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authorUlf Hansson <ulf.hansson@linaro.org>2014-03-01 14:56:05 +0400
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-03-02 03:18:15 +0400
commit37f204164dfb0186a0caf20bc3e3120080bcd788 (patch)
tree71cd2729fa7509d3bed3048e1dad41f8e73ce91e /drivers/base
parent5f59df79837bb809f3945613aba5519cd9755a53 (diff)
downloadlinux-37f204164dfb0186a0caf20bc3e3120080bcd788.tar.xz
PM: Add pm_runtime_suspend|resume_force functions
This patch provides two new runtime PM helper functions which intend to be used from system suspend/resume callbacks, to make sure devices are put into low power state during system suspend and brought back to full power at system resume. The prerequisite is to have all levels of a device's runtime PM callbacks to be defined through the SET_PM_RUNTIME_PM_OPS macro, which means these are available for CONFIG_PM. By using the new runtime PM helper functions especially the two scenarios below will be addressed. 1) The PM core prevents .runtime_suspend callbacks from being invoked during system suspend. That means even for a runtime PM centric subsystem and driver, the device needs to be put into low power state from a system suspend callback. Otherwise it may very well be left in full power state (runtime resumed) while the system is suspended. By using the new helper functions, we make sure to walk the hierarchy of a device's power domain, subsystem and driver. 2) Subsystems and drivers need to cope with all the combinations of CONFIG_PM_SLEEP and CONFIG_PM_RUNTIME. The two new helper functions smothly addresses this. Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/power/Makefile3
-rw-r--r--drivers/base/power/runtime.c84
2 files changed, 85 insertions, 2 deletions
diff --git a/drivers/base/power/Makefile b/drivers/base/power/Makefile
index 2e58ebb1f6c0..1cb8544598d5 100644
--- a/drivers/base/power/Makefile
+++ b/drivers/base/power/Makefile
@@ -1,6 +1,5 @@
-obj-$(CONFIG_PM) += sysfs.o generic_ops.o common.o qos.o
+obj-$(CONFIG_PM) += sysfs.o generic_ops.o common.o qos.o runtime.o
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 domain_governor.o
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index ac495b1357fa..4776cf528d08 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -44,6 +44,7 @@ static int (*rpm_get_resume_cb(struct device *dev))(struct device *)
return RPM_GET_CALLBACK(dev, runtime_resume);
}
+#ifdef CONFIG_PM_RUNTIME
static int (*rpm_get_idle_cb(struct device *dev))(struct device *)
{
return RPM_GET_CALLBACK(dev, runtime_idle);
@@ -1401,3 +1402,86 @@ void pm_runtime_remove(struct device *dev)
if (dev->power.irq_safe && dev->parent)
pm_runtime_put(dev->parent);
}
+#endif
+
+/**
+ * pm_runtime_force_suspend - Force a device into suspend state if needed.
+ * @dev: Device to suspend.
+ *
+ * Disable runtime PM so we safely can check the device's runtime PM status and
+ * if it is active, invoke it's .runtime_suspend callback to bring it into
+ * suspend state. Keep runtime PM disabled to preserve the state unless we
+ * encounter errors.
+ *
+ * Typically this function may be invoked from a system suspend callback to make
+ * sure the device is put into low power state.
+ */
+int pm_runtime_force_suspend(struct device *dev)
+{
+ int (*callback)(struct device *);
+ int ret = 0;
+
+ pm_runtime_disable(dev);
+
+ /*
+ * Note that pm_runtime_status_suspended() returns false while
+ * !CONFIG_PM_RUNTIME, which means the device will be put into low
+ * power state.
+ */
+ if (pm_runtime_status_suspended(dev))
+ return 0;
+
+ callback = rpm_get_suspend_cb(dev);
+
+ if (!callback) {
+ ret = -ENOSYS;
+ goto err;
+ }
+
+ ret = callback(dev);
+ if (ret)
+ goto err;
+
+ pm_runtime_set_suspended(dev);
+ return 0;
+err:
+ pm_runtime_enable(dev);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
+
+/**
+ * pm_runtime_force_resume - Force a device into resume state.
+ * @dev: Device to resume.
+ *
+ * Prior invoking this function we expect the user to have brought the device
+ * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
+ * those actions and brings the device into full power. We update the runtime PM
+ * status and re-enables runtime PM.
+ *
+ * Typically this function may be invoked from a system resume callback to make
+ * sure the device is put into full power state.
+ */
+int pm_runtime_force_resume(struct device *dev)
+{
+ int (*callback)(struct device *);
+ int ret = 0;
+
+ callback = rpm_get_resume_cb(dev);
+
+ if (!callback) {
+ ret = -ENOSYS;
+ goto out;
+ }
+
+ ret = callback(dev);
+ if (ret)
+ goto out;
+
+ pm_runtime_set_active(dev);
+ pm_runtime_mark_last_busy(dev);
+out:
+ pm_runtime_enable(dev);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_force_resume);