpu) {
+ if (get_cpu_device(cpu) == dev) {
+ is_cpu = true;
+ break;
+ }
+ }
+
+ if (!is_cpu)
+ return;
+
+ __genpd_update_cpumask(genpd, cpu, set, 0);
+}
+
+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)
{
@@ -1398,6 +1456,8 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
if (ret)
goto out;

+ genpd_set_cpumask(genpd, dev);
+
dev_pm_domain_set(dev, &genpd->domain);

genpd->device_count++;
@@ -1459,6 +1519,7 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
if (genpd->detach_dev)
genpd->detach_dev(genpd, dev);

+ genpd_clear_cpumask(genpd, dev);
dev_pm_domain_set(dev, NULL);

list_del_init(&pdd->list_node);
@@ -1686,11 +1747,16 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
if (genpd_is_always_on(genpd) && !genpd_status_on(genpd))
return -EINVAL;

+ if (!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) {
+ free_cpumask_var(genpd->cpus);
return ret;
+ }
} else if (!gov) {
pr_warn("%s : no governor for states\n", genpd->name);
}
@@ -1736,6 +1802,7 @@ 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);
+ free_cpumask_var(genpd->cpus);
kfree(genpd->free);
pr_debug("%s: removed %s\n", __func__, genpd->name);

diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 27fca748344a..3f67ff0c1c69 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -16,12 +16,14 @@
#include <linux/of.h>
#include <linux/notifier.h>
#include <linux/spinlock.h>
+#include <linux/cpumask.h>

/* Defines used for the flags field in the struct generic_pm_domain */
#define GENPD_FLAG_PM_CLK (1U << 0) /* PM domain uses PM clk */
#define GENPD_FLAG_IRQ_SAFE (1U << 1) /* PM domain operates in atomic */
#define GENPD_FLAG_ALWAYS_ON (1U << 2) /* PM domain is always powered on */
#define GENPD_FLAG_ACTIVE_WAKEUP (1U << 3) /* Keep devices active if wakeup */
+#define GENPD_FLAG_CPU_DOMAIN (1U << 4) /* PM domain manages CPUs */

enum gpd_status {
GPD_STATE_ACTIVE = 0, /* PM domain is active */
@@ -68,6 +70,7 @@ 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);
unsigned int (*opp_to_performance_state)(struct generic_pm_domain *genpd,
--
2.17.1
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