PM: Make system-wide PM and runtime PM treat subsystems consistently

The code handling system-wide power transitions (eg. suspend-to-RAM)
can in theory execute callbacks provided by the device's bus type,
device type and class in each phase of the power transition.  In
turn, the runtime PM core code only calls one of those callbacks at
a time, preferring bus type callbacks to device type or class
callbacks and device type callbacks to class callbacks.

It seems reasonable to make them both behave in the same way in that
respect.  Moreover, even though a device may belong to two subsystems
(eg. bus type and device class) simultaneously, in practice power
management callbacks for system-wide power transitions are always
provided by only one of them (ie. if the bus type callbacks are
defined, the device class ones are not and vice versa).  Thus it is
possible to modify the code handling system-wide power transitions
so that it follows the core runtime PM code (ie. treats the
subsystem callbacks as mutually exclusive).

On the other hand, the core runtime PM code will choose to execute,
for example, a runtime suspend callback provided by the device type
even if the bus type's struct dev_pm_ops object exists, but the
runtime_suspend pointer in it happens to be NULL.  This is confusing,
because it may lead to the execution of callbacks from different
subsystems during different operations (eg. the bus type suspend
callback may be executed during runtime suspend of the device, while
the device type callback will be executed during system suspend).

Make all of the power management code treat subsystem callbacks in
a consistent way, such that:
(1) If the device's type is defined (eg. dev->type is not NULL)
    and its pm pointer is not NULL, the callbacks from dev->type->pm
    will be used.
(2) If dev->type is NULL or dev->type->pm is NULL, but the device's
    class is defined (eg. dev->class is not NULL) and its pm pointer
    is not NULL, the callbacks from dev->class->pm will be used.
(3) If dev->type is NULL or dev->type->pm is NULL and dev->class is
    NULL or dev->class->pm is NULL, the callbacks from dev->bus->pm
    will be used provided that both dev->bus and dev->bus->pm are
    not NULL.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Kevin Hilman <khilman@ti.com>
Reasoning-sounds-sane-to: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 73 insertions, 95 deletions

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 05b989139b5..052dc53eef3 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -428,26 +428,17 @@ static int device_resume_noirq(struct device *dev, pm_message_t state)
 		pm_noirq_op(dev, &dev->pwr_domain->ops, state);
 	}
 
-	if (dev->bus && dev->bus->pm) {
-		pm_dev_dbg(dev, state, "EARLY ");
-		error = pm_noirq_op(dev, dev->bus->pm, state);
-		if (error)
-			goto End;
-	}
-
 	if (dev->type && dev->type->pm) {
 		pm_dev_dbg(dev, state, "EARLY type ");
 		error = pm_noirq_op(dev, dev->type->pm, state);
-		if (error)
-			goto End;
-	}
-
-	if (dev->class && dev->class->pm) {
+	} else if (dev->class && dev->class->pm) {
 		pm_dev_dbg(dev, state, "EARLY class ");
 		error = pm_noirq_op(dev, dev->class->pm, state);
+	} else if (dev->bus && dev->bus->pm) {
+		pm_dev_dbg(dev, state, "EARLY ");
+		error = pm_noirq_op(dev, dev->bus->pm, state);
 	}
 
-End:
 	TRACE_RESUME(error);
 	return error;
 }
@@ -528,36 +519,34 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
 		pm_op(dev, &dev->pwr_domain->ops, state);
 	}
 
-	if (dev->bus) {
-		if (dev->bus->pm) {
-			pm_dev_dbg(dev, state, "");
-			error = pm_op(dev, dev->bus->pm, state);
-		} else if (dev->bus->resume) {
-			pm_dev_dbg(dev, state, "legacy ");
-			error = legacy_resume(dev, dev->bus->resume);
-		}
-		if (error)
-			goto End;
-	}
-
-	if (dev->type) {
-		if (dev->type->pm) {
-			pm_dev_dbg(dev, state, "type ");
-			error = pm_op(dev, dev->type->pm, state);
-		}
-		if (error)
-			goto End;
+	if (dev->type && dev->type->pm) {
+		pm_dev_dbg(dev, state, "type ");
+		error = pm_op(dev, dev->type->pm, state);
+		goto End;
 	}
 
