Re: [PATCH] PM: add dpm_use_runtime_{suspend, resume} helper functions

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Saturday 27 February 2010, Mark Brown wrote:
> On Fri, Feb 26, 2010 at 05:06:59PM -0500, Alan Stern wrote:
> > On Fri, 26 Feb 2010, Rafael J. Wysocki wrote:
> 
> > > I have one problem with the design.  Namely, dpm_invoke_runtime_*() can
> > > run a callback from another subsystem.  Say you are a device class and you
> > > decide to use dpm_invoke_runtime_*(), but the device's bus type implements
> > > the runtime PM callbacks, so they will be run as device class suspend and
> > > resume callbacks.  That doesn't look particularly clean to me.
> 
> > That is a valid point.  I suppose there could be separate bus-type, 
> > device-type, and device-class versions of these functions, but that 
> > seems like excessive complication with little real benefit.
> 
> I do agree that it'd be good to avoid adding any further complexity here
> - the use case I have is devices that only really have one suspend type
> and don't want or need to know if it's a runtime, disk or memory suspend.

What about the patch below, then (untested)?

Use GENERIC_SUBSYS_PM_OPS for the subsystem and then
UNIVERSAL_DEV_PM_OPS for drivers, possibly passing NULL as idle_fn.

Rafael

---
 drivers/base/power/Makefile      |    1 
 drivers/base/power/generic_ops.c |  119 +++++++++++++++++++++++++++++++++++++++
 include/linux/pm.h               |   67 +++++++++++++++++++--
 3 files changed, 181 insertions(+), 6 deletions(-)

Index: linux-2.6/drivers/base/power/Makefile
===================================================================
--- linux-2.6.orig/drivers/base/power/Makefile
+++ linux-2.6/drivers/base/power/Makefile
@@ -1,6 +1,7 @@
 obj-$(CONFIG_PM)	+= sysfs.o
 obj-$(CONFIG_PM_SLEEP)	+= main.o
 obj-$(CONFIG_PM_RUNTIME)	+= runtime.o
+obj-$(CONFIG_PM_OPS)	+= generic_ops.o
 obj-$(CONFIG_PM_TRACE_RTC)	+= trace.o
 
 ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
Index: linux-2.6/drivers/base/power/generic_ops.c
===================================================================
--- linux-2.6.orig/drivers/base/power/generic_ops.c
+++ linux-2.6/drivers/base/power/generic_ops.c
@@ -6,3 +6,122 @@
  * This file is released under the GPLv2.
  */
 
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+
+#ifdef CONFIG_PM_RUNTIME
+/**
+ * pm_generic_runtime_idle - Generic runtime idle callback for subsystems.
+ * @dev: Device to handle.
+ *
+ * If PM operations are defined for the driver of @dev and they include
+ * ->runtime_idle(), execute it and return the error code returned by it if
+ * nonzero.  Otherwise, execute pm_runtime_suspend() for the device.
+ */
+int pm_generic_runtime_idle(struct device *dev)
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+
+	if (pm && pm->runtime_idle) {
+		int ret = pm->runtime_idle(dev);
+		if (ret)
+			return ret;
+	}
+
+	pm_runtime_suspend(dev);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pm_generic_runtime_idle);
+
+/**
+ * pm_generic_runtime_suspend - Generic runtime suspend callback for subsystems.
+ * @dev: Device to suspend.
+ *
+ * If PM operations are defined for the driver of @dev and they include
+ * ->runtime_suspend(), execute it and return the error code returned by it.
+ * Otherwise, return zero.
+ */
+int pm_generic_runtime_suspend(struct device *dev)
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+	int ret = 0;
+
+	if (pm && pm->runtime_suspend)
+		ret = pm->runtime_suspend(dev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pm_generic_runtime_suspend);
+
+/**
+ * pm_generic_runtime_resume - Generic runtime resume callback for subsystems.
+ * @dev: Device to resume.
+ *
+ * If PM operations are defined for the driver of @dev and they include
+ * ->runtime_resume(), execute it and return the error code returned by it.
+ * Otherwise, return zero.
+ */
+int pm_generic_runtime_resume(struct device *dev)
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+	int ret = 0;
+
+	if (pm && pm->runtime_resume)
+		ret = pm->runtime_resume(dev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pm_generic_runtime_resume);
+#endif /* CONFIG_PM_RUNTIME */
+
+#define CONFIG_PM_SLEEP
+/**
+ * pm_generic_suspend - Generic suspend callback for subsystems.
+ * @dev: Device to suspend.
+ *
+ * If the device has not been suspended at run time, execute the suspend
+ * callback provided by its driver, if defined, and return the error code
+ * returned by it.  Otherwise, return zero.
+ */
+int pm_generic_suspend(struct device *dev)
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+	int ret = 0;
+
+	if (dev->power.runtime_status == RPM_SUSPENDED)
+		return 0;
+
+	if (pm && pm->suspend)
+		ret = pm->suspend(dev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pm_generic_suspend);
+
+/**
+ * pm_generic_resume - Generic resume callback for subsystems.
+ * @dev: Device to resume.
+ *
+ * Execute the resume callback provided by the driver of @dev, if defined.
+ * If it returns 0, change the device's runtime PM status to 'active'.  Return
+ * the error code returned by it.
+ */
+int pm_generic_resume(struct device *dev)
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+	int ret;
+
+	if (!pm || !pm->resume)
+		return 0;
+
+	ret = pm->resume(dev);
+	if (!ret) {
+		pm_runtime_disable(dev);
+		pm_runtime_set_active(dev);
+		pm_runtime_enable(dev);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pm_generic_resume);
+#endif /* CONFIG_PM_SLEEP */
Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -215,18 +215,73 @@ struct dev_pm_ops {
 	int (*runtime_idle)(struct device *dev);
 };
 
