2 files changed, 77 insertions, 1 deletions

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index ff6f992f7a1d..ecac03dcc9b2 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -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);
 
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 8e1399231753..a6e251fe9deb 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -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 */