PM / Domains: Add device stop governor function (v4)

Add a function deciding whether or not devices should be stopped in
pm_genpd_runtime_suspend() depending on their PM QoS constraints
and stop/start timing values.  Make it possible to add information
used by this function to device objects.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Magnus Damm <damm@opensource.se>

3 files changed, 60 insertions, 8 deletions

diff --git a/drivers/base/power/Makefile b/drivers/base/power/Makefile
index 81676dd17900..2e58ebb1f6c0 100644
--- a/drivers/base/power/Makefile
+++ b/drivers/base/power/Makefile
@@ -3,7 +3,7 @@ obj-$(CONFIG_PM_SLEEP)	+= main.o wakeup.o
 obj-$(CONFIG_PM_RUNTIME)        += runtime.o
 obj-$(CONFIG_PM_TRACE_RTC)      += trace.o
 obj-$(CONFIG_PM_OPP)    += opp.o
-obj-$(CONFIG_PM_GENERIC_DOMAINS)        +=  domain.o
+obj-$(CONFIG_PM_GENERIC_DOMAINS)        +=  domain.o domain_governor.o
 obj-$(CONFIG_HAVE_CLK)  += clock_ops.o
 
 ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 9a77080cb799..3af9f5a71ad5 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -38,7 +38,7 @@ static DEFINE_MUTEX(gpd_list_lock);
 
 #ifdef CONFIG_PM
 
-static struct generic_pm_domain *dev_to_genpd(struct device *dev)
+struct generic_pm_domain *dev_to_genpd(struct device *dev)
 {
         if (IS_ERR_OR_NULL(dev->pm_domain))
                 return ERR_PTR(-EINVAL);
@@ -436,6 +436,7 @@ static void genpd_power_off_work_fn(struct work_struct *work)
 static int pm_genpd_runtime_suspend(struct device *dev)
 {
         struct generic_pm_domain *genpd;
+        bool (*stop_ok)(struct device *__dev);
         int ret;
 
         dev_dbg(dev, "%s()\n", __func__);
@@ -446,10 +447,17 @@ static int pm_genpd_runtime_suspend(struct device *dev)
 
         might_sleep_if(!genpd->dev_irq_safe);
 
+        stop_ok = genpd->gov ? genpd->gov->stop_ok : NULL;
+        if (stop_ok && !stop_ok(dev))
+                return -EBUSY;
+
         ret = genpd_stop_dev(genpd, dev);
         if (ret)
                 return ret;
 
+        pm_runtime_update_max_time_suspended(dev,
+                                dev_gpd_data(dev)->td.start_latency_ns);
+
         /*
          * If power.irq_safe is set, this routine will be run with interrupts
          * off, so it can't use mutexes.
@@ -1048,11 +1056,13 @@ static void pm_genpd_complete(struct device *dev)
 #endif /* CONFIG_PM_SLEEP */
 
 /**
- * pm_genpd_add_device - Add a device to an I/O PM domain.
+ * __pm_genpd_add_device - Add a device to an I/O PM domain.
  * @genpd: PM domain to add the device to.
  * @dev: Device to be added.
+ * @td: Set of PM QoS timing parameters to attach to the device.
  */
-int pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
+int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
+                          struct gpd_timing_data *td)
 {
         struct generic_pm_domain_data *gpd_data;
         struct pm_domain_data *pdd;
@@ -1095,6 +1105,8 @@ int pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev)
         gpd_data->base.dev = dev;
         gpd_data->need_restore = false;
         list_add_tail(&gpd_data->base.list_node, &genpd->dev_list);
+        if (td)
+                gpd_data->td = *td;
 
  out:
         genpd_release_lock(genpd);
@@ -1255,8 +1267,10 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
  * pm_genpd_add_callbacks - Add PM domain callbacks to a given device.
  * @dev: Device to add the callbacks to.
  * @ops: Set of callbacks to add.
+ * @td: Timing data to add to the device along with the callbacks (optional).
  */
-int pm_genpd_add_callbacks(struct device *dev, struct gpd_dev_ops *ops)
+int pm_genpd_add_callbacks(struct device *dev, struct gpd_dev_ops *ops,
+                           struct gpd_timing_data *td)
 {
         struct pm_domain_data *pdd;
         int ret = 0;
@@ -1272,6 +1286,8 @@ int pm_genpd_add_callbacks(struct device *dev, struct gpd_dev_ops *ops)
                 struct generic_pm_domain_data *gpd_data = to_gpd_data(pdd);
 
                 gpd_data->ops = *ops;
+                if (td)
+                        gpd_data->td = *td;
         } else {
                 ret = -EINVAL;
         }
@@ -1284,10 +1300,11 @@ int pm_genpd_add_callbacks(struct device *dev, struct gpd_dev_ops *ops)
 EXPORT_SYMBOL_GPL(pm_genpd_add_callbacks);
 
 /**
- * pm_genpd_remove_callbacks - Remove PM domain callbacks from a given device.
+ * __pm_genpd_remove_callbacks - Remove PM domain callbacks from a given device.
  * @dev: Device to remove the callbacks from.
+ * @clear_td: If set, clear the device's timing data too.
  */
-int pm_genpd_remove_callbacks(struct device *dev)
+int __pm_genpd_remove_callbacks(struct device *dev, bool clear_td)
 {
         struct pm_domain_data *pdd;
         int ret = 0;
@@ -1303,6 +1320,8 @@ int pm_genpd_remove_callbacks(struct device *dev)
                 struct generic_pm_domain_data *gpd_data = to_gpd_data(pdd);
 
                 gpd_data->ops = (struct gpd_dev_ops){ 0 };
+                if (clear_td)
+                        gpd_data->td = (struct gpd_timing_data){ 0 };
         } else {
                 ret = -EINVAL;
         }
@@ -1312,7 +1331,7 @@ int pm_genpd_remove_callbacks(struct device *dev)
 
         return ret;
 }
-EXPORT_SYMBOL_GPL(pm_genpd_remove_callbacks);
+EXPORT_SYMBOL_GPL(__pm_genpd_remove_callbacks);
 
 /* Default device callbacks for generic PM domains. */
 
diff --git a/drivers/base/power/domain_governor.c b/drivers/base/power/domain_governor.c
new file mode 100644
index 000000000000..97b21c10c496
--- /dev/null
+++ b/drivers/base/power/domain_governor.c
@@ -0,0 +1,33 @@
+/*
+ * drivers/base/power/domain_governor.c - Governors for device PM domains.
+ *
+ * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_qos.h>
+
+/**
+ * default_stop_ok - Default PM domain governor routine for stopping devices.
+ * @dev: Device to check.
+ */
+bool default_stop_ok(struct device *dev)
+{
+        struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
+
+        dev_dbg(dev, "%s()\n", __func__);
+
+        if (dev->power.max_time_suspended_ns < 0 || td->break_even_ns == 0)
+                return true;
+
+        return td->stop_latency_ns + td->start_latency_ns < td->break_even_ns
+                && td->break_even_ns < dev->power.max_time_suspended_ns;
+}
+
+struct dev_power_governor simple_qos_governor = {
+        .stop_ok = default_stop_ok,
+};