+#ifdef CONFIG_PM_SLEEP
+#define SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
+	.suspend = suspend_fn, \
+	.resume = resume_fn, \
+	.freeze = suspend_fn, \
+	.thaw = resume_fn, \
+	.poweroff = suspend_fn, \
+	.restore = resume_fn,
+#else
+#define SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn)
+#endif
+
+#ifdef CONFIG_PM_RUNTIME
+#define RUNTIME_PM_OPS(suspend_fn, resume_fn, idle_fn) \
+	.runtime_suspend = suspend_fn, \
+	.runtime_resume = resume_fn, \
+	.runtime_idle = idle_fn,
+#else
+#define RUNTIME_PM_OPS(suspend_fn, resume_fn, idle_fn)
+#endif
+
 /*
  * Use this if you want to use the same suspend and resume callbacks for suspend
  * to RAM and hibernation.
  */
 #define SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \
 const struct dev_pm_ops name = { \
-	.suspend = suspend_fn, \
-	.resume = resume_fn, \
-	.freeze = suspend_fn, \
-	.thaw = resume_fn, \
-	.poweroff = suspend_fn, \
-	.restore = resume_fn, \
+SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
+}
+
+/*
+ * Use this for defining a set of PM operations to be used in all situations
+ * (system suspend, hibernation or runtime PM).
+ */
+#define UNIVERSAL_DEV_PM_OPS(name, suspend_fn, resume_fn, idle_fn) \
+const struct dev_pm_ops name = { \
+SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
+RUNTIME_PM_OPS(suspend_fn, resume_fn, idle_fn) \
+}
+
+#ifdef CONFIG_PM_SLEEP
+#define GENERIC_SYSTEM_SLEEP_PM_OPS \
+	.suspend = pm_generic_suspend, \
+	.resume = pm_generic_resume,
+#else
+#define GENERIC_SYSTEM_SLEEP_PM_OPS
+
+#endif
+
+#ifdef CONFIG_PM_RUNTIME
+#define GENERIC_RUNTIME_PM_OPS \
+	.runtime_suspend = pm_generic_runtime_suspend, \
+	.runtime_resume = pm_generic_runtime_resume, \
+	.runtime_idle = pm_generic_runtime_idle,
+#else
+#define GENERIC_RUNTIME_PM_OPS
+#endif
+
+/*
+ * Use this for subsystems (bus types, device types, device classes) that only
+ * need to invoke PM callbacks provided by device drivers supporting both the
+ * system sleep PM and runtime PM.
+ */
+#define GENERIC_SUBSYS_PM_OPS(name) \
+const struct dev_pm_ops name = { \
+GENERIC_SYSTEM_SLEEP_PM_OPS \
+GENERIC_RUNTIME_PM_OPS \
 }
 
 /**