 	if (dev->class) {
 		if (dev->class->pm) {
 			pm_dev_dbg(dev, state, "class ");
 			error = pm_op(dev, dev->class->pm, state);
+			goto End;
 		} else if (dev->class->resume) {
 			pm_dev_dbg(dev, state, "legacy class ");
 			error = legacy_resume(dev, dev->class->resume);
+			goto End;
 		}
 	}
+
+	if (dev->bus) {
+		if (dev->bus->pm) {
+			pm_dev_dbg(dev, state, "");
+			error = pm_op(dev, dev->bus->pm, state);
+		} else if (dev->bus->resume) {
+			pm_dev_dbg(dev, state, "legacy ");
+			error = legacy_resume(dev, dev->bus->resume);
+		}
+	}
+
  End:
 	device_unlock(dev);
 	complete_all(&dev->power.completion);
@@ -644,19 +633,18 @@ static void device_complete(struct device *dev, pm_message_t state)
 		dev->pwr_domain->ops.complete(dev);
 	}
 
-	if (dev->class && dev->class->pm && dev->class->pm->complete) {
-		pm_dev_dbg(dev, state, "completing class ");
-		dev->class->pm->complete(dev);
-	}
-
-	if (dev->type && dev->type->pm && dev->type->pm->complete) {
+	if (dev->type && dev->type->pm) {
 		pm_dev_dbg(dev, state, "completing type ");
-		dev->type->pm->complete(dev);
-	}
-
-	if (dev->bus && dev->bus->pm && dev->bus->pm->complete) {
+		if (dev->type->pm->complete)
+			dev->type->pm->complete(dev);
+	} else if (dev->class && dev->class->pm) {
+		pm_dev_dbg(dev, state, "completing class ");
+		if (dev->class->pm->complete)
+			dev->class->pm->complete(dev);
+	} else if (dev->bus && dev->bus->pm) {
 		pm_dev_dbg(dev, state, "completing ");
-		dev->bus->pm->complete(dev);
+		if (dev->bus->pm->complete)
+			dev->bus->pm->complete(dev);
 	}
 
 	device_unlock(dev);
@@ -741,27 +729,23 @@ static pm_message_t resume_event(pm_message_t sleep_state)
  */
 static int device_suspend_noirq(struct device *dev, pm_message_t state)
 {
-	int error = 0;
-
-	if (dev->class && dev->class->pm) {
-		pm_dev_dbg(dev, state, "LATE class ");
-		error = pm_noirq_op(dev, dev->class->pm, state);
-		if (error)
-			goto End;
-	}
+	int error;
 
 	if (dev->type && dev->type->pm) {
 		pm_dev_dbg(dev, state, "LATE type ");
 		error = pm_noirq_op(dev, dev->type->pm, state);
 		if (error)
-			goto End;
-	}
-
-	if (dev->bus && dev->bus->pm) {
+			return error;
+	} else if (dev->class && dev->class->pm) {
+		pm_dev_dbg(dev, state, "LATE class ");
+		error = pm_noirq_op(dev, dev->class->pm, state);
+		if (error)
+			return error;
+	} else if (dev->bus && dev->bus->pm) {
 		pm_dev_dbg(dev, state, "LATE ");
 		error = pm_noirq_op(dev, dev->bus->pm, state);
 		if (error)
-			goto End;
+			return error;
 	}
 
 	if (dev->pwr_domain) {
@@ -769,8 +753,7 @@ static int device_suspend_noirq(struct device *dev, pm_message_t state)
 		pm_noirq_op(dev, &dev->pwr_domain->ops, state);
 	}
 
-End:
-	return error;
+	return 0;
 }
 
 /**
@@ -857,25 +840,22 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 		goto End;
 	}
 
+	if (dev->type && dev->type->pm) {
+		pm_dev_dbg(dev, state, "type ");
+		error = pm_op(dev, dev->type->pm, state);
+		goto Domain;
+	}
+
 	if (dev->class) {
 		if (dev->class->pm) {
 			pm_dev_dbg(dev, state, "class ");
 			error = pm_op(dev, dev->class->pm, state);
+			goto Domain;
 		} else if (dev->class->suspend) {
 			pm_dev_dbg(dev, state, "legacy class ");
 			error = legacy_suspend(dev, state, dev->class->suspend);
+			goto Domain;
 		}
-		if (error)
-			goto End;
-	}
-
-	if (dev->type) {
-		if (dev->type->pm) {
-			pm_dev_dbg(dev, state, "type ");
-			error = pm_op(dev, dev->type->pm, state);
-		}
-		if (error)
-			goto End;
 	}
 
 	if (dev->bus) {
@@ -886,11 +866,10 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 			pm_dev_dbg(dev, state, "legacy ");
 			error = legacy_suspend(dev, state, dev->bus->suspend);
 		}
-		if (error)
-			goto End;
 	}
 
