@@ -10,6 +10,9 @@
#include <linux/pm_domain.h>
#include <linux/pm_qos.h>
#include <linux/hrtimer.h>
+#include <linux/cpumask.h>
+#include <linux/ktime.h>
+#include <linux/tick.h>
static int dev_update_qos_constraint(struct device *dev, void *data)
{
@@ -245,6 +248,56 @@ static bool always_on_power_down_ok(struct dev_pm_domain *domain)
return false;
}
+static bool cpu_power_down_ok(struct dev_pm_domain *pd)
+{
+ struct generic_pm_domain *genpd = pd_to_genpd(pd);
+ ktime_t domain_wakeup, cpu_wakeup;
+ s64 idle_duration_ns;
+ int cpu, i;
+
+ if (!(genpd->flags & GENPD_FLAG_CPU_DOMAIN))
+ return true;
+
+ /*
+ * Find the next wakeup for any of the online CPUs within the PM domain
+ * and its subdomains. Note, we only need the genpd->cpus, as it already
+ * contains a mask of all CPUs from subdomains.
+ */
+ domain_wakeup = ktime_set(KTIME_SEC_MAX, 0);
+ for_each_cpu_and(cpu, genpd->cpus, cpu_online_mask) {
+ cpu_wakeup = tick_nohz_get_next_wakeup(cpu);
+ if (ktime_before(cpu_wakeup, domain_wakeup))
+ domain_wakeup = cpu_wakeup;
+ }
+
+ /* The minimum idle duration is from now - until the next wakeup. */
+ idle_duration_ns = ktime_to_ns(ktime_sub(domain_wakeup, ktime_get()));
+
+ /*
+ * Find the deepest idle state that has its residency value satisfied
+ * and by also taking into account the power off latency for the state.
+ * Start at the deepest supported state.
+ */
+ i = genpd->state_count - 1;
+ do {
+ if (!genpd->states[i].residency_ns)
+ break;
+
+ /* Check idle_duration_ns >= 0 to compare signed/unsigned. */
+ if (idle_duration_ns >= 0 && idle_duration_ns >=
+ (genpd->states[i].residency_ns +
+ genpd->states[i].power_off_latency_ns))
+ break;
+ i--;
+ } while (i >= 0);
+
+ if (i < 0)
+ return false;
+
+ genpd->state_idx = i;
+ return true;
+}
+
struct dev_power_governor simple_qos_governor = {
.suspend_ok = default_suspend_ok,
.power_down_ok = default_power_down_ok,
@@ -257,3 +310,8 @@ struct dev_power_governor pm_domain_always_on_gov = {
.power_down_ok = always_on_power_down_ok,
.suspend_ok = default_suspend_ok,
};
+
+struct dev_power_governor pm_domain_cpu_gov = {
+ .suspend_ok = NULL,
+ .power_down_ok = cpu_power_down_ok,
+};
@@ -161,6 +161,7 @@ extern int dev_pm_genpd_set_performance_state(struct device *dev,
extern struct dev_power_governor simple_qos_governor;
extern struct dev_power_governor pm_domain_always_on_gov;
+extern struct dev_power_governor pm_domain_cpu_gov;
#else
static inline struct generic_pm_domain_data *dev_gpd_data(struct device *dev)
@@ -206,6 +207,7 @@ static inline int dev_pm_genpd_set_performance_state(struct device *dev,
#define simple_qos_governor (*(struct dev_power_governor *)(NULL))
#define pm_domain_always_on_gov (*(struct dev_power_governor *)(NULL))
+#define pm_domain_cpu_gov (*(struct dev_power_governor *)(NULL))
#endif
static inline int pm_genpd_add_device(struct generic_pm_domain *genpd,
As it's now perfectly possible that a PM domain managed by genpd contains devices belonging to CPUs, we should start to take into account the residency values for the idle states during the state selection process. The residency value specifies the minimum duration of time, the CPU or a group of CPUs, needs to spend in an idle state to not waste energy entering it. To deal with this, let's add a new genpd governor, pm_domain_cpu_gov, that may be used for a PM domain that have CPU devices attached or if the CPUs are attached through subdomains. The new governor computes the minimum expected idle duration time for the online CPUs being attached to the PM domain and its subdomains. Then in the state selection process, trying the deepest state first, it verifies that the idle duration time satisfies the state's residency value. It should be noted that, when computing the minimum expected idle duration time, we use the information from tick_nohz_get_next_wakeup(), to find the next wakeup for the related CPUs. Future wise, this may deserve to be improved, as there are more reasons to why a CPU may be woken up from idle. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Lina Iyer <ilina@codeaurora.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Co-developed-by: Lina Iyer <lina.iyer@linaro.org> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> --- drivers/base/power/domain_governor.c | 58 ++++++++++++++++++++++++++++++++++++ include/linux/pm_domain.h | 2 ++ 2 files changed, 60 insertions(+) -- 2.7.4