PM / Domains: Automatically update overoptimistic latency information

Measure the time of execution of the .stop(), .start(), .save_state()
and .restore_state() PM domain device callbacks and if the result
is greater than the corresponding latency value stored in the
device's struct generic_pm_domain_data object, replace the inaccurate
value with the measured time.

Do analogously for the PM domains' .power_off() and .power_off()
callbacks.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

1 files changed, 39 insertions, 4 deletions

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 91896194e76b..5a8d67d51f0e 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -33,6 +33,20 @@
         __ret;                                                  \
 })
 
+#define GENPD_DEV_TIMED_CALLBACK(genpd, type, callback, dev, field, name)       \
+({                                                                              \
+        ktime_t __start = ktime_get();                                          \
+        type __retval = GENPD_DEV_CALLBACK(genpd, type, callback, dev);         \
+        s64 __elapsed = ktime_to_ns(ktime_sub(ktime_get(), __start));           \
+        struct generic_pm_domain_data *__gpd_data = dev_gpd_data(dev);          \
+        if (__elapsed > __gpd_data->td.field) {                                 \
+                __gpd_data->td.field = __elapsed;                               \
+                dev_warn(dev, name " latency exceeded, new value %lld ns\n",    \
+                        __elapsed);                                             \
+        }                                                                       \
+        __retval;                                                               \
+})
+
 static LIST_HEAD(gpd_list);
 static DEFINE_MUTEX(gpd_list_lock);
 
@@ -48,22 +62,27 @@ struct generic_pm_domain *dev_to_genpd(struct device *dev)
 
 static int genpd_stop_dev(struct generic_pm_domain *genpd, struct device *dev)
 {
-        return GENPD_DEV_CALLBACK(genpd, int, stop, dev);
+        return GENPD_DEV_TIMED_CALLBACK(genpd, int, stop, dev,
+                                        stop_latency_ns, "stop");
 }
 
 static int genpd_start_dev(struct generic_pm_domain *genpd, struct device *dev)
 {
-        return GENPD_DEV_CALLBACK(genpd, int, start, dev);
+        return GENPD_DEV_TIMED_CALLBACK(genpd, int, start, dev,
+                                        start_latency_ns, "start");
 }
 
 static int genpd_save_dev(struct generic_pm_domain *genpd, struct device *dev)
 {
-        return GENPD_DEV_CALLBACK(genpd, int, save_state, dev);
+        return GENPD_DEV_TIMED_CALLBACK(genpd, int, save_state, dev,
+                                        save_state_latency_ns, "state save");
 }
 
 static int genpd_restore_dev(struct generic_pm_domain *genpd, struct device *dev)
 {
-        return GENPD_DEV_CALLBACK(genpd, int, restore_state, dev);
+        return GENPD_DEV_TIMED_CALLBACK(genpd, int, restore_state, dev,
+                                        restore_state_latency_ns,
+                                        "state restore");
 }
 
 static bool genpd_sd_counter_dec(struct generic_pm_domain *genpd)
@@ -182,9 +201,16 @@ int __pm_genpd_poweron(struct generic_pm_domain *genpd)
         }
 
         if (genpd->power_on) {
+                ktime_t time_start = ktime_get();
+                s64 elapsed_ns;
+
                 ret = genpd->power_on(genpd);
                 if (ret)
                         goto err;
+
+                elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
+                if (elapsed_ns > genpd->power_on_latency_ns)
+                        genpd->power_on_latency_ns = elapsed_ns;
         }
 
         genpd_set_active(genpd);
@@ -377,11 +403,16 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
         }
 
         if (genpd->power_off) {
+                ktime_t time_start;
+                s64 elapsed_ns;
+
                 if (atomic_read(&genpd->sd_count) > 0) {
                         ret = -EBUSY;
                         goto out;
                 }
 
+                time_start = ktime_get();
+
                 /*
                  * If sd_count > 0 at this point, one of the subdomains hasn't
                  * managed to call pm_genpd_poweron() for the master yet after
@@ -395,6 +426,10 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
                         genpd_set_active(genpd);
                         goto out;
                 }
+
+                elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
+                if (elapsed_ns > genpd->power_off_latency_ns)
+                        genpd->power_off_latency_ns = elapsed_ns;
         }
 
         genpd->status = GPD_STATE_POWER_OFF;