-	if (dev->pwr_domain) {
+ Domain:
+	if (!error && dev->pwr_domain) {
 		pm_dev_dbg(dev, state, "power domain ");
 		pm_op(dev, &dev->pwr_domain->ops, state);
 	}
@@ -985,28 +964,27 @@ static int device_prepare(struct device *dev, pm_message_t state)
 
 	device_lock(dev);
 
-	if (dev->bus && dev->bus->pm && dev->bus->pm->prepare) {
-		pm_dev_dbg(dev, state, "preparing ");
-		error = dev->bus->pm->prepare(dev);
-		suspend_report_result(dev->bus->pm->prepare, error);
-		if (error)
-			goto End;
-	}
-
-	if (dev->type && dev->type->pm && dev->type->pm->prepare) {
+	if (dev->type && dev->type->pm) {
 		pm_dev_dbg(dev, state, "preparing type ");
-		error = dev->type->pm->prepare(dev);
+		if (dev->type->pm->prepare)
+			error = dev->type->pm->prepare(dev);
 		suspend_report_result(dev->type->pm->prepare, error);
 		if (error)
 			goto End;
-	}
-
-	if (dev->class && dev->class->pm && dev->class->pm->prepare) {
+	} else if (dev->class && dev->class->pm) {
 		pm_dev_dbg(dev, state, "preparing class ");
-		error = dev->class->pm->prepare(dev);
+		if (dev->class->pm->prepare)
+			error = dev->class->pm->prepare(dev);
 		suspend_report_result(dev->class->pm->prepare, error);
 		if (error)
 			goto End;
+	} else if (dev->bus && dev->bus->pm) {
+		pm_dev_dbg(dev, state, "preparing ");
+		if (dev->bus->pm->prepare)
+			error = dev->bus->pm->prepare(dev);
+		suspend_report_result(dev->bus->pm->prepare, error);
+		if (error)
+			goto End;
 	}
 
 	if (dev->pwr_domain && dev->pwr_domain->ops.prepare) {
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 25edc9a3a48..54597c859ec 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -214,12 +214,12 @@ static int rpm_idle(struct device *dev, int rpmflags)
 
 	dev->power.idle_notification = true;
 
-	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_idle)
-		callback = dev->bus->pm->runtime_idle;
-	else if (dev->type && dev->type->pm && dev->type->pm->runtime_idle)
+	if (dev->type && dev->type->pm)
 		callback = dev->type->pm->runtime_idle;
 	else if (dev->class && dev->class->pm)
 		callback = dev->class->pm->runtime_idle;
+	else if (dev->bus && dev->bus->pm)
+		callback = dev->bus->pm->runtime_idle;
 	else
 		callback = NULL;
 
@@ -382,12 +382,12 @@ static int rpm_suspend(struct device *dev, int rpmflags)
 
 	__update_runtime_status(dev, RPM_SUSPENDING);
 
-	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend)
-		callback = dev->bus->pm->runtime_suspend;
-	else if (dev->type && dev->type->pm && dev->type->pm->runtime_suspend)
+	if (dev->type && dev->type->pm)
 		callback = dev->type->pm->runtime_suspend;
 	else if (dev->class && dev->class->pm)
 		callback = dev->class->pm->runtime_suspend;
+	else if (dev->bus && dev->bus->pm)
+		callback = dev->bus->pm->runtime_suspend;
 	else
 		callback = NULL;
 
@@ -584,12 +584,12 @@ static int rpm_resume(struct device *dev, int rpmflags)
 	if (dev->pwr_domain)
 		rpm_callback(dev->pwr_domain->ops.runtime_resume, dev);
 
-	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_resume)
-		callback = dev->bus->pm->runtime_resume;
-	else if (dev->type && dev->type->pm && dev->type->pm->runtime_resume)
+	if (dev->type && dev->type->pm)
 		callback = dev->type->pm->runtime_resume;
 	else if (dev->class && dev->class->pm)
 		callback = dev->class->pm->runtime_resume;
+	else if (dev->bus && dev->bus->pm)
+		callback = dev->bus->pm->runtime_resume;
 	else
 		callback = NULL;